CRS4

Verification of the water balance aspects of the ecmwf era40 reanalysis dynamical dowscaling obtained with the regcm3 model. part II.

Marino Marrocu, Gabriella Pusceddu, Antioco Vargiu
Rapport de recherche , CRS4 - january 2012
One of the tasks of the WP4, of the CLIMB project, is that of transferring information from the large scales, described by global climatic models, to the smaller scales relevant for hydrological modelling in all the basins that are object of hydrological investigation by the project partners, using the current state-of-the-art on statistical downscaling procedures, dynamical downscaling and regional climate models. With the aim to establish the level of uncertainty introduced by the regional dynamic downscaling we implemented the RegCM3 regional climate model, at the relatively high horizontal spatial resolution of about 25km, to downscale a decade (1983-1992) of the ECMWF ERA40 reanalysis in the Western Europe and Mediterranean area. The main aim was that to assess the performance of the RegCM3 describing the runoff (R), the precipitation (P) and the evapotranspiration (E) components of the hydrological budget. This has been made comparing the monthly precipitation averages against a gridded dataset, at the resolution of 0.25°, of measured data (CRU dataset) and then checking physical consistency of the simulated P, R and  E fields. A mesoscale meteorological model pipeline based on a three level nesting procedure using a hydrostatic (BOLAM) and a non-hydrostatic (MOLOCH) model, fed with the ECMWF ERA40 reanalysis has been also set up to simulate 50 events of intense precipitation (more than 200 mm/day) that occurred in Sardinia during the 1950-1999 period. Results show that the water balance components obtained with the regional climate models have in general high and seasonally distributed biases. We conclude that the best strategy was that of post-processing the already available Climate Models outputs, and for doing this we will test some calibration techniques able to adjust the model statistics (climate) of the past to the observed values.

Références BibTex

@TechReport{MPV12,
  author       = {Marrocu, M. and Pusceddu, G. and Vargiu, A.},
  title        = {Verification of the water balance aspects of the ecmwf era40 reanalysis dynamical dowscaling obtained with the regcm3 model. part II.},
  institution  = {CRS4},
  month        = {january},
  year         = {2012},
  address      = {Parco Sc. e Tech  POLARIS Ed. 1, loc Pixina Manna, PULA},
  type         = {TechReport},
  keywords     = {Climate models, auditing},
  url          = {http://publications.crs4.it/pubdocs/2012/MPV12},
}

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» Marino Marrocu
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