ASSESSMENT OF RICE YIELDS IN THE UPPER CHAO PHRAYA RIVER

ASSESSMENT OF RICE YIELDS IN THE UPPER CHAO PHRAYA RIVER BASIN USING H08 MODEL

Adisorn Champathong¹
Santi Sumdin²
Chatchai Chaiyasaen³
Chaiwat Ekkawatpanit⁴
Naota Hanasaki^5
1 Royal Irrigation Department, Thailand, This email address is being protected from spambots. You need JavaScript enabled to view it.
² Thai Meteorological Department, Thailand, This email address is being protected from spambots. You need JavaScript enabled to view it.
³ Thai Meteorological Department, Thailand, This email address is being protected from spambots. You need JavaScript enabled to view it.
⁴ Civil Engineering Department, King Mongkut’s University of Technology Thonburi,
Thailand, This email address is being protected from spambots. You need JavaScript enabled to view it.
⁵National Institute for Environmental Studies, Japan, This email address is being protected from spambots. You need JavaScript enabled to view it. .

ABSTRACT : This study aims to estimate rice yields and cropping calendars in the Upper Chao Phraya River Basin located in the north of Thailand, using H08 model with default parameters. Being an integrated water resources model, the H08 model shows a great potential to evaluate not only hydrological aspect, but also agricultural perspective especially estimate global cropping calendars and crop yields. To investigate the model performance in local perspective, the H08 model is thus firstly conducted in this study. Being provinces with the largest paddy fields, Kamphaeng Phet, Lampang, Phichit, and Uttaradit are chosen to represent the output comparisons in four major river basins comprising Ping, Wang, Yom, and Nan. The study consists of three main processes. Preparing map data and meteorological data are the first step. Secondly, water balance and energy balance are conducted to maintain consistency among the sub model via land surface process module. The final step is to estimate rice yields and cropping calendars through crop growth module. Rainfall and air temperature data are compared between observed and modeled data. Even though the correlations of rainfall data are moderately satisfied, those of air temperature are very high correlation. While the moving-average rice yields are estimated to determine appropriate planting periods in order to gain the maximum rice yields.

KEYWORDS : H08 model, Upper Chao Phraya River basin, GSWP-2, rice yields, cropping calendars