In this project, solar radiation maps of Thailand were developed using satellite data and ground based meteorological data. Digital data from the visible channel of the GMS4 and GMS5 satellites collected during a 6 year-period (1993-1998) were used in this work. The data displayed as images cover the whole area of Thailand with a spatial resolution of 5×5 km². These images were transformed to the cylindrical projection and then navigated using coastline as reference. The post-launched calibration tables were employed to convert gray levels of satellite data into the earth-atmospheric albedo. A physical model was selected for computing solar radiation based on this earth-atmospheric albedo. The surface albedo and the absorption and scattering coefficients of various atmospheric constituents were also determined and used in the model.
For testing its validity, the model was used to calculate monthly average daily global solar radiation at four solar monitoring stations situated in four provinces: Chiang Mai, Ubon Ratchathani, Songkhla and Nakhon Pathom. The results obtained from the model agree well with those of the measurement, with discrepancies for most cases being less than 5 %. Then the model was used to compute monthly average daily global solar radiation for the whole country. The results are presented as maps showing the distribution of solar radiation over the country.
Thailand News
The monthly average daily global solar radiation maps show that the distribution of solar radiation is influenced by the north-east and south-west monsoons. Most parts of the country receive highest solar radiation during April and May, with the values ranging from 20 to 24 MJ/m²-day. The yearly average daily global solar radiation map demonstrates that the regions which receive highest solar radiation are in the north-east and the central parts of country, covering parts of the provinces of Nakhon Ratchasima, Buriram, Surin, Sisaket, Roiet, Yasothon, Ubon, Ratchatani, Udonthani, Suphanburi, Chainat, Ayuttaya and Lopburi. These regions which receive the yearly average daily radiation of 19-20 MJ/m²-day represent 14.3% of the total area of the country. It is found that 50.2% of the area of the country receive the yearly average daily global solar radiation in the range of 18-19 MJ/m²-day and only 0.5% receive radiation less than 16 MJ/m²-day. The yearly average daily global solar radiation for the whole country is found to be 18.2 MJ/m²-day.
These results indicate that Thailand has fairly high solar energy potentials.
Development of Solar Energy Potential Maps from Satellite Data for Thailand
