HR: 1340h
AN: A43D-0136    [Abstracts]
TI: Annual and Interannual Variations of Cirrus Clouds Using MODIS/Terra Data
AU: * Eguchi, N
EM: eguchi.nawo@nies.go.jp
AF: National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, 305-8506 Japan
AU: Yokota, T
EM: yoko@nies.go.jp
AF: National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, 305-8506 Japan
AU: Inoue, G
EM: inouegen@nies.go.jp
AF: National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, 305-8506 Japan
AB: Cirrus clouds in the upper troposphere affect not only on the terrestrial radiative balance but also on the water content and chemical balance in the stratosphere. Since the most of the retrieval algorithm for remote sensing observation is not taken the cirrus clouds effects into account due to the lack of understanding of cirrus clouds, the results inferred from the retrieval including some errors. To understand the characteristics of the cirrus clouds, space-time variations of cirrus clouds on the annual and interannual time scales are investigated by using the monthly cirrus clouds fraction data obtained by the Moderate Resolution Imaging Spectrometer (MODIS) aboard the Terra; that are available from March 2000 to July 2005. As for the seasonal variation, the distribution of cirrus clouds fraction in the tropics is basically consistent with the convective activities. The regions with higher cirrus fraction (> 60 %) are located over the convective region: Africa, South America and the maritime continent throughout the year. On the other hand, the regions with lower cirrus fraction (< 30 %) occur over the eastern Pacific and the Atlantic where the subsidence regions associate with the Walker circulation throughout the year. The higher cirrus fraction is also observed over the latitude larger than 30°N in the boreal winter, especially over the Tibetan Plateau, the western Pacific and the Atlantic. It is found that the longitudinal contrast in the cirrus clouds field is related with the El Niño / Southern Oscillation (ENSO), and that the high cirrus clouds fractions are closely associated with the convective activities. An anomaly of cirrus fraction of these five-year-mean shows that the higher (lower) cirrus fraction with larger than +10% (-10%) is located over the maritime continents and western Pacific (the central Pacific) during the boreal winter 2001 (the La Niña winter); and that the higher (lower) cirrus fraction with larger than +10% (-10%) is located over the Indian ocean, and central Pacific (the maritime continents and western Pacific) during the boreal winter 2003 (the El Niño winter).
DE: 3311 Clouds and aerosols
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005