Publication Date:
2022-05-25
Description:
Author Posting. © American Meteorological Society, 2017. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Atmospheric and Oceanic Technology 34 (2017): 355-373, doi:10.1175/JTECH-D-15-0226.1.
Description:
Passive longwave infrared radiometric satellite–based retrievals of sea surface temperature (SST) at instrument nadir are investigated for cold bias caused by unscreened optically thin cirrus (OTC) clouds [cloud optical depth (COD) ≤ 0.3]. Level 2 nonlinear SST (NLSST) retrievals over tropical oceans (30°S–30°N) from Moderate Resolution Imaging Spectroradiometer (MODIS) radiances collected aboard the NASA Aqua satellite (Aqua-MODIS) are collocated with cloud profiles from the Cloud–Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument. OTC clouds are present in approximately 25% of tropical quality-assured (QA) Aqua-MODIS Level 2 data, representing over 99% of all contaminating cirrus found. Cold-biased NLSST (MODIS, AVHRR, and VIIRS) and triple-window (AVHRR and VIIRS only) SST retrievals are modeled based on operational algorithms using radiative transfer model simulations conducted with a hypothetical 1.5-km-thick OTC cloud placed incrementally from 10.0 to 18.0 km above mean sea level for cloud optical depths between 0.0 and 0.3. Corresponding cold bias estimates for each sensor are estimated using relative Aqua-MODIS cloud contamination frequencies as a function of cloud-top height and COD (assuming they are consistent across each platform) integrated within each corresponding modeled cold bias matrix. NLSST relative OTC cold biases, for any single observation, range from 0.33° to 0.55°C for the three sensors, with an absolute (bulk mean) bias between 0.09° and 0.14°C. Triple-window retrievals are more resilient, ranging from 0.08° to 0.14°C relative and from 0.02° to 0.04°C absolute. Cold biases are constant across the Pacific and Indian Oceans. Absolute bias is lower over the Atlantic but relative bias is higher, indicating that this issue persists globally.
Description:
Authors JWM, NJS,
and JZ acknowledge the support of NASA Project
NNX14AJ13G andNSF Project IIA-1355466.Author JZ
also acknowledges the support of ONR N00014-16-1-2040
(Grant 11843919). Author JWM further recognizes
the Naval Research Enterprise Internship Program
(NREIP). Support for his NREIP
fellowship came from NASA Interagency Agreement
NNG15JA17P on behalf of theMicro-Pulse LidarNetwork
(E. J. Welton). Authors JRC, JAC and DLW acknowledge
the support of Office of Naval Research Code 322
(PE0602435). Author JRC also acknowledges the support
of NASA Interagency Agreement RPO201522 on behalf
of the CALIPSO Science Team (C. R. Trepte).
Description:
2017-08-06
Keywords:
Sea surface temperature
;
Cirrus clouds
;
Lidars/Lidar observations
;
Remote sensing
;
Satellite observations
Repository Name:
Woods Hole Open Access Server
Type:
Article
