Weather and climate needs for lidar observations from space and concepts for their realization
The spectrum of weather and climate needs for lidar observations from space is discussed. This paper focuses mainly on the requirements for winds, temperature, moisture, and pressure. Special emphasis is given to the needs for wind observations and it is shown that winds are required to depict realistically all atmospheric scales in the tropics and the smaller scales at higher latitudes, where both temperature and wind profiles are necessary. The need for means to estimate air-sea exchanges of sensible and latent heat also is noted. Lidar can aid here by measurement of the slope of the boundary layer. Recent theoretical feasibility studies concerning the profiling of temperature, pressure, and humidity by differential absorption lidar (DIAL) from space and expected accuracies are reviewed. Initial ground-based trials provide support for these approaches and also indicate their direct applicability to path-average temperature measurements near the surface. An alternative approach to Doppler lidar wind meas...