Fig. 2: Linkages between the dipole mode index (DMI) and detrended sea surface temperature (SST)/circulation anomalies over the period 1995–2019.
From: A stratospheric precursor of East Asian summer droughts and floods
a Simultaneous correlation coefficient in the global ocean. b Composite differences (southern flood–northern drought year/SFND minus southern drought–northern flood year/SDNF) of horizonal circulation (vectors) and vertical velocity (colors) anomalies at 500 hPa. c As in (b) but for vertically integrated moisture flux (vectors) and its divergence (colors) anomalies. d Lag correlation over the Atlantic region (averaged over 0–80°W). e Lag correlation over the tropical region (averaged over 10°S-10°N). f Lag correlation over the Indian Ocean (averaged over 30-60°E). Solid and dashed contours in (a) are the 5880-gpm geopotential height during SFND and SDNF years, respectively. The locations of the western ridge points of the Western North Pacific Subtropical High (WNPSH) and strength of the WNPSH are indicated by triangles and plus signs in (a), respectively. Orange/black triangles and plus signs represent the SDNF/SFND years, and a larger plus sign means a stronger WNPSH. The NTA, SNA, and SIO indices are the weight-averaged SST anomalies over 0-80°W and 0–20°N, 0–60°W and 55–75°N, and 25–80°E and 35–50°S, respectively. Dashed boxes in (d–f) show the locations of NTA, SNA, and SIO. Straight lines in (d–f) are July and August, and dots indicate values at the 95% confidence level according to Student’s t-test.
