Land Surface Evaporation


Book Description

General circulation model (GCM) experiments in the late 1970's indicated that the climate is sensitive to variations in evaporation at the land surface. Thus, in the context of climate modeling, it became important to develop techniques which would realistically estimate the evaporation flux on land. Land Surface Evaporation: Measurement and Parameterization discusses strategies for the use of experimental data in developing and testing parameterization schemes of the evaporation flux in GCM's. The book reviews state-of-the-art techniques, such as remote sensing, which measure evaporation fluxes over continental surfaces. It evaluates their relevance with respect to the various spatial and temporal scales of interest. This book will provide researchers in climatology, meteorology, hydrology and water management, and remote sensing with a thorough overview of current research in land surface evaporation. It will also give young scientists insight into surface processes.




Land Surface Evaporation


Book Description

General circulation model (GCM) experiments in the late 1970's indicated that the climate is sensitive to variations in evaporation at the land surface. Thus, in the context of climate modeling, it became important to develop techniques which would realistically estimate the evaporation flux on land. Land Surface Evaporation: Measurement and Parameterization discusses strategies for the use of experimental data in developing and testing parameterization schemes of the evaporation flux in GCM's. The book reviews state-of-the-art techniques, such as remote sensing, which measure evaporation fluxes over continental surfaces. It evaluates their relevance with respect to the various spatial and temporal scales of interest. This book will provide researchers in climatology, meteorology, hydrology and water management, and remote sensing with a thorough overview of current research in land surface evaporation. It will also give young scientists insight into surface processes.




Land Surface Evaporation


Book Description










Land Surface Processes in Hydrology


Book Description

General circulation models (GCMs) predict certain changes in the amounts and distribution of precipitation, but the conversion of these predictions of impacts on water resources presents novel problems in hydrologic modeling, particularly with regard to the scale of the processes involved. Therefore improved, distributed GCMs are required. New remote sensing technologies provide the necessary spatially distributed data. However, there are many attendant problems with the translation of remotely sensed signals into hydrologically relevant information. This book elucidates how to improve the representation of land surface hydrologic processes in GCMs and in regional and global scale climate studies. It is divided into five sections: Models and Data; Precipitation; Soil Moisture; Evapotranspiration; Runoff.







On the Estimation of Evaporation from a Land Surface


Book Description

Evaporation from a land surface is a complicated process and the problem of estimating this factor has not been adequately solved up to the present. It is generally known that when underground exchange of water is absent, the equation for the mean water balance over a period of years assumes a simple form where x is the amount of precipitation, y the runoff and z the evaporation. Evaporation is known to be correlated with runoff or precipitation and numerous empirical formulas for the various basins have been derived in the past from a large amount of observational data. Among the best known ones are the Ol'dekop formula. (Author).




Remote Sensing of Evapotranspiration (ET)


Book Description

Evapotranspiration (ET) is a critical component of the water and energy balances, and the number of remote sensing-based ET products and estimation methods has increased in recent years. Various aspects of remote sensing of ET are reported in the 11 papers published in this book. The major research areas covered by this book include inter-comparison and performance evaluation of widely used one- and two-source energy balance models, a new dual-source model (Soil Plant Atmosphere and Remote Sensing Evapotranspiration, SPARSE), and a process-based model (ETMonitor); assessment of multi-source (e.g., remote sensing, reanalysis, and land surface model) ET products; development or improvement of data fusion frameworks to predict continuous daily ET at a high spatial resolution (field-scale or 30 m) by fusing the advanced spaceborne thermal emission reflectance radiometer (ASTER), the moderate resolution imaging spectroradiometer (MODIS), and Landsat data; and investigating uncertainties in ET estimates using an ET ensemble composed of several land surface models and diagnostic datasets. The effects of the differences between ET products on water resources and ecosystem management were also investigated. More accurate ET estimates and improved understanding of remotely sensed ET products are crucial for maximizing crop productivity while minimizing water losses and management costs.




Evapotranspiration Over Heterogeneous Vegetated Surfaces


Book Description

The focus of this work is the development of models to estimate evapotranspiration (ET), investigating the partitioning between soil evaporation and plant transpiration at field and regional scales, and calculating ET over heterogeneous vegetated surfaces. Different algorithms with varying complexities as well as spatial and temporal resolutions are developed to estimate evapotranspiration from different data inputs. The author proposes a novel approach to estimate ET from remote sensing by exploiting the linkage between water and carbon cycles. At the field scale, a hybrid dual source model (H-D model) is proposed. It is verified with field observations over four different ecosystems and coupled with a soil water and heat transfer model, to simulate water and heat transfer in the soil-plant-atmosphere continuum. At the regional scale, a hybrid dual source scheme and trapezoid framework based ET model (HTEM), using remote sensing images is developed. This model is verified with data from the USA and China and the impact of agricultural water-saving on ET of different land use types is analyzed, in these chapters. The author discusses the potential of using a remote sensing ET model in the real management of water resources in a large irrigation district. This work would be of particular interest to any hydrologist or micro-meteorologist who works on ET estimation and it will also appeal to the ecologist who works on the coupled water and carbon cycles. Land evapotranspiration is an important research topic in hydrology, meteorology, ecology and agricultural sciences. Dr. Yuting Yang works at the CSIRO Land and Water, Canberra, Australia.