Title of Presentation: Mid-Term Status of the TWiLiTE Direct Detection Doppler Lidar Development Program

Primary (Corresponding) Author: Bruce Gentry

Organization of Primary Author: NASA Goddard Space Flight Center

Co-Authors: Matthew McGill, Geary  Schwemmer, Michael Hardesty, Alan Brewer, Thomas Wilkerson, Robert Atlas, Marcos Sirota, Scott Lindemann, Floyd Hovis


Abstract:  Global measurement of tropospheric winds is a key measurement for understanding atmospheric dynamics and improving numerical weather prediction.  Global wind profiles remain a high priority for the operational weather community and also for a variety of research applications including studies of the global hydrologic cycle and transport studies of aerosols and trace species.  In addition to space based winds, high altitude airborne Doppler lidar systems flown on research aircraft, UAV’s or other advanced sub-orbital platforms would be of great scientific benefit for studying mesoscale dynamics and storm systems such as hurricanes.  The Tropospheric Wind Lidar Technology Experiment (TWiLiTE) was selected in 2005 by the NASA Earth Science Technology Office as part of the Instrument Incubator Program.  The objective of the three year TWiLiTE program is to advance the technology readiness level of the key technologies and subsystems of a molecular direct detection wind lidar system by validating them, at the system level, in an integrated airborne lidar system.  The TWiLiTE Doppler lidar system is designed for autonomous operation on the WB57, a high altitude aircraft operated by NASA Johnson. The WB57 is capable of flying well above the mid-latitude tropopause so the downward looking lidar will measure complete profiles of the horizontal wind field through the lower stratosphere and the entire troposphere.  The TWiLiTE Doppler lidar instrument will be the first demonstration of an airborne scanning direct detection Doppler lidar and will serve as a critical milestone on the path to a future spaceborne tropospheric wind system.  The completed system will have the capability to profile winds in clear air from the aircraft altitude of 18 km to the surface with 250 m vertical resolution and < 3 m/s velocity accuracy.  Progress in technology development and status of the instrument design will be presented.