基于SPOTNDVI的陕西省耕地复种指数时空变化

The Monitoring for cropping index of arable land in northwest region using SPOTNDVI-A case of Shaanxi Province

复种指数是反映农业生产的一个非常重要信息,准确监测中国耕地复种指数的分布和变化,对于充分挖掘土地资源和气候资源的潜力,以及对准确估测粮食总产具有十分重要的意义。文中采用数据为2000年1月至2007年12月的SPOT-VEGETATION逐旬NDVI数据。结合1∶25万陕西省土地利用现状图,设计一次差分的算法进行VC编程,对陕西省2000-2007连续8年各市县复种指数进行监测。结果表明:复种指数的区域差异还是很明显的。陕北黄土高原西北地区长城沿线区、陕北丘陵区北部地区复种指数小于100%。陕北丘陵区中南部、渭北高原区、关中平原区复种指数多为100%-150%。秦岭山区和汉中盆地、巴山山区复种指数大于150%。可以看出陕西省复种指数多集中在一年一熟或两熟。八年来各地区的复种指数都有不同程度的升高,但每个区域内同时存在复种指数升高和降低的地区。陕北丘陵区、关中地区和汉中盆地复种指数变化的空间格局与地形关系密切,一般而言,陕北丘陵区、关中地区北部的丘陵山地,秦岭和巴山的复种指数变化较大,地势平坦的关中平原和汉中平原地区复种指数增加。

Cropping index is a very important information of agriculture.Monitoring the distribution and changes of it accurately in China is useful to exploit the potential of land climatic resources,as well as reflect great significance to estimation of total grain production accurately.The SPOT-VEGETATION ten days NDVI data from January in 2000 to December in 2007 was used,combined with the 1∶ 250000 land-use maps of Shaanxi Province,we desiged a VC program using differential algorithm to monitor the cropping index of Shaanxi Province＇s cities and counties from 2000 to 2007.The results showed the cropping index is so different among the different districts.In the ares both along the Great Wall in Northwest China Loess Plateau and northern hilly the cropping index are less than 100%.The indexes for the most of areas in southern area of Shaanbei＇s Loess and Guanzhong Plain have reached 100%-150%.The indexes of Qinling mountains and the Hanzhong Basin,Bashan Mountains is greater than 150%.From the above saying we can get the conclusion that the crops were matured twice or once annual in Shaanxi Province.The cropping index of all the regions have increased since eight years ago,but every area also exists index lowered areas.The index changes of Hilly area in northern Shaanxi,Guanzhong region and Hanzhong basin are highly relate to the spatial pattern and terrain.Generally speaking,the cropping index of hilly area in northern Shaanxi,Qinling and Bashan mountains change greatly,the index changes of GuanzhongHanzhong Plain increase greatly.