Characteristics of temperature and precipitation in Northeastern China from 1961 to 2005

Abstract

Northeastern China is one of the regions that would be mostly affected by the changing climates, and created the particular climate pattern and characteristics under climate changes. The pattern and characteristics of climate changes in Northeastern China was analyzed with the methods of the linear regression method, cumulative anomaly method, Mann-Kendall test method and Morlet wavelets analysis method based on daily average air temperature and daily precipitation data observed at 96 meteorological stations covered the Northeastern China from 1961 to 2005. The linear regression method was used to study the variation trends of mean temperature and precipitation on annual-scale and seasonal-scale in recent 45 years. The cumulative anomaly method and Mann-Kendall test method were used to test trends and abrupt changes of annual mean temperature and precipitation. The Morlet wavelet analysis method was used to detect the change interval of annual mean temperature and precipitation. The linear trend rates for annual and seasonal mean temperature and annual and seasonal precipitation were calculated at each meteorological station. Those rates were then interpolated using inverse distance weighted (IDW) interpolation to reveal their spatial distributions. The results showed that the climate in this region showed a significant warming trend, the annual mean temperature varied between 2. 45°C and 5. 72°C, and the annual mean temperature has increased by 0. 38°C/10 a (P<0. 01) in recent 45 years, and an abrupt change from low temperature to high temperature occurred in 1988-1989. In addition, all of the seasonal temperatures showed increasing trends, and the increase of temperature in winter were higher (0. 53°C/10 a) than in the summer (0. 24°C/10 a). The decade change of annual and seasonal mean temperature also showed spatially increasing trends and the higher the latitude, the more obvious the increasing trend. The calefactive range was larger in the northern Da Hinggan Mountains and Xiao Hinggan Mountains, and it was smaller in the Liaohe Plain, Liaodong Peninsula and southern Changbai Mountain. The annual precipitation varied between 430. 40 mm and 678. 72 mm,and the annual precipitation showed a decrease trend in recent 45 years, and decreased by 5. 71 mm/10 a (P >0. 05), the precipitation in 1980s was more than in the other decades, and the abrupt change in precipitation occurred during in 1982-1983. The seasonal precipitation showed various trends, the spring precipitation and winter precipitation showed increasing trend, but the summer precipitation and autumn precipitation showed decreasing trend. The Liaodong Peninsula and southern Changbai Mountain showed significantly decreasing trend in precipitation, whereas, the northern Da Hinggan Mountains and Songnen Plain showed obviously increasing trend. The climate change interval analysis revealed that the annual mean temperature fluctuated significantly with the interval of 11 years, 24 years and 6 years, and the annual mean precipitation fluctuated with interval of 16 years and 6 years, respectively. For this region, the climate was trended to be warmer and dryer in recent 45 years and the temperature and the precipitation showed different interval.