In this study, we use thermal infrared channels to retrieve the optical thickness
and effective particle radius of ice clouds. A physical model is used in conjunction with
Atmospheric Infrared Sounder (AIRS) temperature and water vapor profiles to simulate
the top-of-atmosphere (TOA) brightness temperatures (BTs) observed by the Moderate
Resolution Imaging Spectroradiometer (MODIS) for channels located at 8.5, 11.0, and
12.0 õm (1176, 909, and 833 cm-1). The model is initially validated by comparing
simulated clear-sky BTs to MODIS-observed clear-sky BTs. We also investigate the
effect of introducing a +3 K bias in the temperature profile, a +3 K bias in the surface
temperature, and a +20% bias in the water vapor profile in order to test the sensitivity of
the model to these inputs. For clear-sky cases, the simulated TOA BTs agree with
MODIS to within 2-3 K. The model is then extended to simulate thermal infrared BTs
for cloudy skies, and we infer the optical thickness and effective radius of ice clouds by
matching MODIS-observed BTs to calculations. The optical thickness retrieval is
reasonably consistent with the MODIS Collection 5 operational retrieval for optically
thin clouds but tends to retrieve smaller particle sizes than MODIS.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/4718 |
| Date | 25 April 2007 |
| Creators | Yost, Christopher Rogers |
| Contributors | Yang, Ping |
| Publisher | Texas A&M University |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Thesis, text |
| Format | 2143629 bytes, electronic, application/pdf, born digital |
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