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The 2017 ASCENDS/ABoVE Airborne Campaign and initial look at Pulsed Lidar Measurements of CO2 Column Concentrations
James
B
Abshire, NASA Goddard, james.b.abshire@nasa.gov
(Presenter)
Haris
Riris, NASA Goddard, haris.riris@nasa.gov
Graham
R
Allan, NASA Goddard/Sigma, graham.r.allan@nasa.gov
Jianping
Mao, ESSIC/University of Maryland, jianping.mao@nasa.gov
William
E
Hasselbrack, NASA Goddard/Sigma, wiilliam.e.hasselbrack@nasa.gov
Kenji
Numata, NASA Goddard, kenji.numata@nasa.gov
Jeffrey
Chen, NASA Goddard, jeffrey.r.chen@nasa.gov
Randy
Kawa, NASA Goddard, stephan.r.kawa@nasa.gov
Joshua
Digangi, NASA Langley, joshua.p.digangi@nasa.gov
Yonghoon
Choi, NASA Langley, yonghoon.choi-1@nasa.gov
The 2017 ASCENDS airborne campaign was flown on the NASA DC-8 in late July and early August. The campaign objectives were to assess the accuracy of airborne IPDA lidar measurements of CO2 column concentrations (XCO2), and to extend these lidar measurements to the ABoVE study area in the Arctic. Eight science flights were conducted with simultaneous XCO2 measurements from NASA Goddard’s CO2 Sounder lidar and the NASA Langley ACES lidar along with in-situ CO2 measurements made at aircraft altitude with the AVOCET and Picarro in-situ sensors. Over 40 spiral-down maneuvers were conducted during the campaign over locations in California, Northwest Territories (NWT) Canada and over Alaska, along with the transit flights from California to Alaska and return. Since each spiral maneuver allows comparing the retrievals of XCO2 from the lidar against those computed from in-situ measured CO2, this campaign allowed an unprecedented opportunity to assess the lidar measurements of XCO2 over a diverse set of conditions, including those in the Arctic.
The CO2 Sounder lidar flown on the campaign is a pulsed, multiple-wavelength integrated path differential absorption lidar that measures XCO2 in a nadir path from the aircraft. The lidar measures the range resolved shape of the 1572.33 nm CO2 absorption line to scattering surfaces, including to the ground and to the tops of clouds. The measurements for this campaign used 30 fixed-wavelength samples distributed across the line. Analysis estimates the lidar range and pulse energies at each wavelength 10 times per second. For each second the retrievals solve for the CO2 absorption line shape and the column average CO2 concentrations by using radiative transfer calculations, the aircraft altitude and range to the scattering surface, and the atmospheric conditions.
The presentation will describe all the flight paths, and will present the early results from analyzing the retrieved XCO2 from the CO2 Sounder lidar in the campaign over some of the regions. It will also present the initial results of comparing the lidar-retrieved XCO2 to those computed from the in-situ sensors at some of the spiral-down locations and discuss the ongoing analyses.
Associated Project(s):
Poster Location ID: 11
Session Assigned: Carbon Dynamics
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