Fig. 2: Interannual variability in the TP SPV anomaly.

Time series of the interannual monthly mean TP SPV (PVU) anomalies (relative to the mean over the 1979–2022 period) where the topography is above 3 km for June, July, and August. The purple line denotes the regional mean of TP SPV where the standard deviation of interannual TP SPV is above 5 in June. The red circles denote the typical years of 1983, 1995, and 2022 (the TP SPV in June was especially weak or strong).