Long‐range transport and vertical structure of Asian dust from CALIPSO and surface measurements during PACDEX

Abstract

[1] Knowledge of long-range transport and vertical distribution of Asian dust aerosols in the free troposphere is important for estimating their impact on climate. Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO), surface micropulse lidar (MPL), and standard surface measurements are used to directly observe the long-range transport and vertical distribution of Asian dust aerosols in the free troposphere during the Pacific Dust Experiment (PACDEX). The MPL measurements were made at the Loess Plateau (35.95°N, 104.1°E) near the major dust source regions of the Taklamakan and Gobi deserts. Dust events are more frequent in the Taklamakan, where floating dust dominates, while more intensive, less frequent dust storms are more common in the Gobi region. The vertical distribution of the CALIPSO backscattering/depolarization ratios indicate that nonspherically shaped dust aerosols floated from near the ground to an altitude of approximately 9 km around the source regions. This suggests the possible long-range transport of entrained dust aerosols via upper tropospheric westerly jets. A very distinct large depolarization layer was also identified between 8 and 10 km over eastern China and the western Pacific Ocean corresponding to dust aerosols transported from the Taklamakan and Gobi areas, as confirmed by back trajectory analyses. The combination of these dust sources results in a two-layer or multilayered dust structure over eastern China and the western Pacific Ocean.

Characterization of Atmospheric Organic and Elemental Carbon of PM2.5 in a Typical Semi-Arid Area of Northeastern China

“…Long-range transport of Asian dust is one of the important sources of atmospheric aerosols in the downwind regions, particularly during the dust seasons. Asian dusts can influence ecosystems, environments, and climates (Sokolik and Toon, 1996;Sokolik et al, 2001;Han et al, 2004;Cao et al, 2005;Huang et al, 2006bHuang et al, , 2008. Some Asian dust may settle on the ocean's surface and provide nutrients (e.g., Fe 2+ ) to the oceanic biosphere (Zhuang et al, 1992).…”

Size Distribution and Optical Properties of Particulate Matter (PM10) and Black Carbon (BC) during Dust Storms and Local Air Pollution Events across a Loess Plateau Site

“…At 2:00 on 3 May 2008, the PM 10 concentration increased to its peak value of 1519 µg m -3 after a few hours. However, these two nearly continuous dust events (2 and 3 May; intervals of only a few hours) originated from different emission sources according to the 60-h HYSPLIT air-mass back trajectories (Kalkstein et al, 1987;Stunder, 1997;Draxier and Hess, 1998;Draxler and Rolph, 2008;Huang et al, 2008a;Zhang et al, 2013). These air-mass back trajectories have been considered by previous studies to be an effective method of tracking the transport of dust events (Zhang et al, 2003a, b;Huang et al, 2010;Chen et al, 2013) and have been 29-May-08 5:00-23:00 910 ± 265 92 ± 39 27.0 ± 6.0 0.76 ± 0.04 applied in deserts such as the Taklimakan (Li et al, 2007;Huang et al, 2008a;Zhou et al, 2013) and Mongolia Gobi (Xu 2004;Zhang et al, 2013 to minimum values of 11.3 and 50 Mm -1 with maximum/ minimum ratios of around 2 and 3, respectively, during the morning of 10 April 2008, but the decreasing trends were smaller than that of the PM 10 variation.…”

“…: +86-931-8915-892 E-mail address: wxin@lzu.edu.cn is an active component in the climate system (Prospero, 1999;Zhao et al, 2008). Driven by midlatitude prevailing westerlies, large quantities of mineral particles can be lifted to high altitudes during dust events and thus transported to the eastern Pacific and North America (Jaffe et al, 1999;Prospero, 1999;VanCuren and Cahill, 2002;Huang et al, 2008a;Prospero and Mayol-Bracero, 2013). Additionally, the region also has major sources of anthropogenic aerosols produced by human activities Huang et al, 2014).…”

“…These include the Asian Pacific Regional Aerosol Characterization Experiment (ACE-Asia) (Anderson et al, 2003;Conant et al, 2003;Arimoto et al, 2006;Sullivan et al, 2007), the East Asian Study of Tropospheric Aerosols: an International Regional Experiment (EAST-AIRE) (Anderson et al, 2003;Huebert et al, 2003;Zhang et al, 2003b;Arimoto et al, 2004;Kim et al, 2005;, the Transport and Chemical Evolution over the Pacific (TRACE-P) aircraft mission (Jacob et al, 2003;Tu et al, 2003;Woo et al, 2003;Allen et al, 2004;Mari et al, 2004), the Intercontinental Chemical Transport Experiment-Phase B (INTEX-B) campaign (McKendry et al, 2008;Zhang et al, 2009), and the Pacific Dust Experiment (PACDEX) (Huang et al, 2008a). Although there has been much progress in measuring the physical and optical properties of dust and non-dust aerosols (Cao et al, 2014;Jing et al, 2015), the monthly and seasonal variations in these aerosols have yet to be well quantified, especially across the Loess Plateau, near the dust sources.…”

Optical and microphysical properties of natural mineral dust and anthropogenic soil dust near dust source regions over Northwestern China

“…East Asia includes the Taklimakan, Tengger, Badain Jaran and Gobi Deserts and is thus considered to be one of the major source regions of natural dust in the world, as it produces large amounts of natural mineral dust (Zhang et al, 1997;Wang et al, 2008;Che et al, 2011Che et al, , 2013Ge et al, 2014;Xin, 10 2005Xin, 10 , 2010Xin, 10 , 2015. Once dust aerosols are lifted into the atmosphere by strong surface winds, they can be transported up to thousands of kilometres away from their source regions Liu et al, 2015;Huang et al, 2008). The long-range transport of tropospheric aerosols from their dust source regions in East Asia plays a key role in aerosol radiative forcing (Ge et al, 2011).…”