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1. Introduction This document presents results from a simple, but noteworthy, experiment to understand the degree of soil moisture variability observed within a relatively small sod-covered area located inside the considerable agricultural region of Illinois. Soil moisture is a key component in the hydrologic cycle. It is useful in numerous settings, such as its relation to the magnitudes of localized floods and regional droughts, modeling research on watershed studies, and projected effects
1. Introduction This document presents results from a simple, but noteworthy, experiment to understand the degree of soil moisture variability observed within a relatively small sod-covered area located inside the considerable agricultural region of Illinois. Soil moisture is a key component in the hydrologic cycle. It is useful in numerous settings, such as its relation to the magnitudes of localized floods and regional droughts, modeling research on watershed studies, and projected effects
. The complex atmospheric circulation conditions and the roles as an ecological barrier and as the water tower of China make the Sanjiangyuan region a key region on the TP. A detailed investigation of the hydrological processes of the region contributes to the formulation of effective strategies for regional ecosystem and water resource conservation. As the atmospheric moisture transport process is an important part of the hydrological cycle, knowledge of where moisture comes from (moisture sources
. The complex atmospheric circulation conditions and the roles as an ecological barrier and as the water tower of China make the Sanjiangyuan region a key region on the TP. A detailed investigation of the hydrological processes of the region contributes to the formulation of effective strategies for regional ecosystem and water resource conservation. As the atmospheric moisture transport process is an important part of the hydrological cycle, knowledge of where moisture comes from (moisture sources
-reaching influence of such extreme precipitation fluctuations, there is an urgent need to investigate the physical processes and mechanisms that govern precipitation variability over south China. Sufficient moisture supply is necessary for precipitation generation. The precipitation amount over a region usually depends on the available moisture arising from two main sources: local evaporation and externally advective moisture. The latter is much more important than the former because, even on the most extensive
-reaching influence of such extreme precipitation fluctuations, there is an urgent need to investigate the physical processes and mechanisms that govern precipitation variability over south China. Sufficient moisture supply is necessary for precipitation generation. The precipitation amount over a region usually depends on the available moisture arising from two main sources: local evaporation and externally advective moisture. The latter is much more important than the former because, even on the most extensive
locations (gray dots) with validation sites indicated (black dots). Soil matric potential measurements from the Oklahoma Mesonet heat dissipation sensors are often converted to estimates of soil moisture (i.e., volumetric water content; e.g., Collow et al. 2012 ). That conversion is based on the site- and depth-specific soil water retention curve. The van Genuchten (1980) equation is used to represent the unique water retention curve for each site and depth: The parameters include θ r (cm 3 cm −3
locations (gray dots) with validation sites indicated (black dots). Soil matric potential measurements from the Oklahoma Mesonet heat dissipation sensors are often converted to estimates of soil moisture (i.e., volumetric water content; e.g., Collow et al. 2012 ). That conversion is based on the site- and depth-specific soil water retention curve. The van Genuchten (1980) equation is used to represent the unique water retention curve for each site and depth: The parameters include θ r (cm 3 cm −3
their moisture variables, even when the synoptic-scale flow is well forecast. An essential question is whether the source of these problems lies in deficiencies in microphysics, numerics, or some other model aspect, such as the boundary layer parameterization or initialization. Attempts to address these problems through more sophisticated model microphysics parameterizations have improved model verification but substantial deficiencies still exist. For example, Garvert et al. (2005a , b
their moisture variables, even when the synoptic-scale flow is well forecast. An essential question is whether the source of these problems lies in deficiencies in microphysics, numerics, or some other model aspect, such as the boundary layer parameterization or initialization. Attempts to address these problems through more sophisticated model microphysics parameterizations have improved model verification but substantial deficiencies still exist. For example, Garvert et al. (2005a , b
1. Introduction The origin of precipitation in a region can generally be divided into two main sources: local evaporation and externally advected moisture. Precipitation originating from local evaporation is then referred to as “recycled precipitation” ( Dominguez et al. 2006 ). Soil moisture may influence the generation of precipitation in a region through a feedback loop involving evaporation from the land. These feedback mechanisms are very important components for the land surface
1. Introduction The origin of precipitation in a region can generally be divided into two main sources: local evaporation and externally advected moisture. Precipitation originating from local evaporation is then referred to as “recycled precipitation” ( Dominguez et al. 2006 ). Soil moisture may influence the generation of precipitation in a region through a feedback loop involving evaporation from the land. These feedback mechanisms are very important components for the land surface
1. Introduction The hydrological cycle plays a major role in the global climate system ( Trenberth 1999 ; Pokam et al. 2012 ). To investigate the global energy balance and the climate change, it is important to understand the transport of atmospheric moisture. There have been considerable efforts toward understanding global moisture transport (e.g., Chen 1985 ; Liu and Tang 2005 ; Newman et al. 2012 ). The major source of the atmospheric water vapor is surface evaporation, which is in
1. Introduction The hydrological cycle plays a major role in the global climate system ( Trenberth 1999 ; Pokam et al. 2012 ). To investigate the global energy balance and the climate change, it is important to understand the transport of atmospheric moisture. There have been considerable efforts toward understanding global moisture transport (e.g., Chen 1985 ; Liu and Tang 2005 ; Newman et al. 2012 ). The major source of the atmospheric water vapor is surface evaporation, which is in
intraseasonal time scales compared to the untuned version of Raymond (2001) . The weak temperature gradient approximation when applied to a single-column model approximates the effect of the tropical environment by forcing the column to maintain buoyancy equilibrium with its surroundings via an imposed vertical velocity profile that counters heating with diabatic cooling. This vertical velocity, along with the convergence and divergence it implies, also transports moisture. Grabowski (2001 , 2003) found
intraseasonal time scales compared to the untuned version of Raymond (2001) . The weak temperature gradient approximation when applied to a single-column model approximates the effect of the tropical environment by forcing the column to maintain buoyancy equilibrium with its surroundings via an imposed vertical velocity profile that counters heating with diabatic cooling. This vertical velocity, along with the convergence and divergence it implies, also transports moisture. Grabowski (2001 , 2003) found
on land–atmosphere interactions is the idea that moisture and energy gradients across a landscape are associated with regional weather patterns over a wide range of spatial and temporal scales. Although soil moisture and vegetation impact the atmosphere through feedbacks with the land surface, the dominant processes driving these feedbacks have not been precisely determined and some disagreement still exists on what the primary mechanisms are. Previous research has shown evidence for the
on land–atmosphere interactions is the idea that moisture and energy gradients across a landscape are associated with regional weather patterns over a wide range of spatial and temporal scales. Although soil moisture and vegetation impact the atmosphere through feedbacks with the land surface, the dominant processes driving these feedbacks have not been precisely determined and some disagreement still exists on what the primary mechanisms are. Previous research has shown evidence for the
1. Introduction The absence of small-scale moisture measurements near the surface is a major limitation in forecasting convective precipitation ( Emanuel et al. 1995 ; Dabberdt and Schlatter 1996 ; National Research Council 1998 ). Recent breakthroughs in retrieving near-surface refractivity from weather radar provide new opportunities for high-resolution, near-surface moisture measurements ( Fabry et al. 1997 ; Fabry 2004 ; Cheong et al. 2008 ). Refractivity retrievals obtained from the
1. Introduction The absence of small-scale moisture measurements near the surface is a major limitation in forecasting convective precipitation ( Emanuel et al. 1995 ; Dabberdt and Schlatter 1996 ; National Research Council 1998 ). Recent breakthroughs in retrieving near-surface refractivity from weather radar provide new opportunities for high-resolution, near-surface moisture measurements ( Fabry et al. 1997 ; Fabry 2004 ; Cheong et al. 2008 ). Refractivity retrievals obtained from the
