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Global Comparisons of ERA5 and the Operational HRES Tropospheric Delay and Water Vapor Products With GPS and MODIS

Lookup NU author(s): Chen YuORCiD, Professor Zhenhong Li, Professor Geoffrey Blewitt



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


© 2021. The Authors. Earth and Space Science published by Wiley Periodicals LLC on behalf of American Geophysical Union.Precipitable water vapor (PWV) from numerical weather models, such as the latest generation of European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis (ERA5) and the ECMWF High RESolution (HRES) models, are important to meteorological studies and to error mitigation of geodetic observations such as Interferometric Synthetic Aperture Radar. In this study, we provide global validations of these new weather models with respect to Global Positioning System (GPS, ∼13,000 stations) and Moderate Resolution Imaging Spectrometer (MODIS, ∼1 km resolution) using data from January 2016 to December 2018 of every 1 h. The global standard deviations of the Zenith Tropospheric Delay (ZTD) differences (DSTDs) between weather models and GPS are 1.69 cm for ERA5 and 1.54 cm for HRES. The global PWV DSTDs between weather models and MODIS are 0.34 cm for ERA5 and 0.32 cm for HRES. The two weather models generally perform better in western North America, Europe, and Arctic by having low ZTD DSTDs (<1.3 cm) or PWV DSTDs (<0.3 cm). HRES also has a low ZTD DSTD of less than 1.3 cm in Antarctic, Japan, New Zealand, and Africa and outperforms ERA5 in most regions of the world, despite the fact that 83% of the HRES PWV values are temporally interpolated (from 6 to 1-h). However, under extreme weather conditions, ERA5 performs better owing to its high temporal resolution (1 h). Our results can be used as a global reference for evaluating uncertainties when utilizing these weather models.

Publication metadata

Author(s): Yu C, Li Z, Blewitt G

Publication type: Article

Publication status: Published

Journal: Earth and Space Science

Year: 2021

Volume: 8

Issue: 5

Online publication date: 07/04/2021

Acceptance date: 24/03/2021

Date deposited: 18/06/2021

ISSN (electronic): 2333-5084

Publisher: Blackwell Publishing Ltd


DOI: 10.1029/2020EA001417


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