abstract-different evapotranspiration (et) estimation equations having different accuracy with different conditions have been developed for et estimation. this study will firstly focus on the estimation of 13 climatic equations of daily garlic et estimation whose  et is measured by lysimeter to provide information which can be helpful in selecting an appropriate et equation. the paper aims at s...

been reviewed in final form. Permission, as indicated by the signatures and dates given below, is now granted to submit final copies to the College of Graduate Studies for approval. Abstract Changes in streamflow across the western US illustrate a need to better understand how drought indices derived from climate data track streamflow. Three drought metrics, the (SPEI), and Palmer Drought Sever...

from the mathematical point of view, the fao penman-monteith equation shows a homographic function related to the wind speed. the homographic function has horizontal and vertical asymptotes. in this issue horizontal asymptote is applicable; because the vertical asymptote occurs for negative values of wind speed but the negative sign indicates the direction of the wind speed and only the absolut...

This study compares four different potential evapotranspiration equations according to Priestley Taylor, Kimberly Penman, Penman Monteith (FAO-56) and Hargreaves on a global basis to demonstrate their difference, and assess their impact on the calculation of stream flows. The various equations of potential evapotranspiration show great differences in magnitude. But due to the limited availabili...

Five methods (Thornthwaite, Hamon, Jensen-Haise, Turc, and Penman) for estimating potential evaporation for a reference surface (PEr) were compared to four methods (Priestley-Taylor, McNaughton-Black, Penman-Monteith, and ShuttleworthWallace) for estimating surface-dependent potential evaporation (PEs) using three cover types at each of seven locations from Fairbanks, Alaska, to San Juan, Puert...

In order to better manage the limited water resources in arid regions, accurate determination of plant water requirements is necessary. For that, the evaluation of reference evapotranspiration (ET0)--a basic component of the hydrological cycle--is essential. In this context, the Penman Monteith equation, known for its accuracy, requires a high number of climatic parameters that are not always f...

[1] The Penman-Monteith equation is often used to estimate transpiration, but an important limitation to this approach, especially for mountainous forested sites, is an accurate estimate of canopy conductance averaged over the area of interest (Gs). We propose a method for estimating watershed-scale transpiration using estimates of Gs derived from measurements of stable isotopes. To estimate Gs...

This study evaluates the performance of four evapotranspiration methods (Priestley-Taylor, Penman-Monteith, Hargreaves and Makkink) of differing complexity in a semiarid environment in north China. The results are compared to observed water vapour fluxes derived from eddy flux measurements. The analysis became necessary after discharge simulations using an automatically calibrated version of th...

Evaporation losses from a watertight 6.34 ha rain forest catchment under wet maritime tropical conditions in the Luquillo Experimental Forest, Puerto Rico, were determined using complementary hydrological and micrometeorological techniques during 1996 and 1997. At 6.6 mm d−1 for 1996 and 6.0 mm d−1 for 1997, the average evapotranspiration (ET ) of the forest is exceptionally high. Rainfall inte...