Research Of Spatial And Temporal Character Of Precipitation And Drought And Waterlogging And Its Climate Changing

Climatic characteristics and long-term changes of rainfallintensity(total precipitation heavy rainfall day) have been researchedbased on the daily precipitation and related data at 160 stations between1951 and 2000 in China by using statistical diagnosis such as the trendcoefficient, similarity coefficient etc.. Spatial and temporal characterand climatic variety of rainstorm frequency and its correlation to theglobal warmer have been studied. Variety trend of seasonallycontinuous drought and waterlogging have been analyzed as well; thelong-term variability of precipitation in Xiamen city was analyzedexemplarily. It was found that:1) The rainfall intensity within China was high in summer, then springand fall, to winter, showing in a downward order. Either annual orseasonal precipitation is area related, decreasing gradually fromsoutheast to northwest, peaking at both middle-east parts of Jiang-nanand coastal areas of South China, and touching the valley at southeastpart of Xin-jiang province.2) Averaged annual and seasonal precipitations were all increasing overyears, wherein annual rainfall intensity and summer rainfall intensitywere significantly increasing. The long-term trend of rainfall intensitywas apparently area-dependent. Areal locations showing an upwardtrend of both seasonal and annual rainfall intensity outnumbered thosewith a downward trend, and locations with a significantly increasedprecipitation outnumbered those with a significantly decreasedprecipitation.3) Annual rainfall intensity and summer rainfall intensity had acatastrophe in 1989 and winter rainfall intensity in 1988.4) All around China, averaged air temperature and averaged rainfallintensity had similar monthly variation and spatial distribution, whichwere similar in annual variation and decadal variation and sharedidentical catastrophe points. So it is believed that annual rainfallintensity and annual air temperature had identical variation, and as theclimate is getting warmer, the rainfall intensity will increase in China.5) Annual rainfall intensity and annual air temperature have the samelong term change trend in most parts of China. The SVD analysisresults showed the rainfall intensity field is positive correlation with theannual air temperature field. 6) The distribution of annual heavy rainfall frequency in China showedthat: it was decreasing gradually from southeast to northwest,frequency of rainstorms of Jiang-nan and South China was more greatthan it in West China. And the most affected month was July. The orderof heavy rainfall frequency was the largest in summer, then spring andfall, lastly in winter. The averaged April-September heavy rainfall dayhad a peak area corresponding to the rain-band of the same months.And the shift of the peak area reflects three pauses and two jumpingnorth in China. 7) From 1955 to 2000, annual heavy rainfall daysignificantly increased, by 10.1 days every decade. Areal locationsshowing an increasing trend of annual heavy rainfall day outnumberedthose with a decreasing trend. And annual heavy rainfall day increaseddramatically in 1989.8) Annual averaged air temperature and averagedheavy rainfall day had similar patterns of monthly variation, annualvariation and decadal variation, and shared identical turning points. Soit is believed that annual heavy rainfall day and annual air temperaturehad a positive correlation, and as the climate is getting warmer, theprobability of rainfall will increase in China. 9) Annual heavy rainfallday and annual air temperature shared the same changing in most partsof China. As also shown by SVD analysis, there was a closerelationship between heavy rainfall day field and air temperature field.When air temperature was high in a large area, annual heavy rainfallday was high. 10) After defining seasonally continuous drought andseasonally continuous waterlogging and analyzing their changingtrends, it is found that summer-fall continuous drought had obviouslyincreased trend. 11) The rainfall of Xiamen in near 113a had increasedtrend and obviously phase character, and it had the variation of 7～8a,60-65a and nearly 17a.