Search Results
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
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
Planton 1989 ), which characterize the state of the land surface and forecast the evolution of the lowest layer of the model atmosphere. The surface energy balance relies strongly upon the soil and near-surface conditions and plays a critical role in determining the prognostic variables in land surface models. Vegetation coverage, atmospheric conditions, and the physical properties of the soil impact surface energy fluxes, which both influence and depend heavily upon soil temperature and soil moisture
Planton 1989 ), which characterize the state of the land surface and forecast the evolution of the lowest layer of the model atmosphere. The surface energy balance relies strongly upon the soil and near-surface conditions and plays a critical role in determining the prognostic variables in land surface models. Vegetation coverage, atmospheric conditions, and the physical properties of the soil impact surface energy fluxes, which both influence and depend heavily upon soil temperature and soil moisture
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
, and the color of the vegetation lightens, which increases the albedo of the canopy ( Jacobs and van Pul 1990 ). It is therefore not surprising that soil moisture has been found to play an important role in the weather and climate of Earth’s atmosphere (e.g., Findell and Eltahir 2003 ; Koster et al. 2003 ; Gutowski et al. 2004 ). Soil moisture also plays an important role in land surface hydrology, and specifically in the occurrence and severity of flooding (e.g., Hillel 2003 ). The soil
, and the color of the vegetation lightens, which increases the albedo of the canopy ( Jacobs and van Pul 1990 ). It is therefore not surprising that soil moisture has been found to play an important role in the weather and climate of Earth’s atmosphere (e.g., Findell and Eltahir 2003 ; Koster et al. 2003 ; Gutowski et al. 2004 ). Soil moisture also plays an important role in land surface hydrology, and specifically in the occurrence and severity of flooding (e.g., Hillel 2003 ). The soil
the amount of water available for aquifer recharge. Thus, soil moisture observations are being utilized by water resource managers in their long- and short-term management of water storage facilities (i.e., dams and reservoirs). Our ability to make accurate long-term observations of soil moisture on regional scales can also have a large impact on our ability to understand the impact of global climate change on our water supply. Providing timely weather, hydrological, and climatological forecasts
the amount of water available for aquifer recharge. Thus, soil moisture observations are being utilized by water resource managers in their long- and short-term management of water storage facilities (i.e., dams and reservoirs). Our ability to make accurate long-term observations of soil moisture on regional scales can also have a large impact on our ability to understand the impact of global climate change on our water supply. Providing timely weather, hydrological, and climatological forecasts
1. Introduction Soil moisture is an important component of the hydrological cycle as it plays an integral role in mass and energy exchange between the land surface and the atmosphere. As a result, accurate estimation of soil moisture can improve weather and streamflow forecasting in climate and hydrological models ( Berg and Mulroy 2006 ; Reichle et al. 2007 , 2008 ). Remotely sensed soil moisture data have become readily available from a variety of satellite platforms such as the Advanced
1. Introduction Soil moisture is an important component of the hydrological cycle as it plays an integral role in mass and energy exchange between the land surface and the atmosphere. As a result, accurate estimation of soil moisture can improve weather and streamflow forecasting in climate and hydrological models ( Berg and Mulroy 2006 ; Reichle et al. 2007 , 2008 ). Remotely sensed soil moisture data have become readily available from a variety of satellite platforms such as the Advanced
the climatology of drylines, have not been researched as comprehensively. There have only been a few studies that focused on the evapotranspiration or soil moisture effect on the dryline ( Ziegler et al. 1995 ; Shaw 1995 ; Grasso 2000 ), and all of them incorporated atmospheric models. Curiously, no studies used observed soil moisture data and its effect on the dryline. This study examines observed soil moisture values as a surrogate for evapotranspiration and relates them to the daily position
the climatology of drylines, have not been researched as comprehensively. There have only been a few studies that focused on the evapotranspiration or soil moisture effect on the dryline ( Ziegler et al. 1995 ; Shaw 1995 ; Grasso 2000 ), and all of them incorporated atmospheric models. Curiously, no studies used observed soil moisture data and its effect on the dryline. This study examines observed soil moisture values as a surrogate for evapotranspiration and relates them to the daily position
1. Introduction Soil moisture plays a vital role in linking drought, climate, and vegetation. Soil moisture data, collected from depths below the surface over the long term as well as at higher temporal and spatial resolutions, are valuable for assessing the extent and severity of drought quite accurately. There are also a variety of drought indices and a thorough description on their tractability, transparency, sophistication, extendability, and dimensionality is given by Keyantash and Dracup
1. Introduction Soil moisture plays a vital role in linking drought, climate, and vegetation. Soil moisture data, collected from depths below the surface over the long term as well as at higher temporal and spatial resolutions, are valuable for assessing the extent and severity of drought quite accurately. There are also a variety of drought indices and a thorough description on their tractability, transparency, sophistication, extendability, and dimensionality is given by Keyantash and Dracup
1. Introduction Soil moisture is a crucial variable for numerical weather and climate prediction as it controls the partitioning of energy into latent and sensible heat fluxes at the soil–atmosphere interface. In addition it is a key variable in hydrological processes (i.e., runoff, evaporation from bare soil, and transpiration from the vegetation cover) and has an impact on plant growth and carbon fluxes ( Dirmeyer et al. 1999 ; Entekhabi et al. 1999 ). Soil moisture is also important for
1. Introduction Soil moisture is a crucial variable for numerical weather and climate prediction as it controls the partitioning of energy into latent and sensible heat fluxes at the soil–atmosphere interface. In addition it is a key variable in hydrological processes (i.e., runoff, evaporation from bare soil, and transpiration from the vegetation cover) and has an impact on plant growth and carbon fluxes ( Dirmeyer et al. 1999 ; Entekhabi et al. 1999 ). Soil moisture is also important for
