A Feasibility Study of a Field-specific Weather Service for Small-scale Farms in a Topographically Complex Watershed

Abstract:

Adequate downscaling of synoptic forecasts is a prerequisite for improved agrometeorological service to rural areas in South Korea where complex terrain and small farms are common. Geospatial schemes based on topoclimatology were used to scale down the Korea Meteorological Administration (KMA) temperature forecasts to the local scale (~30 m) across a rural catchment. Local temperatures were estimated at 14 validation sites at 0600 and 1500 LST in 2013/2014 using these schemes and were compared with observations. A substantial reduction in the estimation error was found for both 0600 and 1500 temperatures compared with uncorrected KMA products. Improvement was most remarkable at low lying locations for the 0600 temperature and at the locations on west- and south-facing slopes for the 1500 temperature. Using the downscaled real-time temperature data, a pilot service has started to provide field-specific weather information tailored to meet the requirements of small-scale farms. For example, the service system makes a daily outlook on the phenology of crop species grown in a given field using the field-specific temperature data. When the temperature forecast is given for tomorrow morning, a frost risk index is calculated according to a known phenology–frost injury relationship. If the calculated index is higher than a pre-defined threshold, a warning is issued and delivered to the grower's cellular phone with relevant countermeasures to help protect crops against frost damage. The system was implemented for a topographically complex catchment of 350km²with diverse agricultural activities, and more than 400 volunteer farmers are participating in this pilot service to access user-specific weather information.