Hyperspectral Aerosol Optical Depths from TCAP Flights
4STAR (Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research), the world’s first hyperspectral airborne tracking sunphotometer, acquired aerosol optical depths (AOD) at 1 Hz during all July 2012 flights of the Two Column Aerosol Project (TCAP). Root-mean square differences from AERONET ground-based observations were 0.01 at wavelengths between 500-1020 nm, 0.02 at 380 and 1640 nm and 0.03 at 440 nm in four clear-sky fly-over events, and similar in ground side-by-side comparisons. Changes in the above-aircraft AOD across 3-km-deep spirals were typically consistent with integrals of coincident in situ (on DOE Gulfstream 1 with 4STAR) and lidar (on NASA B200) extinction measurements within 0.01, 0.03, 0.01, 0.02, 0.02, 0.02 at 355, 450, 532, 550, 700, 1064 nm, respectively, despite atmospheric variations and combined measurement uncertainties. Finer vertical differentials of the 4STAR measurements matched the in situ ambient extinction profile within 14% for one homogeneous column. For the AOD observed between 350-1660 nm, excluding strong water vapor and oxygen absorption bands, estimated uncertainties were ~0.01 and dominated by (then) unpredictable throughput changes, up to +/-0.8%, of the fiber optic rotary joint. The favorable intercomparisons herald 4STAR’s spatially-resolved high-frequency hyperspectral products as a reliable tool for climate studies and satellite validation.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 1123243
- Report Number(s):
- PNNL-SA-97236; KP1704010
- Journal Information:
- Journal of Geophysical Research. D. (Atmospheres), 118(21):12180-12194, Journal Name: Journal of Geophysical Research. D. (Atmospheres), 118(21):12180-12194
- Country of Publication:
- United States
- Language:
- English
Similar Records
Tracking Elevated Pollution Layers with a Newly Developed Hyperspectral Sun/Sky Spectrometer (4STAR): Results from the TCAP 2012 and 2013 Campaigns
New Shortwave Array Spectroradiometer-Hemispheric (SAS-He): Hyperspectral Design and Initial Applications