Agricultural drought can have long-lasting and harmful impacts on both the agricultural ecosystem and economy. Recently, as climate change has increased global warming, the frequency and intensity of droughts are increasing as weather and environmental factors that directly affect agriculture are rapidly changing. In South Korea, severe droughts have occurred every year for the past seven years. Compared to paddies supplied with water from agricultural reservoirs, upland crops are highly vulnerable to drought due to a lack of irrigation facilities. The consumption requirements for upland crops cannot be satisfied by rainfall alone and require supplementation through irrigation. The amount of upland crop consumption and irrigation water should be calculated not only by the amount of evaporation but also by taking into account the soil moisture movement. Soil moisture is a key variable for defining the agricultural drought index; however, in situ soil moisture observations are unavailable for many areas. Remote sensing techniques can allow surface soil moisture observations at different tempo-spatial resolutions. Soil available water content is an important factor used in evaluating upland drought impacts. It is recognized as a major factor in water resource circulation. This study proposes a practical method to perform drought risk assessments for upland crops based on evaporation and soil moisture by utilizing Famine Early Warning Systems Network evaporation acidity satellite images provided by the United States Geological Survey.

Damage due to climate change is increasing worldwide; in South Korea, the increase in temperature is greater than the average global temperature increase. These changes in temperature have increased the frequency of and damage caused by droughts. To reduce drought damage, the importance of efficient water management policies and evapotranspiration, an index used for water management policies, is increasing. Analyzing the variation in evapotranspiration is relevant to understanding climate change and agricultural water management. Owing to the lack of evapotranspiration data collected using a Lysimeter, evapotranspiration has been estimated using the FAO-56 Penman–Monteith (PM) equation on meteorological datasets as recommended by the United Nations Food and Agriculture Organization. Long-term meteorological data with a maximum of 100 years were collected from 12 sites to estimate evapotranspiration. The objectives of this study were the following: (1) estimate evapotranspiration based on the PM equation, (2) analyze the trends in temperature and evapotranspiration, and (3) evaluate the relationship between temperature and evapotranspiration through correlational analysis. The results improve our understanding of climate change and provide a valuable reference for regional water resource management. We estimated evapotranspiration and analyzed the tendency of temperature and evapotranspiration. As a result, analysis of seasonal ET0 at all stations represented generally increasing trends in spring, summer, and autumn with generally decreasing trends in winter. Results of the seasonal Mann–Kendall test between temperature metrics (maximum, average, minimum) and ET0 showed that the maximum temperature exhibited a distinct increase in spring and winter in some areas. In this study, we determined the strength of the relationship between temperature and ET0 using the Pearson correlation coefficient. The results of evaluating the relationship between each temperature metric and evapotranspiration showed that the maximum temperature had the strongest relationship compared to the average and minimum temperatures.

Damage due to climate change is increasing worldwide; in South Korea, the increase in temperature is greater than the average global temperature increase. These changes in temperature have increased the frequency of and damage caused by droughts. To reduce drought damage, the importance of efficient water management policies and

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