TARFOX Experiment Description

LASE (Lidar Atmospheric Sensing Experiment) airborne lidar, operates on the NASA ER-2 high altitude research aircraft, and will produce measurements of aerosols and water vapor vertical profiles from the aircraft altitude (16-21 km) down to the surface. Such profiles show the vertical context in which the TARFOX in situ and radiometric measurements are made, thus supporting the vertical extension of the in situ measurements and detecting any unsampled layers or inhomogeneities, which would impact the airborne and satellite radiative flux measurements. The LASE instrument is the first fully-engineered, autonomous DIAL (Differential Absorption Lidar) system for the measurement of water vapor, aerosols, and clouds in the troposphere. LASE uses a double-pulsed Ti: Sapphire laser for the transmitter with a 30 ns pulse length and 150 mj/pulse. The laser beam is "seeded" to operate on a selected water vapor absorption line in the 815 nm region using a laser diode with an onboard absorption reference cell. A 38 cm diameter telescope collects the back scattered signals and directs them onto two detectors and three signal digitizers with different gain settings. LASE collects DIAL data at 5 Hertz while onboard a NASA/Ames ER-2 aircraft flying at altitudes from 16-21 km. LASE was designed to meet the performance specifications provided by the DIAL water vapor instrument requirements, to operate autonomously, and to perform within the aircraft environmental and physical contraints. The LASE instrument was custom built and tested at NASA Langley Research Center in Hampton, VA. During TARFOX, LASE was not operated when the ER-2 was below 60,000 feet. If the aircraft dipped below 60,000 feet, a pressure switch was activated and LASE was shutdown. In addition, to ensure eye safety, while LASE was in operation, the other TARFOX in situ aircraft (C130, C131, and Pellican) flew at altitudes below 15,000 feet whenver they were vertically aligned with the ER-2 LASE aircraft.

Link to additional TARFOX Experiment Description/Overview (on TARFOX Home Page).