First long-term detection of paleo-oceanic signature of dust aerosol at the southern marginal area of the Taklimakan Desert

Abstract

We firstly conducted a long-term in-situ field measurement at a marginal area (Hotan) of the southern Taklimakan Desert covering all four seasons. Detailed chemical characterization of dust aerosol over Hotan showed several unconventional features, including (1) ubiquity of high Na+ and Cl− abundances in the Taklimakan dust aerosol and its Cl−/Na+ ratio close to seawater; (2) high Ca content in the Taklimakan dust (7.4~8.0%) which was about two times of that in the natural crust; (3) high abundance of soluble sulfate concentrations and strong correlations between sulfate and Na+ and Cl− as well as typical mineral tracers such as Al and Ca. Our results collectively indicated that the dust aerosol from the Taklimakan Desert was characterized of evident paelo-oceanic signature as the Taklimakan Desert was found as an ocean in the ancient times from the perspective of paleogeology. It was estimated that primary sources dominated the total abundances of sulfate during the dust seasons while previous climate modeling works had seldom considered the cooling effects of sulfate from the Taklimakan Desert.

Spatial and seasonal variations in atmospheric aerosols over Nigeria: Assessment of influence of intertropical discontinuity movement

“…They are categorized into two origins; primary particles are emitted directly in solid or liquid form into the atmosphere space. Primary aerosol particles are natural sources (Peacock, 2008) such as volcanic ash particles (Arnalds et al, 2013; Butwin et al, 2018), and deserts and oceans (Reynolds et al, 2017; Zhou et al, 2018). The deserts are usually wind-driven dust particles from the pool of soil.…”

Saltation–Sandblasting Processes Driving Enrichment of Water-Soluble Salts in Mineral Dust

“…All water-soluble ion contents in the laboratory-generated dust aerosols and bulk soil samples are shown in Table S1. Table summarizes the results of the laboratory-generated dust aerosols, also compared with those of ambient dust collected over the Taklamakan Desert. − The average contents of SO 4 2– , Ca 2+ , Mg 2+ , and K + are similar in the gravel dust and sand dust; they ranged from 2% to 4%, 1.4% to 4%, 0.2% to 0.3%, and 0.2% to 0.3%, respectively. These values were similar to that in the ambient dust aerosol collected over the Taklamakan Desert, which averaged 2%–5%, 0.6%–5%, 0.01%–0.4%, and 0.1%–0.2%.…”

“…High sulfate concentrations (3%–4% of mineral dust mass) have always been observed in dust aerosols over the Taklamakan Desert. ,− Wu et al investigated the origin of these dust sulfates and concluded that they were substantially derived from surface soil in the desert area. Arid salt lakes or saline–alkaline lands distributed in the basin contain soluble salts and are thought to be the possible source of these salts. , However, these regions are not widely distributed in the basin, and the salts they release do not explain why dust aerosols always contain high sulfate levels.…”

“…Moreover, more and more studies showed that they were not practical dust source areas because the salt crusts formed on their surfaces strongly suppress dust deflation. − Sandy and gravel deserts are two major sedimentary environments in the Taklamakan Desert. They occupy over 90% of the total basin area and are traditionally identified as the primary dust source. − However, chemical analysis showed that the soils collected from these sandy and gravel deserts in the Taklamakan Desert contain very low water-soluble sulfate, , and the contents were much lower than the observed dust sulfates. ,− …”