Research On The Climate Temporal And Spatial Variability Of Northeast China

According to daily temperature, precipitation and sunshine duration data over NortheastChina during1961-2010, the spatial and temporal characteristics of climate change, includingthe change trend, cycle and mutation of temperature, precipitation and sunshine duration,were analyzed using linear regression, wavelet analysis and the Mann-Kendall (MK) test,respectively. Moreover, the≥10°C accumulated temperature and wet and dry conditionswere also analyzed. The results show that:(1) There is a continuing increase trend of average annual temperature, with the value of0.36°C/10a. Meanwhile,5a,11a and more than30a cycles exist. The mutation of theaverage annual temperature occurs in1988, then it maintains a high warming trend.(2) Average annual precipitation steadily increases, with a trend of8.6mm/10a. There is along cycle of about30a, accompanied two short oscillating periods of13a and3a.Precipitation occurs without obvious mutations in the past50years.(3) Sunshine duration shows significant decrease trend of-35.8h/10a. The cycle ofsunshine duration is similar to that of average annual temperature, i.e., there are5a,11a andmore than30a cycles. The mutation occurs in1978, and then the sunshine duration showsobvious decrease trend.(4) The≥10°C accumulated temperature generally shows a rising trend of68.4°C/10a.The areas with high≥10°C accumulated temperature expand a little from south to north.(5) The wet and dry index shows relatively strong fluctuations, dry and wet conditions withthe stage and low-frequency variation.whereas it generally accompanies a non-significantincrease trend, climate tendency is0.3/10a.The moist district shows signs of expansion fromthe southeast to the northeast. Semi-arid area also extends from southwest to the centralregion.