TY - JOUR
T1 - Spatio-temporal drought patterns of multiple drought indices based on precipitation and soil moisture
T2 - A case study in South Korea
AU - Kwon, Moonhyuk
AU - Kwon, Hyun Han
AU - Han, Dawei
PY - 2019/10/7
Y1 - 2019/10/7
N2 - This study aims to explore the spatio-temporal characteristics of meteorological and agricultural droughts using the Standardized Precipitation Index (SPI) and Standardized Soil Moisture Index (SSI), respectively, as well as their relationships over the past three decades (1986-2016) in South Korea. The SSI shows less frequent droughts and longer drought duration compared to the SPI, due to the gradual decrease in the autocorrelation functions of the SSI. The strongest cross-correlations are observed at a 1-month lag between the SPI and SSI for most stations. Thus, the SPI could be more appropriate for defining the onset of a drought, whereas the SSI appears to be more effective for describing drought persistence. Moreover, the transition from meteorological to agricultural droughts is significantly dependent on the season, indicating that the transition between them is highly correlated with antecedent moisture conditions. The copula-based Multivariate Standardized Drought Index (MSDI) is introduced to explicitly postulate interdependence between the SPI and SSI in the context of a multivariate probability distribution. We employ a hierarchical agglomerative clustering approach along with a quantile regression model to better understand the spatio-temporal pattern of the MSDI. More drought episodes under moderate to severe drought conditions are observed along the southern coast of South Korea. Additionally, persistent droughts with higher severity are observed in the northern part of South Korea, which may be attributed to a significant decreasing trend (or increasing drought risk).
AB - This study aims to explore the spatio-temporal characteristics of meteorological and agricultural droughts using the Standardized Precipitation Index (SPI) and Standardized Soil Moisture Index (SSI), respectively, as well as their relationships over the past three decades (1986-2016) in South Korea. The SSI shows less frequent droughts and longer drought duration compared to the SPI, due to the gradual decrease in the autocorrelation functions of the SSI. The strongest cross-correlations are observed at a 1-month lag between the SPI and SSI for most stations. Thus, the SPI could be more appropriate for defining the onset of a drought, whereas the SSI appears to be more effective for describing drought persistence. Moreover, the transition from meteorological to agricultural droughts is significantly dependent on the season, indicating that the transition between them is highly correlated with antecedent moisture conditions. The copula-based Multivariate Standardized Drought Index (MSDI) is introduced to explicitly postulate interdependence between the SPI and SSI in the context of a multivariate probability distribution. We employ a hierarchical agglomerative clustering approach along with a quantile regression model to better understand the spatio-temporal pattern of the MSDI. More drought episodes under moderate to severe drought conditions are observed along the southern coast of South Korea. Additionally, persistent droughts with higher severity are observed in the northern part of South Korea, which may be attributed to a significant decreasing trend (or increasing drought risk).
KW - clustering analysis
KW - multivariate drought index
KW - quantile regression
KW - SPI
KW - SSI
UR - http://www.scopus.com/inward/record.url?scp=85065196231&partnerID=8YFLogxK
U2 - 10.1002/joc.6094
DO - 10.1002/joc.6094
M3 - Article (Academic Journal)
AN - SCOPUS:85065196231
VL - 39
SP - 4669
EP - 4687
JO - International Journal of Climatology
JF - International Journal of Climatology
SN - 0899-8418
IS - 12
ER -