Evapotranspiration (ET) is an important component of the hydrologic cycle that transfers large quantities of water vapor away from Earth's surface into the atmosphere. In addition to having agricultural water management applications, including monitoring water rights compliance and irrigation scheduling, estimating ET is also important to quantify water used by...
The Columbia River Channel Improvement Project (CRCIP) was constructed along 166.6 km (103.5 miles) of Columbia River (from River Mile 3 to 106.5), which was from Interstate 5 Bridge (between Portland and Vancouver) to the river mouth, before emptying into the Pacific Ocean. It deepened the river by 0.9 m...
Finite, uncertain, and increasingly expensive
energy resources require a better understanding of energy
utilization in all sectors of the national economy including agriculture. A significant portion of energy used
in agriculture is required for the manufacturing, installation, transporting, and operation of irrigation systems.
Quantification of the amounts of energy used...
Regionalized variable analysis has been used to study
a number of meteorological and hydrological variables
including precipitation (Delhomme and Delfinier, 1973),
streamfiow (Villeneuve et al., 1979) and hydraulics of
groundwater aquifers (Gambolati and Volpi, 1979). In the
research work reported in this thesis, an attempt was
made to characterize the...
Theoretical derivations to describe pan evaporation, E[subscript p], and evapotranspiration, ET[subscript r], were developed based on a flow equation expressed as the product of the driving force for vapor between the evaporative surface and a plane of reference times a conductivity coefficient of vapor through air. Under the assumptions of...
Research was conducted to determine the applicability of using the theory of
regionalized variables or geostatistics in characterizing the spatial variability of reference
evapotranspiration (ETr) over various climatic regimes for the state of Oregon. The state was
divided into five climatic regions based on topographic features and local meteorological
conditions:...
The HAPEX-MOBILHY regional experiment provided an significant opportunity to analyze
the partition of energy and distribution of water over land surfaces. The combination of
remotely sensed data and ground instrument networks over the large-scale in situ experiment
allowed investigation of spatial and temporal variation of such hydrologic parameters as the...
Daily evaporative flux and meteorological data from three sites were
collected and analyzed. Analysis included evaluation of several
reference evapotranspiration estimating methods which were theoretically
based on distinct physical laws. The estimating methods included pan
evaporation, energy-based Priestly-Taylor, and combination methods with
and without biological adjustments. The data set represented...
The major objectives of this study were an
evaluation of the Meteorological Office Rainfall and
Evaporation Calculation System (MORECS) evapotranspiration
(ET) model using the Penman-Monteith equation and
comparison of the MORECS and measured surface resistance.
Meteorological, soil and plant parameters were measured in
an alfalfa field over two growing seasons....