Validation of ERA5-Land temperature and relative humidity on four Peruvian glaciers using on-glacier observations Validation of ERA5-Land temperature and relative humidity on four Peruvian glaciers using on-glacier observations

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Vol19 No.7: 1849-1873 

Title】Validation of ERA5-Land temperature and relative humidity on four Peruvian glaciers using on-glacier observations

Author】BONSHOMS Martí1*; UBEDA Jose1,2; LIGUORI Giovanni3,4; KÖRNER Philipp5; NAVARRO Álvaro1,6; CRUZ Rolando7

Addresses】1 Departamento de Geografía, Universidad Complutense de Madrid, Madrid 28040, Spain; 2 Guías de Espeleología y Montaña, Torremocha del Jarama 28189, Spain; 3 Department of Physics and Astronomy, University of Bologna, Bologna 40127, Italy; 4 School of Earth, Atmosphere and Environment, Monash University, Melbourne 3800, Australia; 5 Institute of Hydrology and Meteorology, Technische Universität Dresden, Dresden 01737, Germany; 6 ESRI-España, Madrid 28037, Spain; 7 Área de Evaluación de Glaciares y Lagunas. Autoridad Nacional del Agua, Huaraz 02002, Peru

Corresponding author】BONSHOMS Martí

Citation】Bonshoms M, Ubeda J, Liguori G, et al. (2022) Validation of ERA5-Land temperature and relative humidity on four Peruvian glaciers using on-glacier observations. Journal of Mountain Science 19(7). https://doi.org/10.1007/s11629-022-7388-4

DOI】https://doi.org/10.1007/s11629-022-7388-4

Abstract】Weather and climate conditions drive the evolution of tropical glaciers which play an important role as water reservoirs for Peruvian inhabitants in the arid coast and semi-arid Andean region. The scarcity of long-term high-quality observations over Peruvian glaciers has motivated the extensive use of reanalysis data to describe the climatic evolution of these glaciers. However, the representativeness and uncertainties of these reanalysis products over these glaciers are still poorly constrained. This study evaluates the ability of the ERA5-Land reanalysis (ERA5L) to reproduce hourly and monthly 2 m air temperature and relative humidity (T2m and Rh2m, respectively) over several Peruvian glaciers. We compared the ERA5L with data from four on-glacier automatic weather stations (AWS), whose hourly time series were completed with nearby stations, for the period January 2017 to December 2019. Results indicates a better performance of the reanalysis for T2m (r >0.80) than for Rh2m (~0.4< r <~0.6) in all four glaciers. Concerning the observations, both parameters show a daily cycle influenced by the presence of the glacier. This influence is more prominent during the dry months when the so-called glacier damping and cooling effects are stronger. On a monthly time scale, the ERA5L validation for both parameters are better in wet outer tropical sites (RMSE between ±0.2°C for T2m and between 3%-7% for Rh2m) rather than in dry outer tropical sites (RMSE between ±0.2°C for T2m and between 3%-7% for Rh2m). Among all sites considered in the study, the Rh2m bias is the highest in the Cavalca glacier (correlation of 0.81; RMSE 13%, MAE 11% and bias 8.3%) and the lowest in Artesonraju glacier (correlation of 0.96; RMSE 3%; MAE 2.3% and bias -0.8%). Based on certain considerations outlined in this paper, it is appropriate to use ERA5L to characterize T2m and Rh2m conditions on Peruvian glaciers, particularly in the wet outer tropics.

Keywords】ERA5 Land; Tropical glaciers; Temperature; Relative humidity; Peru; Validation