TY - JOUR

T1 - Role of mineral dust in the nitrate preservation during the glacial period

T2 - Insights from the RICE ice core

AU - Venugopal, Abhijith U.

AU - Bertler, Nancy A. N.

AU - Pyne, Rebecca L.

AU - Kjaer, Helle A.

AU - Winton, V. Holly L.

AU - Mayewski, Paul A.

AU - Cortese, Giuseppe

PY - 2022/2/1

Y1 - 2022/2/1

N2 - Nitrate (NO3-), an abundant aerosol in polar snow, is a complex environmental proxy to interpret owing to its diverse sources and susceptibility to post-depositional processes. During the last glacial period, when dust concentrations in the Antarctic ice were upto similar to 50 times than today, mineral dust appears to have a stabilizing effect on the NO3- concentration in snow. However, the mechanism leading to the stabilization remains unclear. Here, we present the new and highly resolved records of NO3- and non-sea salt calcium (nssCa(2+), a proxy for mineral dust) from the Roosevelt Island Climate Evolution (RICE) ice core. We focus on the glacial period from 83 to 26 kilo years Before Present (ka BP). The data show a statistically significant correlation between NO3- and nssCa(2+) over this period. To put our findings into a spatial context, we compare RICE data with existing records from east Antarctica (EPICA Dome C [EDC], Vostok and central Dome Fuji) and West Antarctica (West Antarctic Ice Sheet Divide Ice Core [WDC]). Spatial analysis suggests that nssCa(2+) is contributing to the effective scavenging of NO3- from the atmosphere perhaps through the formation of calcium nitrate (Ca(NO3)(2)). The geographic pattern implies that the process of Ca(NO3)(2) formation occurs during the long-distance transport of mineral dust from mid-latitude source regions by Southern Hemisphere Westerly Winds (SHWW). The data also suggest that the correlation observed at various Antarctic locations may depend on the level of dust reaching the sites from the mid-latitude sources.

AB - Nitrate (NO3-), an abundant aerosol in polar snow, is a complex environmental proxy to interpret owing to its diverse sources and susceptibility to post-depositional processes. During the last glacial period, when dust concentrations in the Antarctic ice were upto similar to 50 times than today, mineral dust appears to have a stabilizing effect on the NO3- concentration in snow. However, the mechanism leading to the stabilization remains unclear. Here, we present the new and highly resolved records of NO3- and non-sea salt calcium (nssCa(2+), a proxy for mineral dust) from the Roosevelt Island Climate Evolution (RICE) ice core. We focus on the glacial period from 83 to 26 kilo years Before Present (ka BP). The data show a statistically significant correlation between NO3- and nssCa(2+) over this period. To put our findings into a spatial context, we compare RICE data with existing records from east Antarctica (EPICA Dome C [EDC], Vostok and central Dome Fuji) and West Antarctica (West Antarctic Ice Sheet Divide Ice Core [WDC]). Spatial analysis suggests that nssCa(2+) is contributing to the effective scavenging of NO3- from the atmosphere perhaps through the formation of calcium nitrate (Ca(NO3)(2)). The geographic pattern implies that the process of Ca(NO3)(2) formation occurs during the long-distance transport of mineral dust from mid-latitude source regions by Southern Hemisphere Westerly Winds (SHWW). The data also suggest that the correlation observed at various Antarctic locations may depend on the level of dust reaching the sites from the mid-latitude sources.

KW - RICE ice core

KW - Last glacial period

KW - Mineral dust-nitrate coupling

KW - Nitrate scavenging

KW - Atmospheric process

KW - A new coastal record

KW - CONTINUOUS-FLOW ANALYSIS

KW - DOME C

KW - NITRIC-ACID

KW - ISOTOPIC CONSTRAINTS

KW - SCALE VARIABILITY

KW - ROOSEVELT ISLAND

KW - SOUTHERN-OCEAN

KW - ROSS SEA

KW - SNOW

KW - ANTARCTICA

U2 - 10.1016/j.gloplacha.2022.103745

DO - 10.1016/j.gloplacha.2022.103745

M3 - Journal article

VL - 209

JO - Global and Planetary Change

JF - Global and Planetary Change

SN - 0921-8181

M1 - 103745

ER -