Based on the temperature indices established by expert group on the detection,monitoring and indices of climate change,spatial characteristics of temperature indices from 278 meteorological stations in China during 1961-2008 were studied.The results showed that day number of freezing point went down gradually from northwest to southeast,as well as the most regions of China.Day number of summer was mostly over 50 d in China and over 100 d in Eastern China except for the most part of Northeast China,while there was an increase trend in the most regions of China.Growth period was generally above 150 d in China and increased with the decrease of latitude from north to south,while the trend coefficient of growth period in 236 stations was positive.
Based on the summer precipitation data from 53 stations in Liaoning Province and sea surface temperature(SST) data of Hadley Center in 1961-2009,the decadal variation of the relationship between summer precipitation and SST over Nino3 oceanic regions in the previous autumn was studied.The results showed that their correlation was decreased obviously in recent 30 years.In 1961-1974,summer rainfall could be forecasted according to the SST anomaly over Nino3 oceanic regions in the previous autumn,and there were above 25 stations with the sign accuracy of over 66.7%.However,there were only five stations with the same accuracy during 1980-2009.From 1961 to 1974,25 stations showed block distribution in the central and northeastern Liaoning,but the distribution of five stations was spotty in 1980-2009.Before the middle and latter half of the 1970s,Liaoning had more(less) summer rainfall when SST over the equatorial central and eastern Pacific was higher(lower) in the previous autumn.However,it was difficult to build indicative relationship above since 1980s.
By means of SNHT,cumulative-departure and rank test,the homogeneity test of annual mean temperature series from 48 stations in Liaoning Province from 1961 to 2008 was carried out,and the reasons for heterogencity formation were analyzed combining with the historical evolution data of these stations.The results showed that all of the three methods were valid for the heterogencity test of temperature series,and there was certain complement between rank test and SNHT test.Station relocation was the main reason for temperature heterogencity,and heterogencity breakpoint mainly appeared in 1970s.
