Publication date: 1 August 2017
Source:Palaeogeography, Palaeoclimatology, Palaeoecology, Volume 479
Author(s): Jiongxin Xu
Dust storms occur frequently in arid and semi-arid regions of China and other parts of the world, exerting a considerable influence on air quality in densely populated areas. Instrumental observations of dust storms are only available over the past 50 to 60years, limiting our ability to understand dust storm variability over longer timescales. However, tropical sea surface temperatures have been reconstructed over the past four centuries, using geochemical records from corals. Here we show that tropical Pacific sea surface temperatures, as recorded by corals, can be used to reconstruct dust storm frequency at one-year resolution. Based on the coral-reconstructed annual sea-surface temperature anomaly data from two regions (the western Pacific; 25°N–25°S, 110–155°E, and the eastern Pacific; 10°N–10°S, 175°E–85°W) published by Tierney et al. (2015), we reconstructed the frequency of dust storms in northern China (DSFCN) for the period from 1617 to 1953CE. The reconstructed DSFCN variation can be divided into several distinct periods: (1) DSFCN increased from 1617 to 1650, then (2) decreased from 1650 to 1675, (3) remained unchanged from 1675 to 1755, (4) increased again from 1755 to 1860, (5) remained unchanged from 1860 to 1925, and finally (6) decreased rapidly from 1925 to 1995. We propose the following causal chain to explain the observed relationship between DSFCN and SST: as tropical Pacific Ocean SST increases, the Siberian High weakens and the Eastern Asian Trough strengthens. As the air pressure difference weakens, the East Asian Winter Monsoon weakens, and strong wind frequency decreases, causing DSFCN to decrease as well. The statistical results support this interpretation of the causal chain.
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