Studies On Changes And Cause Of The Minimum Air Temperature In Songnen Plain Of China During 1961～2010

For studing impact of land use change on minmum temperature in the Songnen Plain of China, with Observed minimum air temperature and Reanalysis minimum air temperature(NCEP-R1) in 1961-2010, nighttime land surface temperature of MOD11A2 in 2000-2010 and land use of 1960,1990,2010, use climate tendency, Observation Minus Reanalysis(OMR) and spatial analysis methods, in recent 50 a. The results show us:1. From 1961 to 2010, Songnen Plain Land Use Change Characteristics of mainly arable land, construction land, unused land, woodland, grassland and water area reduce. Among them, the cultivated land area increased by 25181.3 km2; unused land, construction land and forest land were increased by 17998.7 km2, 10345.3 km2, 5574.6 km2. Unused land and construction land area is the fastest growth rate, respectively 22 times and 9 times in 1960, followed by arable land. The water area decreased by 35921.3 km2, The grassland area decreased by 22694.1 km2, the reduction rate was faster than that of grassland waters. It remains the same land use types, the largest area of cultivated land, forest, grassland, water, construction land, unused land.2. During 1961-2010, with the land use change in the Songnen Plain, the maximum air temperature and diurnal temperature range trend has decreased, the minimum air temperature trend has increased, and impact of land use change on minimum air temperature trend is greater than maximum air temperature trend. It can be seen that the impact of land use change on the maximum temperature is not high; it is the most important reason for the lowest temperature rise; the main reason for the decrease of the temperature day is the change of land use.3. Effects of land use change on the minimum temperature of the results are as follows: unused land>water>grassland>built up>agricultural land>Forestland. Unused land other types of land use is high, when other types of land use into unused land, will lead to the lowest temperatures, When other types of land use into farmland or woodland, will lead to the lowest temperature decreased, the non forest land into woodland decreased most minimum temperature. Analysis of the reasons may be affected by the albedo rate and thermal conductivity.4. Obtained by the analysis of Songnen Plain in different land use types of night ground temperature, the minimum ground temperature, the effects of land use change of minimum temperature, night ground temperature and the minimum ground temperature results are basically the same. In continuous unused land under the influence of temperature warming up, cultivated land, forest land than other land use types of low, woodland manifestation is the lowest; other types of land turned into unused land the lowest temperatures, and turned into agricultural land, Forestland is cooling.