Dr.  Ruting  Yang
Beijing Normal University,  China

Title: Evidence for Intensification in Meteorological Drought Since the 1950s and Recent Dryness–Wetness Forecasting in China

Abstract:

Drought is one of the major environmental stressors, which is threatening the living environment of mankind. The standardized precipitation evapotranspiration index (SPEI) at a 12-month timescale was used to monitor dry–wet conditions in China during 1951–2021. The modified Mann–Kendall (MMK) and Pettitt tests were used to assess the temporal trend and nonlinear behavior of annual drought variability. In addition, the seasonal autoregressive integrated moving average (SARIMA) model was applied to forecast the dry–wet behavior in the year 2022 at 160 stations, and the hotspot areas for extreme dryness–wetness in China were identified in the near term. The results indicate that the dry–wet climate in China overall shows interannual variability characterized by intensified drought. The climate in the Northeast China (NEC), North China (NC), Northwest China (NWC), and Southwest China (SWC) has experienced a significant (p < 0.05) drying trend; however, the dry–wet changes in the East China (EC) and South Central China (SCC) are highly spatially heterogeneous. The significant uptrend in precipitation is mainly concentrated to the west of 100° E; the rising magnitude of precipitation is higher in eastern China near 30° N, with a changing rate of 20–40 mm/decade. Each of the sub-regions has experienced significant (p < 0.01) warming over the past 71 years. Geographically, the increase in temperature north of 30° N is noticeably higher than that south of 30° N, with trend magnitudes of 0.30–0.50 °C/decade and 0.15–0.30 °C/decade, respectively. The response of the northern part of eastern China to the warming trend had already emerged as early as the 1980s; these responses were earlier and more intense than those south of 40° N latitude (1990s). The drying trends are statistically significant in the northern and southern regions, bounded by 30° N, with trend magnitudes of −0.30–−0.20/decade and −0.20–−0.10/decade, respectively. The northern and southwestern parts of China have experienced a significant (p < 0.05) increase in drought level since the 1950s, which is closely related to significant warming in recent decades. This study shows the consistency of the spatial distribution of variations in precipitation and the SPEI along 30° N latitude. A weak uptrend in the SPEI, i.e., an increase in wetness, is shown in eastern China surrounding 30° N, with a changing rate of 0.003–0.10/decade; this is closely associated with increasing precipitation in the area. Drought forecasting shows that drying areas are located in NWC, the western part of NC, the western part of SWC, and the southern part of SCC in 2022. The climate is expected to show wetting characteristics in NEC, the southeastern part of NC, and the eastern part of EC. The dry–wet conditions spanning the area between 30–40° N and 100–110° E exhibit a greater spatial variability. The region between 20–50° N and 80–105° E will continue to face intense challenges from drought in 2022. This study provides evidence for the temporal variability of meteorological drought in different sub-regions of China. The findings could contribute to understanding the spatial effect of climate change on regional dry–wet variation since the 1950s, particularly in the context of global warming.

Biography:

Ruting Yang is currently pursuing a PhD in Hydraulic Engineering at Beijing Normal University. Her research focuses on hydrology and water resources. She has focused on the changes in water resources under climate change and published papers in SCI journal.