Abstract
This study developed a farmland meteorology estimation system to support precise cultivation management. The system is suitable for application even in areas of hilly, mountainous, or sloping terrain. This system provides daily maximum, minimum, and mean air temperatures, daily relative humidity, and daily accumulations of solar radiation, reference evapotranspiration, and precipitation, together with 6-hourly predictions of precipitation. These data are estimated from the Automated Meteorological Data Acquisition System (AMeDAS) observation data without any observation devices except for the precipitation data. Precipitation data is just an Analysis and Forecast of Precipitation produced by the Japan Meteorological Agency. The estimation methods used for air temperature and solar radiation are based on original techniques developed by the National Agriculture and Food Research Organization. Air temperature data are estimated by a model that uses a radiative cooling scale to determine temperature differences between estimation sites and an AMeDAS site. Solar radiation data constitute the sum of direct and diffuse solar radiations; the former are estimated using a model of atmospheric transmittance and the latter are estimated using models for dimensionless parameters of direct and diffuse solar radiation. Other meteorological data are estimated according to the Irrigation and Drainage Paper No. 56, produced by the Food and Agriculture Organization of the United Nations. An automated device for the acquisition of air temperature has also been developed for the temperature difference estimation model. This device acquires data with similar accuracy to AMeDAS without needing an AC power supply.
