武汉、宜昌20世纪平均气温突变的诊断分析

THE DIAGNOSIS AND ANALYSIS OF ABRUPT CHANGES IN THE MEAN TEMPERATURE DURING THE 20 th CENTURY IN WUHAN AND YICHANG

:同时利用信噪比法(YA法)、累积距平(CA法)、移动T检验(MTT法)对武汉1905～1997年、宜昌1924～1997年年、季、月平均气温序列诊断分析后发现:1)YA法(时段m≥10年)最严格,MTT法在m≤10时与之相当,CA法对月的突变可提供较多背景信息;2)两地20年代初有一次短期升温突变(m=5),40年代末有一次时段较长的较强降温突变,后者4季均有正贡献尤以春夏季最大,宜昌在20～60年代有多次短期突变,其中1967年有降温突变,此后相对平静,武汉则在1986/1987年冬有升温突变,宜昌的冬暖迟于、弱于武汉,从而使20～40年代同为两地本世纪最热的3个年代,宜昌自50年代至今仍为负距平,武汉90年代才转为正距平;3)CA法指出冬、春季的许多月份在70～90年代有升温突变的可能,年值则未达YA、MTT法突变标准,这一趋势值得注意。

The abrupt changes in yearly,seasonal and monthly mean temperatures (T) during 1905～1997 in Wuhan and during 1924～1997 in Yichang were diagnosed using three methods.The results show:(1) YA method is the strictest,which is matched by MTT method when the period m≤10 a and CA method can supply more information about the abrupt change of monthly T; (2) there are a brief heating abrupt (m=5) in the early 20th century and a long time decreasing abrupt in late 40's in Wuhan and Yichang, T in Yichang changed frequently from 20's to 60's and calmed down later,T in winter abrupted increasingly in 1986/1987 in Wuhan,warm winter came later than that in Wuhan;(3) T in many months in winter and spring abrupted increasingly in recent years in Wuhan that may lead to increasing abrupt of yearly T in late 90's.