Mechanisms Associated With Tropospheric Dry Static Stability Change During the Last Glacial Maximum

Abstract

AbstractThe processes governing tropospheric stratification alterations during the Last Glacial Maximum (LGM) are investigated using the Paleoclimate Modeling Intercomparison Project Phase 3/4 (PMIP3/PMIP4) simulations. The results demonstrate a decrease in static stability in the tropics during both December‐January‐February (DJF) and June‐July‐August (JJA), while an increase is observed in the extratropics during DJF. Further analysis reveals that the rise in static stability over high‐latitude ocean is driven by shifts in surface frozen lines, whereas the increased static stability over ice sheet margins is due to the cooling effect of ice sheet slopes. The study finds that the dry static stability change in ice sheet‐covered areas remains significant and robust in both PMIP3 and PMIP4. However, a weaker stabilization signal is detected in the North Atlantic in PMIP4. These findings provide valuable insights into the processes shaping tropospheric stratification during the LGM and underscore the importance of accounting for ice sheet effects in paleoclimate simulations.