碩士 / 國立臺灣大學 / 大氣科學研究所 / 95 / The high resolution (hourly, resampled to 0.50×0.50) window (11.5μm~12.5μm ) brightness temperature (Tbb) data from Japan’s Geostationary Meteorological Satellite-5 (GMS-5) during 1997－2003 were used to investigate the diurnal variation of clouds in the Maritime Continent during boreal winter. The results showed that a low value of the mean Tbb accompanied a high value of the Tbb standard deviation in the Maritime Con-tinent during boreal winter. Over large islands, the total variance of cloud fluctuation was primarily contributed from the diurnal variation with only a minor contribution from the variations with a time scale longer than one day. Over the oceans, on the other hand, the diurnal variation had an insignificant contribution to the total variance of cloud fluctuations. We can conclude that the local thermodynamic effect is the domi-nating factor causing cloud variations over island. The large scale atmospheric distur-bances have a large impact on cloud variations over oceans but not over islands.
The results also showed that the diurnal variation of clouds is enhanced during the active phase periods, and the diurnal phase is only related to the local dynamic process but not related to the intensity of large-scale convection over both islands and oceans. During the active phase, the diurnal amplitude is much amplified over oceans than that over lands.
The diurnal variation of clouds over the land region is mainly due to local thermo-dynamic response to the solar heating cycle. Over the oceans, three types of mecha-nisms could be separated. Over the convective ocean, it could be suggested that ther-modynamic response contributes to the maximum cloudiness in the afternoon. Over non-convective oceans, the radiation cooling could be the reason for the maximum cloudiness during night time. Over the oceans adjacent to lands, the diurnal variation of clouds is highly influenced by land effect resulting in a phase propagating to several hundred kilometers oceans from lands.
| Identifer | oai:union.ndltd.org:TW/095NTU05022008 |
| Date | January 2007 |
| Creators | Hui-Wen Chuang, 莊蕙文 |
| Contributors | 柯文雄, 周明達 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | en_US |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 64 |
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