Abstract
This study attempts to analyze several drought features in South Korea from various perspectives using a three-month standard precipitation index. In particular, this study aims to evaluate changes in spatial distribution in terms of frequency and severity of droughts in the future due to climate change, using IPCC (intergovernmental panel on climate change) GCM (general circulation model) simulations. First, the Mann-Kendall method was adopted to identify drought trends at the five major watersheds. The simulated temporal evolution of SPI (standardized precipitation index) during the winter showed significant drying trends in most parts of the watersheds, while the simulated SPI during the spring showed a somewhat different feature in the GCMs. Second, this study explored the low-frequency patterns associated with drought by comparing global wavelet power, with significance test. Future spectra decreased in the fractional variance attributed to a reduction in the interannual band from 2 to 8 years. Finally, the changes in the frequency and the severity under climate change were evaluated through the drought spell analyses. Overall features of drought conditions in the future showed a tendency to increase (about 6%) in frequency and severity of droughts during the dry season (i.e., from October to May) under climate change.
Highlights
There exists a degree of climate variability on all time scales, and floods and droughts are extremes associated with variability in precipitation
We examined the spatial distribution of the severity and frequency in the dry stages in the major river basins
Climate change is expected to change the hydrological pattern, frequency, and intensity of droughts, leading to a higher number of drought-related disasters, the importance of developing a strategy for better assessing the impact of climate change on extremes associated with drought
Summary
There exists a degree of climate variability on all time scales, and floods and droughts are extremes associated with variability in precipitation. Climate variability characterized by a slow-varying oscillation in the climate system can modify the likelihood of hydrologic extreme events. Climate change refers to any long-term, significant change in the expected patterns of average weather in a specific region [4]. It has been widely acknowledged that the frequency and magnitude of extreme hydrologic events can be modulated by enhanced climate variability driven by climate change [1, 3, 5]. According to the precipitation outlook based on climate change scenarios [4], increasing concentrations of greenhouse gases are likely to trigger very different patterns of heavy rain, extreme drought, and heavy snow in some regions [6]
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