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Potential Evapotranspiration estimation for Indian conditions : Improving accuracy through calibration coefficients

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Title Potential Evapotranspiration estimation for Indian conditions : Improving accuracy through calibration coefficients
Potential Evapotranspiration estimation for Indian conditions : Improving accuracy through calibration coefficients
 
Creator ICAR_CRIDA_AICRPAM
 
Subject Potential Evapotranspiration,calibration coefficients
 
Description Not Available
The global water consumption is doubling every 20 years and projected
increase in food demand will have to be met by irrigation. Appropriate
scheduling of irrigation increase the irrigation water use efficiency allowing
more water available for other human and environmental uses. Timing and
quantum of water to be applied requires data on Actual Evapotranspiration
(AET). The measurement of AET is a very difficult and time consuming
task. Because of this, the concept of Potential Evapotranspiration (PET) is
widely used. Direct measurement of PET across locations is cost prohibitive
for a country like India and an indirect method using meteorological data is
a potential alternative. Though a number of empirical formulae / approaches
are available, availability of climatic data limits their application across all
the locations. In the present investigation, seven methods were employed
to estimate the PET and the resultant values were compared with PenmanMonteith estimated PET for 51 locations across the country. On an annual
basis,Turc method resulted in more errors followed by Thornthwaite and
Blaney-Criddle. During southwest monsoon period PET estimated from
Open pan and Christiansen pan method resulted in more errors whilst during
northeast monsoon season Hargreaves and Christiansen pan resulted in more
errors. During summer, modified Penman and Hargreaves are the best
methods to adopt. During winter modified Penman and PET from Open
pan resulted in few errors. Hargreaves method is surprisingly resulted in
more errors during winter season compared to summer.
Calibration coefficients were evolved on annual and seasonal basis for
different methods to reduce the errors in PET estimation in comparison to
Penman-Monteith method. The efficiency of these coefficients were
determined using an independent data set which showed that the errors can
be minimized to a great extent by applying these coefficients. A station
close by the 51 stations studied or per se climatologically analogous can
employ the calibration coefficients directly. Maps indicating the spatial
distribution of the coefficients across the country were presented so that
any user can estimate PET for a station interspersed two PET isolines.
Not Available
 
Date 2020-01-17T08:25:01Z
2020-01-17T08:25:01Z
2012-01-01
 
Type Technical Bulletin
 
Identifier Not Available
Not Available
http://krishi.icar.gov.in/jspui/handle/123456789/30720
 
Language English
 
Relation Not Available;
 
Publisher ICAR_CRIDA_AICPRAM_NICRA