Assessment of Agricultural Drought Considering the Hydrological Cycle and Crop Phenology in the Korean Peninsula

Abstract

Hydrological changes attributable to global warming increase the severity and frequency of droughts, which in turn affect agriculture. Hence, we proposed the Standardized Agricultural Drought Index (SADI), which is a new drought index specialized for agriculture and crops, and evaluated current and expected droughts in the Korean Peninsula. The SADI applies crop phenology to the hydrological cycle, which is a basic element that assesses drought. The SADI of rice and maize was calculated using representative hydrological variables (precipitation, evapotranspiration, and runoff) of the crop growing season. In order to evaluate the effectiveness of SADI, the three-month Standardized Precipitation Index, which is a representative drought index, and rainfed crop yield were estimated together. The performance evaluation of SADI showed that the correlation between rainfed crop yield and SADI was very high compared with that of existing drought index. The results of the assessment of drought over the past three decades provided a good indication of a major drought period and differentiated the results for crops and regions. The results of two future scenarios showed common drought risks in the western plains of North Korea. Successfully validated SADIs could be effectively applied to agricultural drought assessments in light of future climate change, and would be a good example of the water-food nexus approach.

Do Satellite Surface Soil Moisture Observations Better Retain Information About Crop‐Yield Variability in Drought Conditions?

“…Based on that, SPI‐3 was assumed to be representative for describing agricultural drought conditions. Previous works on agricultural drought analysis also selected SPI‐3 (i.e., Bachmair et al, ; Lim et al, ; Sigdel & Ikeda, ), supporting our decision. For example, Bachmair et al () performed a correlation analysis between SPI at different time scales and remote sensing‐based vegetation indices for Europe.…”

Water-Centric Nexus Approach for the Agriculture and Forest Sectors in Response to Climate Change in the Korean Peninsula

“…Indeed, the temperature rise and associated increase in precipitation volatility are expected to cause significant damage to non-irrigated rice paddies. These results are remarkably similar to previous agriculture/drought cases for the same periods and areas [23], which suggests that they accurately reflect the impact of drought or disrupted water balance on productivity. In particular, the decline in productivity in the western plains is likely to be a major threat to food security.…”

“…Although some weather data had a coarser spatial resolution, they were given a spatial resolution of 1 km 2 to determine the spatial difference and quantification of water supply and demand. Previous research also indicated that a spatial resolution of 1 km 2 was appropriate for agriculture and forestry in studies of the Korean Peninsula [23,31].…”

“…The annual average temperature in this region is 10-16 • C, and the annual precipitation is approximately 1000-1400 mm [26]. Because the Korean Peninsula is located in the mid-latitude, a region highly affected by climate change, the increase in temperature and variability in precipitation is expected to increase significantly [23,25]. If the current greenhouse gas emission continues, the average temperature will rise by 7 • C at the end of the 21st century and the precipitation will increase by 14%; however, drought is also expected to increase significantly [30].…”

“…The hydrological changes caused by climate change can affect this supply-demand balance [19,20]. In North Korea, the supply-demand balance of such water has collapsed in the past because of deforestation [21], and the Korean Peninsula is expected to experience increased agricultural droughts attributable to climate change [22,23].…”