HRDL is an eye-safe, 2 µm wavelength, solid-state, coherent Doppler lidar coupled with a high speed platform-attitude- correcting scanner and an advanced signal processor. HRDL was designed and built by NOAA/ETL to provide the high spatial and velocity resolution measurements needed to advance physical understanding of boundary layer processes. Better understanding leads to improved models and ultimately to more accurate weather and climate forecasts.

HRDL Applications

• Boundary layer measurements including: entrainment zone processes, vertical convective velocities, high resolution in stable, neutral, sheer driven B.L.'s, momentum fluxes and turbulence kinetic energy.
• Temporally and spatially averaged divergence.
• Future simultaneous water vapor.
• Space-based Lidar risk reduction.
• Cloud studies including: deep penetration in water clouds, ice/water discrimination, vertical velocities in cirrus, boundary layer dynamics, and synergies with radar.

HRDL Achievements

• HRDL, a coherent Doppler lidar with unprecedented 5 cm/s and 30 m range resolution, has been designed and built by ETL.
• HRDL has played a key role in two major field campaigns designed to study the convective, nocturnal, and marine boundary layers.
• HRDL is providing the high resolution data needed to better observe boundary layer structure and understand the dynamics of energy and chemical species exchange through this key region. this improved physical understanding will be parameterized in models, resulting in better weather, pollution transport, and climate forecasts.
• Short-term weather predications will ultimately be improved by HRDL backscatter measurements because they will be used to set engineering requirements for space-based wind lidar performance.

Recent improvements

• A new frequency feedback loop has been developed providing a frequency stability of 0.2MHz even in rough environment.
• The average power has been increased to about 2W using advanced diode laser technology, a better design of the laser resonator, as well as improved cooling of the laser crystal.
• HRDL has been operated successfully on a shipborne platform. Further tests on airborne platforms are under the way.

Field campaigns

• NAURU99
• CASES99