DRAFT
Toward an Earth Observing Laboratory

A Strategic Plan for
Observing Facilities and Related Services

Atmospheric Technology Division
National Center for Atmospheric Research
June, 2004

I. Introduction

The Atmospheric Technology Division (ATD) evolved from the NCAR Facilities Division, an organization that focused on logistical support to solar expeditions, the provision of ordinary meteorological surface instruments, and rudimentary research aircraft. In 1973, ATD reorganized and redirected its activities from logistical support to the development and deployment of advanced instruments and research platforms, allocated to NSF grantees by means of a semi-annual competitive proposal process. Initial emphasis was placed on meteorology—users of ATD facilities mainly focused on cloud physics and mesoscale dynamics to improve the understanding of weather phenomena. Such studies required short-term field campaigns, over a limited area, using small aircraft and ground-based observing systems. Many research opportunities were located in NCAR’s “backyard”, the continental United States; however, the Global Atmospheric Research Programme (GARP) was conducted in the 1970s under the auspices of the World Meteorological Organization (WMO). ATD made important contributions to GARP by means of novel global ballooning techniques and the development of an instrumented Lockheed Electra aircraft. For the past 30 years, ATD has provided state-of-the-art research aircraft, electromagnetic and acoustic remote sensors, and in situ surface and sounding systems, which have contributed significantly to advances in the atmospheric sciences.

ATD’s mission is central to the motivation for a National Center; to provide observing facilities and related services otherwise difficult to mount by any single university department or small groups of NCAR scientists. This is accomplished through:

• Lower atmosphere process studies of short duration and limited spatial domain.
• Multi-user access to advanced observing systems, platforms and data services that satisfy multiple needs of various NSF-sponsored communities.
• Focused education and outreach activities.

The current organization includes two major facilities: the Research Aviation Facility, which develops and operates airborne platforms; and the Research Technology Facility, which develops and deploys instruments and surface-based observing systems. Other support services include the Research Data Program, which provides field coordination Internet tools and cyberinfrastructure during field campaigns and data services thereafter; and the Design and Fabrication Service, offering advanced instrument mechanical design and manufacture. Field program coordination and visitor and educational programs are managed out of the ATD director's office. ATD also supports the Analytical Photonics and Optoelectronics Laboratory (APOL) in collaboration with the Atmospheric Chemistry Division.

The challenges of the 21st century take geosciences to the most remote regions of the planet and beyond. The largest number of field projects today are motivated by climate science, serving to discover important processes, quantifying their rates, and verifying their distribution and role in the climate system as these are explicitly modeled, parameterized and observed from space-based platforms. Physical science, while essential, is now insufficient as biogeochemical influences become increasingly important for furthering our understanding. "Whole atmosphere" studies explore various coupled processes from solar-terrestrial influences in the upper atmosphere, down through the land surfaces, and the upper oceans. Such multi-disciplinary challenges are no longer separable from meteorology and have emerged as truly trans-disciplinary investigations.

ATD is at a critical juncture in its history. This strategic plan is in response to the evolution that is taking place in science and technology and at the National Center. It is the result of deliberations among the technical and scientific staff of ATD, and specific external advice provided by university and NCAR colleagues. While it focuses primarily on the current mission of the Division, it anticipates the establishment of NCAR’s Earth Observing Laboratory (EOL). An underlying theme in this plan is "extensibility" of the Division in execution of its mission. Extensibility in this context has several dimensions including: greater reliance on strategic and collaborative partnerships; service to new areas of science; utilization of new technologies and platforms; a wider range of service options, including PI self-service; an increased presence in education and outreach; and increased connectivity to the community through innovative visitor programs. Extensibility also has organizational implications to facilitate a strong evolution from ATD to an EOL. ATD will re-align itself to achieve a dynamic equilibrium for sustained excellence and to accommodate future programs. Importance and uniqueness in service to earth system science will be the principal criteria driving ATD's transition to an EOL.

Section II lays out the foundation for our strategy by “matching observations with challenges in science”. It identifies observing systems needs as applied to weather, climate, water cycle, free-tropospheric and lower-stratospheric chemistry, air quality, biogeoscience, and prospects for “whole-atmosphere” studies.

Section III articulates the criteria to be applied when making decisions regarding the development and service of observational facilities, and delineates the broad categories of instrumentation affected.

These strategies are further developed in Section IV through application of advanced technologies to favored program areas such as:

• Detection and quantitative estimation of water vapor
• Detection and estimation of chemical trace species
• Hydrometeor and aerosol sampling
• Airborne volumetric precipitation estimation and categorization
• Scaling biogeoscience processes to geoscience applications
• GPS-based global monitoring stations for integration with satellite data

Section V discusses the golden age of research aviation, marking the development and operation of HIAPER; the continuing role of heavy lift turboprop aircraft; and an examination of unpiloted and autonomous aircraft operations as part of our facilities research mission.

A roadmap to the future is described in Section VI. Here, criteria and mechanisms for a sustainable ATD program are discussed; establishing equilibrium between development and deployment; identifying emerging technologies; forging partnerships to extend facilities and services; gaining comprehensive external advice; meeting challenges to excellence in divisional support services; emphasizing educational foci; and, nurturing our human resources.

Organizational implications are discussed in Section VII. These are examined from the thematic functions of an extensible ATD, having four generic building blocks:

• The foundation of supporting skills and services
• Engines for new and improved observing systems
• Delivery mechanisms to provide field program support
• Innovation to sustain importance and relevance

This section encapsulates the strategic approaches and goals leading to the fulfillment of ATD’s mission together with a vision for the transition to an EOL.

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II. Matching Observations with Challenges in Science

This section briefly discusses some scientific challenges in the atmospheric sciences in relation to observations. Observations have traditionally played a leading role in atmospheric science discovery, and in the testing and interpretation of theory. The growth of numerical experimentation has created additional need for atmospheric observations, to provide the foundation for the parameterization of subgrid scale processes, and to initialize and to evaluate the simulations. Interdisciplinary research frontiers, such as the biogeosciences and the water cycle, have increased the demand for essentially similar reasons, often in coupled model applications.

Understanding Weather and Weather Prediction

Public safety and the mitigation of a ~3 trillion dollar economic sensitivity are the principal socio-economic drivers that underlie hazardous weather research at the basic and applied research levels. Improving predictions through improved understanding remains critical to the needs of societies worldwide.

The carefully charted record of skill in weather prediction leads to a clear challenge for weather research. While various measures of forecast skill point to major improvements in geopotential height field, anomaly correlation, temperature, and wind forecasts, quantitative precipitation forecasts are relatively stagnated. This is especially true in summer at mid-latitudes and in the tropics, where strong forcing, associated with balanced dynamics, is greatly diminished.

The observations required for precipitation forecast studies are extensive and complex, as reported in several plans of the U.S. Weather Research Program. The prediction of precipitation is, inherently, a mesoscale dynamical and cloud-scale problem, requiring high spatial and temporal resolution information of the type provided by radars in phenomena such as heavy warm season rainfall, winter cyclones, fronts, severe convective storms, flash floods and tropical cyclones. While observations of winds, temperature and water vapor within the boundary layer are all important to the understanding and prediction of these weather events, several expert committees have focused sharply on the specific need for highly resolved, three-dimensional water vapor fields. It is also widely recognized that unresolved processes in cloud microphysics and in the generation and dissipation of turbulence are influential in the prediction of precipitation, thereby requiring renewed investigations of related processes by means of airborne in situ and remote sensing instruments.

High resolution observations and high resolution models are co-dependent tools, both being essential for warnings and short range forecasts (~1-day or less) of hazardous weather. High resolution is often needed to explicitly resolve the critical physical processes in these events (e.g., deep moist convection and orographic precipitation). It is a challenge to obtain accurate initial conditions, both with respect to the observational infrastructure and to the data assimilation techniques. The exploration of ensemble prediction techniques, while relaxing the resolution requirements, often imposes stringent demands to fully characterize observational error co-variances as part of the data assimilation process.

The performance of limited area models is sensitive to lateral boundary conditions, typically provided by global operational models. The observational requirements for global and synoptic-scale research are well summarized by the goals of THORPEX (http://www.wmo.int/THORPEX), a long-term Global Atmosphere Research Programme under the WMO World Weather Research Programme. Objectives of THORPEX include fundamental and applied studies with forecast impact objectives from 1 to 14 days. The foremost observational research requirement for global numerical experimentation is to test the concept of providing targeted in situ soundings to complement satellite observations at times and places that are objectively identified by the likelihood to improve forecast skill, or to quantify and reduce forecast uncertainty. The experimental research associated with these objectives may be conducted on a regional scale for the short- to medium- ranges of prediction. Ultimately, however, the research and forecast demonstrations must be conducted on a global scale.

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Monitoring Climate

• Critical goals for climate research are to:
• Identify and quantify the causes and magnitude of regional climate change
• Reduce uncertainties in the prediction of this change
• Collaborate with the weather research community to identify and quantify changes in regional weather hazards and water resources
• Collaborate with the social sciences community to evaluate socio-economic impacts and to contribute to national and international policy decisions

The needs for long-term climate monitoring require regular and sustained measurements of water vapor, temperature, clouds, greenhouse gases, and radiation budgets at both the surface and high in the atmosphere. Many of these quantities are either observed directly or otherwise inferred from space-based instruments. In some situations for some variables space-based observing systems do not suffice as stand-alone estimates of critical variables, requiring augmentation from in situ and/or earth-based remote sensing instruments. Especially in the planetary boundary layer over continents and beneath clouds in baroclinic zones at mid-latitudes, estimates of water vapor may lack reliability and the accuracy sufficient to predict cloud field evolution and quantitative precipitation.

Supplementary earth-based measurements help to reduce uncertainty in the current mean state and serve to evaluate and validate errors in satellite observations. The current international network of upper air observations in support of numerical weather prediction is quite helpful in this regard, however, this network lacks the consistency, stability, sensitivity and accuracy needed for the long term climate record. In situ upper tropospheric water vapor measurements are an especially weak component of the global observing system. A well-recognized need exists within the climate research community to establish a global reference network of earth-based observations, elements of which would be fully traceable to laboratory standards. At a minimum, the standard meteorological variables should be addressed in such a network.

Detailed observations of cloud microphysical properties and aerosols are required to improve the climatological knowledge of aerosols (sources, sinks and transports). Unlike global atmospheric monitoring discussed previously, the study of cloud-aerosol interactions; to quantify and understand aerosol’s indirect effects on clouds, and to improve cloud and aerosol parameterization schemes in climate models, requires specialized airborne observations including concentration, size distribution, composition, and condensation and ice activation properties. Improved knowledge of the cloud and aerosol fields and their treatment in climate models should correspond to the improved treatment of radiative and precipitation processes.

The Water Cycle and the Role of Clouds and Storms in Climate Dynamics

The role of clouds in climate has been a highest priority in climate change research from the inception of the U. S. Global Change Research Program. However, the efforts to seriously tackle this problem in its totality have been relatively inadequate and almost singularly focused on the radiative properties of clouds and their role in global radiative equilibrium. This has been an important and necessary area of investigation, which has made considerable progress.

Clouds and storms as radiative entities have their origin and dissipation in dynamical-physical processes, which are incompletely understood and either poorly represented or unrepresented in global climate models. The genesis and dissipation of clouds and storms is the result of several forcings, most of which are not directly radiative in nature. In the case of deep, moist convection, the diurnal cycle is quite poorly represented in global climate models. Furthermore, the predictions of precipitation amount and distribution have little or no skill with respect to variability within today’s climate system.

One might ask, how can society “take stock” in predictions of future regional climates when today’s global models fail to reproduce precipitation variability in the current mean state? The answer is clear. Neither researchers nor those responsible for public policy should heed such guidance until variability in the current mean state is skillfully predicted. The societal importance of this issue resides in the local water balance. Until science manages to skillfully predict the sense of such changes, climate predictions will be of greatly diminished utility to society.

Water-related issues are critical with respect to water quality, flooding, drought, and the apportionment of limited water resources in arid regions, particularly those with rapidly growing urban populations. Addressing many of these questions requires water cycle research that includes aspects of weather, climate dynamics, and biogeoscience studies. It also includes surface and subsurface hydrology and society’s use of water resources. Focus areas of current water cycle research include improving the prediction of seasonal variations in the water cycle and “closing” the water budget in basins of relatively limited size. Future work may extend this research to larger and more complex basins in areas of societal and economic importance. It is essential that linkages be strengthened between the process-diagnostic community at weather scales and parameterization in climate system model developments.

The required observations naturally focus on measurements of water in all its phases on the Earth’s surface, subsurface and within the atmosphere. Current weaknesses include the measurement of precipitation, water vapor, and the complexity of measuring subsurface water in the face of spatial variations in earth properties. The hydrological community is undertaking a coordinated effort to improve facilities for the latter measurement. Supporting meteorological observations are required, particularly within the surface and boundary layer. These measurements should have the capability to extend to seasonal and inter-annual time-scales.

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Chemistry and Dynamics of the Free Troposphere and Lower Stratosphere

Ozone concentrations in the upper troposphere/lower stratosphere (UT/LS) are highly dependent upon the budget of reactive hydrogen radicals (HOx). Measurement-model comparisons of these radicals reveal vastly different temporal and spatial relationships, and hence point to large gaps in our understanding of UT/LS chemical cycling. There are also large uncertainties in the budgets of soluble HOx precursors and the characteristics of cloud processing as these gases are transported from polluted regions of the lower troposphere to the UT/LS by large convective systems. ATD scientists, in close collaboration with scientists from ACD, universities, and national laboratories, have begun to define the need and critical measurements for such studies (http://www.acd.ucar.edu/UTLS/index.htm). Core measurements to address these questions include atmospheric tracers such as CO, CO2, O3 and H2O vapor, in addition to chemical species such as HOx radicals and radical reservoir species, such as formaldehyde (CH2O). Measurement of volatile organic hydrocarbons and their decomposition products (e.g. CH2O) throughout the free troposphere is central to the clarification of hydrocarbon oxidation mechanisms. In addition, measurements of water vapor isotopes (HDO/H2O) are highly desirable throughout the UT/LS to help elucidate the mechanisms responsible for the growth of water vapor in the stratosphere.

A series of systematic radical studies from research aircraft is the principal means to address this challenge, together with meteorological kinematic and thermodynamic information from flight level and remote sensing instruments.

Air Quality in Climate

The pollution export from large urban areas, sometimes called “mega-cites”, is highly uncertain. As the world faces unprecedented population growth, pollution will have an increasingly adverse effect on human health, agriculture, natural ecosystems, visibility, and in some cases on weather and climate. There are critical gaps in our understanding of:

• gas phase photochemistry
• hydrocarbon oxidation
• the formation/evolution of aerosols and reactions of gas phase species on such aerosols
• chemical transformation pathways, and
• the effect of urban pollution on the levels of ozone, aerosols and hydroxyl radicals in such pollution outflow.

In addition to observing these chemical species, research into pollution export requires measurements of the local and regional meteorology, particularly winds and stability in the lower troposphere. The Megacity Impacts on Regional and Global Environments (MIRAGE) study is one such program where NCAR scientists, including scientists from ATD, will actively participate along with researchers from the wider community to address these issues.

Biogeosciences

Leaf Chamber

Understanding and prediction of the earth’s system involves biological processes that play key roles in modulating global and local carbon, nitrogen, trace-gas, water, and energy cycles. In turn, ecosystems and biogeochemical cycles are sensitive to physical and chemical forcing and the growing influence of human activities. Research in the biogeosciences is vital to detecting human impacts on natural ecosystems and assessing various strategies for mitigating climate change.

Key questions concern the local, regional, and continental-scale exchanges of carbon, nitrogen, and reactive species, and their relationships to underlying ecosystem processes and environmental, climatic, atmospheric-chemistry, and land-use perturbations. Also, methodological research into improved techniques for estimating regional fluxes of CO and other greenhouse gases is of primary importance to domestic carbon management efforts and international climate treaties. Finally, biogeochemical processes are highly coupled, so there is a strong need to understand the non-linear feedbacks between cycling of carbon, nitrogen, iron, and sulfur and climate, air quality, and ecosystem function in order to improve predictions.

Since the natural “time steps” for biogeosciences are the growing season and annual cycle, measurement strategies typically require ground-based instrumentation that can be deployed over a complete annual cycle supplemented by intensive periods of airborne measurements. The key basic ground-based and airborne observations to address these needs include:

• High-accuracy CO concentrations and fluxes
• CO isotope and O/N ratios
• Concentrations of HO, CO, CH, NO, SF, O and other species
• H), O and energy fluxes
• Multi-spectral remote sensing measurements

Because biogeochemical fluxes are typically not directly measurable on the scales of interest, these fluxes must be inferred from measurements of spatial variations in atmospheric concentrations. Large arrays on local, regional continental, and global scales are needed to conduct this research, especially for CO as well as supporting meteorological observations. Vegetation is a critical factor, thus requiring observations of soil and plant exchanges of CO and reactive species; hyper-spectral measurement of vegetation, soil and hydrological variables; and accurate surface temperature.

Whole Atmosphere Constituents and Dynamics

A major national challenge over the next decade will be the development of improved “whole atmosphere” climate models. This endeavor requires the skills and participation of modelers and experimentalists from both the lower and upper atmosphere communities. Observations from space will be a central component of the effort, involving the synthesis, evaluation and validation of satellite data over the entire depth of the Earth’s atmosphere. Several instruments will be operational over the next decade and will provide global coverage of trace gases such as O, CO, HO, NO, NO, HNO, SO, CHO, BrO, HO, acetone, methanol, HCN, HNO, and PAN in the troposphere and lower stratosphere.

An important dynamical priority for upper-atmospheric research is the examination of short period gravity waves in the mesopause, to study, for example, the temperature anomaly in this region. Accurate treatment of the breaking and propagation of gravity waves is necessary for long-term simulations of the atmosphere, especially as related to the simulation of retardation in the meridional component of flow. This problem is genuinely of “whole atmosphere” dimension in that the excitation of such waves is thought to be caused by deep tropical convection, convection more generally, and tropospheric flow over cordilleras, especially at mid- and high latitudes.

Observational strategies for these upper-atmosphere studies are likely to involve high altitude airborne and ground-based instruments to detect and track gravity wave propagation from the tropopause region under a variety of meteorological conditions. This would likely include flight level observations of detailed hydrodynamic stability conditions; characterization of the triggering impulses (e.g. stratospheric penetrations by thunderstorms); stratospheric/mesospheric propagation and amplification; and the process of wave breaking in shear, mainly by means of various lidar technologies.

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III. Criteria for Facility Development and Service

Given the strong demand for integrated observations of increasing complexity and accuracy, it is necessary to state the rationale for, and overarching criteria influencing, the choices that ATD and the community will inevitably face. The following criteria will guide ATD decisions in developing and supporting facilities for NSF researchers:

• The primary focus of ATD will continue to be major national facilities consisting of unique observing systems and platforms; otherwise not readily accessible to NSF-sponsored principal investigators; and supported for field programs by the NSF deployment pool.
• Scientific impact and breadth of application are the principal criteria for selection of such facilities. Other factors, such as technological readiness and cost effectiveness are also considered.
• A secondary focus is to provide a limited set of “user-operated” instruments to the community. Such instruments will be: easily or autonomously operated; easily maintained; commonly sought after; not commercially available at the performance level required; and not necessarily eligible for NSF deployment pool funds.
• Strategic partnerships will be employed to maximize the provision of and accessibility to major observing systems and platforms. Such partnerships are of long duration; involving very large or multiple observing systems; and are most likely to be established with major research laboratories, foreign governments and the private sector.
• Collaborative partnerships will be employed at the instrument development and software development levels. One favored area is to extend ATD’s capabilities for airborne and ground-based trace constituent sampling. Such collaborations are at the PI level and often engage university, NCAR, and other-laboratory scientists.
• National needs may also influence choices in those instances where ATD is uniquely positioned to assist the nation.

These broad statements are made in the context of an “extensible” ATD, casting a wide net of partnerships and collaborations, together with a measure of self-reliance from our users under appropriate circumstances. ATD plans to apply the above criteria to the following broad categories of instrumentation:

• Optical sensing systems, including high power lidar remote sensing systems and various “near-field” constituent and turbulence-scale air motion instruments. Both categories of instruments are envisioned for airborne and ground-based applications.
• Flight-level in situ sensing, including hydrometeor, aerosol and trace gas devices for the detection or capture of substances, measuring state variables, and turbulence scale motions.
• Passive remote sensing, including infrared and microwave frequencies and interferometric spectrometer techniques for airborne and ground-based applications.
• Radio remote sensing, from the HF band through millimeter-wave frequencies, with emphasis on airborne systems.
• Sounding systems, including novel deployment mechanisms designed to meet both global observing system needs and process study requirements.
• Surface layer arrays, for bio-physical networks and turbulence-scale transfer applications.

As will be discussed in a later section of this plan, systematic integration of observations is an overarching consideration to meet future science needs. In some instance, the performance of "stand-alone" instruments may be secondary to the performance of a comprehensive suite, especially on research aircraft.

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IV. Favored Areas for Application of Advanced Technologies

The renewal initiatives of ATD are subject to broad consultation. Advice from the user community, NSF, and senior NCAR management are weighed with each major decision. Based upon input provided to ATD in the course of developing this plan, a few areas of facilities and service are favored at this time, though not to the exclusion of other needs.

ATD as a World Leading Resource for the Measurement of Water Vapor

Improved measurements of water vapor will impact research for every category of scientific challenge discussed in Section II. It follows that a most important emphasis within ATD is the provision of accurate water vapor measurements at heights ranging from the planetary surface layer to the stratosphere. This goal is an enormous challenge since water vapor content can vary more than three orders of magnitude in the troposphere alone. Atmospheric water routinely co-exists in three phases, which presents additional challenges for an all-weather observing strategy when coupled with stringent accuracy needs of ~1 %. Furthermore, need for improved performance touches nearly every type of observing system currently deployed by ATD including in situ aircraft measurements, sounding and surface observations, fluxes from the Earth’s surface, and remote sensing at optical and microwave frequencies.

“Backbone” water vapor measurements for climate monitoring may be served by “reference radiosondes” (soundings with traceable standards); surface-based, GPS radio path length “wet delay” observations; and low earth orbit GPS radio occultation. ATD has already moved down the path of developing a reference radiosonde that employs chilled mirror technology, previously developed for the Swiss radiosonde.

Water vapor fields commonly contain large and irregular gradients. One consequence of water vapor patchiness is that it is consistently under-sampled. Hence, surface-based scanning and airborne remote sensing are extremely valuable tools from which to assemble coherent fields when combined with more precise and better resolved in situ observations. Scanning water vapor differential absorption lidar (DIAL) systems are key to meeting a major portion of this need, especially in the planetary boundary layer and the UT/LS regions. A strategic partnership with University of Hohenheim, Germany, and the LEANDRE group sponsored by CNRS/INSU, France, offers promise for considerable advances in both ground-based and airborne systems, respectively. Advanced Raman lidar technology or perhaps microwave passive sensing may also play significant roles in the broader picture of applications. Finally, ATD, in collaboration with McGill University, Canada, has provided a leadership role in the development of a radar refractivity technique based on the same physical principals as used with GPS technology. This technique is valuable for boundary layer water vapor studies since the measurement is both highly sensitive to and resolves the local variability. It has an advantage over optical techniques insofar as it works over an extended horizontal range.

Airborne flight-level measurements are a necessity on both HIAPER and the C-130. One promising approach is the adaptation of tunable diode laser systems currently under development within the joint ATD/ACD APOL.

Planetary surface layer measurements, including fluxes and adaptive arrays for biogeoscience and turbulence applications, will also require accurate water vapor sensors. The large number of sensors required dictates very low unit cost in a very low power environment, thereby presenting a considerable engineering challenge.

Addressing Critical Needs for Sensing Chemical Trace Species

The discussions in Section II clearly portray the need for improved measurements over a wide array of trace species for research as applied to atmospheric chemistry, climate change and the biogeosciences. The list of species is quite long and it is neither practical nor desirable for ATD to establish expertise for all these species as long as healthy partnerships are established with the broader community. However, the underlying need to measure a few “core” species recurs across several disciplines, from the surface to the UT/LS region. Species that clearly fall into this category include CO2, O3 and H2O. The ability to measure these species with great accuracy and precision will be needed on both the C-130 and HIAPER over their operating ranges. Collaborative development activities in APOL on airborne tunable diode laser systems are a likely path to obtaining these measurements. APOL's recent extension into use of non-linear telecommunication optical mixing technology will achieve even higher performance in a smaller, autonomously operated, instrument package. Surface-based measurements will also be required for these species, although some surface applications will sacrifice accuracy for a larger number of species.

In addition to meeting the cross-cutting needs of the community, ATD may develop instruments for otherwise unmet community requirements to measure a critical species. The development of sensors to measure formaldehyde (CH2O), an important radical reservoir species formed by hydrocarbon oxidation processes throughout the atmosphere, is one example of such a capability.

Hydrometeor and Aerosol Sampling

Knowledge of hydrometeor and aerosol phases, number concentrations, size distributions, composition, activation spectrum, sedimentation characteristics and other properties are essential both to climate system and weather prediction. Their distributions and processes strongly influence radiative transfer in clear and cloudy sky conditions, diabatic influences in the presence of precipitation, and chemical reaction pathways and rates.

Both in situ and remote sensing techniques are essential for capturing samples. Remote sensing techniques include backscatter and differential absorption lidars; polarimetric and multi-parameter radars; interferometric infrared spectrometry and passive microwave imaging radiometry. In situ techniques include collection of physical samples, near-field optical spectrometry, video photography and other approaches.

The majority of devices listed above will help to constitute integrated flight laboratories aboard the HIAPER and C-130 aircraft as part of atmospheric chemistry, climate process and weather studies.

Airborne Volumetric Aerosol, Cloud, Precipitation and Air Motion Sensing

ATD is at the dawn of a new era in which the coordinated use of active airborne remote sensing devices can address air motion sensing, aerosol, cloud microphysical, and precipitation questions. For example, HIAPER will support payloads that include scanning lidar, millimeter (cloud) radar, and centimetric (precipitation) radar. The quantitative interpretation of these datasets is extremely powerful when the observations and analyses are fully integrated. Individually, each of the datasets has “blind spots”, meaning ambiguities in physical interpretation when absent information from other electromagnetic frequencies. Lidars are suited to detection of aerosol and optically thin clouds, which may or may not contain precipitation-sized particles. Millimeter radars are most capable of detecting and categorizing cloud-sized hydrometeor phase and particle type. The introduction of larger, and larger concentrations of, precipitation leads to diagnostic ambiguities and “blindness” resulting from absorption and excessive scattering. Lidar and cloud radar data interpretations are both enhanced when such analyses are conducted in the context of centimetric radar fields which quantify the spatial distribution, phase, mass and size distribution of precipitation-sized hydrometeors via polarimetric/Doppler techniques. The multiple-frequency observations, as a whole, act to constrain the individual solutions, rendering the results more comprehensive and more quantitative.

Airborne Doppler radar has been central to major advances in mesoscale meteorology for two decades, the most advanced version of which was developed as ELDORA-ASTRAIA as part of Franco-American partnership circa 1990. This era of airborne Doppler utilization was dominated by “stand-alone” data acquisition, analysis and interpretation, an approach that was non-optimal but sufficient for the meteorological objectives.

Raman-shifted eye-safe Aerosol Lidar (REAL)	Lidar PPI scan (horizontal slice) showing the inhomogeneous distribution of aerosols (pollutants) in the atmospheric surface layer in a major urban area.

Airborne precipitation and cloud radars, together with airborne lidar, each with Doppler/polarimetric capabilities, render any medium-to-large research aircraft platform far more powerful in pursuit of various weather, chemistry and climate process investigations. UT/LS chemistry investigations in the presence of deep convection, radiative transfer properties and internal dynamics of optically dense cirrus cloud studies; clear and cloudy planetary boundary layer conditions; and transport studies are among the myriad of applications for this powerful combination of active airborne remote sensors. ATD is unique in its expertise to bring such capabilities to reality for a broad spectrum of applications including “clouds as constituent transporters”, “clouds as chemical processors” and “clouds as constituent producers” studies; mesoscale dynamics in weather; boundary layer properties in pollution; and “whole atmosphere” studies associated with the triggering and propagation of gravity waves.

Scaling Biogeoscience Processes to Geophysical Scales Through Sensor Arrays

Biogeoscience has uniquely defined measurement requirements, among which is the up-scaling of microscale transfers between the atmosphere, soil and vegetation to scales that impact atmospheric motions. The need for this up-scaling can be met by large numbers of surface sensors measuring critical variables such as CO2, and, optimally, temperature, pressure, wind and water vapor. This research also demands observations over a season or annual cycle, suggesting that deployments of long duration need to be robust and relatively autonomous. Considerable benefit will be derived if the arrays are adaptive both to environmental and instrumentation performance changes, thereby having limited capabilities for self-diagnosis and self-calibration. Miniaturization of sensor and communication technology is a likely path of development. Large arrays of small, low-power sensors will present exciting new capabilities for the NSF bio-complexity community. The adaptive arrays will be supplemented with more traditional flux towers, sounding and/or profiler sites, and periodic airborne measurements as appropriate. Large sensor arrays may also serve weather, climate and water cycle research objectives.

Evolving GPS Sounding Systems to Complement Growing Satellite Capabilities

Basic sounding and profiling systems provide researchers with high resolution vertical profiles of temperature, wind, pressure and humidity. These relatively simple instruments remain critical to support a broad spectrum of scientific challenges, spanning most disciplines, for the community of researchers. While such information is often not the primary need in most investigations, the supporting data are necessary for interpreting more specialized measurements. An evolution in the type of sounding measurements required by researchers will occur as satellite capabilities continue to advance with a greater than 10 increase in satellite data streams over the next decade.

The need for soundings will co-evolve with observations from space, where the in situ soundings will complement the weaknesses of satellite data. With this assumption in mind, several areas of development are needed as follows:

• ATD will continue to develop a low-cost miniature dropsonde that focuses on obtaining vertical profiles of wind versus height. Stratospheric balloons, such as driftsonde, are a possible deployment mechanism for releasing miniature dropsondes or a full dropsonde system at any location over the globe.
• Calibration and validation of satellite sensors continue to require in situ sensors. Traceable reference sounding systems match well with ATD expertise and will be developed as part of the global observing system in support of climate monitoring and weather prediction. Operations in support of such systems either would be delegated to operational agencies worldwide or possibly become a function of the emerging EOL at NCAR.
• Given the formidable technological difficulties in obtaining meaningful radiance measurements immediately above heterogeneous land surfaces (particularly in the water vapor absorption bands) in situ sounding measurements in the lower troposphere will continue in the NSF research community. Continued deployment of radiosondes in support of process studies is likely; however, it is equally likely that active and passive remote sensing at optical, infrared and microwave frequencies will assume this role for research over land in the coming decade.

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V. NCAR's Golden Age for Research Aviation

Research aviation was one of the first scientific support activities at NCAR. Scientists and engineers have pioneered many of the developments found in modern research aircraft. For example, the introduction of air motion sensing ushered in a new era in atmospheric investigations by aircraft1 that have been the backbone of airborne research for decades. The ELDORA radar, although it is more than a decade old, still represents the best in airborne observations for study of convection and mesoscale dynamics.

HIAPER’s arrival ushers in a long-awaited2 new era in research aviation at NCAR and for the community it serves. The HIAPER acquisition includes significant new instrumentation, much of it developed independently of ATD, thus activating the collaborative partnership strategy as part of a newly “extensible” ATD. The challenge to ATD over the next five years is to coordinate and integrate the suite of new and “standard” instruments and data systems, and to fill the remaining instrumentation gaps. Upon completion of this rapid development phase, the collaborative enterprise will have, literally and figuratively, reached new heights in research aviation.

The new HIAPER Gulfstream V	The C-130

ATD will implement a new paradigm for utilization of long range research aircraft using high bandwidth capabilities for data acquisition, manipulation, storage, and transmittal. In the old paradigm, scientists flew on an aircraft and operated instrumentation. In the new generation of research aircraft, scientists will remotely control instrumentation, view data, and develop real-time awareness of an experiment from any location that can access the network. Near real-time data from satellite, ground networks, other aircraft, and numerical models will be routinely transmitted to the aircraft and the research team to assist in selecting the best places to conduct airborne sampling. Real-time aircraft data will be available for assimilation into and comparison with numerical models, which will run concurrently with the airborne sampling, allowing the numerical experiment to be a key component of the field experiment. The above factors will facilitate the participation of greater numbers of scientists and students from diverse locations, who will address more areas of inquiry.

HIAPER cyberinfrastructure will set a new standard for airborne data acquisition, manipulation and communication. Progress in several areas of airborne research (flux measurements, turbulence sampling) depends upon improving the time or spatial resolution of the instruments. Today’s instruments produce at least a factor of 10 better resolution and at least a factor of 100 more data per instrument for a two dimensional imaging probe than legacy instruments. For example, the volume of hydrometeor imagery data from a recent C-130 field program exceeds all of the imagery data from all NCAR aircraft missions over a 10 year period using legacy instruments. While this trend affords substantial opportunities to understand hydrometeor processes, it has made the analysis of imagery data more challenging. Such challenges will require collaborative partnerships to efficiently mine and otherwise condition data to facilitate analyses from a new generation of airborne instruments.

A major challenge is to understand the interactions of physical sampling with the measured parameter (concentration, temperature, turbulence, etc.) at various airspeeds and flight conditions. Computational fluid dynamics (CFD) is an example of an emerging technology that may facilitate the unbiased sampling of species, such as cloud and aerosol particles, and trace gas chemistry. Understanding the airflow is especially important for HIAPER because of its wide range of airspeeds and altitudes. A CFD development effort will yield the basic flow structure (e.g. vector airflow, boundary layer structure, particle enhancement factors) around the aircraft so that instruments can be designed properly and placed at optimal locations, where calibrations factors are most certain.

Uninhabited Air Vehicles (UAVs) constitute another category of emerging technology that will profoundly affect the national fleet. ATD’s strategy is to emphasize research and development for those applications where UAVs are expected to perform in a superior or more cost-effective manner. Airspace issues have so far limited the application of UAVs, however, these issues are currently being addressed and solutions are expected within a 5 to 10 year time frame3 . Much of the instrumentation developed for HIAPER will find application on UAVs, further extending the flight envelope of these instruments to regions and for durations well beyond HIAPER’s reach. Many geoscience applications of UAVs are envisioned, including their use to deploy daughter UAVs as sounding devices in the remote stratosphere and troposphere and to perform extended-period sampling, well beyond human endurance on piloted aircraft. Finally, a positive feedback is derived from UAV command, control, and miniaturization technologies, which will also serve our piloted aircraft fleet, allowing for more comprehensive payloads on both the C-130 and HIAPER.

Extended Mission Opportunities

The opportunity has recently arisen to consider research flight support to polar regions on skied aircraft for NSF Polar Programs and USGS. ATD will further examine the scientific benefits, costs and logistics associated with support to Antarctic research, including instrumentation on the New York National Guard (transportation) aircraft. Preliminary assessments suggest that the latter option may not be feasible.

Additionally, NASA has taken a new course with its research aircraft program, seeking cost-shared partnerships for several of its aircraft, including the well-instrumented, heavy payload and long range DC-8. Tradeoffs are complex between this class of aircraft, HIAPER, and the C-130, and will be carefully examined with respect to potential strategic partnerships and direct benefits to the NSF-sponsored user community.

A Systems Approach

Recent developments in science have demanded broader suites of instrumentation. For example, while aircraft have been used for decades to sample trace gases, aerosols, and clouds, very few payloads have been comprehensive enough to measure the complex chemistry and dynamics that occur in clouds, such as the production of NOx, the effects of aerosols on cloud properties (e.g. albedo, cloud active nuclei), aqueous phase cloud chemistry, and transport and redistribution of trace gases. More disciplines are joining forces (chemists, clouds physicists, radar meteorologists) to provide these comprehensive payloads in order to address issues in cloud chemistry, clouds as chemical reactors, and convective cloud transport. This trend will continue, placing greater demand on integrated sensor systems that function as more than the sum of their parts. ATD will configure airborne instrumentation from a systems perspective, where the performance specifications of individual instruments, in some instances, may become secondary to the collective effectiveness and comprehensiveness of an instrument suite best matched to the global science objectives.

In the future, more scientists will participate in airborne research, but fewer of them will fly on aircraft. ATD will continue to provide and improve instrumentation for airborne measurements, but a larger fraction of instrumentation with increased technological diversity will fly on the aircraft. ATD will rely more heavily on strategic partnerships with other agencies, other countries and the private sector; and collaborative partnerships, forged within NCAR and with the university community. The collaborations that emerge from the HIAPER MRE instrumentation solicitation will be the “launch pad” for an increasingly extensible ATD. In this environment, the need for effective project management, already a major focus, will place greatly increased demands on ATD, especially as related to calibration, validation and data distribution.

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VI. Roadmap to the Future

A Dynamic Equilibrium: Deployment and Development

ATD has dual responsibilities to provide field project support with the current stable of instruments and platforms while continuing to develop, or otherwise acquire, new and improved observing capabilities. Tension between these competing activities is inevitable and therefore must be carefully managed according to principals that ensure sustained relevance and excellence. Thus, ATD must first define the programmatic balance, manage the levels of effort required to sustain this balance and negotiate with NCAR and NSF to ensure a globally balanced allocation of resources.

• Programmatic balance is that level of field support consistent with the timely renewal of observing systems and services. At the instrument level “timely renewal” is approximately 10 years, both from a “responsiveness to science” perspective as well as for the maintainability of hardware/software sub-systems. To achieve a steady state, non-labor resources available to the renewal function should equal approximately 10% of ATD’s observing systems holdings (exclusive of new or replacement aircraft platforms).
• Levels of effort must ensure a sustained balance between field project support and the renewal of observing systems. On a three-year planning horizon, in coordination with the NSF, ATD will plan periods of enhanced (or suppressed) field support (or renewal) to match capacity with community needs to the extent reasonable and feasible.
• NSF and NCAR management must ensure that the global allocation of resources, including deployment pool funds, is balanced between: NSF’s capacity to award experimental research; ATD’s capacity to deploy observing systems; and ATD’s capacity to renew these facilities and services.

Identifying Emerging Technologies

This photo shows the re-circulating Lissajous beam pattern on the back mirror of an astigmatic Herriott trace gas absorption cell developed by APOL. This photo was also taken using an infrared beam viewer.

Business as usual for ATD is the novel application of well known technologies to meet near term research needs. In the future, ATD will identify and explore emerging technologies that hold promise for application to the atmospheric and related sciences. ATD will establish a small team, working out of the Division Directorate on a "flow-through" basis, to investigate potentially fruitful emerging technologies. Drawn from senior engineering and scientific staff, Affiliate Scientists, NCAR science division appointees, and post-doctoral appointees, and representing the broad knowledge of the community, the team will investigate and advocate new ideas for technology applications.

Once a technology has been identified as promising, an exploratory development may be supported. If successful, the development would next attempt a "proof of concept" in geophysical application. If the "proof of concept" is successful, the project could be mainstreamed into the ATD development suite for implementation. This “path to operations” helps to manage risk inherent to innovation while supporting on-going investigations that have limited funding requirements. Initial targets may include those technologies that provide higher performance, with more reliability, are more easily supported and less costly; autonomous airborne and ground-based operation; or supra-seasonal deployments requiring minimal personnel.

Partnerships - an Extensible ATD

ATD will broaden its ability to serve the NSF research community and national needs through partnerships and mechanisms of various types that: effectively expand expertise and instrumentation; provide clear opportunities for participation by NSF and other mission agencies; forge university collaborations where ATD can act as a unifying resource to coordinate and integrate diverse research efforts.

• Forge strategic and collaborative partnerships with universities, laboratories and programs of NCAR, government laboratories, and the private sector, to improve and extend ATD's native renewal capacity.
• Practice increased pragmatic partnerships with our scientist-users to effect increased field support, including self-support in field operations, for limited categories of ATD equipment and services.
• Widen our expertise through the assisted exploration of emerging technologies with partners outside the geoscience community.

The mechanisms to be employed in these partnerships include:

• Extensive use of NCAR Affiliate Scientist appointments, of order 10 ongoing simultaneous appointments. Grantees of HIAPER MRE instruments will constitute the first wave of such appointments.
• focused workshops with sponsorship of selected participants.
• summer study groups on emerging technologies with world renowned experts from far-flung disciplines.
• The use of reciprocal external sabbaticals and internal sabbaticals for cross-fertilization of scientists and technologists.
• Greater participation in graduate education advisorships, especially in the engineering disciplines.

Comprehensive External Advice

ATD will seek ongoing advice and counsel from users and scientific managers to remain responsive and proactive on behalf of the NSF community in the operation of its facilities and in setting renewal priorities. Currently, the Observing Facilities Advisory Panel (OFAP) reviews in detail all field project requests for the NSF and all national facility operators, including ATD. OFAP also comments on development activities of the division and university facilities. In addition to OFAP, ATD will constitute a permanent external advisory committee (EAC) to ensure that the scientific priorities and divisional practices remain in alignment with the needs of the community. The EAC charge solicits advice on all aspects of the ATD program including field services, development activities, human resources, education, strategic partnerships, and emerging technologies. This committee will maintain communication crucial to the NSF and its Facility Advisory Committee (FAC).

The EAC will be drawn from university facility users, scientific researchers and instrumentation specialists, and will meet regularly. In order to provide the most salient and effective advice, the committee will be regularly informed of planned major national and international field campaigns, advancements in technology and their potential geoscience applications, and information on emerging science directions.

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Sustained Excellence in Data Quality and Service

Emphasis on multi-disciplinary science will push ATD to expand connectivity and service beyond traditional methods. Access to new, real-time, operational data sources and existing databases (e.g. GIS) will enable scientists to conduct research using more comprehensive datasets. ATD will work toward achieving total Internet accessibility of its data streams, both real-time and post project, using standardized cyberinfrastructure services. This strategy will blend the cyberinfrastructure domain into the developments in data services infrastructure that will occur over the next decade.

The tools, processes and importance of ATD data access, quality and management have advanced significantly in recent years. Data handling and production have evolved from paper reports and tapes distributed months after project's end to web-based data access and display while in the field, near immediate delivery of preliminary data and enhanced Internet distribution tools soon after a project ends. There are new efforts to advance data activities at both UCAR and on the national level such as UCAR’s Community Data Portal (CDP), National Science Digital Library (NSDL), Thematic Real-time Environmental Distributed Data Services (THREDDS) and the Data Management Working Group (DMWG). These will provide central access points and the infrastructure to discover, intercompare and more easily assimilate a wide variety of data sources – both sampled and model-generated.

As a primary activity, ATD will continue to expand its online data holdings for Internet distribution by a factor of ~30 over the next five years due to anticipated growth in image and scanning data. This large increase in data volume will require additional automation in order to simply maintain the status quo. ATD will enhance its digital infrastructure and computerization for real-time data distribution, automated data quality inspections, calibration history, and metadata and data delivery to advance its capabilities in data access and management.

With expanded resources and partnerships including JOSS, UNIDATA, SCD, RAP and others, ATD will have a unique opportunity to develop and implement a cyberinfrastructure domain for observing platforms. This domain would encompass deploying cyberinfrastructure to allow virtual project participation, interactive collaboration and increased access to operational and research quality real-time data streams, and data discovery facilitated by databases of observational data and metadata. Data services will connect to digital library objects (e.g. journal articles) in which scientists and students can immediately interact with case study datasets through online display and analysis tools.

Sustained Excellence in Mechanical Design and Fabrication (DFS)

The challenges in mechanical design and fabrication are associated with strong evolution in the types of instruments, their sizes, and the environment on platforms in which these operate. ATD’s Design and Fabrication Services will respond to the increased demands associated with HIAPER, other high-performance aircraft environments, and instruments destined for operation in space.

The era of extreme miniaturization will produce very large arrays of small sensor systems, often deployed in heterogeneous vegetative canopies ranging from tundra to rainforests. To meet these requirements and others, ATD will continue to modernize its suite of fabrication machines, design software tools, and refine its skills related to packaging micro-sized systems containing nanotechnology sensors.

Educational Foci

Educational activities are an essential part of NCAR's mission. ATD's educational activities have three main purposes:

• Educate the general public through active participation in UCAR E&O administered programs, including K-12 programs such DLESE, and Super-Science Saturday. Coordination and conduct of tours and demonstrations of ATD facilities and science while “on location” at field projects.
• Active participation in and co-sponsorship of UCAR E&O programs such as SOARS that facilitate undergraduate experiences in engineering and experimental science, helping to supply the pipeline of fresh talent.
• Activities at the post graduate level, which are intended to capture the highest caliber of engineering-science talent for ATD programs. These include: adjunct faculty appointments at UCAR Member universities; advisory participation in the supervision of graduate theses and dissertations; classroom teaching; co-sponsored graduate student residence in ATD during dissertation research; and recruitment of post-doctoral candidates through the Advanced Studies Program.

By working through established UCAR-administered education, outreach and training programs, ATD will assist a range of educational experiences in support of NCAR's educational mission. For example, new and innovative educational resources such as virtual classrooms, digital libraries, study modules and access to real-time data from field campaigns are available through UCAR's DLESE, COMET, and Unidata programs. ATD will provide unique educational opportunities for undergraduate students in engineering, through its participation in the SOARS program, and for atmospheric science students at graduate and undergraduate levels, by means of structured involvement in field campaigns.

Nurturing Our Human Resources

ATD re-states its ongoing commitment to staff development as a goal in itself, as well as a means for ATD staff to continue to serve as bridges to the scientific user community and to assist in deciding future technological directions for the division. ATD will be proactive in affording professional and intellectual enrichment opportunities for all staff, such as:

• presenting challenges through assignment of new activities and responsibilities.
• access to individual mentoring to address career goals.
• establishing successful staff development as a metric for evaluation of senior staff
• providing new leadership and growth opportunities through joint appointments between development labs and facilities and across sub-disciplines.

ATD also advocates the establishment of an "Early Career Engineer" program at NCAR, similar to the current recruitment of early career scientists, to encourage growth in the ranks of skilled engineers at the Center. ATD will also continue to utilize joint scientific appointments and NCAR Scientist I appointments to increase the disciplinary breadth of presence and expertise within the division.

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VII. Implications for the Organization

To more fully meet the challenges of 21st century geosciences, ATD will evolve toward an Earth Observing Laboratory (EOL) through a gradual and selective broadening of its mission. The long term evolution of EOL is dependent upon the evolution of science itself; the actions of near-neighbors in the federally-funded establishment; and the contributions of our international partners. The overarching strategy is to:

• build on existing strengths of ATD
• adopt an extensible structure, amenable to an evolving mission
• reaffirm its commitment to excellence through innovation in service to science

Community expectations include several departures from past practice. Recall that ATD, with rare exception, has supported short-period process studies in the lower atmosphere and it has maintained datasets only from its own observing systems. ATD has provided limited logistical support for the deployment of its own observing systems and personnel. Finally, ATD has kept formal data assimilation activities at “arms length”.

As identified in Section II, there are obvious and compelling reasons for ATD to contribute to global monitoring technologies in climate, and to observations for diagnostics and verification of “whole atmosphere" simulations. There is also a critical need to enhance observing systems and services in support of water cycle and biogeochemical investigations in the lower atmosphere. To extend basic capabilities to these communities, there is an evident need to provide (and to provide training for) user-operated, automated, and autonomous observing systems, often in deployments of long duration. Furthermore, ATD must integrate its observing systems, datasets and data archives with those of others, especially for large ongoing programs of research. These and other prospective program adaptations represent a considerable evolution of the ATD enterprise in both its technological and its service aspects. The related innovations must permeate the fabric of the Earth Observing Laboratory from its inception. It follows that EOL would be on firm ground to incorporate new activities such as:

• Acquisition and integration of satellite datasets with those of other origins
• Acquisition of long-duration time series, sometimes in support of “one-of-a-kind” projects for a fixed set of investigators
• Provision of baseline chemical and biologically-oriented sensor systems
• Facilitation of both real-time and off-line data assimilation
• Integration of diverse datasets from both internal and external sources
• Provision of logistical support consistent with coordination, collaboration and programmatic inclusiveness.

The figure below schematically illustrates the “building blocks” of ATD as it is currently positioned to evolve toward an EOL. Included are the broad thematic functions of the division together with specific activities in each. The thematic functions and activities are briefly described as follows:

The Foundation - Supporting Skills and Services:

These are provided to the entire organization and to external users. Focused activities include mechanical design and fabrication, cyberinfrastructure and data services, and field project coordination.

The Engine - Development Laboratories:

Laboratories are defined by cohesive technologies and platforms. Focused activities include remote and near field optical sensing systems, millimeter through HF radio sensing, adaptive bio-physical surface arrays, GPS-based global sounding systems, and airborne flight-level sensing (including state variables, air motions, cloud/aerosol physics, gaseous constituent sampling).

The Delivery – Observing Facilities:

Included in this thematic function are support for both ground based and airborne systems. Activities incorporate research aviation and surface-based “field observing” deployments.

The Innovation - Sustaining Importance and Relevance:

Activities designed to promote a culture of technological and scientific discovery, education and outreach themes. Focused activities include exploration of emerging technologies (not yet applied to geoscience), and original experimental research intended to demonstrate novel diagnostic techniques and the utility of observations in relation to numerical experimentation.

ATD will think of itself and structure itself in a manner that is easily extensible to the broader mission of an EOL. Organizational structure along cohesive and functional lines will facilitate the current mission of ATD and also position it for evolution toward the future EOL mission. For example, operation of a space-based instrument, or a suite of instruments on one or more satellites, is fully analogous to services provided through airborne and ground-based observing system deployments. Logistical services and datasets associated with collaborative institutions and facilities could be accommodated under corresponding “building blocks” currently within ATD. The introduction of new technologies could lead to the formation of new development laboratories along with the sunset of others as these are retired or diminished in relevance to the emerging science challenges.

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1David Atlas, 1973: NCAR Facilities Perspective—Past and Future. Atmospheric Technology, 1, 2. [back to text]
2The acquisition of a mid-sized jet aircraft such as the G-V has been the top priority as reported in airborne scientific fleet workshop reports in 1982, 1987, and 1992. [back to text]
3Access of UAVs to the national airspace is being aggressively pursued by an interagency/industry group under the Access 5 program, with major support from NASA (e.g. $101 M budget for “UAV in the NAS” program.) [back to text]