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Proposing Institution

Institute for Meteorology and Climate Research
Project Manager

Dr. Frederik De Roo
Kreuzeckbahnstrasse 19
82467 Garmisch-Partenkirchen
The frequently observed phenomenon of desert-growth is a topic of huge relevance both for the human population living in semi-arid regions and due to its environmental feedback. Amongst the various attempts to tackle this problem, afforestation in semi-arid regions is a promising approach. The pine forest Yatir was artificially planted at the northern edge of the Israeli Negev desert by the Israeli government in 1964-1969 to investigate the forest’s influence on the local micro-climate. Even though the incoming net radiation is very large in summer (around 600 at noontime) and the amount of precipitation is very low (285mm annual mean), the forest still manages to cool itself, which is necessary for its survival. Due to the lack of available water, enhancing the sensible heat flux, instead of the latent heat flux, has to trigger this cooling effect. The before mentioned effect was first investigated by Rotenberg and Yakir [Science, 327(5964):451-454, 2010] and named “canopy convector effect” (CCE). However, the precise fluid-mechanical mechanism behind the CCE is still unclear. Studying the CCE of the Yatir forest and the conditions for its well-functioning will help to judge the chance of success for future afforestation projects in semi-arid regions. The goal of the proposed modeling study is to investigate the dependency of the CCE on the main features of the Yatir forest scenario by means of large eddy simulations. The three main features are the albedo difference between the dark trees and the lighter desert, the roughness elements of the forest canopy, and the underlying topography. To investigate the influence of this three properties on the CCE, several simulations of the full Yatir forest will be performed. Due to the need for resolving the single trees (10m canopy height), the large horizontal extension of the forest (12km x 6km) and the height of the atmospheric boundary layer (1km), a large number of grid points has to be used for the simulations, which is the reason for the project proposal at SuperMUC. This study fits within the “Climate feedbacks and benefits of semi-arid forests” (CliFF) project.

Impressum, Conny Wendler