Enhancement of the relationship between the winter Arctic oscillation and the following summer circulation anomalies over central East Asia since the early 1990s
Considering the possible lag of the impact of the winter Arctic oscillation (AO) on the subsequent summer climate anomalies over East Asia and that the relationship between them may differ during different periods, the non-stationary relationship between these systems and the corresponding mechanism of connection are investigated in this study. A regime shift of the winter AO index was detected around 1988, with mean AO indices of −0.69 and 0.10 for 1958–1987 and 1988–2014, respectively, and their differences passed the 99% confidence level. After the regime shift and especially since the early 1990s, negative (positive) winter AO indices corresponds with positive (negative) height anomalies over central East Asia (CEA) during the following summer. Meanwhile, the westerly jet stream tends to be northward (southward) and the East Asian summer monsoon (EASM) is strong (weak), which contributes to the warm (cold) anomalies over central China and the significantly enhanced (reduced) rainfall over northeast China. After the early 1990s, the enhanced connection of the winter AO and the following summer height anomalies over CEA is largely due to the enhanced connection of the winter AO and the following Indian summer monsoon (ISM) rainfall during the same period. The negative (positive) winter AO favors increasing (decreasing) rainfall over the ISM region, which triggers a positive (negative) circumglobal teleconnection (CGT), and results in significantly positive (negative) height anomalies over CEA. One way the winter AO could influence the following ISM rainfall is that the negative (positive) winter AO memories will be maintained by the positive (negative) sea surface temperature (SST) anomalies over the tropical Atlantic of the following summer, which are responsible for the La Niña (El Niño) developing phase and increases (decreases) the ISM rainfall.
KeywordsArctic oscillation Regime shift Central East Asia Indian summer monsoon Tropical Atlantic Circumglobal teleconnection
This study acknowledges the support of the National Basic Research Program of China (973 Program) (2013CB430204), National Natural Science Foundation of China (41530531, 41575082, 41575074, 41475064, 41675107).
- Adler RF, Huffman GJ, Chang A, Ferraro R, Xie PP, Janowiak J, Rudolf B, Schneider U, Curtis S, Bolvin D, Gruber A, Susskind J, Arkin P, Nelkin E (2003) The version-2 global precipitation climatology project (GPCP) monthly precipitation analysis (1979–present). J Hydrol 4:1147–1167Google Scholar
- Chen W (2002) Impacts of El Niño and La Niña on the cycle of the East Asian winter and summer monsoon (in Chinese). Chin. J Atmos Sci 26:595–610Google Scholar
- Chen W, Graf HF, Huang RH (2000) The interannual variability of East Asian winter monsoon and its relation to the summer monsoon. Adv Atmos Sci 17:46–60Google Scholar
- Chen M, Xie P, Janowiak JE, Arkin PA (2002) Global land precipitation: a 50-yr monthly analysis based on gauge observations. J Hydrol 3:249–266Google Scholar
- He W, Feng G, Gao X, Li J (2006) Amplitude death in non-feedback coupled chaotic system (in Chinese). Acta Physica Sinica 55:6192–6196Google Scholar
- Kalnay E, Kanamitsu M, Kistler R, Collins W, Deaven D, Gandin L, Iredell M, Saha S, White G, Woolen J, Zhu Y, Chelliah M, Ebisuzaki W, Higgins W, Janowiak J, Mo KC, Ropelewski C, Wang J, Leetmaa A, Reynolds R, Jenne R, Joseph D (1996) The NCEP/NCAR 40-year reanalysis project. Bull Am Meteo Soc 77:437–471CrossRefGoogle Scholar