Modeling study on the transport of summer dust and anthropogenic aerosols over the Tibetan Plateau

Abstract

Abstract. The Tibetan Plateau (TP) is located at the juncture of several important natural and anthropogenic aerosol sources. Satellites have observed substantial dust and anthropogenic aerosols in the atmosphere during summer over the TP. These aerosols have distinct effects on the earth's energy balance, microphysical cloud properties, and precipitation rates. To investigate the transport of summer dust and anthropogenic aerosols over the TP, we combined the Spectral Radiation-Transport Model for Aerosol Species (SPRINT-ARS) with a non-hydrostatic regional model (NHM). The model simulation shows heavily loaded dust aerosols over the northern slope and anthropogenic aerosols over the southern slope and the east of the TP. The dust aerosols are primarily mobilized around the Taklimakan Desert, where a portion of the aerosols are transported eastward due to the northwesterly current; simultaneously, a portion of the particles are transported southward when a second northwesterly current becomes northeasterly because of the topographic blocking of the northern slope of the TP. Because of the strong upward current, dust plumes can extend upward to approximately 7-8 km a.s.l. over the northern slope of the TP. When a dust event occurs, anthropogenic aerosols that entrained into the southwesterly current via the Indian summer monsoon are transported from India to the southern slope of the TP. Simultaneously, a large amount of anthropogenic aerosol is also transported from eastern China to the east of the TP by easterly winds. An investigation on the transport of dust and anthropogenic aerosols over the plateau may provide the basis for determining aerosol impacts on summer monsoons and climate systems.

Modeling dust sources, transport, and radiative effects at different altitudes over the Tibetan Plateau

“…This dust transport can be attributed to the effect of the TP, which could provide more favorable conditions (i.e., cyclonic and dry convection) to make dust uplift into the upper troposphere . The North African dust can be transported westward across the Atlantic Ocean by African easterly waves, which are a major global dust long-range transport and have been addressed by many studies (e.g., Liu et al, 2008;Su and Toon, 2011;Nowottnick et al, 2011;Ben-Ami et al, 2012;Yu et al, 2013). Beyond that, the North African dust could transport into Europe (Park et al, 2005;Lee et al, 2010) and the Middle East (Hu et al, 2019a).…”

“…These changes over the TP are primarily attributed to increasing greenhouse gases (e.g., Duan et al, 2006;Ren et al, 2006), but other major factors could also contribute to these changes, such as absorbing aerosols (e.g., dust and black carbon), which can heat the atmosphere and reduce the snow albedo (Kang et al, 2000;Lau et al, , 2010Xu et al, 2009). The intercontinental transport of dust aerosols originating from surrounding major deserts, i.e., the Gobi and Taklamakan deserts on the northern side and Sahara and Arabian deserts on the western side, frequently assaults the TP (Huang et al, 2008;Liu et al, 2008) and greatly influences the regional climate over the TP Wu et al, 2007). Meanwhile, the TP plays an important role in the global-scale transport of dust through dynamical and thermal forcing in the mid-latitudes .…”

Effect of Aerosols on the Ice Cloud Properties Over the Tibetan Plateau

“…Over the TP, abundant ice clouds are produced. Simultaneously, the TP is drastically affected by natural and anthropogenic aerosol sources, which provide a large number of aerosol particles lifted to the atmosphere over the TP (Huang, Lin, et al, 2006Jia et al, 2015;Liu et al, 2015). Additionally, sustained warming over the TP associated with global warming has been reported Duan & Xiao, 2015;Niu et al, 2004;Rangwala et al, 2009Rangwala et al, , 2013.…”

“…Thus, under warmer climate conditions over the TP, the aerosol-cloud interaction is an important physical process contributing to the hydrological cycle surrounding the TP. In recent studies, much effort has been focused on the aerosol Liu et al, 2015) and cloud properties (Fujinami & Yasunari, 2001;Hua et al, 2018;Li & Fu, 2005;Sato et al, 2007;Taniguchi & Koike, 2008) over the TP; however, there are few studies on the relationship between aerosols and clouds.…”

Air quality and climate change, Topic 3 of the Model Inter-Comparison Study for Asia Phase III (MICS-Asia III) – Part 2: aerosol radiative effects and aerosol feedbacks

“…Aerosols change weather and climate via the following pathways: they absorb and scatter solar and thermal radiation to alter the radiative balance of the earth-atmosphere system (Gao et al, 2019b;Liu et al, 2011;Jia et al, 2018), which is referred to as direct effects, and they serve as cloud condensation nuclei (CCN) and/or ice nuclei (IN) to modify cloud properties, which is referred to as indirect effects (Haywood and Boucher, 2000). The suppression of cloud convection induced by direct effects of absorbing aerosols is known as the semidirect effect Lohmann and Feichter, 2005). Increases in cloud droplet number can increase cloud albedo for a constant liquid water path (LWP), which is further classified as the first indirect effect or Twomey effect (Twomey, 1991).…”