Abstract

Using a more realistic cirrus cloud model, the characteristics of transmittance, emittance, and optical thickness and their relationships to cirrus in a diverse set of cases are studied by solving the equation of transfer of IR radiation. The doubling method is employed in the multiple scattering calculation. The satellite-observed brightness temperatures for different cases are computed, and stepwise regression analyses are performed to yield retrieval equations for sea surface temperature (SST). It is shown that the radiative properties of cirrus depend strongly on particle concentration, thus on the optical thickness of clouds. For clear atmospheres, channel 8 (11.2 μm) is more transparent than other channels. For cirrus clouds only, when the optical thickness of cirrus τc is <0.10, channel 8 is still more transparent, while, with τc increasing from 0.2 to between 4 and 8, channel 12 (4 μm) becomes the most transparent. When τc ≥ 8, the transparency of channel 12 decreases and those of other channels increase. For a very large τc the transparency of VAS channels will become almost equal. In addition, the IR absorption emittance of cirrus and the brightness temperatures also have sensitivities to different cloud optical thicknesses. The general retrieval equation for the determinations of SST, which is suitable for the clear air model as well as for the cirrus cloud atmospheres (with our definition of cirrus), is obtained through a combination of channels 12, 8, 6 (4.5 μm), and 5 (13.3 μm). The retrieval error is <1.0 K. The error analyses indicate that the clear air retrieval equations should not be used for SST determination in cirrus conditions.

© 1991 Optical Society of America

Full Article  |  PDF Article
OSA Recommended Articles
Simulation of retrieval of the base height and thickness of cirrus clouds from satellite data

Lisheng Xu and Jianyun Zhang
J. Opt. Soc. Am. A 9(9) 1536-1546 (1992)

Numerical simulation of the influence of volcanic aerosols on VAS derived SST determinations

Lisheng Xu and William L. Smith
Appl. Opt. 25(7) 1137-1144 (1986)

References

You do not have subscription access to this journal. Citation lists with outbound citation links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Cited By

You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Figures (6)

You do not have subscription access to this journal. Figure files are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Tables (6)

You do not have subscription access to this journal. Article tables are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Equations (32)

You do not have subscription access to this journal. Equations are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Metrics

You do not have subscription access to this journal. Article level metrics are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription