The impact of climate change on hydrometeorological droughts at a basin scale

Abstract:The aim of this study is to analyze the characteristics of drought, such as intensity and trends, based on SPEI (Standardized Precipitation Evapotranspiration Index) at 8 stations in South Korea from 1981 to 2010. The traditional SPEI is based on the Thornthwaite equation for estimating evapotranspiration; SPEI_th. However, a standard of agricultural water management in Korea suggests the FAO Penman-Monteith equation; SPEI_pm. Therefore, we analyzed the intensity, variability, and trends of drought using SPEI_th and SPEI_pm, respectively, and compared the results. SPEI_pm showed slightly more intensive drought rather than SPEI_th except for Chuncheon and Gwangju. In 5 stations-excluding Cheoncheon, Gwangju and Jinju-the cumulative probability that SPEI_pm was below −1.5 was significantly increased from 1981-1995 to 1996-2010. In addition, the northwest and southwest regions had higher intensity of 1-month droughts, and the central and southwest regions had a higher intensity of 3-month droughts. According to the Mann-Kendall test, there was a decreasing trend of 1-month SPEI during the fall season and 3-month SPEI during winter season.

Section: Introductionmentioning

confidence: 99%

Analysis of Drought Intensity and Trends Using the Modified SPEI in South Korea from 1981 to 2010

Bae

Lee

Yoo

et al. 2018

“…Thus, it has been widely used around the world for hydrological processes and soil movement, the assessment of water resources and water quality, and in the movement and transformation of nutrients (such as nitrogen, phosphorus) and pesticides [40,41]. In recent years, the model has been increasingly applied in evaluating climate impacts on water resources at the basin scale, for small to large catchments [42][43][44][45][46][47].…”

Section: Swat (Soil and Water Assessment Tool) Modelmentioning

confidence: 99%

Simulation and Prediction of Climate Variability and Assessment of the Response of Water Resources in a Typical Watershed in China

Jin

Zhu

Zhao

et al. 2016

Abstract:The assessment of water resource responses to climate change is required in water resource planning and management, protecting environmental quality, and managing watersheds. This study modeled surface runoff and baseflow responses to variations in precipitation (0%, ±10%, and ±20%) and temperature (0 • C, ±1 • C, and ±2 • C) in 25 types of scenarios in the Lanhe Watershed (1140 km 2 ), which possesses the typical hydrological and meteorological characteristics of the Loess Plateau in China. The study is based on the Soil and Water Assessment Tool (SWAT), which was calibrated and validated using the coefficient of determination (R 2 ), Nash-Suttcliffe (Ens), and Percent bias (PBIAS), using the observed streamflow of Shangjingyou Station, a unique gauging station in the study area. The model was calibrated with daily streamflow, from 1967 to 1996, and then validated from 1997 to 2011. R 2 , Ens, and PBIAS were 0.95 and 0.84, 0.78 and 0.72, and 0.6% and −9.1% in annual and monthly calibration periods, 0.90 and 0.78, 0.74 and 0.67, and 22.1% and 18.8% in annual and monthly validation periods, and the overall performance ratings was "satisfactory". The assessment indicates that surface runoff is likely to be more affected than baseflow when altering temperatures and precipitation, and the noticeable changes of surface and baseflow are from June to September and October to November, respectively. Results also indicate that surface runoff and baseflow are very sensitive to the projected reduction in temperature, rather than to an increase of temperature, while precipitation is a constant. In turn, when the temperature is a constant, the surface runoff is sensitive to the projected increase in precipitation and the baseflow is sensitive to the decrease in precipitation.

“…As an elementary unit of hydrologic processes, basin with a high degree of functional integrity contains abundant hydrological information. Basin-scale analysis is beneficial to reveal the interactions among multiple hydrologic variables [25]. Thus, it is highly worthwhile to study meteorological drought at a basin scale.…”

Section: Introductionmentioning

confidence: 99%

SPI Based Meteorological Drought Assessment over a Humid Basin: Effects of Processing Schemes

Zhou

Liu

2016

Meteorological drought monitoring is important for drought early warning and disaster prevention. Regional meteorological drought can be evaluated and analyzed with standardized precipitation index (SPI). Two main processing schemes are frequently adopted: (1) mean of all SPI calculated from precipitation at individual stations (SPI-mean); and (2) SPI calculated from all-station averaged precipitation (precipitation-mean). It yet remains unclear if two processing schemes could make difference in drought assessment, which is of significance to reliable drought monitoring. Taking the Poyang Lake Basin with monthly precipitation recorded by 13 national stations for 1957-2014, this study examined two processing schemes. The precipitation mean and SPI mean were respectively calculated with the Thiessen Polygon weighting approach. Our results showed that the two SPI series individually constructed from two schemes had similar features and monitoring trends of regional meteorological droughts. Both SPI series had a significantly positive correlation (p < 0.005) with the number of precipitation stations. The precipitation-mean scheme reduced the extent of precipitation extremes and made the precipitation data more clustered in some certain, it made less precipitation deviate from the precipitation-mean series farther when less precipitation occurred universally, which would probably change the drought levels. Alternatively, the SPI-mean scheme accurately highlighted the extremes especially for those with wide spatial distribution over the region. Therefore, for regional meteorological drought monitoring, the SPI-mean scheme is recommended for its more suitable assessment of historical droughts.