Can Barents Sea Ice Decline in Spring Enhance Summer Hot Drought Events over Northeastern China?

Abstract

In July–August (JA) of 2016, northeastern China (NEC) suffered from the most severe hot drought event of the past 50 years, leading to profound impacts on agriculture, the ecosystem, and society. Results indicate that the loss of sea ice over the Barents Sea (SICBS) in March might have influenced the hot drought events over NEC in JA for the period of 1997–2016. Further analyses reveal that lower SICBS is closely related to thinner snow depth over western Eurasia (SDWEA) in April. The decline of SDWEA leads to drier soil from the Yangtze River valley to northern China during May–June, which is favorable for precipitation deficiency over NEC in JA. Besides, the loss of SICBS in March and decline of SDWEA in April are closely related to the polar–Eurasia teleconnection pattern and dry soil over NEC in JA, which provides favorable atmospheric circulation patterns for occurrences of hot droughts. The large ensemble simulations from the Community Earth System Model and the numerical experiments based on version 4 of the Community Atmosphere Model further confirmed their connections and the associated possible physical processes. Therefore, snow depth and soil moisture might serve as linkages between Barents Sea ice in March and hot droughts over NEC during JA, and the Barents Sea ice in March might be an important potential predictor for the summer hot droughts over NEC.

A Detectable Anthropogenic Shift Toward Intensified Summer Hot Drought Events Over Northeastern China

“…Consequently, the influence of human activities (GHG and ANT) and historical simulation are detectable in terms of the increasing trend of SHDEs over NEC. However, the interannual and interdecadal variations of SHDEs over NEC are not detected by external forcings, which indeed might be linked to internal variability (e.g., Li, Chen, Wang, Sun, & Ma, ).…”

“…Because northeastern China (NEC) is the granary of the country, droughts often lead to a serious deficiency in water supply and a severe reduction in crop production, which have further influences on the quality of human life and result in numerous economic losses. For example, the extreme summer hot drought event that occurred in 2016 over NEC led to severe yield reductions and economic losses reaching up to CNY15.61 billion (Li, Chen, Wang, Sun, & Ma, ). Thus, it is highly important to understand the changing characteristics of summer hot drought events (SHDEs) over NEC and its associated possible mechanisms.…”

“…In addition to these drought indices, another index based the concept of the multivariate copula is introduced (AghaKouchak et al, ; Cheng et al, ; Michele et al, ; Salvadori & De Michele, ). This drought index uses a probability‐based index that considers the joint effect of precipitation deficiency and high SAT, which is easier to identify the severity of hot drought event and has been used to investigate the influence of the internal natural forcing (Barents Sea ice decline in March) on the variations of SHDEs over NEC on the interannual scale (Li, Chen, Wang, Sun, & Ma, ). Therefore, this probability‐based index could be further applied to investigate the long‐term changes in SHDEs over NEC as well as the potential contributions of the strengthened human activities.…”

Is the Regional Precipitation Predictable in Decadal Scale? A Possible Approach for the Decadal Prediction of the Summer Precipitation Over North China

“…First, an empirical statistical model is built to predict the DI of the DP index (DI_DP) using multivariate regression []. Based upon previous studies, we look for the potential DI_Predictors mainly from the contributions of previous SST (Zhou et al, ), snow cover (Ding et al, ; Li et al, ), and sea ice concentration (Guo et al, ). The DI_Predictors have to lead the DI_DP at least 3 years to avoid the DI_Predictors using any information from prediction period.…”

“…On the other hand, the contribution of the Arctic SIC to summer precipitation over NC has been excessively explored (Uotila et al, ; Wu et al, ; Wu et al, ; Zhao et al, ). The anomalies of Arctic SIC is closely related to the anomalies of snow cover over Eurasia, which can cause anomalous soil moisture over east Asia (Zhang & Zuo, ) and a polar‐Eurasia teleconnection pattern (Li et al, ) to future influence the following summer circulation anomalies over NC. Additionally, corresponding to the anomalous Arctic SIC, the large‐scale circulation anomalies can cause the SST anomalies in the North Pacific (Guo et al, ), which can persist into following seasons and influence the precipitation anomalies over NC through circulation teleconnection (Wang et al, ) or anomalies land‐sea thermal contrast (Guo, ).…”