Observed 20th century desert dust variability: impact on climate and biogeochemistry

作者：N. M. Mahowald, Silvia Kloster, Sebastian Engelstaedter, Jefferson Keith Moore, Sujoy Mukhopadhyay, Joseph R. McConnell, Samuel Albani, Scott C. Doney, Anwesa Bhattacharya, Mark A. J. Curran, Mark G. Flanner, Forrest M. Hoffman, David M. Lawrence, Keith Lindsay, Paul A. Mayewski, Jason C. Neff, Daniel Rothenberg, Elizabeth Ruth Thomas, PETER E. THORNTON, Charles Sutton Zender · 发表于：Atmospheric chemistry and physics · 年份：2010 · DOI：10.5194/acp-10-10875-2010 · 被引用次数：501 · 研究领域：Atmospheric chemistry and aerosols、Aeolian processes and effects、Atmospheric and Environmental Gas Dynamics

Abstract. Desert dust perturbs climate by directly and indirectly interacting with incoming solar and outgoing long wave radiation, thereby changing precipitation and temperature, in addition to modifying ocean and land biogeochemistry. While we know that desert dust is sensitive to perturbations in climate and human land use, previous studies have been unable to determine whether humans were increasing or decreasing desert dust in the global average. Here we present observational estimates of desert dust based on paleodata proxies showing a doubling of desert dust during the 20th century over much, but not all the globe. Large uncertainties remain in estimates of desert dust variability over 20th century due to limited data. Using these observational estimates of desert dust change in combination with ocean, atmosphere and land models, we calculate the net radiative effect of these observed changes (top of atmosphere) over the 20th century to be −0.14 ± 0.11 W/m2 (1990–1999 vs. 1905–1914). The estimated radiative change due to dust is especially strong between the heavily loaded 1980–1989 and the less heavily loaded 1955–1964 time periods (−0.57 ± 0.46 W/m2), which model simulations suggest may have reduced the rate of temperature increase between these time periods by 0.11 °C. Model simulations also indicate strong regional shifts in precipitation and temperature from desert dust changes, causing 6 ppm (12 PgC) reduction in model carbon uptake by the terrestrial biosphere o...