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Larry K. Berg, Laura D. Riihimaki, Yun Qian, Huiping Yan, and Maoyi Huang

1. Introduction and motivation It is well recognized that the southern Great Plains (SGP) low-level jet (LLJ) plays an important role in the regional-scale moisture transport over the central United States (e.g., Uccellini and Johnson 1979 ; Helfand and Schubert 1995 ; Stensrud 1996 ; Higgins et al. 1997 ; Schubert et al. 1998 ; Tollerud et al. 2008 ; Frye and Mote 2010 ). A number of different mechanisms have been suggested as the cause of LLJs, as highlighted by Kraus et al. (1985

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Jiangfeng Wei, Robert E. Dickinson, and Haishan Chen

1. Introduction How precipitation is related to soil moisture is an important issue for the study of land–atmosphere interaction. Large-scale observations are lacking and local observations are very limited, so many processes in the soil moisture–precipitation (S–P) interaction are still not well understood. Findell and Eltahir (1997) assumed that soil moisture may have some influence on subsequent precipitation and found a positive correlation between the observed soil moisture and

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Maria Tsukernik and Amanda H. Lynch

Yamazaki 2004 ; Tietavainen and Vihma 2008 ) suggested that the atmospheric moisture flux from lower latitudes could be used as an effective proxy for continental precipitation. Indeed, in the cold and dry Antarctic environment the evaporation term is negligible, and the net precipitation can be effectively approximated by the total moisture transported across the Southern Ocean onto the continent. Meridional transport of moisture in the atmosphere, therefore, can provide a much needed proxy for the

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M. Issa Lélé, Lance M. Leslie, and Peter J. Lamb

most limiting parameters for sustaining life, agriculture, and economic development in the sub-Saharan West African countries. Therefore, the role played by the atmospheric moisture transfer and its phase transitions through evaporation, latent heat release, and associated energy transports and exchanges are of central importance for the WAM dynamics and variability. This is because hydrological processes play an important role in determining the scales of the major circulation patterns (e

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Luis Gimeno, Raquel Nieto, Ricardo M. Trigo, Sergio M. Vicente-Serrano, and Juan Ignacio López-Moreno

1. Introduction About 90% of the water in the atmosphere emanates from the oceans, lakes, and other open water bodies ( Quante and Matthias 2006 ). Through atmospheric transport and associated transfer processes, some of the water that evaporates over the oceans reaches the land and may precipitate. It is crucial to understand the processes that govern moisture transport in the troposphere ( Trenberth et al. 2003 ) and how transport might affect the hydrological cycle ( Alley et al. 2007

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Cathy Hohenegger, Peter Brockhaus, Christopher S. Bretherton, and Christoph Schär

1. Introduction Interactions between land and the atmosphere play an important role in our climate system and have been the focus of modeling studies on a wide range of time and spatial scales (e.g., Pielke 2001 ; Betts 2004 ; Koster et al. 2004 ; Schär et al. 1999 ). On seasonal time scales, soil moisture anomalies may maintain/amplify subsequent extreme events such as droughts, floods, or summer heat waves (e.g., Beljaars et al. 1996 ; Trenberth and Guillemot 1996 ; Fischer et al. 2007

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Benjamin A. Schenkel and Robert E. Hart

their tropical environment for weeks following TC passage for the region within approximately 250 km of the TC track ( Hart et al. 2007 , 2008 ; Schenkel and Hart 2011 ) and potentially on spatial scales extending across entire ocean basins ( Sobel and Camargo 2005 ). However, these studies did not objectively define the mean spatiotemporal scales of the environmental moisture anomalies due to a single TC or how these moisture anomalies are generated. Accordingly, the present study objectively

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Sonia I. Seneviratne, Randal D. Koster, Zhichang Guo, Paul A. Dirmeyer, Eva Kowalczyk, David Lawrence, Ping Liu, David Mocko, Cheng-Hsuan Lu, Keith W. Oleson, and Diana Verseghy

1. Introduction Soil moisture memory, in essence the fact that the soil can “remember” a wet or dry anomaly long after the conditions responsible for the anomaly are forgotten by the atmosphere, is a key aspect of land–atmosphere interactions and has major implications for seasonal forecasting. Indeed, due to its inherent memory, soil moisture is one of the major “slow” drivers of the climate system and possibly the chief source of forecast skill for summer precipitation over land in the

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Qing Liu, Rolf H. Reichle, Rajat Bindlish, Michael H. Cosh, Wade T. Crow, Richard de Jeu, Gabrielle J. M. De Lannoy, George J. Huffman, and Thomas J. Jackson

1. Introduction Soil moisture is an important component of the land surface water budget. Large-scale soil moisture data are useful in many research fields such as hydrology, agriculture, and ecology ( Robock et al. 1998 ; Koster et al. 2008 ; Entekhabi et al. 2010a ). Soil moisture is also a critical variable that needs to be carefully initialized for weather and climate prediction ( Beljaars et al. 1996 ; Drusch 2007 ; Mahfouf 2010 ). In situ measurements of soil moisture, however, are

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Laurel L. De Haan and Masao Kanamitsu

1. Introduction It has been well understood for many years that the response of general circulation models to tropical sea surface temperatures (SSTs) is of primary importance to climate prediction. However, it has become apparent more recently that soil moisture has an important secondary role. As a result, there has been an increased interest in understanding the impact of soil moisture on near-surface temperature and precipitation in general circulation models (GCMs). The influence of soil

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