Publication Abstracts

Lin 1995

Lin, B., 1995: Observations of Cloud Water Path and Precipitation over Oceans Using ISCCP and SSM/I data. Ph.D. thesis. Columbia University.

Liquid/ice water path and rainfall rate of oceanic clouds are estimated using optical and microwave (i.e., the International Satellite Cloud Climatology Project and Special Sensor Microwave/Imager) combined remote sensing data.

According to sensitivity tests on microwave emission-based liquid water path retrieval method, microwave remote sensing is not very sensitive to cloud liquid water because the uncertainties caused by water vapor, near surface windspeed, cloud water temperature and sea surface temperature are large (about 7 mg/cm2 or in visible optical depth about 11), suggesting that optical cloud determination is needed for microwave retrievals. For warm, non-precipitating clouds, both optical and microwave data show that the averaged liquid water path is about 5 mg/cm2, while for cold ones, optical water path is considerably larger than microwave liquid water path due to cloud ice. Clouds in the tropics and cold hemisphere have higher ice water path values (around 10 mg/cm2 than in warm hemisphere. Ice fractions of non-precipitating clouds usually increase with decreasing cloud top temperatures. Although only about 7% of clouds are precipitating, they contribute significantly to averaged liquid water path values, especially in the tropics, because they hold nearly ten times as much liquid water as non-precipitating clouds.

Based on scattering calculations and microwave brightness temperature simulations, estimated ice water path of precipitating particles and rainfall rate for cold, precipitating clouds are about 27 mg/cm2 and 5 mm/hr, respectively. Although warm precipitation is generally about 10-20% of the total precipitation, it sometimes contributes a large portion (about 35%) of the total in the tropics, suggesting that it can not be neglected in rainfall estimations. Global precipitation fields, especially rainfalls in western Pacific warm pool regions, shift considerably with season. Maximum annual precipitation is located in the eastern Pacific, with values about 5000 mm due to persistent precipitation during all seasons. Peak values of western Pacific annual rainfall occur in southeast of western Pacific islands, while local maxima are produced by midlatitude storms occurring off the east coasts of continents.

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BibTeX Citation

@phdthesis{li04300u,
  author={Lin, B.},
  title={Observations of Cloud Water Path and Precipitation over Oceans Using ISCCP and SSM/I data},
  year={1995},
  school={Columbia University},
  address={New York, N.Y.},
}

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RIS Citation

TY  - THES
ID  - li04300u
AU  - Lin, B.
PY  - 1995
BT  - Observations of Cloud Water Path and Precipitation over Oceans Using ISCCP and SSM/I data
PB  - Columbia University
CY  - New York, N.Y.
ER  -

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