North Atlantic Modulation of Interdecadal Variations in Hot Drought Events over Northeastern China

Abstract

Based on the long-term reanalysis datasets and the multivariate copula method, this study reveals that the frequency of summer hot drought events (SHDEs) over northeastern China (NEC) shows interdecadal variations during 1925–2010. It is revealed that the summer sea surface temperature (SST) over the North Atlantic has a significant positive correlation with the frequency of SHDEs over NEC on the decadal time scale, indicating a potential influence of the Atlantic multidecadal oscillation (AMO). Further analyses indicate that during the positive phases of the AMO, the warming SST over the North Atlantic can trigger a stationary Rossby wave originating from the North Atlantic, which splits into two wave trains propagating along two different routes. One is a zonally orientated wave train that resembles the Silk Road pattern, whereas the other is an arching wave train that resembles the polar–Eurasian pattern. A negative (positive) phase of the Silk Road pattern (polar–Eurasian pattern) may result in the weakened westerly wind along the jet stream, the downward vertical motion, and the anomalous positive geopotential center over NEC, providing favorable conditions for precipitation deficiency and high temperature and resulting in increased SHDEs. Thus, the Silk Road pattern and the polar–Eurasian pattern serve as linkages between the AMO and SHDEs over northeastern China in summer on the interdecadal time scale. Model simulations from CAM4 perturbed with warmer SST in the North Atlantic show precipitation deficiency and high temperature conditions over northeastern China in summer, supporting the potential impacts of the North Atlantic SST on SHDEs over northeastern China. The results suggest that the phase of the AMO should be taken into account in the decadal prediction of SHDEs over northeastern China in summer.

Influence of Large‐Scale Circulation Patterns on Compound Dry and Hot Events in China

“…During the positive phase of AMO (warm SST over North Atlantic), a stationary Rossby wave originates from the west of North Atlantic and propagates eastward with two distinct pathways, which comprises of a zonally orientated wave train (from north Atlantic to East Asia) that resembles the negative phase of the Silk Road pattern, and an arching wave train (from north Atlantic to the polar region and then to East Asia) that resembles the positive phase of the Polar‐Eurasian pattern (H. Li et al., 2020). These wave activities and teleconnections affect the regional atmospheric circulation, resulting in an anomalous anticyclonic center, anomalous descending motions, and weakened upper‐level westerly jet stream in northeastern (and parts of northern) China (H. Li et al., 2020; G. W. Zhang et al., 2020). As a result, the anomaly of regional circulation patterns creates favorable conditions for less precipitation and warmer temperature there (Hong et al., 2020; H. Li et al., 2018; H. Li et al., 2020).…”

“…In this study, the gridded monthly precipitation and temperature data at 0.5° spatial resolution during 1921–2016 are obtained from the Climatic Research Unit (CRU TS v. 3.25) of the University of East Anglia (Harris et al., 2014). The main reason for choosing this period is that large uncertainties exist in the CRU data set before 1920 in China due to sparse meteorology stations (H. Li et al., 2020). Indices of four major large‐scale circulation patterns (ENSO, NAO, PDO, and AMO), which have been shown to have major influences on the climate over Asia (Dittus et al., 2018; Gao et al., 2017; C. C. Qian et al., 2014; Si & Ding, 2016; Shi et al., 2019; Sung et al., 2006), are employed in this study.…”

The influence of the Atlantic multidecadal oscillation on the interdecadal variability of winter precipitation in the Greater Mekong Subregion

“…As an important regulator of climate variability in the Northern Hemisphere, the Atlantic multidecadal oscillation (AMO) exerts a significant influence on the East Asian monsoon circulation, extreme precipitation, and high‐temperature events (Curtis, 2008; Chen et al ., 2010; Gao et al ., 2018; Li et al ., 2020). The AMO‐related sea surface temperature anomalies (SSTAs) over the North Atlantic modulate Rossby waves by changing diabatic heating and transient eddy activities (Li et al ., 2008; Fan et al ., 2018), and further influence the atmospheric circulation anomalies over East Asia (Zhu et al ., 2011; Fan et al ., 2018).…”

Monitoring landcover change and desertification processes in northern China and Mongolia using historical written sources and vegetation indices

“…Subsequent dry years, hot drought phenomena, and rising temperatures during the early growing season and summer can further strengthen the vulnerability of the steppe grassland in northern China (see Fig. 9) Li et al, 2020).…”