基于空间信息的农业干旱综合监测模型及其应用

为提高农业干旱监测的准确性,采用遥感信息与地面气象观测数据相结合的方法进行农业干旱监测研究。选择适合高植被覆盖区旱情监测的标准化植被供水指数及适合热带气候区旱情监测的综合降水指数作为参数,通过与同步实测土壤含水量的数据融合构建了海南岛农业干旱综合指数模型。经检验,模型的均方根误差RMSE为4.65%,相对均方根误差RMSEr为19.28%,模型具有较高的精度,可以用来监测海南岛的农业干旱。应用模型对2004年10月至2005年1月海南岛农业干旱进行了监测。结果表明,海南岛旱情西部重于东部、北部重于南部、四周平原重于中部山区。2004年10月上旬起旱情持续加重,12月上旬达到旱情高峰,12月中旬旱情略有缓解,但直至监测末期2005年1月下旬旱情依然严重。旱情最严重的时段(2004年12月上旬),海南岛干旱影响范围广,水田和旱地的重旱面积比例分别为59%和61%,其他林地的重旱面积比例也达到了20%。监测期内,海南岛作物生长过程受到明显抑制,干旱造成NDVI累积值较上一生长季同期下降6.34%,2004年10月至12月海南岛天然橡胶减产约1.16万t。该文为农业干旱监测提供参考。

Comprehensive monitoring model for agricultural drought and its application based on spatial information

To improve the accuracy of the agricultural drought monitoring, the comprehensive monitoring model coupled with the remote sensing data and meteorological data was used. This model was established based on the relationship between the standardization vegetation supply water index (VSWIS), the comprehensive precipitation index (CPI) and the synchronous soil moisture data measured in the study area. The VSWIS was suitable for monitoring drought at high density vegetation area, and the CPI was suitable for monitoring drought at tropical area. The root mean square error (RMSE) of the model was 4.65% and the relative root mean square error (RMSEr) was 19.28%. Furthermore, the model was used to evaluate the change of the agricultural drought in Hainan island from October 2004 to January 2005. The results indicated that the drought in the study area were significantly different. Overall, the drought in the west and north were more serious than that in the east and south of the island respectively, and the drought in the plain was more serious than that in the mountain area. In terms of the time changes, the drought approached maximum in early December 2004. Until late January 2005, the drought was still serious. The heavy drought area of paddy, upland and special woodland accounted for 59%, 61% and 20% respectively. Crop growing was constrained obviously by this drought. Compared with last year, the value of the accumulated normalized difference vegetation index (NDVI) was reduced by 6.34%, and yield of the natural rubber was reduced about 1.16×104t from October to December in 2004. The research provides a reference for monitoring agricultural drought.