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contributor authorLawrence, David M.
contributor authorSlingo, Julia M.
date accessioned2017-06-09T17:13:48Z
date available2017-06-09T17:13:48Z
date copyright2005/10/01
date issued2005
identifier issn1525-755X
identifier otherams-81452.pdf
identifier urihttp://onlinelibrary.yabesh.ir/handle/yetl/4224457
description abstractA recent model intercomparison, the Global Land?Atmosphere Coupling Experiment (GLACE), showed that there is a wide range of land?atmosphere coupling strengths, or the degree that soil moisture affects the generation of precipitation, amongst current atmospheric general circulation models (AGCMs). Coupling strength in the Hadley Centre atmosphere model (HadAM3) is among the weakest of all AGCMs considered in GLACE. Reasons for the weak HadAM3 coupling strength are sought here. In particular, the impact of pervasive saturated soil conditions and low soil moisture variability on coupling strength is assessed. It is found that when the soil model is modified to reduce the occurrence of soil moisture saturation and to encourage soil moisture variability, the soil moisture?precipitation feedback remains weak, even though the relationship between soil moisture and evaporation is strengthened. Composites of the diurnal cycle, constructed relative to soil moisture, indicate that the model can simulate key differences in boundary layer development over wet versus dry soils. In particular, the influence of wet or dry soil on the diurnal cycles of Bowen ratio, boundary layer height, and total heat flux are largely consistent with the observed influence of soil moisture on these properties. However, despite what appears to be successful simulation of these key aspects of the indirect soil moisture?precipitation feedback, the model does not capture observed differences for wet and dry soils in the daily accumulation of boundary layer moist static energy, a crucial feature of the feedback mechanism.
publisherAmerican Meteorological Society
titleWeak Land–Atmosphere Coupling Strength in HadAM3: The Role of Soil Moisture Variability
typeJournal Paper
journal volume6
journal issue5
journal titleJournal of Hydrometeorology
identifier doi10.1175/JHM445.1
journal fristpage670
journal lastpage680
treeJournal of Hydrometeorology:;2005:;Volume( 006 ):;issue: 005
contenttypeFulltext


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