Fig. 4: Winter atmospheric response (perturbation experiment minus control experiment) in the LTHF2X, LTHF3X, and LTHF4X experiments.

a SAT (°C, shade) and SLP (hPa, contour) response in the LTHF2X experiment. b 500 hPa geopotential height response (gpm) in the LTHF2X experiment. c 700 hP zonal wind response (m s−1) in the LTHF2X experiment. d−f same as a−c, but for response in the LTHF3X experiment. g−i same as a−c, but for response in the LTHF4X experiment. Solid and dashed contours represent positive and negative anomalies, respectively, omitting the zero contours. The contour interval is 1 hPa in a, d, g. Stippling as in Fig. 1.