A twentieth century major soluble ion record of dust and anthropogenic pollutants from Inilchek Glacier, Tien Shan

Abstract

Using a high‐resolution (~18 samples/year) major soluble ion record (Na+, K+, Mg2+, Ca2+, Cl−, NO3−, and SO42−) covering the period 1908–1995 A.D. from the Inilchek Glacier, Tien Shan, Kyrgyzstan, we provide a detailed climate and environmental proxy record for the region. Chemical concentrations, empirical orthogonal function analyses, and noncrustal excess calculations are used to identify natural and potential anthropogenic depositional trends. Dominant dust proxy species (i.e., Ca2+) reveal highest concentrations during the 1950s–1970s, with declining decadal trends through the end of the record. These trends likely reflect decreases in central Asian dust storm activity post‐1950, which has been associated with coupled atmospheric circulation variability and anthropogenic activities. Comparison between Ca2+ and ERA‐Interim (1979–1995) climate reanalysis data indicates a strong relationship to spring (March–May) geopotential height patterns in northwest China and southern Siberia associated with the Siberian High. Noncrustal contribution (excess) estimates of NO3−, K+, SO42−, and Cl− concentrations suggest discernable anthropogenic inputs began between the 1950s and 1970s, increased into the middle/late 1980s, and declined in the 1990s. Excess trends coincide with Former Soviet Union consumption, production, and emission of fossil fuels and fertilizers, reflecting the rapid growth of agriculture and industry, as well as economic declines in the middle to late 1980s/early 1990s. Excess‐Cl− trends reflect timings that coincide with the construction of the Pavlodar Chemical Plant and the military production of Cl2 in Kazakhstan. NOAA Hybrid Single‐Particle Lagrangian Integrated Trajectory back trajectory frequency analysis suggests eastern Uzbekistan (e.g., Fergana Valley), Kyrgyzstan, and southern Kazakhstan as the primary pollutant sources to the study region.

The Elbrus (Caucasus, Russia) ice core record – Part 2: history of desert dust deposition

“…Chin et al, 2014). Recent broad-scale assessments of changes in dust emissions show a doubling of the dust deposition in many sedimentary archives since the mid-18th century, which was attributed to anthropogenic land use and short-term climate variability (Hooper and Marx, 2018). Globally, anthropogenic dust sources account for 25 % of emissions, but this value varies and can be considerably higher -up to 75 % in some regions (Ginoux et al, 2012).…”

A high‐resolution atmospheric dust record for 1810–2004 A.D. derived from an ice core in eastern Tien Shan, central Asia

“…The negative correlations between 850 hPa geopotential height and the Miaoergou log-Dust indicate that as pressure is Journal of Geophysical Research: Atmospheres 10.1002/2017JD026699 reduced, atmospheric dust concentrations increase. Relatively lower pressure may be associated with enhanced regional cyclonic activity and/or a weakening or shift in the strength and position of the SH [Grigholm et al, 2017]. 4.3.4.…”

“…The Geladaindong ice core in the central TP showed high dust concentrations in the eighteenth and nineteenth centuries and low concentrations in the twentieth century [ Grigholm et al ., ; Zhang et al ., ]. The Inilchek ice core in central Tien Shan showed the highest dust concentrations during the 1950s to 1970s and lower dust concentration since the 1980s [ Grigholm et al ., ].…”

“…The Geladaindong ice core in the central TP showed high dust concentrations in the eighteenth and nineteenth centuries and low concentrations in the twentieth century [Grigholm et al, 2015;Zhang et al, 2015]. The Inilchek ice core in central Tien Shan showed the highest dust concentrations during the 1950s to 1970s and lower dust concentration since the 1980s [Grigholm et al, 2017]. Tien Shan is located in a remote area of central Asia, surrounded by important dust source areas (Figure 1): the Taklimakan desert (the world's second largest shifting sand desert) in the south, the Southern Mongolian Gobi and the Northern Mongolian Plateau in the east, the Gurbantunggut desert in the northwest, and the Peski Sary-Ishikotrau desert in the west [Liu et al, 2011].…”

“…Therefore, the ice core records from this region can offer an opportunity to understand the environmental changes over the most important dust sources in central Asia. In Tien Shan, previous studies on aeolian dust have been limited, with the longest available records representing only 88 years (1908–1995 A.D.) [ Grigholm et al ., ]. In this study, we present a 195 year atmospheric dust deposition record (1810–2004 A.D.) developed from a shallow ice core retrieved from the Miaoergou Glacier located in eastern Tien Shan (Figure ).…”