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利用2006年7~8月的NOAA/AVHRR数据,依据温度植被干旱指数(TVDI)对2006年四川伏旱进行监测与评估。采用了干旱监测合成滤云新技术,分析了Ts—NDVI特征空间属性和TVDI指数干旱监测能力,提出了四川伏旱TVDI计算模型、分级标准、和影响评估方法,结果表明:1)按最大地表温度原则得到的旬合成数据比按最大植被指数原则得到的旬合成数据具有更强的旱情监测能力;2)在Ts—NDVI特征空间中当NDVI较小时干湿边几乎同为水平直线,两者相差约45℃;3)TVDI指数因其大小不同而对旱情的监测能力也不一样,较小时说明没有干旱发生,较大时则一定有干旱发生,中间段对干旱的监测具有不确定性;4)2006年四川伏旱遥感监测与气候监测结果基本一致,农作物受旱面积与饮水困难人口数估算误差在10%以内。
Based on the NOAA / AVHRR data from July to August in 2006, the 2006 drought monitoring and assessment in Sichuan Province was conducted based on the temperature and vegetation index of drought (TVDI). A new technology of drought monitoring and synthesis filter was adopted. Characteristics of Ts-NDVI feature space and TVDI index drought monitoring capability were analyzed. TVDI calculation model, classification criteria and impact assessment method were proposed. The results show that: 1) According to the maximum surface temperature Compared with the ten-day synthesized data obtained from the principle of maximum vegetation index, the ten-day synthetic data obtained by the principle has stronger drought monitoring ability; 2) When the NDVI is small in the Ts-NDVI characteristic space, the wet and dry edges are almost the same as the horizontal straight line, About 45 ℃; 3) The TVDI index has different ability to monitor the drought due to its different size. When it is smaller, it shows that no drought occurs, when larger, it must have a drought and the middle section has the uncertainty of monitoring the drought. 4 ) In 2006, the remote sensing monitoring of drought-induced drought in Sichuan was basically consistent with the results of climate monitoring. The estimation error of the area of drought-affected crops and water-stressed people was less than 10%.