Performance of the State-Of-The-Art Gridded Precipitation Products over Mountainous Terrain: A Regional Study over Austria

Abstract

During the last decade, satellite-based precipitation products have been believed to be a potential source for forcing inputs in hydro-meteorological and agricultural models, which are essential especially over the mountains area or in basins where ground gauges are generally sparse or nonexistent. This study comprehensively evaluates several newly released precipitation products, i.e., MSWEP-V2.2, IMERG-V05B, IMERG-V06A, IMERG-V05-RT, ERA5, and SM2RAIN-ASCAT, at daily and monthly time-scales over Austria. We show that all the examined products are able to reproduce the spatial precipitation distribution over the country. MSWEP, followed by IMERG-V05B and -V06A, show the strongest agreement with in situ observations and perform better than other products with respect to spatial patterns and statistical metrics. Both IMERG and ERA5 products seem to have systematic precipitation overestimation at the monthly time-scale. IMERG-V06A performs slightly better than IMERG-V05B. With respect to heavy precipitation (P > 10 mm/day), MSWEP compare to other products demonstrate advantages in detecting precipitation events with a higher spatial average of probability of detection (POD) and lower false alarm ratio (FAR) scores skill (0.74 and 0.28), while SM2RAIN and ERA5 reveal lower POD (0.35) and higher FAR (0.56) in this precipitation range in comparison with other products. However, the ERA5 and MSWEP indicate robust average POD and FAR values with respect to light/moderate precipitation (10 mm > P ≥ 0.1 mm) with 0.94 and 0.11, respectively. Such robustness of MSWEP may be rooted in applying the daily rain gauges in calibration processes. Moreover, although all products accurately map the spatial precipitation distribution they still have difficulty capturing the effects of topography on precipitation. The overall performance of the precipitation products was lower in the peripheries of the study area where most stations are situated in the mountainous area and was higher over the low altitude regions. However, according to our analysis of the considered products, MSWEP-V2.2, followed by IMERG-V06S and -V05B, are the most suitable for driving hydro-meteorological, agricultural, and other models over mountainous terrain.

Validation of GPM IMERG V05 and V06 Precipitation Products over Iran

“…4 and 5). The same results were reported by Sharifi et al (2018) andO et al (2017) over the northeast and southeastern Austria, respectively. This should be noted that the Global Precipitation Climatology Centre (GPCC) dataset is used for adjusting the IMERG final run.…”

“…POD ranges from 0 to 1 (the perfect score) and is utilized to estimate the hit rate. POD denotes the ratio of the number of precipitation events that are correctly detected by the SPPs to the total number of actual events (Sharifi et al 2018). FAR represents the fraction of falsely detected events (Xu et al 2017).…”

“…Although the IPP has been evaluated for many areas, at present, only a few studies have attempted to assess the reliability of IMERG products for Iran; one study compared IMERG, TMPA-3B42, and ERA-Interim precipitation products for four provinces in Iran from March 2014 to February 2015 (Sharifi et al 2016). The results showed that all products underestimated precipitation in the studied areas, but there was a slight underestimation for IMERG.…”

Assessment of Precipitation Estimation from the NWP Models and Satellite Products for the Spring 2019 Severe Floods in Iran

“…However, in terms of maximum precipitation, the UKMO overestimated, while the satellite and other models showed underestimation over the Karkheh Basin during the second flood event. This might be due to high moisture in the atmosphere and the occurrence of small scale precipitation systems that were dominant during this event [23]. Additionally, from the median and the 25th and 75th percentiles of the box-plots, one can infer that the precipitation estimated by IMERG, followed by ECMWF, was more accurate than the other products in both basins, while the UKMO whiskers extended to the highest extreme data points in comparison to the other products.…”

“…However, IMERG real-time V05 performed substantially better than TMPA-3B42-real-time V7 and ERA5-HRES, particularly, in regions dominated by convective storms. In another study, Sharifi et al [23] examined the accuracy of six SPEs and gridded precipitation models against a dense network of 872 stations over Austria, in terms of extreme events and different altitude categories. They also found that the latest version of IMERG-V06A performed better than the other products (except MSWEP-2.2), which was consistent with the study results by Beck et al [22].…”