Projection on elevation-dependent and latitude-dependent warming over Antarctica from CMIP6 under different socioeconomic scenarios

Abstract

Many studies have focused on elevation-dependent warming (EDW) across high mountains, but few studies have examined both EDW and LDW (latitude-dependent warming) on Antarctic warming. This study analyzed the Antarctic amplification (AnA) with respect to EDW and LDW under SSP1–2.6, SSP2–4.5, SSP3–7.0 and SSP5–8.5 from Coupled Model Intercomparison Project Phase 6 (CMIP6) during the period 2015–2100. The results show that the AnA appears under all socioeconomic scenarios, and the greatest signal appears in austral autumn. In the future, Antarctic warming is not only elevation-dependent, but also latitude-dependent. Generally, positive EDW of mean temperature (Tmean), maximum temperature (Tmax) and minimum temperature (Tmin) appear in the range of 1.0–4.5 km, and the corresponding altitudinal amplification trends are 0.012/0.012/0.011 (SSP1–2.6)—0.064/0.065/0.053 (SSP5–8.5) °C decade−1•km−1. Antarctic EDW demonstrates seasonal differences, and is strong in summer and autumn and weak in winter under SSP3–7.0 and SSP5–8.5. For Tmean, Tmax and Tmin, the feature of LDW is varies in different latitude ranges, and also shows seasonal differences. The strongest LDW signal appears in autumn, and the warming rate increases with increasing latitude at 64–79°S under SSP1–2.6. The similar phenomenon can be observed at 68–87°S in the other cases. Moreover, the latitude component contributes more to the warming of Tmean and Tmax relative to the corresponding altitude component, which may relates to the much larger range of latitude (∼2600 km) than altitude (∼4.5 km) over Antarctica, while the EDW contributes more warming than LDW in the changes in Tmin in austral summer. Moreover, surface downwelling longwave radiation, water vapor and latent heat flux are the potential factors influencing Antarctic EDW, and the variation in surface downwelling longwave radiation can also be considered as an important influencing factor for Antarctic LDW. Our results provide preliminary insights into EDW and LDW in Antarctica.