The influence of regional circulation patterns on wet and dry mineral dust and sea salt deposition over Greenland

Abstract

Annually resolved ice core records from different regions over the Greenland ice sheet (GrIS) are used to investigate the spatial and temporal variability of calcium (Ca 2+ , mainly from mineral dust) and sodium (Na + , mainly from sea salt) deposition. Cores of high common inter-annual variability are grouped with an EOF analysis, resulting in regionally representative Ca 2+ and Na + records for northeastern and central Greenland. Utilizing a regression and validation method with ERA-40 reanalysis data, these common records are associated with distinct regional atmospheric circulation patterns over the North American Arctic, Greenland, and Central to Northern Europe. These patterns are interpreted in terms of transport and deposition of the impurities. In the northeastern part of the GrIS sea salt records reflect the intrusion of marine air masses from southeasterly flow. A large fraction of the Ca 2+ variability in this region is connected to a circulation pattern suggesting transport from the west and dry deposition. This pattern is consistent with the current understanding of a predominantly Asian source of the dust deposited over the GrIS. However, our results also indicate that a significant fraction of the inter-annual dust variability in NE and Central Greenland is determined by the frequency and intensity of wet deposition during the season of high atmospheric dust loading, rather than representing the variability of the Asian dust source and/or long-range transport to Greenland. The variances in the regional proxy records explained by the streamfunction patterns are high enough to permit reconstructions of the corresponding regional deposition regimes and the associated circulation patterns.

Decadal Variability in a Central Greenland High-Resolution Deuterium Isotope Record and Its Relationship to the Frequency of Daily Atmospheric Circulation Patterns from the North Atlantic Region

“…3. A similar pattern is associated with enhanced mineral dust and sea salt deposition in Greenland during winter (Hütterli et al 2006; their Figure 5). Therefore the seasonal patterns associated to the deuterium variability during winter (Barlow et al 1993) can be considered as the signature of high (low) frequency of patterns 8 (5) of winter daily circulation.…”

“…The variable position of moisture source gives a stronger NAO signal in Greenland ice cores than the variability of SST associated to the two NAO phases (Sodemann et al 2008). However, NAO does explain just part of the variability in certain proxy records from Greenland (Hütterli et al 2006). An alternative approach is to establish a direct connection between proxy records from Greenland and synoptic scale phenomena (Hütterli et al 2005;Fischer and Mieding 2005;Rimbu et al 2007).…”

Lead atmospheric deposition rates and isotopic trends in Asian dust during the last 9.5kyr recorded in an ombrotrophic peat bog on the eastern Qinghai–Tibetan Plateau

“…1) are some of the largest sources of global atmospheric dust (Merrill et al, 1994) and contribute, with the deserts of Mongolia, to 70% of the total Asian emissions to the atmosphere . Asian dust is transported globally and has been found in aerosols and archives in regions as far removed as Pacific ocean islands (Kurtz et al, 2001) and marine sediments (Pettke et al, 2000), North America (VanCuren, 2003;Zdanowicz et al, 2006), Europe and Greenland Hutterli et al, 2007). These deserts are likely candidates for the deposition of natural soil-derived Pb to HYLK-1.…”

High-Resolution Greenland Ice Core Data Show Abrupt Climate Change Happens in Few Years

“…Changes in sea-ice extent are expected to influence sea-salt export to Greenland through changing the distance to open water and altering sea-salt aerosol contributions from sea-ice and open-water sources. However, meteorological conditions play an important role in modulating the sea-salt uplift, transport, and deposition on the Greenland ice sheet (29). Although insufficient quantitative understanding of the processes involved is available, the lack of a fast response of the marine sea-salt proxy may be seen as a gradual change in sea ice or as a combination of changes in sea ice and meteorology, compensating for each other to some extent.…”