High Latitude Dust in the Earth System

TOM BRADWELL2 ; MATTHEW BADDOCK1; DIEGO GAIERO; ELEANOR DARLINGTON; RICHARD HODGKINS; GUDRUN GISLADOTTIR ; TOM MOCKFORD ; CHERYL MCKENNA NEUMAN; THROSTUR THORSTEINSSON; BULLARD, JOHANA; JOHN CRUSIUS; SANTIAO GASSÓ; ROBERT MCCULLOCH; HELENA STEWART

REVIEWS OF GEOPHYSICS

AMER GEOPHYSICAL UNION

Año: 2016 vol. 54 p. 1 - 39

8755-1209

Natural dust is often associated with hot, subtropical deserts, but significant dust events have been reported from cold, high latitudes. This review synthesizes current understanding of high latitude (≥50°N and ≥40°S) dust source geography and dynamics and provides a prospectus for future research on the topic. Although the fundamental processes controlling aeolian dust emissions in high latitudes are essentially the same as in temperate regions, there are additional processes specific to, or enhanced in cold regions. These include low temperatures, humidity, strong winds, permafrost and niveo-aeolian processes all of which can affect the efficiency of dust emission and distribution of sediments. Dust deposition at high latitudes can provide nutrients to the marine system, specifically by contributing iron to high nutrient-low chlorophyll oceans; it also affects ice albedo and melt rates. There have been no attempts to quantify systematically the expanse, characteristics or dynamics of high latitude dust sources. To address this, we identify and compare the main sources and drivers of dust emissions in the northern (Alaska, Canada, Greenland, Iceland) and southern (Antarctica, New Zealand, Patagonia) hemispheres. The scarcity of year-round observations and limitations of satellite remote sensing data at high latitudes are discussed. It is estimated that under contemporary conditions high latitude sources cover >500,000 km2 and contribute at least 80-100 Tg yr-1 of dust to the Earth system (c. 5% of the global dust budget); both are projected to increase under future climate change scenarios.