地表温度-植被指数特征空间干旱监测方法的改进

    Improvement of Ts-NDVI space method in drought monitoring

    • 摘要: Ts-NDVI特征空间干旱监测方法易受地表及卫星观测状态的影响,干、湿边不稳定,该文提出了用多年同期卫星观测数据改进的方法,首先,针对某观测期,分别构建每年的仅基于当年卫星数据的单一时段特征空间,然后,分别用最大、最小值合成法,在已构建的各年单一时段特征空间的干、湿边中提取不同植被指数应对的最大、最小地表温度,合成各年通用的Ts-NDVI特征空间的干、湿边。用TERRA-MODIS数据、降水量及SPI进行试验和验证,表明该改进方法不改变像素的实际观测值,不依赖地面辅助数据,增强了Ts-NDVI特征空间的稳定性,比改进前特征空间能更准确的反映地表干湿状态,与监测同期及前期总体降水都密切相关。

       

      Abstract: In order to improve the instability of dry and wet edges of Ts-NDVI space in drought monitoring, a general Ts-NDVI space method was presented in the paper. Firstly, the single Ts-NDVI space of every year was constructed separately. Then the maximum and minimum temperatures were extracted respectively from the dry and wet edges of the single spaces to combine the general space suitable to all years. The experiment and validation were conducted with MODIS data, precipitation and SPI. The results show that the general space without changing the actual observation of every pixel is free from the any in-situ ancillary data. The general space method improves the stability of Ts-NDVI space, and can give more accurate surface moisture information than the primary single space. The general space is not only related to the recent rainfall but also related to the past cumulative rainfall.

       

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