Moisture source and transport variability in East Antarctica and its response to climate modes during the past two centuries

• Main Authors: Ejaz, T., Rahaman, W., Thamban, M., Laluraj, C., Mahalinganathan, K., Redkar, B.
• Format: Conference Object
• Language: English
• Published: 2023
• Subjects: Antarctic; East Antarctica; Pacific; The Antarctic; Antarc*; Antarctica; DML; ice core; Ice Sheet; Sea ice
• Online Access: https://gfzpublic.gfz-potsdam.de/pubman/item/item_5019837

Moisture source and transport to coastal Antarctica are crucial for regulating the Antarctic precipitation, sea ice variability, and ice sheet mass balance. To assess the mass balance in the coastal regions, which are very sensitive to climate change, it is important to have past relative humidity (RH) records over the coastal region. The instrumental record of RH in the Antarctic region is limited to 1979, which is too short to discern long-term climate variability on an annual to decadal time scale. This study used off-axis integrated cavity output spectroscopy for high-precision measurements of d17O and d18O in newly retrieved ice core IND33 (1809-2013 CE). The derived parameter 17O-excess has been used as a robust proxy for RH. Therefore, we have reconstructed the first long-term RH for the past two centuries based on the 17O-excess ice core record. The reconstructed RH record significantly correlates with precipitation and sea ice concentration over the DML and its proximal oceanic sector. This indicates moisture supply from the proximal oceanic sector control precipitation and thereby control mass accumulation on the Antarctic ice sheet. Our preliminary investigation suggests that climate modes and teleconnections control RH variability. El Niño Southern Oscillation (ENSO) controls the interannual RH variability. However, the Interdecadal Pacific Oscillation (IPO) controls the decadal variability of RH and positively correlates with the DML region. Southern Annular Mode (SAM) dominantly controls the westerlies; therefore, we suggest shifting SAM to a positive phase strengthens the westerlies and reduces relative humidity over the DML region.