An idealized model sensitivity study on Dead Sea desertification with a focus on the impact on convection
<p>The Dead Sea desertification-threatened region is affected by continual lake level decline and occasional but life-endangering flash floods. Climate change has aggravated such issues in the past decades. In this study, the impact on local conditions leading to heavy precipitation from the c...
Main Authors: | , |
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Format: | Article |
Language: | English |
Published: |
Copernicus Publications
2020-10-01
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Series: | Atmospheric Chemistry and Physics |
Online Access: | https://acp.copernicus.org/articles/20/12011/2020/acp-20-12011-2020.pdf |
Summary: | <p>The Dead Sea desertification-threatened region is affected by continual lake
level decline and occasional but life-endangering flash floods. Climate
change has aggravated such issues in the past decades. In this study, the
impact on local conditions leading to heavy precipitation from the changing
conditions of the Dead Sea is investigated. Idealized sensitivity
simulations with the high-resolution COSMO-CLM (COnsortium for Small-scale MOdelling and Climate Limited-area Modelling) and several numerical weather prediction (NWP) runs on an
event timescale are performed on the Dead Sea area. The simulations are
idealized in the sense that the Dead Sea model representation does not accurately
represent the real conditions but those given by an external dataset. A
reference or Dead Sea simulation covering the 2003–2013 period and a twin
sensitivity or bare soil simulation in which the Dead Sea is set to bare
soil are compared. NWP simulations focus on heavy precipitation events
exhibiting relevant differences between the Dead Sea and the bare soil
decadal realization to assess the impact on the underlying
convection-related processes.</p>
<p>The change in the conditions of the Dead Sea is seen to affect the
atmospheric conditions leading to convection in two ways. (a) The local
decrease in evaporation reduces moisture availability in the lower boundary
layer locally and in the neighbouring regions, directly affecting atmospheric
stability. Weaker updraughts characterize the drier and more stable atmosphere
of the simulations in which the Dead Sea has been dried out. (b) Thermally
driven wind system circulations and resulting divergence/convergence fields
are altered, preventing in many occasions the initiation of convection because of the omission of convergence lines. On a decadal scale, the difference
between the simulations suggests a weak decrease in evaporation, higher air
temperatures and less precipitation (less than 0.5 %).</p> |
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ISSN: | 1680-7316 1680-7324 |