Increased Dust Aerosols in the High Troposphere Over the Tibetan Plateau From 1990s to 2000s

Abstract

Dust aerosols are a major type of aerosol over the Tibetan Plateau (TP) and influence climate at local to regional scales through their effects on thermal radiation and snow‐albedo feedback. Based on the Modern‐Era Retrospective Analysis for Research and Applications, Version 2 (MERRA‐2) aerosol data set, we report an increase of 34% in the atmospheric dust in the high troposphere over the TP during the spring season in the 2000s in comparison to the 1990s. This result is supported by an increase of 157% (46%) in the dust deposition flux in the Mugagangqiong (Tanggula) ice cores and an increase of 69% in the aerosol index (AI) from Earth Probe (EP) Total Ozone Mapping Spectrometer (TOMS), as well as by increases of simulated dust aerosols over the TP derived from the Community Earth System Model (CESM) and models from the Coupled Model Intercomparison Project Phase 6 (CMIP6). The increased atmospheric dust over the TP is caused by two aspects: (1) There was a higher dust emission over the Middle East during the 2000s than during the 1990s, which is explained by less precipitation and 25.8% higher cyclone frequency over the Middle East. The increased cyclone frequency uplift more dust from the surface over the Middle East to the central Asia in the middle troposphere. (2) Enhanced midlatitude zonal winds help transport more dust in the middle troposphere from central Asia to Northwest China, and thereafter, an increase in northerly winds over Northwest China propels dust southward to the TP.

Heterogeneous Nucleation of Midlevel Cloud Layer Influenced by Transported Asian Dust Over Wuhan (30.5°N, 114.4°E), China

“…As seen in Figure 2, the lower layer (below 2.5 km) was back‐calculated to the lower troposphere (1.5–2.0 km) of the Taklimakan Desert (see the red line). The upper layer (above 3.0 km) appeared to link to the surface of the northern slope of the Tibetan Plateau, which is always influenced by dust transported from the Taklimakan Desert (Chen et al., 2013) and the deserts of the Middle East (Feng et al., 2020) (see the blue line).…”

“…As seen in Figure 2, the lower layer (below 2.5 km) was back-calculated to the lower troposphere (1.5-2.0 km) of the Taklimakan Desert (see the red line). The upper layer (above 3.0 km) appeared to link to the surface of the northern slope of the Tibetan Plateau, which is always influenced by dust transported from the Taklimakan Desert (Chen et al, 2013) and the deserts of the Middle East (Feng et al, 2020) (see the blue line). Figure 3 shows profiles of the aerosol extinction coefficient α, dust mass concentration M d , backscatter ratio R, volume depolarization ratio δ, and particle depolarization ratio δ p during 0915-0930 LT.…”

Provenance of Aeolian Dust Revealed by (234U/238U) Activity Ratios in Cryoconites From High‐Altitude Glaciers in Western China and Its Transport and Settlement Mechanisms

“…Moreover, previous research also suggests that the dust on the TP can be lifted to middle troposphere by the “chimney effect,” then transported (S. Chen et al., 2017; Feng et al., 2020; Yumimoto et al., 2009), and settled to the surrounding TP glaciers, suggesting that the dust events of the plateau itself and TP dust can also produce important glacier dust input (Dong et al., 2020; Wu et al., 2010; Xu et al., 2009, 2012). It comprehensively reflects the influence of key meteorological conditions and large terrain of the dust transport and deposition.…”

Multi-decadal monsoon characteristics and glacier response in High Mountain Asia

“…Mugagangqiong Glacier (34.248 • N 87.490 • E, hereafter 'MUGA' for tables and figures) is a 2 km 2 glacier in the arid central Tibetan Plateau. The glacier has been the focus of few studies, typically regarding ice cores and historic atmospheric dust concentrations (Feng et al 2020), though is also one of several investigation sites established across the Tibetan Plateau in the last decade (Yang et al 2022). The site specific information of each glacier is given in table 1.…”