Evaluation of the ERA5 reanalysis as a potential reference dataset for hydrological modelling over North America

Abstract

Abstract. The European Centre for Medium-Range Weather Forecasts (ECMWF) recently released its most advanced reanalysis product, the ERA5 dataset. It was designed and generated with methods giving it multiple advantages over the previous release, the ERA-Interim reanalysis product. Notably, it has a finer spatial resolution, is archived at the hourly time step, uses a more advanced assimilation system and includes more sources of data. This paper aims to evaluate the ERA5 reanalysis as a potential reference dataset for hydrological modelling by considering the ERA5 precipitation and temperatures as proxies for observations in the hydrological modelling process, using two lumped hydrological models over 3138 North American catchments. This study shows that ERA5-based hydrological modelling performance is equivalent to using observations over most of North America, with the exception of the eastern half of the US, where observations lead to consistently better performance. ERA5 temperature and precipitation biases are consistently reduced compared to ERA-Interim and systematically more accurate for hydrological modelling. Differences between ERA5, ERA-Interim and observation datasets are mostly linked to precipitation, as temperature only marginally influences the hydrological simulation outcomes.

Did ERA5 Improve Temperature and Precipitation Reanalysis over East Africa?

“…Our analysis for near-surface temperature and precipitation data in Africa showed substantial changes with the introduction of the new reanalysis product. ERA5 data were generally closer to observations than ERA-interim, which agrees with findings of studies on other aspects of the datasets [34][35][36][37].…”

“…In particular in lesser developed countries, the ease of access plays an important role when choosing suitable climate data. ERA5 underwent some substantial changes in the assimilation system in terms of the model as well as the included observation data from its predecessor ERA-interim, and first evaluation studies have shown its improvements in terms of surface energy fluxes [34], surface irradiance [35], and surface climate in North America [36,37]. These results are encouraging, suggesting that also the African climate representation may have improved in ERA5 reanalysis.…”

Global BROOK90 R Package: An Automatic Framework to Simulate the Water Balance at Any Location

“…Moreover, there are issues with the meteorological forcing dataset that should be considered. At present, with its long time-series, good spatiotemporal resolution, and large number of parameters available [99], ERA5 is one of the best and complete global-gridded reanalysis meteorological datasets [34,[100][101][102][103]. However, its derived precipitation is still far from "state-of-the-art" conditions [104][105][106][107].…”

“…The biggest limitations of the dataset are the server restrictions: data retrieval per request is limited to a maximum of 120,000 items (~13 years for five variables) and download speed is strongly affected by the query length of other users' requests. Developers and researchers claim a high quality of the data with regard to a global coverage and the temporal resolution [32][33][34][35][36]. The uncertainty of the dataset can be estimated by the analysis of 10 reanalysis ensemble members, while in the package presented the mean reanalysis output is used.…”

Revisiting global vegetation controls using multi-layer soil moisture

“…This way, distinguishing shallow and deep SM is expected to allow for a more accurate identification of global vegetation controls as the accessibility and availability of water for plants varies in space and time. For this purpose, the state-of-the-art ERA5 reanalysis provides SM estimates from multiple layers (Hersbach et al 2019;Jing et al, 2018), and has been successfully applied in hydro-meteorological studies (Jing et al, 2018;Tarek et al, 2020;.…”