当前世界环境

列城地区位于北纬32-36°和东经75-80°之间，海拔2500 - 6000米。列城是该国最大的地区，面积为45,100公里²。农业是这个地区农村人口的主要职业。对数据的初步分析显示，小麦种植面积从2003年开始增加。值得注意的是，大麦种植面积同时减少。值得注意的是，从2003年起，小麦作物取代了大麦作物。这种种植方式的变化与气候条件的变化有关。从2003年开始，5月份的月平均日最低气温从4°C上升到2007年的8°C。同样，2003年以前的月平均日最高气温较高(>20°C)，但2003 - 2009年的月平均日最高气温下降(15 - 20°C)。2003年以前5月降雪是常见现象，但2003 - 2009年没有降雪。因此，假设5月份最低和最高温度的增加使农民能够种植小麦而不是大麦。 Moreover, during the month of April, snowfall events were significantly reduced in 2003-2009 and in month of May snowfall events was not recorded at all. This may perhaps another reason which enabled farmers to sow the wheat crop during last week of April to mid of May. Interestingly during last two years, the cropping pattern is again reversed. The acreage under wheat crop was decreased and the acreage under barley increased. Such reversal may be due to re-occurrence of snowfall events during first two weeks of May, which was absent during 2003-2009. Therefore, it is quite apparent that weather condition influenced the cropping pattern and crop acreage. However, many other factors like timely availability of seed, quality of seeds as per need of local farmers as they prefer some straw producing varieties, crop rotation pattern, etc., also plays some role in shifting of cropping pattern. Long term data base on crop-weather relationship among with the other factors may help in developing crop weather modeling.