Recent global dust trend and connections to climate forcing

Dust is an important indicator of climate change. In paleoclimate research, sediments bearing signals of dust deposition offer a rich archive for climate change history. However, the dust-climate link is very complex due to the various direct and indirect feedbacks in the Earth system. In this study, we examine two issues: (1) given the recent global warming, what are the dust variations, both globally and in key dust regions, and (2) what are the climate drivers behind the variations? Using synoptic data for the period 1974-2012, we analyzed the global trend of dust frequency and visibility-derived dust concentrations and their characteristics in key dust regions, including North Africa, the Middle East, Southwest Asia, Northeast Asia, South America, and Australia. We also examined the likely climate drivers for dust variations in the different regions by computing the correlations between the time series of dust and of major climate indices - the Multivariate El Niño/Southern Oscillation Index, North Atlantic Oscillation, and Atlantic Multidecadal Oscillation (AMO). It was found that over the period 1984-2012, the global mean (excluding North America and Europe) near-surface dust concentration decreased at 1.2% yr-1. This decrease is mainly due to reduced dust activities in North Africa, accompanied by reduced activities in Northeast Asia, South America, and South Africa. A significant negative correlation between Saharan dust and AMO was detected, and it seems reasonable to suggest that under present climate, the global dust trend is determined by the climate systems governing the Atlantic and North African regimes. Key Points The recent history of global dust frequency and concentration is investigated Dust variations are determined, both globally and in key dust regions Climate drivers behind the dust variations are identified ©2013. American Geophysical Union. All Rights Reserved.