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A gridded hourly precipitation dataset for Switzerland using rain‐gauge analysis and radar‐based disaggregation
Author(s) -
Wüest Marc,
Frei Christoph,
Altenhoff Adrian,
Hagen Martin,
Litschi Michael,
Schär Christoph
Publication year - 2010
Publication title -
international journal of climatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.58
H-Index - 166
eISSN - 1097-0088
pISSN - 0899-8418
DOI - 10.1002/joc.2025
Subject(s) - precipitation , quantitative precipitation estimation , rain gauge , radar , environmental science , quantitative precipitation forecast , meteorology , climatology , weather radar , plateau (mathematics) , computer science , geography , geology , mathematical analysis , telecommunications , mathematics
Rain gauges and weather radars both constitute important devices for operational precipitation monitoring. Gauges provide accurate yet spotty precipitation estimates, while radars offer high temporal and spatial resolution yet at a limited absolute accuracy. We propose a simple methodology to combine radar and daily rain‐gauge data to build up a precipitation dataset with hourly resolution covering a climatological time period. The methodology starts from a daily precipitation analysis, derived from a dense rain‐gauge network. A sequence of hourly radar analyses is then used to disaggregate the daily analyses. The disaggregation is applied such as to retain the daily precipitation totals of the rain‐gauge analysis, in order to reduce the impact of quantitative radar biases. Hence, only the radar's advantage in terms of temporal resolution is exploited. In this article the disaggregation method is applied to derive a 15‐year gridded precipitation dataset at hourly resolution for Switzerland at a spatial resolution of 2 km. Validation of this dataset indicates that errors in hourly intensity and frequency are lower than 25% on average over the Swiss Plateau. In Alpine valleys, however, errors are typically larger due to shielding effects of the radar and the corresponding underestimation of precipitation periods by the disaggregation. For the flatland areas of the Swiss Plateau, the new dataset offers an interesting quantitative description of high‐frequency precipitation variations suitable for climatological analyses of heavy events, the evaluation of numerical weather forecasting models and the calibration/operation of hydrological runoff models. Copyright © 2009 Royal Meteorological Society