ABSTRACT
Although the total volume of soil moisture is very small compared to the total amount of water on Earth (i.e., only 0.0012%; Chow et al. 1988), it is a key variable within the hydrological cycle as it affects both water and heat fluxes. For instance, during precipitation events, the infiltration rate is controlled by soil moisture, and, consequently, it determines the amount of runoff produced. Also, the evapotranspiration rate is controlled by the wetness condition of the soil. Because of this, soil moisture is a crucial variable in the development of crops. Knowledge of the spatial and temporal variability of soil moisture is thus of high merit for watershed applications such as flood prediction, drought monitoring, and crop irrigation scheduling. Unfortunately, acquiring ground measurements of soil moisture is labor intensive. Hence measurements are often limited to a few locations in space and/or to some instances in time (e.g., field campaigns). This shortcoming
CONTENTS
13.1 Introduction ........................................................................................................................ 323 13.2 Soil Roughness Parameterization .................................................................................... 325
13.2.1 Profile Length ......................................................................................................... 327 13.2.2 Number of Profile Measurements ....................................................................... 328 13.2.3 Instrument Accuracy .............................................................................................330
