ABSTRACT: We present a new, modified version of the reconnaissance drought index (RDI), named the N-RDI. To calculate the N-RDI, precipitation and potential evapotranspiration (PET) were replaced with spatially normalized precipitation and PET. To assess the capability of N-RDI, the RDI and N-RDI were computed at monthly, seasonal, and annual time scales over Iran based on a climatic data series of 12 stations from 1967-2019. Interpolated maps of the RDI, N-RDI, and annual yield of rain-fed winter wheat were then prepared using the inverse distance weighting method. Four regions in Iran (with different climate conditions) were then selected, and 30 random points were chosen in each area. Finally, the capabilities of N-RDI and RDI were compared based on the correlation coefficient (CC) between the difference in the mean rain-fed winter wheat yield (DMRWWY) and the difference in the average RDI (Da-RDI) and the average N-RDI (Da-N-RDI) at selected points, in different regions at different time scales. The CCs were higher between DMRWWY and Da-N-RDI than between DMRWWY and Da-RDI in humid (H) and semi-arid (SA) regions, in H and hyper-arid (HA), in SA and arid (A), in SA and HA, and in A and HA regions in 88.23% of selected periods. Moreover, CCs were greater between DMRWWY and Da-N-RDI than between DMRWWY and Da-RDI in H and A regions in 76.47% of selected periods. The results showed that the capability of the N-RDI for assessing drought in large basins is greater than that of the RDI.

中文翻译：

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新版勘察干旱指数 N-RDI

摘要：我们提出了一个新的修改版本的勘察干旱指数 (RDI)，名为 N-RDI。为了计算 N-RDI，降水量和潜在蒸散量 (PET) 被空间归一化降水量和 PET 取代。为了评估 N-RDI 的能力，根据 1967-2019 年 12 个站点的气候数据系列，在伊朗的月度、季节和年度时间尺度上计算了 RDI 和 N-RDI。然后使用反距离加权法绘制雨养冬小麦的 RDI、N-RDI 和年产量的插值图。然后选择了伊朗的四个地区（气候条件不同），每个地区随机选择了 30 个点。最后，N-RDI 和 RDI 的能力是根据平均雨养冬小麦产量差异 (DMRWWY) 与平均 RDI (Da-RDI) 和平均 N- RDI (Da-N-RDI) 在不同时间尺度的不同区域的选定点。DMRWWY 和 Da-N-RDI 之间的 CC 在潮湿 (H) 和半干旱 (SA) 地区、H 和超干旱 (HA)、SA 和干旱 (A) 中高于 DMRWWY 和 Da-RDI 之间，在 SA 和 HA，以及在 88.23% 的选定时期内的 A 和 HA 区域。此外，在选定时期的 76.47% 中，在 H 和 A 区域，DMRWWY 和 Da-N-RDI 之间的 CC 大于 DMRWWY 和 Da-RDI 之间的 CC。结果表明，N-RDI评估大流域干旱的能力优于RDI。