Recent developments of the numerical weather prediction models make it possible to use very high resolution models in the daily operational routine. The COSMO-I2 operational configuration reflects this trend. The model setup makes it possible to produce operational weather forecasts all the Italian country at a resolution of 2.8 km. Such a high resolution grid requires an adequate analysis procedure, so that the initial model fields can represent properly the characteristics of the atmospheric state typical of those scales. In particular, in this paper the attention is focused on the use of a high density weather stations network and on the assimilation of surface data, in particular the T2m (2 metres air temperature). ARPA Piemonte owns such a network, with a much higher number of stations in Piemonte region rather than the only 8 SYNOPs in the same area (see figure 1 for their geographical location). The goal of the work presented in this paper is to take advantage of such a network for enhancing the quality of the COSMO-I2 analysis production. In previous studies (Milelli et al., 2008; 2010), it has been shown how the assimilation of T2m has a major importance in making the forecast simulation differ significantly if it is included in the surface data assimilation or not. The step to this main goal presented in this paper deals with the study of the effect of the assimilation of the T2m on the surface fluxes, hence on how it influences the coupling between the soil state and the atmospheric state. It has been studied how the temperature data assimilation introduces perturbations in the model simulations.

The effects of T2m assimilation on surface fluxes in COSMO-I2

GALLI, MARCO;CASSARDO, Claudio
2011-01-01

Abstract

Recent developments of the numerical weather prediction models make it possible to use very high resolution models in the daily operational routine. The COSMO-I2 operational configuration reflects this trend. The model setup makes it possible to produce operational weather forecasts all the Italian country at a resolution of 2.8 km. Such a high resolution grid requires an adequate analysis procedure, so that the initial model fields can represent properly the characteristics of the atmospheric state typical of those scales. In particular, in this paper the attention is focused on the use of a high density weather stations network and on the assimilation of surface data, in particular the T2m (2 metres air temperature). ARPA Piemonte owns such a network, with a much higher number of stations in Piemonte region rather than the only 8 SYNOPs in the same area (see figure 1 for their geographical location). The goal of the work presented in this paper is to take advantage of such a network for enhancing the quality of the COSMO-I2 analysis production. In previous studies (Milelli et al., 2008; 2010), it has been shown how the assimilation of T2m has a major importance in making the forecast simulation differ significantly if it is included in the surface data assimilation or not. The step to this main goal presented in this paper deals with the study of the effect of the assimilation of the T2m on the surface fluxes, hence on how it influences the coupling between the soil state and the atmospheric state. It has been studied how the temperature data assimilation introduces perturbations in the model simulations.
2011
11
3
21
http://www.cosmo-model.org/content/model/documentation/newsLetters/newsLetter11/
COSMO; UTOPIA; Limited area model; Data assimilation; Temperature
Marco Galli; Massimo Milelli; Claudio Cassardo
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/133763
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