Contribution of the tropical western Atlantic thermal conditions during the preceding winter to summer temperature anomalies over the lower reaches of the Yangtze River basin–Jiangnan region

Abstract

Using the National Centers for Environmental Prediction-National Center for Atmospheric Research reanalysis and National Oceanic and Atmospheric Administration extended reconstructed sea surface temperature (SST) data sets, we examine the preceding factors in the Atlantic Ocean contributing to summer high temperature anomalies over the lower reaches of the Yangtze River basin-Jiangnan (LRYB-JN) region. We find that summer LRYB-JN surface air temperature (SAT) anomalies are highly correlated with, and physically connected to, the preceding winter SST and SAT anomalies in the tropical western Atlantic (TWA) region [(10 ∘ -30 ∘ N, 60 ∘ -35 ∘ W) and (0 ∘ -10 ∘ N, 50 ∘ -35 ∘ W)]. The effect of preceding winter thermal conditions in the TWA region can be explained by the following two mechanisms. Coupled with SST, positive TWA SAT anomalies can persist from the preceding winter to summer and excite a zonal wave train at middle latitudes extending from the Atlantic to Eurasia, with a deep and stable high pressure anomaly centred over the LRYB-JN region. As a result, high temperature anomalies occur over the LRYB-JN region. In addition to the above mechanism, the TWA SST-SAT coupled anomalies also exert an impact on summer LRYB-JN SAT by modulating the tropical Indian Ocean (TIO) SAT and SST variation, which causes summer LRYB-JN SAT anomalies. Given the contributions of TWA SAT anomalies, independent of and in concert with the TIO SAT variation, we define a preceding winter TWA-TIO SAT index, which measures the concurrent variation of TWA and TIO SATs. The preceding winter TWA-TIO index is more significantly correlated with the summer LRYB-JN SAT and therefore can reflect the latter better than the individual TWA or TIO SAT index.

A role of the Atlantic Ocean in predicting summer surface air temperature over North East Asia?

“…This is a promising result since changes of SAT relative to a long-term trend are difficult to predict over land (Bellucci et al 2013;among others). This mechanism is found to be robust at a 2-5 year leadtime and is consistent with the literature (Wu et al 2016a, b;Lin et al 2016) and has been associated with changes over the Atlantic Ocean (Lu et al 2006;Lin et al 2016;Wu et al 2016a, b;Wang et al 2017). We also tested this mechanism in observations with a comparison between the previous positive phase of the AMV (1950)(1951)(1952)(1953)(1954)(1955)(1956)(1957)(1958)(1959)(1960)(1961)(1962)(1963)(1964)(1965) and the last negative phase of the AMV (1979AMV ( -1993 and found a similar result but with an opposite sign: a Rossby wave extends from the Atlantic Ocean leading to negative SAT anomalies over NEA (Fig.…”

“…7). The results obtained above that show that Asia's climate was modulated by a wave pattern is consistent with a growing body of evidence that highlights the importance of Rossby waves on this area (Lu et al 2002;Enomoto et al 2003;Enomoto 2004;Ding et al 2011;Kosaka et al 2011;Huang et al 2012;Wu et al 2016a, b;Lin et al 2016;Wang et al 2017). The associated pattern is known as "silk road" or CGT pattern, depending on the path of the wave.…”

“…Rossby waves that impact eastern China have been associated with changes over the (1) Atlantic Ocean (Wu et al 2016a, b;Lin et al 2016;Wang et al 2017), (2) the Pacific Ocean (Ding et al 2011;Lin et al 2016) and (3) the Indian summer monsoon (Enomoto et al 2003). Diabatic heating due to increased precipitation over these areas can lead to disturbances at upper-level and to a propagation of energy via a Rossby wave (Hoskins et al 1977;Hoskins and Karoly 1981;Lau 1997).…”

Co-variability of the summer NDVIs on the eastern Tibetan Plateau and in the Lake Baikal region: Associated climate factors and atmospheric circulation

“…The SSTAs in the tropical Atlantic Ocean can affect downstream climate through stimulating wave train pattern [ 81 – 83 ]. The correlation between the negative I SN−Atlantic between 200 hPa V-winds ( Fig 11 ) shows two wave trains from the Atlantic to East Asia at the mid-low and mid-high latitudes, respectively, in which the wave train at the mid-low latitudes is generally similar to the Silk Road teleconnection [ 84 , 85 ].…”

A tripole pattern of summer surface air temperature anomalies over northern Eurasia and its precursory signals in the tropical Atlantic and northern Asian land

“…Specifically, the SSTAs in the Atlantic Ocean not only influence climate anomalies in adjacent Europe (Cassou et al ., 2005; Sutton and Hodson, 2005, 2007; Feudale and Shukla, 2011a, 2011b; Sutton and Dong, 2012; Saeed et al ., 2014), but also remotely adjust, to some extent, Asian circulation and associated climate variability on different timescales (Goswami et al ., 2006; Lu et al ., 2006; Li et al ., 2008, 2015; Wu et al ., 2009; Wu et al ., 2010, 2011; Zuo et al ., 2013; Sun, 2014; Krishnamurthy and Krishnamurthy, 2016; Wang et al ., 2017). Therefore, attention should be paid to the contribution of the SSTAs in the Atlantic Ocean when investigating integral structures of climate anomalies over Eurasia.…”