Abstract
Drought is one of the most important environmental disasters. Assessment of the effects of oceanic atmospheric oscillations upon regional drought behavior has valuable implications for water resources management, especially for arid regions. This study aims to explore the climate drivers of drought conditions in Xinjiang, an arid region in mid-latitude Asia. Standardized Precipitation Evapotranspiration Index (SPEI) was adopted to describe drought variation over Xinjiang during the period of 1951–2020. Teleconnection effects of El Niño Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO), Atlantic Multidecadal Oscillation (AMO), and Arctic Oscillation (AO) on Xinjiang drought variability were analyzed based on cross-correlation and stepwise regression methods. Partial correlation analysis was applied to discuss the responding mechanism of drought behavior to teleconnection signals from the perspective of regional climate factors. Findings from this study indicate that synchronous ENSO featured by Nino3.4 index has a significant positive correlation with Xinjiang dry/wet variation. El Niño may favor to wetness in Xinjiang, while La Niña may exacerbate drought effect in the region. ENSO mainly acts on the short-term drought variability in Xinjiang region. The synchronous PDO makes a leading contribution on drought variation at 12-month time scale among the four signals. The significant positive correlation between PDO and drought variation suggests that positive-phase (negative-phase) PDO may contribute to wetting (drying) epochs in Xinjiang region. AMO indicates a significant negative correlation with Xinjiang drought on both synchronous and asynchronous modes. Positive (negative) phase AMO may favor to dry (wet) effects in Xinjiang. AMO appears a predominant teleconnection effect on long-term drought variability, and fluctuates a persistent anti-phase mode with Xinjiang dry/wet variability since the mid-1980s. AO mainly acts on short-term drought fluctuations, indicating a significant negative correlation with drought behavior within a 12-month moving time window. Positive (negative) phase AO may contribute to dry (wet) epochs over Xinjiang. ENSO and PDO affect short-term dry/wet variation mainly through the teleconnection effect on precipitation variability. AMO mainly influences Xinjiang drought evolution by acting on regional temperature variation. The influence of internal atmospheric variability on regional climate behavior has a delayed effect, and drought variability is affected by precursor pattern of teleconnection likewise.
Highlights
Drought is a kind of climate phenomenon characterized by a shortage of water, which is insufficient to meet human survival and economic development [1]
To attribute the apparent increase in the regional drought occurrence to climate variability, we investigated the impact of the large-scale atmospheric circulation patterns, i.e., El Niño Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO), Atlantic Multidecadal Oscillation (AMO), and Arctic Oscillation (AO)
Positive phase PDO favors to wetness in Xinjiang, which is consistent with the effect of ENSO mode on drying and wetting variations in the region
Summary
Drought is a kind of climate phenomenon characterized by a shortage of water, which is insufficient to meet human survival and economic development [1]. As global warming intensifies since the late 1970s, the risk of drought increases [2]. Arid regions in northwestern China (where Xinjiang located) face severe drought risk and water crises [8]. Warmer climate states appear to produce greater climate variability, which means that global warming will intensify the hydrological cycle, with wet regions becoming wetter and dry regions becoming drier [12]. This is crucial in arid regions, since the added pressure of limited water resources is further exacerbated by climate warming [13]. Global climate change has sharpened focus on the social and economic challenges associated with water deficits, in regions where anthropogenic demands exceed supply [14], such as Xinjiang [5,15], an arid region in central Asia
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