Information content of OCO-2 oxygen A-band channels for retrieving marine liquid cloud properties

Richardson, M. and Stephens, G. L. (2018) Information content of OCO-2 oxygen A-band channels for retrieving marine liquid cloud properties. Atmospheric Measurement Techniques, 11 (3). pp. 1515-1528. ISSN 1867-8548 doi: 10.5194/amt-11-1515-2018

Abstract/Summary

Information content analysis is used to select channels for a marine liquid cloud retrieval using the high-spectral-resolution oxygen A-band instrument on NASA's Orbiting Carbon Observatory-2 (OCO-2). Desired retrieval properties are cloud optical depth, cloud-top pressure and cloud pressure thickness, which is the geometric thickness expressed in hectopascals. Based on information content criteria we select a micro-window of 75 of the 853 functioning OCO-2 channels spanning 763.5–764.6 nm and perform a series of synthetic retrievals with perturbed initial conditions. We estimate posterior errors from the sample standard deviations and obtain ±0.75 in optical depth and ±12.9 hPa in both cloud-top pressure and cloud pressure thickness, although removing the 10 % of samples with the highest χ2 reduces posterior error in cloud-top pressure to ±2.9 hPa and cloud pressure thickness to ±2.5 hPa. The application of this retrieval to real OCO-2 measurements is briefly discussed, along with limitations and the greatest caution is urged regarding the assumption of a single homogeneous cloud layer, which is often, but not always, a reasonable approximation for marine boundary layer clouds.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/76928
Identification Number/DOI	10.5194/amt-11-1515-2018
Refereed	Yes
Divisions	Science > School of Mathematical, Physical and Computational Sciences > Department of Meteorology
Publisher	European Geosciences Union
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