Publication Abstracts

Rossow and Garder 1993

Rossow, W.B., and L.C. Garder, 1993: Validation of ISCCP cloud detections. J. Climate, 6, 2370-2393, doi:10.1175/1520-0442(1993)006<2370:VOICD>2.0.CO;2.

The International Satellite Cloud Climatology Project (ISCCP) began in 1983 to collect and analyze weather satellite datasets to produce a new global cloud climatology as part of the World Climate Research Program. The first step of the analysis is detection of the presence of clouds at each location and time by a series of tests on the space/time variations of infrared and visible radiances. This paper describes the validation of the ISCCP cloud detection by verifying the accuracy of the inferred clear sky radiances. Comparison of retrieved surface temperatures to other measurements shows that the bias errors are < 2K and random errors are about 2K for sea surface (monthly means at 280 km scales) and that bias errors are < 2K and random errors are about 4K for land surfaces (3-hourly at 280 km scale). Bias errors over a few persistently cloudy locations are sometimes -(2-4)K and over winter sea ice may be about +2K. Surface reflectances are confirmed to be within 3% of other measurements and models for ocean, except for sunglint geometries, and to be within 3-5% for land surfaces. Sufficiently accurate validation data are not available for visible reflectances of sea ice and snow-covered land, but some tests of specific cases sufggest that errors are ∼ 10%. These errors in clear sky radiances suggest uncertainties in the ISCCP cloud detections of about 10% with a small (2-6%) negative bias over land. Some specific regions exhibit both larger rms uncertainties and somewhat larger biases in cloud amount approaching 10%. ISCCP cloud detections ar more in error over the polar regions than anywhere else. Based on comparisons with an analysis of radiances measures at other wavelengths, the ISCCP analysis appears to miss 15-25% of the clouds in summer but only 5-10% of the winter clouds.

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BibTeX Citation

  author={Rossow, W. B. and Garder, L. C.},
  title={Validation of ISCCP cloud detections},
  journal={J. Climate},

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RIS Citation

ID  - ro03500i
AU  - Rossow, W. B.
AU  - Garder, L. C.
PY  - 1993
TI  - Validation of ISCCP cloud detections
JA  - J. Climate
VL  - 6
SP  - 2370
EP  - 2393
DO  - 10.1175/1520-0442(1993)006%3C2370%3AVOICD%3E2.0.CO;2
ER  -

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