Role of land surface processes and diffuse/direct radiation partitioning in simulating the European climate

Davin, E. L.; Seneviratne, S. I. (2012). Role of land surface processes and diffuse/direct radiation partitioning in simulating the European climate. Biogeosciences, 9(5), pp. 1695-1707. European Geosciences Union 10.5194/BG-9-1695-2012

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The influence of land processes and in particular of diffuse/direct radiation partitioning on surface fluxes and associated regional-scale climate feedbacks is investigated using ERA-40 driven simulations over Europe performed with the COSMO-CLM2 Regional Climate Model (RCM). Two alternative Land Surface Models (LSMs), a 2nd generation LSM (TERRA_ML) and a more advanced 3rd generation LSM (Community Land Model version 3.5), and two versions of the atmospheric component are tested, as well as a revised coupling procedure allowing for variations in diffuse/direct light partitioning at the surface, and their accounting by the land surface component.

Overall, the RCM performance for various variables (e.g., surface fluxes, temperature and precipitation) is improved when using the more advanced 3rd generation LSM. These improvements are of the same order of magnitude as those arising from a new version of the atmospheric component, demonstrating the benefit of using a realistic representation of land surface processes for regional climate simulations. Taking into account the variability in diffuse/direct light partitioning at the surface further improves the model performance in terms of summer temperature variability at the monthly and daily time scales. Comparisons with observations show that the RCM realistically captures temporal variations in diffuse/direct light partitioning as well as the evapotranspiration sensitivity to these variations. Our results suggest that a modest but consistent fraction (up to 3 %) of the overall variability in summer temperature can be explained by variations in the diffuse to direct ratio.

Item Type:

Journal Article (Original Article)

UniBE Contributor:

Davin, Édouard Léopold

Subjects:

500 Science > 550 Earth sciences & geology

ISSN:

1726-4189

Publisher:

European Geosciences Union

Language:

English

Submitter:

�douard Léopold Davin

Date Deposited:

25 Apr 2022 15:43

Last Modified:

05 Dec 2022 16:14

Publisher DOI:

10.5194/BG-9-1695-2012

BORIS DOI:

10.48350/167150

URI:

https://boris.unibe.ch/id/eprint/167150

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