Measurement of atmospheric CO 2 column concentrations to cloud tops with a pulsed multi-wavelength airborne lidar

Mao, Jianping; Ramanathan, Anand; Abshire, James B.; Kawa, Stephan R.; Riris, Haris; Allan, Graham R.; Rodriguez, Michael; Hasselbrack, William E.; Sun, Xiaoli; Numata, Kenji; Chen, Jeff; Choi, Yonghoon; Yang, Mei Ying Melissa

We have measured the column-averaged atmospheric COinline-formula2 mixing ratio to a variety of cloud tops by using an airborne pulsed multi-wavelength integrated-path differential absorption (IPDA) lidar. Airborne measurements were made at altitudes up to 13 km during the 2011, 2013 and 2014 NASA Active Sensing of COinline-formula2 Emissions over Nights, Days, and Seasons (ASCENDS) science campaigns flown in the United States West and Midwest and were compared to those from an in situ sensor. Analysis of the lidar backscatter profiles shows the average cloud top reflectance was inline-formula∼ 5 % for the COinline-formula2 measurement at 1572.335 nm except to cirrus clouds, which had lower reflectance. The energies for 1 inline-formulaµs wide laser pulses reflected from cloud tops were sufficient to allow clear identification of COinline-formula2 absorption line shape and then to allow retrievals of atmospheric column COinline-formula2 from the aircraft to cloud tops more than 90 % of the time. Retrievals from the COinline-formula2 measurements to cloud tops had minimal bias but larger standard deviations when compared to those made to the ground, depending on cloud top roughness and reflectance. The measurements show this new capability helps resolve COinline-formula2 horizontal and vertical gradients in the atmosphere. When used with nearby full-column measurements to ground, the COinline-formula2 measurements to cloud tops can be used to estimate the partial-column COinline-formula2 concentration below clouds, which should lead to better estimates of surface carbon sources and sinks. This additional capability of the range-resolved COinline-formula2 IPDA lidar technique provides a new benefit for studying the carbon cycle in future airborne and space-based COinline-formula2 missions.



Mao, Jianping / Ramanathan, Anand / Abshire, James B. / et al: Measurement of atmospheric CO2 column concentrations to cloud tops with a pulsed multi-wavelength airborne lidar. 2018. Copernicus Publications.


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