Evapotranspiration of partially vegetated surfaces from remote sensing
نویسندگان
چکیده
Evapotranspiration (ET) estimates are required for many applications in agricultural and environmental management, from hydrological applications to crop models and irrigation scheduling. Improvement in irrigation water management is achieved when crop water use is accurately quantified in time and space. Conventionally, ET can be measured using Bowen ratio energy balance systems, eddy covariance systems, surface renewal systems, weighing lysimeters and sap flows, among others. Although these techniques can provide accurate estimates of ET over a homogeneous area, they are mainly based on site measurements that are local, and cannot represent the spatial variability of ET within a field or region. Satellite data are ideally suited for deriving spatially continuous fields of ET using energy balance techniques. However for partially vegetated surfaces (i.e. orchards), the use of those techniques has been limited due to the low spatial resolution obtained from some type of sensors at the satellite platform, that difficult its utilization at a farm level. Here, the use of methodologies of images fusion that integrate information from different sensors, offer an opportunity to achieve a characterization with more detail that consistently can be used at a farm level. The main goal of this study is to evaluate the performance of a surface energy balance (SEB) model and an image fusion algorithm to estimate ET for partially vegetated surfaces. Special interest is focused in instantaneous and daily evapotranspiration. Surface energy fluxes calculated with a SEB model from both original and fused images are compared with Eddy Covariance measurements made over a blueberry and cherry orchard fields.
منابع مشابه
An Improvement on Land Surface Temperature Determination by Producing Surface Emissivity Maps
Emissivity mapping of the Earth’s surface is the prerequisite to thermal remote sensing. A precise determinationof a surface's temperature is dependent upon the availability of precise emissivity data for that surface. The presentstudy area is a part of sugarcane plantation fields in the west part of Khuzestan province. In this work, TemperatureEmissivity Separation algorithm (TES) was applied ...
متن کاملEstimation of Actual Evapotranspiration, Water productivity, and Irrigation Efficiency of Wheat Fields in Surface and Sprinkler Irrigation Systems Using Remote Sensing
In arid and semi-arid regions, water resource management and optimization of applying irrigation water are particularly important. For optimization of applying irrigation water, the estimated values of actual evapotranspiration are necessary for avoiding excessive or inadequate applying water. The estimation of actual crop evapotranspiration is not possible in large areas using the traditional ...
متن کاملEffects of Karun 4 Dam Construction on Climatic Parameters Using Remote Sensing
In this study, using Modis images and wets pass model, the value of evapotranspiration for the northern Karun basin was estimated monthly from 2000 to 2014. The value of correlation coefficient for the obtained evaporations was R2 = 0.72. This model was calibrated and verified for different regions with different parameters. Data from 2000 to 2009 were used for calibration and data from 2010 to...
متن کاملEstimating Daily Global Evapotranspiration Using Penman-Monteith Equation and Remotely Sensed Land Surface Temperature
Daily evapotranspiration (ET) is modeled globally for the period 2000–2013 based on the Penman–Monteith equation with radiation and vapor pressures derived using remotely sensed Land Surface Temperature (LST) from the MODerate resolution Imaging Spectroradiometer (MODIS) on the Aqua and Terra satellites. The ET for a given land area is based on four surface conditions: wet/dry and vegetated/non...
متن کامل