摘要
為了建立台灣春雨長期預報的基礎，研究春雨的年際變化。我們分析台灣春雨在時間和空間分佈的特徵，並以台灣地區二、三、四月的多雨年（溼年）和少雨年（乾年）為準，分析多雨年和少雨年的北半球500毫巴高度場以及全球海面溫度場。台灣的春雨在空間分佈上較為均勻，而在不同的月份則相關並不顯著。二月乾年綜觀環流場的特徵為亞洲高緯度地區為負距平而中緯度和副熱帶地區為正距平，溼年則相反。三月乾年綜觀環流場的特徵為亞洲向東延伸到北美洲高緯度地區為負距平而中緯度和副熱帶地區為正距平，溼年則相反。四月乾年之主要特徵為中亞到阿拉斯加地區高緯度帶為負距平，而亞洲的副熱帶和熱帶地區為正距平。多雨年則從中亞北部向東南延伸到東亞地區為負距平。以傅氏轉換分析高度場在波數域的特徵，結果發現，能分辨台灣春季乾溼年500毫巴環流特徵的主要在中高緯度平均緯流和超長波，特別是波數1、2和3。二月和三月乾年的海面溫度分佈主要的特徵是北半球多為正距平而南半球多為負距平，從印度洋往東延伸的負距平區延伸到台灣附近海面。四月的乾年北半球多為正值區，南半球除10°S以北的太平洋外，皆為負值區。這些現象的出現，都可以回溯好幾個月，且乾溼年大致相反。由此推論，台灣春季降水的年際變化是全球氣候系統變化的一部份。海面溫度由於有相當的延續性，所以可能成為台灣春雨預報的一領先指標。
並列摘要
In order to build up the basis of the long-range forecasting of the spiring rainfall in Taiwan area, the interannual variability of the rainfall is studied. The characteristics of the spatial and temporal distribution of the rainfall have been examined. Furthermore, Northern hemispheric 500mb geopotential height and global sea surface temperature have been studied with referring to the abundant and deficit rainfall months of February, March and April in the Western Taiwan.The monthly rainfall in Taiwan area is much homogeneously distributed over areas. However, the correlations among the rainfall in the individual month is not significant. The general characteristics of the 500mb geopotential height in the Dry February is that negative anomalies appear in the high latitudes in Asia while positive anomalies appear in the mid-latitude and the Tropical area. Those in a dry March are that negative anomalies extend from Asia to North America in the high latitude while positive anomalics appear in the mid-latitudes and the subtropics. The jataposition of the positive and negative anomalies is reversed in the wet years. The main feature of dry April is that negative anomalies stride over the high latitudes from Mid-Asia to Alaska while positive anomalies appear in the subtropics and tropics. Those in a wet year are negative anomalies appear in the area extend from northern Mid-Asia southeastward to Eastasia.The characteristics of the geopotential height in the wave number domain is studied with applying Fourier transformation. It is shown that the features on the 500mb can heroed the dry and wet of the Spring in the Taiwan area are the mean zonal circulation and extra-long waves, especially those of wave number 1, 2, and 3 in the middle and high latitudes.The main feature of the global SST in the Dry February and March are that anomal in the most of the Northern hemisphere are positive while those of the most of the Southern hemisphere are negative. Negative anomalies extended from the Indian Ocean eastward to the viciuity of the Taiwan. In a dry April, positive anomalies appear in the most of the Northern hemisphere while the negative anomalies appear in the most of the Southern hemisphere except those of the area 10S northward in the Pacific Ocean. Those sympotom can be traced back some months, and they are opposive in the wet and dry years. It is implied that the interannual variability of the Spring rainfall in the Taiwan area is a component of the variations in the global climate system. Due to its persistency, the SST could be a plannsible predictor of the Spring rainfall in the Taiwan area.