Land-surface topographic attributes can be useful for estimating stable spatial patterns of crop yield caused by spatial variability in soils and water availability. We present spatial analyses of grain yield for three fields of dryland winter wheat in northeastern Colorado using topographic attributes as explanatory variables. Topographic attributes including elevation, slope, aspect, curvatur...

The Topographic Wetness Index (TWI) is a commonly used proxy for soil moisture. predictive capability of TWI influenced by the flow-routing algorithm and resolution Digital Elevation Model (DEM) that derived from. Here, we examine using 11 algorithms at DEM resolutions 1–30 m. We analyze relationship between field-quantified moisture statistical modeling methods 5,200 study plots with over 46 0...

Accurately predicting soil moisture patterns in the landscape is a persistent challenge. In humid regions, topographic wetness indices (TWIs) are widely used to approximate relative soil moisture patterns. However, there are many ways to calculate TWIs and very few field studies have evaluated the different approaches – especially in the US. We calculated TWIs using over 400 unique formulations...

A description and analysis is given of a wetness duration experiment, carried out in a potato field in the centre of the Netherlands in September 2005. The observations are used to design and evaluate a within-canopy dew model which provides the leaf wetness distribution within the canopy caused by dew processes and by precipitation. This withincanopy dew model consists of three layers (bottom,...

The frequencies flown on the Special Sensor Microwave Imager (SSM/I) are sensitive to liquid water near the earth’s surface. These frequencies are primarily atmospheric window channels, which receive the majority of their radiation from the surface. Liquid water near the surface depresses the emissivity as a function of wavelength. The relationship between brightness temperatures at different f...