A Soil Moisture–Rainfall Feedback Mechanism: 2. Numerical experiments

Zheng, Xinqian; Eltahir, Elfatih A. B.

doi:10.1029/97wr03497

Cited by 79 publications

(54 citation statements)

References 37 publications

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“…Eltahir (1998) proposed a hypothesis to describe the physical mechanisms of soil moisture-rainfall feedback. In addition, Zheng (1998) confirmed this hypothesis in West African monsoon rainfall using a two-dimensional model.…”

Section: Introductionsupporting

confidence: 69%

Study on Spatially Averaged Evaporation under Soil Moisture Heterogeneity Affected by Permafrost Micro-topography.

Hirose¹,

Koike²,

Ishidaira

2002

Journal of the Meteorological Society of Japan

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We discuss the effect of the soil moisture heterogeneity on the spatially averaged fluxes in the Tibetan Plateau. Using the observational data obtained during the GAME/Tibet Pre-phase Observing Period (POP) in 1997 and the Intensive Observing Period (IOP) in 1998, we show the seasonal variability of the soil moisture distribution. The water and energy flow processes in the permafrost region are studied. Based on the observational results, the 1-D heat and water flow model is applied to the Tibetan Plateau. This model demonstrates the seasonal variability of soil moisture distribution. To examine the effect of the soil moisture distribution, spatially averaged evaporation is calculated by this model in two different ways: one by using the spatially averaged soil moisture and the other by considering the soil moisture heterogeneity. We compare with two kinds of the spatially averaged evaporation. The comparison indicates that it is important for the estimation of spatially averaged fluxes to consider the effect of soil moisture heterogeneity.

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Section: Introductionsupporting

confidence: 69%

Study on Spatially Averaged Evaporation under Soil Moisture Heterogeneity Affected by Permafrost Micro-topography.

Hirose¹,

Koike²,

Ishidaira

2002

Journal of the Meteorological Society of Japan

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“…According to Eltahir (1998), the soil mois-ture conditions over any large region should be associated with relatively large moist static energy in the boundary layer, which favours the occurrence of more rainfall. This hypothesis was also confirmed for West African monsoons by Zheng and Eltahir (1998). In this vein, van der Ent and Savenije (2011) quantified the spatial and temporal scale of moisture recycling independent of the size and shape of the region and found that approximately 70 % of the precipitation in the centre of the South American continent is of terrestrial origin, as in many regions of Africa but specifically in the CRB, where strong moisture feedback occurs.…”

Section: Moisture Contribution From the Sources: Forward Analysismentioning

confidence: 60%

A Lagrangian perspective of the hydrological cycle in the Congo River basin

et al. 2017

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Abstract. The Lagrangian model FLEXPART is used to identify the moisture sources of the Congo River basin (CRB) and investigate their role in the hydrological cycle. This model allows us to track atmospheric parcels while calculating changes in the specific humidity through the budget of evaporation minus precipitation. This method permits the annual-scale identification of five continental and four oceanic principal regions that provide moisture to the CRB from both hemispheres over the course of the year. The most important is the CRB, which provides more than 50 % of the total atmospheric moisture contribution to precipitation over itself. Additionally, both the land that extends to the east of the CRB and the eastern equatorial South Atlantic Ocean are very important sources, while the Red Sea source is merely important in the (E − P ) budget over the CRB despite its high evaporation rate. The moisture-sink patterns over the CRB in air masses that were tracked forward in time from all the sources follow the latitudinal rainfall migration and are mostly highly correlated with the pattern of the precipitation rate, ensuring a link between them. In wet (dry) years, the contribution of moisture to precipitation from the CRB over itself increases (decreases). Despite the enhanced evaporative conditions over the basin during dry years, the vertically integrated moisture flux (VIMF) divergence inhibits precipitation and suggests the transport of moisture from the CRB to remote regions.

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“…Over Europe, Schär et al [1999] identified positive soil moisture-precipitation feedbacks using regional climate model (RCM) simulations. In West Africa, Zheng and Eltahir [1998] showed a positive soil moisture-rainfall feedback when imposing a large-scale soil moisture anomaly in their numerical experiments. A decrease of local rainfall in the wetlands of South Florida due to land use change was shown by Pielke et al [1999] using RCM experiments.…”

Section: Introductionmentioning

confidence: 99%

“…One final comment on land use change climate studies is that most of the numerical experiments imposed exaggerated changes in order to obtain statistical significance of the results. For example, the soil moisture anomaly in West Africa by Zheng and Eltahir [1998] was imposed over an exceptionally large area. Different results were obtained in the same region when realistic land use change was imposed.…”

Section: Introductionmentioning

confidence: 99%

Impact of the Sudd wetland on the Nile hydroclimatology

Mohamed

Hurk

Savenije

et al. 2005

Water Resources Research

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[1] Large evaporation occurs over the Sudd wetland, a huge swamp located on the upper Nile. Historically, water resources planners have had the intention to reduce the Sudd evaporation by shortcut channels (e.g., Jonglei canal). The question is: What is the effect of draining the Sudd wetland on the regional water cycle and on the Nile water flow? A regional climate model has been applied to the Nile Basin, with a special modification to include routing of the Nile flood over the Sudd. The impact of the wetland on the Nile hydroclimatology has been studied by comparing two model scenarios: the present climatology and a drained Sudd scenario. The results indicate that draining the entire Sudd has negligible impact on the regional water cycle owing to the relatively small area covered by the wetland. The runoff gain would then be up to $36 Gm 3 yr À1 . However, the impact on the microclimate is large. The relative humidity will drop by 30-40% during the dry season, and temperature will rise by 4°-6°C. The impact during the wet season is small.

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A Soil Moisture–Rainfall Feedback Mechanism: 2. Numerical experiments

Cited by 79 publications

References 37 publications

Study on Spatially Averaged Evaporation under Soil Moisture Heterogeneity Affected by Permafrost Micro-topography.

Study on Spatially Averaged Evaporation under Soil Moisture Heterogeneity Affected by Permafrost Micro-topography.

A Lagrangian perspective of the hydrological cycle in the Congo River basin

Impact of the Sudd wetland on the Nile hydroclimatology

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