Discipline: Ecology Environmental and Earth Sciences
Subcategory: Climate Change
Emily J. Rosenthal - Millersville University
Co-Author(s): Heather Cronk, Rob Nelson and Chris O’Dell, Colorado State University, Fort Collins, CO
Synergistic studies of various A-train sensors with the recently launched OCO-2 observatory are now underway. OCO-2 is meant to measure carbon dioxide from hyperspectral measurements of near-infrared reflected sunlight, but can only obtain high accuracy in clear scenes. In this study, we compare
the results of the OCO-2 O2-A band cloud screening algorithm to CALIPSO observations, to determine their level of agreement in terms of both cloud and aerosol properties. Both CALIPSO optical depth as well as vertical information were analyzed in the context of the OCO-2 O2-A cloud screening algorithm. In general, we find that for high optical depth CALIPSO measurements, OCO-2 identified most (~70%) of scenes as cloudy. The opposite was also true: for low optical depth CALIPSO measurements, OCO-2 identified most of the scenes as clear. Further, it was found that OCO-2 misidentifies ~40% of scenes containing thick, low clouds, while properly identifying nearly all scenes containing high clouds. These preliminary results confirm expectations derived from previous simulationbased work. Future studies include the dependence of these results on cloud phase, optical thickness detection limits, and potential solar zenith angle dependencies.
References: D.M Winker, J.P. (2010, September). The CALIPSO Mission A Global 3D View of Aerosols and Clouds. Retrieved July 22, 2015, from American Meteorological Society: http:// journals.ametsoc.org/doi/pdf/10.1175/2010BAMS3009.
Thomas E. Taylor, C.W. (2012, January 1). Comparison of CloudScreening Methods Applied to COSAT Near-InfraredSpectra. Retrieved July 22, 2015, from IEEXplore: http:// ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=5967900
Murphy, R. (2014, July 3).OCO-2 Takes the A-Train to Study Earth’s Atmosphere. Retrieved July 22, 2015, from NASA: http:// www.jpl.nasa.gov/news/news.php?feature=4204
C.W. O’Dell, B.C. (2012, January 12). The ACOS CO2 retrieval algorithm – Part 1: Description and validation against synthetic observations. Retrieved July 22, 2015, from Atmosphere Measurement Techniques: www.atmos-meastech.net/5/99/2012/amt-5-99-2012.html
Funder Acknowledgement(s): This work has been supported by the National Science Foundation Research Experiences for Undergraduates Site in Climate Science at Colorado State University under the cooperative agreement No. AGS-1461270.
Faculty Advisor: Christopher O'Dell,