| Summary: | 碩士 === 國立臺灣海洋大學 === 海洋科學系 === 93 === The purpose of this thesis is to apply air temperature from observatory of the Central Weather Bureau (CWB) and the Pathfinder sea surface temperature (SST) data derived from the 5-channel Advanced Very High Resolution Radiometer (AVHRR) on board the National Oceanic and Atmospheric Administration (NOAA) polar orbiting satellites at Tamsui to study local climate change. The air temperature trend at Tamsui between 1982 and 2003 is 0.03 °C/year by using linear regression method. The air temperature is strongly influenced by El Niño events and the most important is that peak values of the yearly mean air temperature are during El Niño events. By using linear regression method, the SST trend is 0.073 °C/year that is larger than the air temperature trend. Our results demonstrate that the air temperature and SST are in warming trend during past 20 years, especially high SST warming trend in spring and winter. The air temperature trend is slightly affected by seasonal variation and the SST trend is warmer than the air temperature trend.
From the results of temperature data set extracted by the Empirical Mode Decomposition (EMD) method, the air temperature and SST at Tamsui are not only influenced by annual cycle, but also by equatorial stratospheric wind for a quasi-biennial oscillation (QBO) (28-month period), a ENSO-like signal (3 to 7-year period) and one of the sunspot cycles (11-year period). Because the enormous heat capacity of the ocean, the mean temperature change of ocean is smaller than that of atmosphere, the oscillation of annual SST variation is smaller than air temperature variation. Thus, high correlations are between temperature variation and the sunspot number. With a phase lag, the correlation between SST and the sunspot number is smaller than that between the air temperature and the sunspot number. The solar radiation directly influences the air temperature, so that the change of air temperature is quick. However, the change of SST is slow because of enormous specific heat.
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