|Title||Origin of seasonal predictability for summer climate over the Northwestern Pacific|
|Publication Type||Journal Article|
|Year of Publication||2013|
|Authors||Kosaka Y, Xie SP, Lau NC, Vecchi GA|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|Type of Article||Article|
|Keywords||air-sea interaction; air-temperature; East Asian summer monsoon; el-nino; enso; indian-ocean; interbasin interaction; model; monsoon rainfall; part i; sea-surface temperature; sst; tropical variability; western north pacific|
Summer climate in the Northwestern Pacific (NWP) displays large year-to-year variability, affecting densely populated Southeast and East Asia by impacting precipitation, temperature, and tropical cyclones. The Pacific-Japan (PJ) teleconnection pattern provides a crucial link of high predictability from the tropics to East Asia. Using coupled climate model experiments, we show that the PJ pattern is the atmospheric manifestation of an air-sea coupled mode spanning the Indo-NWP warm pool. The PJ pattern forces the Indian Ocean (IO) via a westward propagating atmospheric Rossby wave. In response, IO sea surface temperature feeds back and reinforces the PJ pattern via a tropospheric Kelvin wave. Ocean coupling increases both the amplitude and temporal persistence of the PJ pattern. Cross-correlation of ocean-atmospheric anomalies confirms the coupled nature of this PJIO mode. The ocean-atmosphere feedback explains why the last echoes of El Nino-Southern Oscillation are found in the IO-NWP in the form of the PJIO mode. We demonstrate that the PJIO mode is indeed highly predictable; a characteristic that can enable benefits to society.