重庆市1961-2010年≥10℃积温的时空变化和对农作物生产的影响

On Spatio-Temporal Changes of Accumulated Temperature Greater than or Equal to 10 Degrees Centigrade in Chongqing and Their Effects on Crop Production from 1961 to 2010

基于重庆市34个气象站点1961-2010年的气象资料、DEM以及农业统计年鉴,本文首先利用回归分析法计算重庆地区积温与高程的关系模型;其次结合GIS技术对积温进行地形校正,得到重庆市以10年为尺度的积温栅格面;再对其进行空间分析和统计分析,研究它近50年的变化特征并分析其对农作物生产的影响.结果表明：1重庆市≥10℃平均积温值经历了先降后升的过程,其中上世纪80年代最低,21世纪第一个10年最高;≥10℃积温分布以积温段ⅳ（4 000~5 000℃）、积温段ⅴ（〉5 000℃）为主,二者所占面积比例之和约为75%;积温段ⅱ（2 000~3 000℃）、ⅲ（3 000~4 000℃）、ⅳ（4 000~5 000℃）的面积总体上呈现先增加后降低的趋势;积温段ⅰ（≤2 000℃）变化复杂;2各年代的积温空间演变均以无变化区所占面积比例最大;上世纪60到70、80到90年代的积温段变化单一,其他各年代间积温段的变化较复杂;3上世纪80年代后,随着积温的升高,稻谷等作物的种植面积缩小,而稻谷、油菜等作物单产增加,但农用化肥施用量和农药施用量也随之增加.

With regression analysis,relational models of accumulated temperature and elevation in Chongqing region has been deduced based on the data of mean daily air temperature recoded in 34 meteorological stations in Chongqing from 1961 to 2010,the digital elevation model of Chongqing and Chongqing Agricultural Statistical Annual.Then,accumulated temperature grid surfaces for 10 years scale of Chongqing have been achieved with the GIS technology to emendate accumulated temperature according to terrain.Finally,spatial analysis and statistical analysis of the accumulated temperature grid surfaces have been made to study their variation characteristics during recent 50 years and analyze their impact on crop production.The results showed that 1）the average value of≥10℃accumulated temperature of Chongqing experienced an earlier decreasing and later raising process in which the lowest value occurred in the 1980 s and highest in the first decade of the 21 st century.The accumulated temperature segment iv and v,which totally accounted for about 75% were the main proportion of the distribution of the ≥10℃ accumulated temperature.The total areas of accumulated temperature segment ii,iii and iv showed a trend of decrease after increase.Nevertheless,the accumulated temperature segment i changed in complex.2）the unchanged areas of accumulated temperature spatial evolution of each decade occupied the largest ratio.From1960 sto 1970sand 1980 sto 1990sin the last century,the accumulated temperature segments changed in a single,but the accumulated temperature segments between the other years changed more complicatedly.3）after the 1980 s,with the rise of accumulated temperature,yields of rice,rapeseed and other crops increased despite though the area of rice and other crops had been reduced.Meanwhile,the application amount of agricultural fertilizer and pesticides had been increased as well.