Radiative Effects of Various Cloud Types as Classified by the Split Window Technique over the Eastern Sub-tropical Pacific Derived from Collocated ERBE and AVHRR Data

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概要

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• The radiative effects of several cloud types as classified by the split window (11 and 12 μm) technique were studied using coincident and collocated Earth Radiation Budget Experiment (ERBE) S-8 data and Advanced Very High Resolution Radiometer (AVHRR) data from NOAA-9. The parameter investigated was cloud radiative forcing (CRF), the difference between clear and cloudy shortwave flux (SW) and longwave flux (OLR) at the top of the atmosphere. In computing the CRF, the accuracy of clear SW and OLR is essential. Clear scene IDs in the ERBE dataset were evaluated using coincident and collocated AVHRR image data. The mean visible reflectance and SW for clear footprints defined by the ERBE are reasonably small and are 3.2% and 89.0 Wm^-2, respectively. However, the values computed using our technique are smaller, 2.7% and 83.9 Wm^-2, respectively. The use of collocated AVHRR image data improves clear footprint definition and implies that care should be taken when computing CRF from ERBE data alone. The CRF from several cloud types classified by the split window were compared. Cumulonimbus clouds show the largest impact on top of the atmosphere radiation for both SW and OLR. Cirrus and low-level cumulus clouds have similar effects on OLR, but large differences between them are seen for SW. The impact of low-level cumulus clouds on SW is much larger than that of cirrus clouds. Some optically thin cirrus clouds show positive cloud radiative forcing (warming effect). The relationships between OLR and cloud types (including cloud-free) as classified by the split window technique were investigated. By using brightness temperature differences between the split window channels, OLR estimation is improved for cloud-free and low-level cumulus clouds when compared with OLR estimated by the National Oceanic and Atmospheric Administration (NOAA) operational algorithm.

• 社団法人日本気象学会の論文
• 2002-12-25

著者

• Inoue Toshiro

  Meteorological Res. Institute/jma

• Inoue Toshiro

  Meteorological Research Institute Tsukuba

• ACKERMAN Steven

  Cooperative Institute for Meteorological Satellite Studies, University of Wisconsin

• Ackerman Steven

  Cooperative Institute For Meteorological Satellite Studies University Of Wisconsin

• Inoue T

  Univ. Tokyo Tokyo Jpn

関連論文

• Characteristics of Cloud Size of Deep Convection Simulated by a Global Cloud Resolving Model over the Western Tropical Pacific(The International Workshop on High-Resolution and Cloud Modeling, 2006)
• Statistical Relationship between ISCCP Cloud Type and Vertical Relative Humidity Profile
• Radiative Effects of Various Cloud Types as Classified by the Split Window Technique over the Eastern Sub-tropical Pacific Derived from Collocated ERBE and AVHRR Data
• Comparison of a Split-window and a Multi-spectral Cloud Classification for MODIS Observations
• Characteristics of deep convection over the Amazonia during LBA using GOES and PR/TRMM data

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