The CALIPSO Night Validation Flights (CALIPSO-NVF) airborne deployment was conducted in August 2022 out of Bermuda. The goal was to conduct a series of nighttime underflights of the CALIPSO satellite with the NASA Langley High Spectral Resolution Lidar (HSRL-2). Airborne measurements from the NASA Langley HSRL-2 instrument are essential for verifying the calibration accuracy of the CALIPSO lidar and for acquiring information on aerosol optical properties used for its aerosol profile retrievals. By flying under the CALIPSO ground track, HSRL-2 provides an independent measurement of lidar attenuated backscatter with a higher signal-to-noise ratio. To obtain this important validation dataset, the HSRL-2 was flown on board the LaRC B-200 King Air as CALIPSO passed within range of the aircraft. The western Atlantic Ocean was selected for CALIPSO-NVF to allow unobstructed, 45-minute flights along the satellite ground track. Five nighttime underflights were executed in total – four in cloud-free skies on August 7, 10, 12, and 17th, yielding ideal data from both instruments for calibration validation. The fifth flight on August 18th targeted measurements beneath cirrus to assess the accuracy of CALIPSO aerosol retrievals through high clouds at night, an important but previously unexplored validation target. Total research flight time was 17.7 hours, sampling 2,200 km along the CALIPSO ground track.

Aircraft flight paths and co-located CALIPSO ground tracks during the deployment.