scholarly journals Inverse modeling of the 2021 spring super dust storms in East Asia

2022 ◽  
Author(s):  
Jianbing Jin ◽  
Mijie Pang ◽  
Arjo Segers ◽  
Wei Han ◽  
Li Fang ◽  
...  
Keyword(s):  
East Asia ◽  
Northern China ◽  
Life Cycles ◽  
Dust Storms ◽  
Dust Deposition ◽  
Concentration Data ◽  
Long Distance ◽  
The North ◽  
Modis Aod ◽  
Imperfect Knowledge

Abstract. This spring, super dust storms reappeared in East Asia after being absent for a (two) decade(s). The event caused enormous losses both in Mongolia and in China. Accurate simulation of such super sandstorms is valuable for the quantification of health damages, aviation risks, and profound impacts on the Earth system, but also to reveal the driving climate and the process of desertification. However, accurate simulation of dust life cycles is challenging mainly due to imperfect knowledge of emissions. In this study, the emissions that lead to the 2021 spring dust storms are estimated through assimilation of MODIS AOD and ground-based PM10 concentration data. To be able to use the AOD observations to represent the dust load, an Angstrom-based data screening is designed to select only observations that are dominated by dust. In addition, a non-dust AOD bias correction has been designed to remove the part of the AOD that could be attributed to other aerosols than dust. With this, the dust concentrations during the 2021 spring super storms could be reproduced and validated with concentration observations. The emission inversion results reveal that wind blown dust emissions originated from both China and Mongolia during spring 2021. Specifically, 18.3M and 27.2M ton of particles were released in Chinese desert and Mongolia desert respectively during these severe dust events. By source apportionment it has been estimated that 58 % of the dust deposited in the densely populated Fenwei Plain (FWP) in the northern China originate from transnational transport from Mongolia desert. For the North China Plain (NCP), local Chinese desert play a less significant roles in the dust affection; the long-distance transport from Mongolia contributes for about 69 % to the dust deposition in NCP, even if it locates more than 1000 km away from the nearest Mongolian desert.

scholarly journals Investigation of severe dust storms over the Pan-Eurasian area using multi-satellite observations and ground-based measurements

2018 ◽  
Author(s):  
Lu She ◽  
Yong Xue ◽  
Jie Guang ◽  
Yahui Che ◽  
Cheng Fan ◽  
...  
Keyword(s):  
Air Quality ◽  
Dust Storm ◽  
Northern China ◽  
Dust Storms ◽  
Satellite Observations ◽  
Central China ◽  
Dust Particles ◽  
Gobi Desert ◽  
Long Distance ◽  
Hysplit Model

Abstract. The deserts in East Asia are one of the most influential mineral dust source regions in the world. Large amounts of dust particles are emitted and transported to distant regions. A super dust storm characterized by long-distance transport occurred over the Pan-Eurasian Experiment (PEEX) area in early May 2017. In this study, multi-satellite/sensor observations and ground-based measurements combined with the HYbrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model were used to analyse the dynamical processes of the origin and transport of the strong dust storm. The optical and microphysical properties of the dust particles were analysed using Aerosol Robotic Network (AERONET) measurements. From the multi-satellite observations, the dust storms were suggested to have originated from the Gobi Desert on the morning of 3 May 2017, and it transported dust northeastward to the Bering Sea, eastward to the Korean Peninsula and Japan, and southward to southern Central China. The air quality in China drastically deteriorated as a result of this heavy dust storm; the PM10 (particulate matter less than 10 mm in aerodynamic diameter) concentrations measured at some air quality stations located in northern China reached 4000 μg/m3. During the dust event, the maximum AOD values reached 3, 2.3, 2.8, and 0.65 with sharp drops in the extinction Ångström exponent (EAE) to 0.023, 0.068, 0.03, and 0.097 at AOE_Baotou, Beijing, Xuzhou-CUMT, and Ussuriysk, respectively. The dust storm introduced great variations in the aerosol property, causing totally different spectral single-scattering albedo (SSA) and volume size distribution (VSD). The combined observations revealed comprehensive information about the dynamic transport of dust and the dust affected regions, and the effect of dust storms on the aerosol properties.

scholarly journals Correcting model biases of CO in East Asia: impact on oxidant distributions during KORUS-AQ

2020 ◽  
Author(s):  
Benjamin Gaubert ◽  
Louisa K. Emmons ◽  
Kevin Raeder ◽  
Simone Tilmes ◽  
Kazuyuki Miyazaki ◽  
...  
Keyword(s):  
East Asia ◽  
North China ◽  
Climate Models ◽  
Northern China ◽  
Liaoning Province ◽  
Late Winter ◽  
Model Errors ◽  
Chemical Production ◽  
The North ◽  
Chemistry Research

Abstract. Global coupled chemistry-climate models underestimate carbon monoxide (CO) in the Northern Hemisphere, exhibiting a pervasive, negative bias against measurements peaking in late winter and early spring. While this bias has been commonly attributed to underestimation of direct anthropogenic and biomass burning emissions, chemical production and loss via OH reaction from emissions of anthropogenic and biogenic VOCs play an important role. Here we investigate the reasons for this underestimation using aircraft measurements taken in May and June 2016 from the Korea United States Air Quality (KORUS‐AQ) experiment in South Korea and the Air chemistry Research In Asia (ARIAs) in the North China Plain (NCP). For reference, multispectral CO retrievals (V8J) from the Measurements of Pollution in the Troposphere (MOPITT) are jointly assimilated with meteorological observations using an Ensemble Adjustment Kalman Filter (EAKF) within the global Community Atmosphere Model with Chemistry (CAM-chem) and the Data Assimilation Research Testbed (DART). With regard to KORUS-AQ data, CO is underestimated by 42 % in the Control-Run and by 12 % with the MOPITT assimilation run. The inversion suggests an underestimation of anthropogenic CO sources in many regions, by up to 80 % for Northern China, with large increments over the Liaoning province and the North China Plains (NCP). Yet, an often-overlooked aspect of these inversions is that correcting the underestimation in anthropogenic CO emissions also improves the comparison with observational O3 datasets, and observationally constrained box model simulations of OH and HO2. Running a CAM-chem simulation with the updated emissions of anthropogenic CO reduces the bias by 29 % for CO, 18 % for ozone, 11 % for HO2 and 27 % for OH. Longer lived anthropogenic VOCs whose model errors are correlated with CO are also improved while short-lived VOCs, including formaldehyde, are difficult to constrain solely by assimilating satellite retrievals of CO. During an anticyclonic episode, better simulation of O3, with an average underestimation of 5.5 ppbv and a reduction in the bias of surface formaldehyde and oxygenated VOCs can be achieved by separately increasing by a factor of two the modeled biogenic emissions for the plant functional types found in Korea. Results also suggest that controlling VOC and CO emissions, in addition to wide spread NOx controls, can improve pollution ozone over East Asia.

scholarly journals Large-scale dust event in East Asia, as revealed by the Himawari-8 DUST RGB, lidar network observations, and field survey

2019 ◽  
Vol 99 ◽  
pp. 01004
Author(s):  
Kenji Kai ◽  
Yuki Minamoto ◽  
Kotaro Nakamura ◽  
Minrui Wang ◽  
Kei Kawai ◽  
...  
Keyword(s):  
East Asia ◽  
Large Scale ◽  
Meteorological Data ◽  
Northern China ◽  
Dust Storms ◽  
Gobi Desert ◽  
Horqin Sandy Land ◽  
Sandy Land ◽  
Dust Event ◽  
Multiple Sources

A large-scale dust event occurred in East Asia during early May 2017, and transported dust was measured all over Japan. We performed an analysis of the entire dust event using multiple sources: a local ceilometer measurement, measurements from an optical particle counter in the Gobi Desert (Dalanzadgad, Mongolia), a study of Dust RGB imagery obtained from Himawari-8, lidar measurements from Japan, and meteorological data. Our results show that three extratropical low pressure systems occurred consecutively in Mongolia and generated dust storms in the Gobi Desert. Remarkably, the Dust RGB imagery shows both the occurrence and the transportation of the dust, and was able to detect two dust outbreaks in the Horqin Sandy Land of Northern China and their transportation to eastern Japan; this shows that the Horqin Sandy Land was one of the source regions of this dust event.

A Simulated Climatology of Asian Dust Aerosol and Its Trans-Pacific Transport. Part I: Mean Climate and Validation

2006 ◽  
Vol 19 (1) ◽  
pp. 88-103 ◽  
Author(s):  
T. L. Zhao ◽  
S. L. Gong ◽  
X. Y. Zhang ◽  
J-P. Blanchet ◽  
I. G. McKendry ◽  
...  
Keyword(s):  
North America ◽  
East Asia ◽  
Dry Deposition ◽  
Northern China ◽  
Asian Dust ◽  
Dust Aerosol ◽  
Western North America ◽  
The North ◽  
Source Regions ◽  
Aerosol Emission

Abstract The Northern Aerosol Regional Climate Model (NARCM) was used to construct a 44-yr climatology of spring Asian dust aerosol emission, column loading, deposition, trans-Pacific transport routes, and budgets during 1960–2003. Comparisons with available ground dust observations and Total Ozone Mapping Spectrometer (TOMS) Aerosol Index (AI) measurements verified that NARCM captured most of the climatological characteristics of the spatial and temporal distributions, as well as the interannual and daily variations of Asian dust aerosol during those 44 yr. Results demonstrated again that the deserts in Mongolia and in western and northern China (mainly the Taklimakan and Badain Juran, respectively) were the major sources of Asian dust aerosol in East Asia. The dust storms in spring occurred most frequently from early April to early May with a daily averaged dust emission (diameter d < 41 μm) of 1.58 Mt in April and 1.36 Mt in May. Asian dust aerosol contributed most of the dust aerosol loading in the troposphere over the midlatitude regions from East Asia to western North America during springtime. Climatologically, dry deposition was a dominant dust removal process near the source areas, while the removal of dust particles by precipitation was the major process over the trans-Pacific transport pathway (where wet deposition exceeded dry deposition up to a factor of 20). The regional transport of Asian dust aerosol over the Asian subcontinent was entrained to an elevation of <3 km. The frontal cyclone in Mongolia and northern China uplifted dust aerosol in the free troposphere for trans-Pacific transport. Trans-Pacific dust transport peaked between 3 and 10 km in the troposphere along a zonal transport axis around 40°N. Based on the 44-yr-averaged dust budgets for the modeling domain from East Asia to western North America, it was estimated that of the average spring dust aerosol (diameter d < 41 μm) emission of ∼120 Mt from Asian source regions, about 51% was redeposited onto the source regions, 21% was deposited onto nondesert regions within the Asian subcontinent, and 26% was exported from the Asian subcontinent to the Pacific Ocean. In total, 16% of Asian dust aerosol emission was deposited into the North Pacific, while ∼3% of Asian dust aerosol was carried to the North American continent via trans-Pacific transport.

US and Russian policies and strategies in the Middle East: Iraq and Syria as a model

2019 ◽  
pp. 220
Author(s):  
Esraa Aladdin Noori ◽  
Nasser Zain AlAbidine Ahmed
Keyword(s):  
Middle East ◽  
East Asia ◽  
Balance Of Power ◽  
Western World ◽  
International Conflicts ◽  
The South ◽  
The West ◽  
The North ◽  
East Region ◽  
Middle East Region

The Russian-American relations have undergone many stages of conflict and competition over cooperation that have left their mark on the international balance of power in the Middle East. The Iraqi and Syrian crises are a detailed development in the Middle East region. The Middle East region has allowed some regional and international conflicts to intensify, with the expansion of the geopolitical circle, which, if applied strategically to the Middle East region, covers the area between Afghanistan and East Asia, From the north to the Maghreb to the west and to the Sudan and the Greater Sahara to the south, its strategic importance will seem clear. It is the main lifeline of the Western world.

Maritime and River Traders, Landing Places, and Emporia Ports in the Merovingian Period in and Around the Low Countries

2020 ◽  
pp. 763-796
Author(s):  
Dries Tys
Keyword(s):  
North Sea ◽  
Institutional Economics ◽  
New Institutional Economics ◽  
Central Position ◽  
Economic Activities ◽  
Early Medieval ◽  
Low Countries ◽  
Long Distance ◽  
The North ◽  
The North Sea

The origin, rise, and dynamics of coastal trade and landing places in the North Sea area between the sixth and eighth centuries must be understood in relation to how coastal regions and seascapes acted as arenas of contact, dialogue, and transition. Although the free coastal societies of the early medieval period were involved in regional to interregional or long-distance trade networks, their economic agency must be understood from a bottom-up perspective. That is, their reproduction strategies must be studied in their own right, independent from any teleological construction about the development of trade, markets, or towns for that matter. This means that the early medieval coastal networks of exchange were much more complex and diverse than advocated by the simple emporium network model, which connected the major archaeological sites along the North Sea coast. Instead, coastal and riverine dwellers often possessed some form of free status and large degrees of autonomy, in part due to the specific environmental conditions of the landscapes in which they dwelled. The wide estuarine region of the Low Countries, between coastal Flanders in the south and Friesland in the north, a region with vast hinterlands and a central position in northwestern Europe, makes these developments particularly clear. This chapter thus pushes back against longstanding assumptions in scholarly research, which include overemphasis of the influence of large landowners over peasant economies, and on the prioritization of easily retrievable luxuries over less visible indicators of bulk trade (such as wood, wool, and more), gift exchange, and market trade. The approach used here demonstrates that well-known emporia or larger ports of trade were embedded in the economic activities and networks of their respective hinterlands. Early medieval coastal societies and their dynamics are thus better understood from the perspective of integrated governance and economy (“new institutional economics”) in a regional setting.

scholarly journals Springtime daily variations in lower-tropospheric ozone over east Asia: the role of cyclonic activity and pollution as observed from space with IASI

2015 ◽  
Vol 15 (18) ◽  
pp. 10839-10856 ◽  
Author(s):  
G. Dufour ◽  
M. Eremenko ◽  
J. Cuesta ◽  
C. Doche ◽  
G. Foret ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
East Asia ◽  
Tropospheric Ozone ◽  
North China Plain ◽  
North China ◽  
Low Pressure ◽  
The North ◽  
The North China Plain ◽  
Co Observations ◽  
Low Pressure Systems

Abstract. We use satellite observations from IASI (Infrared Atmospheric Sounding Interferometer) on board the MetOp-A satellite to evaluate the springtime daily variations in lower-tropospheric ozone over east Asia. The availability of semi-independent columns of ozone from the surface up to 12 km simultaneously with CO columns provides a powerful observational data set to diagnose the processes controlling tropospheric ozone enhancement on synoptic scales. By combining IASI observations with meteorological reanalyses from ERA-Interim, we develop an analysis method based only on IASI ozone and CO observations to identify the respective roles of the stratospheric source and the photochemical source in ozone distribution and variations over east Asia. The succession of low- and high-pressure systems drives the day-to-day variations in lower-tropospheric ozone. A case study analysis of one frontal system and one cut-off low system in May 2008 shows that reversible subsiding and ascending ozone transfers in the upper-troposphere–lower-stratosphere (UTLS) region, due to the tropopause perturbations occurring in the vicinity of low-pressure systems, impact free and lower-tropospheric ozone over large regions, especially north of 40° N, and largely explain the ozone enhancement observed with IASI for these latitudes. Irreversible stratosphere–troposphere exchanges of ozone-rich air masses occur more locally in the southern and southeastern flanks of the trough. The contribution to the lower-tropospheric ozone column is difficult to dissociate from the tropopause perturbations generated by weather systems. For regions south of 40° N, a significant correlation has been found between lower-tropospheric ozone and carbon monoxide (CO) observations from IASI, especially over the North China Plain (NCP). Considering carbon monoxide observations as a pollutant tracer, the O3–CO correlation indicates that the photochemical production of ozone from primary pollutants emitted over such large polluted regions significantly contributes to the ozone enhancements observed in the lower troposphere via IASI. When low-pressure systems circulate over the NCP, stratospheric and pollution sources play a concomitant role in the ozone enhancement. IASI's 3-D observational capability allows the areas in which each source dominates to be determined. Moreover, the studied cut-off low system has enough potential convective capacity to uplift pollutants (ozone and CO) and to transport them to Japan. The increase in the enhancement ratio of ozone to CO from 0.16 on 12 May over the North China Plain to 0.28 over the Sea of Japan on 14 May indicates photochemical processing during the plume transport.

scholarly journals Controlling Shipping Along the North European Trade Axis

1971 ◽  
Vol 24 (4) ◽  
pp. 553-556
Author(s):  
D. J. Lindsay
Keyword(s):  
Weather Conditions ◽  
North Coast ◽  
Baltic Basin ◽  
Long Distance ◽  
The North ◽  
Large Numbers ◽  
Straight Line ◽  
European Trade ◽  
Trade Route ◽  
The Baltic

By the North European Trade Axis is meant the trade route from Ushant and Land's End, up the English Channel, through the Dover Strait fanning out to serve eastern England, the north coast of continental Europe and leading to the Baltic Basin. Recent events in this area have left a feeling that some form of tightening of control is not only desirable, but is rapidly becoming imperative. There is a basic conflict between the two forms of shipping using the area: the local users who use the area more or less constantly, and the long-distance traders, usually much larger, which arrive in the area for a brief stay after a prolonged period at sea, which has usually been in good weather conditions. Frequently these latter ships have a very poor notion of the hornet's nest into which they are steaming when they arrive. The net result is all too often the same: the local users, with familiarity breeding contempt, wander about as they see fit, with scant regard for routing or the regulations; all too often the big ships arrive from sea with navigating staffs who are too confused, sometimes too ignorant—and sometimes too terrified—to do much more than blunder forward in a straight line hoping for the best. Quite obviously this is not a total picture, and there are large numbers of ships which navigate perfectly competently, but the minority of those which do not seem to be rising rapidly, and show every sign of continuing to increase.

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