Assessment of regional drought vulnerability and risk using principal component analysis and a Gaussian mixture model

Due to the complex characteristics of drought, drought risk needs to be quantified by combining drought vulnerability and drought hazard. Recently, the major focus in drought vulnerability has been on how to calculate the weights of indicators to comprehensively quantify drought risk. In this study, principal component analysis (PCA), a Gaussian mixture model (GMM), and the equal-weighting method (EWM) were applied to objectively determine the weights for drought vulnerability assessment in Chungcheong Province, located in the west-central part of South Korea. The PCA provided larger weights for agricultural and industrial factors, whereas the GMM computed larger weights for agricultural factors than did the EWM. The drought risk was assessed by combining the drought vulnerability index (DVI) and the drought hazard index (DHI). Based on the DVI, the most vulnerable region was CCN9 in the northwestern part of the province, whereas the most drought-prone region based on the DHI was CCN12 in the southwest. Considering both DVI and DHI, the regions with the highest risk were CCN12 and CCN10 in the southern part of the province. Using the proposed PCA and GMM, we validated drought vulnerability using objective weighting methods and assessed comprehensive drought risk considering both meteorological hazard and socioeconomic vulnerability.

     

Evaluation of multi-sensor satellite data for monitoring different drought impacts

Drought is a natural disaster that significantly affects human life; therefore, precise monitoring and prediction is necessary to minimize drought damage. Conventional drought monitoring is based predominantly on ground observation stations; however, satellite imagery can be used to overcome the disadvantages of existing monitoring methods and has the advantage of monitoring wide areas. In this research, we assess the applicability of drought monitoring based on satellite imagery, focusing on historic droughts in 2001 and 2014, which caused major agricultural and hydrological issues in South Korea. To assess the applicability and accuracy of the drought index, drought impact areas in the study years were investigated, and spatiotemporal comparative analyses between the calculated drought index and previously affected areas were conducted. For drought monitoring based on satellite imagery, we used hydro-meteorological factors such as precipitation, land surface temperature, vegetation, and evapotranspiration, and applied remote sensing data from various sensors. We verified the effectiveness of using precipitation data for meteorological drought monitoring, vegetation and land surface temperature data for agricultural drought monitoring, and evapotranspiration data for hydrological drought monitoring. Moreover, we confirmed that the Standard Precipitation Index (SPI) can be indirectly applied to agricultural or hydrological drought monitoring by determining the temporal correlation between SPI, calculated for various time scales, and satellite-based drought indices.     

Investigating effect of climate change on drought propagation from meteorological to hydrological drought using multi-model ensemble projections

Stochastic Environmental Research and Risk Assessment - Climate change is a main driving force that affects the hydrological cycle, leading to an increase in natural hazards. Among these natural...     

Characteristics of tropical cyclone-induced precipitation over the Korean River basins according to three evolution patterns of the Central-Pacific El Niño

This study carried out a comparative analysis of the changes in tropical cyclone (TC) genesis, TC track, and TC intensity focusing on TCs that affected the Korean peninsula (KP) according to three evolutionary patterns (prolonged, abrupt and symmetric-decay) of the abnormal sea surface temperature in the Central-Pacific (CP) region. As a result of the analysis, the activity pattern of TCs was found to vary depending on the evolution patterns of the CP El Niño, and such changes appeared to result in clear variations in the regional rainfall in Korea. In the prolonged-decaying and symmetric-decaying years, the KP received considerable TC rainfall. On the other hand, in abrupt-decaying years, it was subtly affected by the TC rainfall. Although rather limited conditions and relatively short observation data were used to analyze the effects of the evolution pattern of the CP El Niño on TCs, the results can be used to quantitatively identify the spatial features of TCs affecting the KP. These results are expected to be helpful in managing the disaster risks in vulnerable areas, including plans to secure stable water resources in the basin, and in establishing effective and active measures to cope with natural disasters by extreme events over the KP.