Triple Oxygen and Hydrogen Isotope based Climate Reconstruction using Ice Core Records from Coastal Dronning Maud Land East Antarctica

Abstract

Antarctic ice sheet is one of the most critical climate archives. The ice core records newlineretrieved from the ice sheet plays a critical role in understanding the past climate on an newlineannual to decadal timescale. Major climatic oscillations like El Niño Southern newlineOscillation (ENSO), Pacific Decadal Oscillation (PDO), Interdecadal Pacific newlineOscillation (IPO) and their phase relation with the Southern Annular Mode (SAM) newlinelargely control Antarctic climate variability. However, the relative roles of these climate newlinemodes remain elusive, particularly in the backdrop of global warming. To investigate newlinethe role of these climate modes in the Antarctic temperature variability, this study used newlinea well-dated and annually resolved new ice core (IND33) collected as part of the Indian newlineScientific Expedition to Antarctica along with published ice core records (DML07, newlineDML05, and DML17) of stable water isotopes (and#61540;18O, and#61540;D) for the past two centuries newline(1809 2013 CE) from Dronning Maud Land (DML) in East Antarctica. The Principal newlineComponent Analysis (PCA) performed on the ice core records of the DML region newlineunveils that the first principal component explaining the maximum variability (and#8764;32%) newlinein and#948;18O records is related to late spring to summer (Nov Dec Jan) temperature rather newlinethan the mean annual temperature. This indicates that reconstructed annual temperature newlinebased on Antarctic ice core and#948;18O records in the DML region could be biased toward the newlinetemperature of the months/seasons of higher precipitation with low-moderate wind newlinespeed, which are suitable for better preservation of the ice core signals. This study newlinereconstructed the DML temperature record of the past two centuries (1809 2019 CE) newlineat an annual resolution based on the and#948;18O ice core record (1809 1993 CE) combined newlinewith the recent ERA5 surface air temperature record (1994 2019 CE). The newlinereconstructed temperature anomaly record reveals a significant cooling trend in the 19th newlinecentury during 1809 1907 CE at a rate of and#8722;0.164 ± 0.045°C decadeand#8722;1 followed by a newlineIV newlinewarming trend fro