Estimation of global radiation from sunshine hours and temperature observations
Mr.S. Prakarnrat (1), Mr.W. Waranuchit (1)
(1) Senior Meteorologist
Estimation of global radiation from sunshine hours and temperature observations
The estimation of global radiation is a generally optional method in case of unavailability of recorded data in target areas. In such situation, sunshine hours and temperature are usually favorably applied as variables to determine global radiation.
Data set of sunshine duration during 1997-1998 from 8 agrometeorological stations allocated at various parts of Thailand ; Mae Choe (Chiang Mai), Nan , Tak Fa (Nakhon Sawan) , Tha Phra (Khon Kaen) , Pak Chong (Nakhon Ratchasima) , Ubon Ratchathani , Kaqmpaengsaen (Nakhon Pathom) , and Kho Hong (Songkhla) were selected. Their highly correlation with precision global radiation obtained from GAME-T project was analyzed by Angstrom’s equation (1924) on monthly basis .The calculated output of daily global radiation for the year 1999 was satisfactorily agreed with the measured data at 95 % of significant level.
In addition, a simple model of relationship between atmospheric transmittance and daily range of air temperature originally developed by Bristow and Campbell ( 1984 ) was modified to account global radiation in Bangkok area successfully ( W. Waranuchit , 1998 ).The model was categorized into each month and the variables of daily range of air temperature were adjusted upon rainfall situation .Such model was brought to re-estimate global radiation in Bangkok during the period of 1997 – 2000 . The verification would be presented herewith as the comparative method.
Submittal Information
Name :
Date :
Mr.Saman Prakarnrat and Mr.Wirat Waranuchit
01-Jun-01-16:36:21
Organization :
Theme :
Agrometeorological Division, Meteorological Department
