Abstract The Brazilian state of Pernambuco has approximately 88% of its territory located in the semiarid region, suffering from the irregularities of precipitation and the phenomenon of droughts, which increases the need for constant monitoring of climatic events. This study consisted of estimating meteorological and agricultural drought for the study area with soil moisture data from the Soil Moisture and Ocean Salinity satellite and MODIS products, covering the period from 2010 to 2017 and considering three climatic regions in Pernambuco: Mata, Agreste and Sertao. This research was divided into two main phases: the first was to obtain drought indices calculated from the remote sensing information, with emphasis on producing the Soil Moisture Agricultural Drought Index (SMADI) that uses the soil moisture data in its calculation; the second phase was to correlate the response of the severity of SMADI and other indices with the results of productivity and harvested area for corn and sorghum crops, as obtained from official databases. The results found in the first phase of the study using the SMADI index obtained for the agricultural areas of the state showed long consecutive periods of drought, lasting longer than one year. The hydrological year from 2012 to 2013 presented the longest duration of the event for the Mata and Sertao regions, while for the Agreste the longest period was from 2016 to 2017. The correlations of corn production with the severity of the SMADI values were more significant than sorghum because corn is more sensitive to water stress. The study also concluded that the severity detected by SMADI correlated more significantly with sorghum culture than any of the other indices; that is, SMADI was more sensitive to identify water stress in this crop than the other indices used. The results demonstrated that SMADI can provide early warnings of drought impacts on rainfed agricultural systems and may serve to indicate the adoption of more resistant crops to water stress conditions.

中文翻译：

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用于农业干旱评估的土壤水分指数：SMADI 在巴西伯南布哥州的应用

摘要 巴西伯南布哥州约 88% 的领土位于半干旱地区，受降水不规律和干旱现象的影响，这增加了对气候事件的持续监测的需要。本研究包括利用来自土壤水分和海洋盐度卫星的土壤水分数据和 MODIS 产品估算研究区的气象和农业干旱，涵盖 2010 年至 2017 年期间，并考虑伯南布哥的三个气候区：马塔、阿格雷斯特和塞尔陶。本研究分为两个主要阶段：一是获取遥感信息计算的干旱指数，重点是生成土壤水分农业干旱指数（SMADI），利用土壤水分数据进行计算；第二阶段是将 SMADI 和其他指数的严重程度的反应与从官方数据库中获得的玉米和高粱作物的生产力和收获面积的结果相关联。使用该州农业区的 SMADI 指数在研究的第一阶段发现的结果显示，干旱持续时间很长，持续时间超过一年。2012-2013年水文年对Mata和Sertao地区事件持续时间最长，而在Agreste最长的时间是2016-2017年。玉米产量与SMADI值严重程度的相关性大于高粱，因为玉米对水分胁迫更敏感。该研究还得出结论，与任何其他指数相比，SMADI 检测到的严重程度与高粱培养的相关性更显着；也就是说，与其他使用的指数相比，SMADI 对识别该作物的水分胁迫更为敏感。结果表明，SMADI 可以提供干旱对雨养农业系统的影响的早期预警，并可能有助于表明采用对水分胁迫条件更具抗性的作物。