Evaluation of precipitation datasets against local observations in southwestern Iran. (5th January 2020)

• Record Type: Journal Article
• Authors: Fallah, Ali; Rakhshandehroo, Gholam Reza; Berg, Peter; O, Sungmin; Orth, Rene
• Is Part Of: International journal of climatology. Volume 40:Number 9(2020)
• Page Start: 4102
• Page End: 4116
• Publication Date: 2020-01-05
• Subjects: evaluation -- interpolated dataset -- Karun basin -- precipitation datasets -- reanalysis dataset -- satellite rainfall estimate; Climatology -- Periodicals; Climat -- Périodiques; Climatologie -- Périodiques; 551.605
• DOI: 10.1002/joc.6445
• Languages: English
• ISSNs: 0899-8418

Abstract

Abstract: This study provides a comprehensive evaluation of a great variety of state‐of‐the‐art precipitation datasets against gauge observations over the Karun basin in southwestern Iran. In particular, we consider (a) gauge‐interpolated datasets (GPCCv8, CRU TS4.01, PREC/L, and CPC‐Unified), (b) multi‐source products (PERSIANN‐CDR, CHIRPS2.0, MSWEP V2, HydroGFD2.0, and SM2RAIN‐CCI), and (c) reanalyses (ERA‐Interim, ERA5, CFSR, and JRA‐55). The spatiotemporal performance of each product is evaluated against monthly precipitation observations from 155 gauges distributed across the basin during the period 2000–2015. This way, we find that overall the GPCCv8 dataset agrees best with the measurements. Most datasets show significant underestimations, which are largest for the interpolated datasets. These underestimations are usually smallest at low altitudes and increase towards more mountainous areas, although there is large spread across the products. Interestingly, no overall performance difference can be found between precipitation datasets for which gauge observations from Karun basin were used, versus products that were derived without these measurements, except in the case of GPCCv8. In general, our findings highlight remarkable differences between state‐of‐the‐art precipitation products over regions with comparatively sparse gauge density, such as Iran. Revealing the best‐performing datasets and their remaining weaknesses, we provide guidance for monitoring and modelling applications which rely on high‐quality precipitation input. Abstract : Topographical map of the Karun basin in Iran. The location of precipitation gauge stations utilized in this study is marked with purple diamonds and triangles (synoptic stations).