Fig. 2: Inter-model regression patterns of future changes under the SSP5-8.5 scenario onto the present-day IPWP size.

a Regressed future changes in SSTs (sea surface temperature, shading:  °C), 850 hPa stream function (contour interval: 0.3 × 10³ s⁻¹), and rotational wind (vectors, m s⁻¹). b Regressed future changes in 500 hPa vertical velocity (×10⁴ Pa s⁻¹; the upward motion is negative), 200 hPa velocity potential (contour interval: 0.3 × 10³ s⁻¹), and divergent wind (vectors, m s⁻¹). c Regressed future changes in zonal stream function (shading, 10⁸ kg s⁻¹) along the equator (meridional mean between 5°S and 5°N). Contours indicate MMEM of zonal stream function (10¹⁰ kg s⁻¹) in the present-day (1950–1999). Stipples indicate regions of significance at the 99% confidence level in a student t-test. Positive values indicate a clockwise movement and negative values indicate the reverse; the resulting zero line is the center of the strongest upward motion. The purple box is the region used to define the strength of Walker circulation.