Multi-instrument comparison of top-of-atmosphere reflected solar radiation

Show simple item record Loeb, NG en Wielicki, BA en Su, W en Loukachine, K en Sun, W en Wong, T en Priestley, KJ en Matthews, G en Miller, WF en Davies, Roger en 2012-03-26T01:23:21Z en 2007 en
dc.identifier.citation Journal of Climate 20(3):575-591 2007 en
dc.identifier.issn 0894-8755 en
dc.identifier.uri en
dc.description.abstract Imaging Spectroradiometer (MODIS), Multiangle Imaging Spectroradiometer (MISR), and Sea-Viewing Wide-Field-of-View Sensor (SeaWiFS) between 2000 and 2005 are analyzed in order to determine if these data are meeting climate accuracy goals recently established by the climate community. The focus is primarily on top-of-atmosphere (TOA) reflected solar radiances and radiative fluxes. Direct comparisons of nadir radiances from CERES, MODIS, and MISR aboard the Terra satellite reveal that the measurements from these instruments exhibit a year-to-year relative stability of better than 1%, with no systematic change with time. By comparison, the climate requirement for the stability of visible radiometer measurements is 1% decade 1 . When tropical ocean monthly anomalies in shortwave (SW) TOA radiative fluxes from CERES on Terra are compared with anomalies in Photosynthetically Active Radiation (PAR) from SeaWiFS—an instrument whose radiance stability is better than 0.07% during its first six years in orbit—the two are strongly anticorrelated. After scaling the SeaWiFS anomalies by a constant factor given by the slope of the regression line fit between CERES and SeaWiFS anomalies, the standard deviation in the difference between monthly anomalies from the two records is only 0.2 W m 2 , and the difference in their trend lines is only 0.02 0.3 W m 2 decade 1 , approximately within the 0.3 W m 2 decade 1 stability requirement for climate accuracy. For both the Tropics and globe, CERES Terra SW TOA fluxes show no trend between March 2000 and June 2005. Significant differences are found between SW TOA flux trends from CERES Terra and CERES Aqua between August 2002 and March 2005. This discrepancy is due to uncertainties in the adjustment factors used to account for degradation of the CERES Aqua optics during hemispheric scan mode operations. Comparisons of SW TOA flux between CERES Terra and the International Satellite Cloud Climatology Project (ISCCP) radiative flux profile dataset (FD) RadFlux product show good agreement in monthly anomalies between January 2002 and December 2004, and poor agreement prior to this period. Commonly used statistical tools applied to the CERES Terra data reveal that in order to detect a statistically significant trend of magnitude 0.3 W m 2 decade 1 in global SW TOA flux, approximately 10 to 15 yr of data are needed. This assumes that CERES Terra instrument calibration remains highly stable, long-term climate variability remains constant, and the Terra spacecraft has enough fuel to last 15 yr. en
dc.publisher American Meteorological Society en
dc.relation.ispartofseries Journal of Climate en
dc.rights Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher. Details obtained from en
dc.rights.uri en
dc.title Multi-instrument comparison of top-of-atmosphere reflected solar radiation en
dc.type Journal Article en
dc.identifier.doi 10.1175/JCLI4018.1 en
pubs.issue 3 en
pubs.begin-page 575 en
pubs.volume 20 en
dc.rights.holder Copyright: American Meteorological Society en
pubs.end-page 591 en
dc.rights.accessrights en
pubs.subtype Article en
pubs.elements-id 140620 en Science en Physics en
pubs.record-created-at-source-date 2012-03-26 en

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