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Generation of Skillful Forecasts at Station scale through Objective Bias Correction: Multiple Site Evaluation for Summer Surface Temperature

IR@C-MMACS: CSIR-Centre for Mathematical Modelling and Computer Simulation, Bangalore

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Title Generation of Skillful Forecasts at Station scale through Objective Bias Correction: Multiple Site Evaluation for Summer Surface Temperature
 
Creator Goswami, P
Mallick, S
 
Subject Climate Modelling
 
Description One factor that limits skill of the numerical models is the bias in the model forecasts with respect to observations. Similarly, while the meso-scale models today can support horizontal grid spacing down to a few kilometers or less, downscaling of model forecasts to arrive at station scale values will remain a necessary step for many applications. While generic improvement in model skill requires parallel and comprehensive development in model and other forecast methodology, one way of achieving skill in station scale forecasts without (effort-intensive) calibration of model is to implement an objective bias correction (referred to as debiasing). We show that a non-linear objective debiasing can transform zero-skill forecasts from a meso-scale model (MM5) to forecasts with significant skill. We consider 12 locations over India representing urban sites in different geographical conditions during May-August, 2009. The model MM5 was integrated for 24 hours with initial conditions from [global gridded analysis (FNL)] of the National Centers for Environmental Prediction Global Forecast System (Final) for each of the days of May-August, 2009 in a completely operational setting (without assuming any observed information on dynamics beyond the time of the initial condition). It is shown that for all the locations and the four months, the skill of the debiased forecast is significant against essentially zero skill of raw forecasts. The procedure provides an applicable forecast strategy to attain realizable significant skill in station scale forecast. Potential skill, derived using in-sample data for calibrating the debiasing parameters, shows promise of further improvement with large samples.
 
Publisher CSIR Centre for Mathematical Modelling and Computer Simulation
 
Date 2011-01
 
Type Monograph
NonPeerReviewed
 
Format application/pdf
 
Identifier http://cir.cmmacs.ernet.in/265/1/rrcm1101.pdf
Goswami, P and Mallick, S (2011) Generation of Skillful Forecasts at Station scale through Objective Bias Correction: Multiple Site Evaluation for Summer Surface Temperature. Technical Report. CSIR Centre for Mathematical Modelling and Computer Simulation , C-MMACS,Bangalore 560037,India. (Unpublished)
 
Relation http://cir.cmmacs.ernet.in/265/