Open AccessA method for statistical downscaling of seasonal ensemble predictions
Author(s) -
FEDDERSEN HENRIK,
ANDERSEN UFFE
Publication year - 2005
Publication title -
tellus a
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 77
eISSN - 1600-0870
pISSN - 0280-6495
DOI - 10.1111/j.1600-0870.2005.00102.x
Subject(s) - downscaling , precipitation , climatology , environmental science , ensemble average , meteorology , general circulation model , climate change , geography , geology , oceanography
A model output statistics based method for downscaling seasonal ensemble predictions is outlined, and examples of ensemble predictions of precipitation and 2‐m temperature are verified against observing stations in Scandinavia, Europe, north‐western America, the contiguous United States and Australia. The downscaling from seasonal ensemble predictions from coupled ocean/atmosphere general circulation models to daily precipitation time series for individual observing stations is performed in three steps: (i) a spatial downscaling of ensemble mean seasonal means from dynamical model output to station level by means of patterns derived from a singular value decomposition analysis of model output and observations; (ii) application of the downscaling transformation to the model output ensemble and subsequent calibration of the downscaled ensemble; (iii) a stochastic generation of daily precipitation conditioned on predictions of the probability of a wet day in the season and daily persistence. In the majority of the examples, the downscaling is found to provide more skilful predictions than the raw dynamical model output.