Evaluation of two satellite-based products against ground-based observation for drought analysis in the southern part of
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Evaluation of two satellite‑based products against ground‑based observation for drought analysis in the southern part of Iran Seyedeh Mahboobeh Jafari1 · Mohammad Reza Nikoo2 · Maryam Dehghani2 · Mohammadali Alijanian3 Received: 17 February 2018 / Accepted: 23 April 2020 © Springer Nature B.V. 2020
Abstract Water stress or more specifically drought assessment plays a key role in water management, especially in extreme climate conditions. Basically, globally gridded satellite-based precipitation products are potential sources of data as alternatives for ground-based measurements. However, for a reliable application, they should be evaluated in different regions. In this paper, two satellite-based rainfall products, namely Modern-Era Retrospective Analysis for Research and Applications (MERRA)-Land and Global Land Data Assimilation System-2 (GLDAS-2), have been evaluated against ground-based observations in terms of precipitation and their application for drought analysis. At first, the coarse-resolution MERRA-Land is downscaled to the finer resolution of interest for better comparison. After comparison of these datasets against ground-based observations in terms of precipitation, it is concluded that MERRA-Land can better estimate precipitation. Then, the nonparametric SPIs at various timescales are derived to analyze how well MERRA-Land performs in drought monitoring. Different categorical and statistical error indices are used to assess the efficiency of MERRA-Land in capturing drought events. The results revealed that the downscaled MERRA-Land data can properly detect short-term and mid-term drought events known as agricultural and meteorological droughts throughout the study area, respectively. In addition, drought maps show that the majority of lands experience midterm scale drought which are in agreement with ground-based observations. The methodology adopted in this study can be applied in areas lacking in rain-gauge stations which significantly extend current capabilities for drought monitoring and early warning systems. Keywords Drought · Satellite-based product · Downscaling · MERRA-Land · GLDAS-2 · Iran
* Mohammad Reza Nikoo [email protected] Extended author information available on the last page of the article
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Natural Hazards
1 Introduction Drought is a natural inevitable phenomenon that can occur anywhere regardless of its climate. Its impacts, however, are highly variable from one region to another. In contrast to other natural hazards such as earthquake which is constrained both in terms of duration and area, drought is a slow and complex process with serious consequences even at global scale. For instance, the 2010 Russian drought and heat wave resulted in an increase in global food prices (Wegren 2011). Droughts are broadly classified into four groups including meteorological droughts, considering deficit in precipitation; hydrological droughts, considering deficit in water storage volume; agricultural droughts, considering deficit in soil moisture; and socioeconom
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