松嫩平原2000—2012年生长季农作物含水量变化分析

The Analysis of Crop Water Content Change over the Songnen Plain in the Growing Season During the Period 2000-2012

利用2000—2012年松嫩平原MODIS影像,基于GVMI指数反演了松嫩平原生长季(5—10月)农作物含水量,并进行了时空变化特征及其原因分析。结果表明:松嫩平原2000—2012年生长季农作物含水量呈显著增长趋势,且东部农作物含水量普遍高于西部,大致呈由东南向西北递减的趋势;农作物含水量与降水量成正相关关系,但其显著性与地域有关,降水量较多的区域,降水量与农作物含水量相关不显著,降水量较少的区域,降水量与农作物含水量相关显著;农作物含水量与气温呈负相关趋势,但不显著,气温越高的区域对农作物含水量的影响越大;农作物含水量与粮食产量呈显著正相关,粮食产量随农作物含水量的升高而增大。

In the process of photosynthesis, water is one of the irreplaceable and indispensable raw materials. Crop water content is one of the main factors in plant photosynthesis, and has a great significance for the growth of crops. Remote sensing technology with the characteristics of rapid, economical and macroscopic changes provides an important real-time dynamic data source for crop water content monitoring. In this paper Moderate Resolution Imaging Spectroradiometer（MODIS） 500 m reflectance dataset is used for the retrieval of crop water content over Songnen Plain during the period 2000-2012. MODIS data have higher temporal resolution and larger spatial coverage. Global Vegetable Moisture Index（GVMI） has higher correlation and stability with vegetation water content to retrieval of crop water content of Songnen Plain in the growing season during the period 2000-2012, then the temporal and spatial change charactersics and the reasons were analyzed. The results showed that：（1） The crop water content of Songnen Plain during the period 2000-2012 showed a trend of significant growth. The crop water content of 2012 is the highest, while 2001 is the lowest. The crop water content changes with crop growth in the growing season： it＇s higher in July and August than other months. The crop water content has uneven distribution in Songnen Plain, the southeast is higher than others, and the west variable coefficient of crop water content is higher than the east. The crop water content of Songnen Plain shows that a trend of growth is mainly distributed in central, northwest and southeast areas.（2） Precipitation has a certain influence on crop water content of cities in Songnen Plain, and is quite regional. The crop water content of Qiqihaer, Daqing, Baicheng and Songyuan in the west Songnen Plain has a more significant correlation than the cities in the east, but the influence of precipitation change on crop water content in the same period is smaller.（3） The temperature effect on crop water content of cities in Songnen Plain has the latitude zonality. The temperature has a higher influence on Baicheng, Songyuan, Daqing, Changchun and Siping which have a lower latitude than Heihe, Qiqihaer, Suihua and Harbin with a higher latitude. The influence of temperature on crop water content in the same period is smaller.（4） The crop water content has a significant correlation with the grain yield of the cities in Songnen Plain as the grain yield increases according to crop water content.