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.

scholarly journals Development and evaluation of an operational SDS forecasting system for East Asia: CUACE/Dust

2008 ◽  
Vol 8 (4) ◽  
pp. 787-798 ◽  
Author(s):  
C. H. Zhou ◽  
S. L. Gong ◽  
X. Y. Zhang ◽  
Y. Q. Wang ◽  
T. Niu ◽  
...  
Keyword(s):  
East Asia ◽  
Northeast Asia ◽  
Detailed Comparison ◽  
Dust Aerosol ◽  
Meteorological Model ◽  
Source Regions ◽  
Aerosol Emission ◽  
Operational Forecasts ◽  
Lidar Measurements ◽  
Forecasting System

Abstract. CUACE/Dust, an operational mesoscale sand and dust storm (SDS) forecasting system for East Asia, has been developed by online coupling a dust aerosol emission scheme and dust aerosol microphysics onto a regional meteorological model with improved advection and diffusion schemes and a detailed Northeast Asia soil erosion database. With improved initial dust aerosol conditions through a 3-DVar data assimilation system, CUACE/Dust successfully forecasted most of the 31 SDS processes in East Asia. A detailed comparison of the model predictions for the 8–12 March SDS process with surface network observations and lidar measurements revealed a robust forecasting ability of the system. The time series of the operationally forecasted dust concentrations for a number of representative stations for the whole spring 2006 (1 March–31 May) were evaluated against surface PM10 monitoring data, showing a good agreement in terms of the SDS timing and magnitudes at and near the source regions where dust aerosols dominate. For the operational forecasts of spring 2006 in East Asia, a TS (threat score) system evaluated the performance of CUACE/Dust against all available observations and rendered a spring averaged TS value of 0.31 for FT1 (24 h forecasts), 0.23 for FT2 (48 h forecasts) and 0.21 for FT3 (72 h forecasts).

A Simulated Climatology of Asian Dust Aerosol and Its Trans-Pacific Transport. Part II: Interannual Variability and Climate Connections

2006 ◽  
Vol 19 (1) ◽  
pp. 104-122 ◽  
Author(s):  
S. L. Gong ◽  
X. Y. Zhang ◽  
T. L. Zhao ◽  
X. B. Zhang ◽  
L. A. Barrie ◽  
...  
Keyword(s):  
Interannual Variability ◽  
El Niño ◽  
North China ◽  
El Nino ◽  
Asian Dust ◽  
Dust Aerosol ◽  
The North ◽  
Source Regions ◽  
The Pacific ◽  
Dust Loading

Abstract A 44-yr climatology of spring Asian dust aerosol emission, column loading, deposition, trans-Pacific transport routes, and budgets during 1960–2003 was simulated with the Northern Aerosol Regional Climate Model (NARCM). Interannual variability in these Asian dust aerosol properties simulated by the model and its climate connections are analyzed with major climatic indices and records in ground observations. For dust production from most of the source regions, the strongest correlations were with the surface wind speed in the source region and the area and intensity indices of the Asian polar vortex (AIAPV and IIAPV, respectively). Dust emission was negatively correlated with precipitation and surface temperatures in spring. The strength of the East Asian monsoon was not found to be directly related to dust production but rather with the transport of dust from the Asian subcontinent. The interannual variability of dust loading and deposition showed similar relations with various climate indices. The correlation of Asian dust loading and deposition with the western Pacific (WP) pattern and Atmospheric Circulation Index (ACI) exhibited contrasting meridional and zonal distributions. AIAPV and IIAPV were strongly correlated with the midlatitude zonal distribution of dust loading and deposition over the Asian subcontinent and the North Pacific. The Pacific–North American (PNA) pattern and Southern Oscillation index (SOI) displayed an opposite correlation pattern of dust loading and deposition in the eastern Pacific, while SOI correlated significantly with dust loading over eastern China and northeast Asia. The Pacific decadal oscillation (PDO) was linked to variations of dust aerosol and deposition not only in the area of the eastern North Pacific and North America but also in the Asian dust source regions. The anomalies of transport flux and its divergence as well as dust column loading were also identified for eight typical El Niño and eight La Niña years. A shift of the trans-Pacific transport path to the north was found for El Niño years, which resulted in less dust storms and dust loading in China. In El Niño years the deserts in Mongolia and western north China closer to the polar cold air regions contributed more dust aerosol in the troposphere, while in La Niña years the deserts in central and eastern north China far from polar cold regions provided more dust aerosol in the troposphere. On the basis of the variability of Asian dust aerosol budgets, the ratio of inflow to North America to the outflow from Asia was found to be correlated negatively with the PNA index and positively with the WP index.

scholarly journals Asian dust storm influence on North American ambient PM levels: observational evidence and controlling factors

2008 ◽  
Vol 8 (10) ◽  
pp. 2717-2728 ◽  
Author(s):  
T. L. Zhao ◽  
S. L. Gong ◽  
X. Y. Zhang ◽  
D. A. Jaffe
Keyword(s):  
North America ◽  
North Pacific ◽  
Asian Dust ◽  
Observational Evidence ◽  
Dust Storms ◽  
Western North America ◽  
Transport Pathway ◽  
The North ◽  
Asian Dust Storms ◽  
The North Pacific

Abstract. New observational evidence of the trans-Pacific transport of Asian dust and its contribution to the ambient particulate matter (PM) levels in North America was revealed, based on the interannual variations between Asian dust storms and the ambient PM levels in western North America from year 2000 to 2006. A high correlation was found between them with an R2 value of 0.83. From analysis of the differences in the correlation between 2005 and 2006, three factors explain the variation of trans-Pacific transport and influences of Asian dust storms on PM levels in western North America. These were identified by modeling results and the re-analysis data. They were 1) Strength of frontal cyclones from Mongolia to north eastern China: The frontal cyclones in East Asia not only bring strong cold air outbreaks, generating dust storms in East Asia, but also lift Asian dust into westerly winds of the free troposphere for trans-Pacific transport; 2) Pattern of transport pathway over the North Pacific: The circulation patterns of westerlies over the North Pacific govern the trans-Pacific transport pattern. Strong zonal airflow of the westerly jet in the free troposphere over the North Pacific favor significant trans-Pacific transport of Asian dust; 3) Variation of precipitation in the North Pacific: The scavenging of Asian dust particles by precipitation is a major process of dust removal on the trans-Pacific transport pathway. Therefore, variation of precipitation in the North Pacific could affect trans-Pacific transport of Asian dust.

scholarly journals Air Quality in East Asia during the heavy haze event period of 10 to 15 January 2013

2021 ◽  
Vol 15 ◽  
pp. 1-9
Author(s):  
Soon-Ung Park ◽  
Jeong Hoon Cho
Keyword(s):  
Eastern China ◽  
Northern China ◽  
Asian Dust ◽  
Dust Aerosol ◽  
Anthropogenic Aerosols ◽  
The Public ◽  
Inorganic Aerosols ◽  
Source Regions ◽  
Haze Event ◽  
Aerosol Modeling

A prolonged heavy haze event that has caused for the Environmental Protection Bureau (EPB) in Beijing to take emergency measures for the protection of the public health and the reduction of air pollution damages in China has been analyzed with the use of the Aerosol modeling System (AMS) to identify causes of this event. It is found that the heavy haze event is associated with high aerosols and water droplets concentrations. These high aerosol concentrations are mainly composed of anthropogenic aerosols, especially secondary inorganic aerosols formed by gas-to-particle conversion of gaseous pollutants in the eastern part of China whereas those in the northeastern parts of China are composed of the mixture of the anthropogenic aerosols and the Asian dust aerosol originated from the dust source regions of northern China and Mongolia. These high aerosol concentrations are found to be subsequently transported to the downwind regions of the Korean Peninsula and Japan causing a prolonged haze event there. It is also found that the Asian dust aerosol originated from northern China and Mongolia and the anthropogenic aerosols produced by chemical reactions of pollutants in the high emissions region of eastern China can cause significantly adverse environmental impacts in the whole Asian region by increased atmospheric aerosol loadings that may cause respiration diseases and visibility reduction and by excess deposition of aerosols causing adverse impacts on terrestrial and marine eco-systems.

scholarly journals Asian dust storm influence on North American ambient PM levels: observational evidence and controlling factors

2007 ◽  
Vol 7 (4) ◽  
pp. 9663-9686 ◽  
Author(s):  
T. L. Zhao ◽  
S. L. Gong ◽  
X. Y. Zhang ◽  
D. A. Jaffe
Keyword(s):  
North America ◽  
North Pacific ◽  
Asian Dust ◽  
Observational Evidence ◽  
Dust Storms ◽  
Western North America ◽  
Transport Pathway ◽  
The North ◽  
Asian Dust Storms ◽  
The North Pacific

Abstract. New observational evidence of the trans-Pacific transport of Asian dust and its contribution to the ambient particulate matter (PM) levels in North America was revealed, based on the interannual variations between Asian dust storms and the ambient PM levels in western North America from year 2000 to 2006. A high correlation was found between them with an R2 value of 0.83. From analysis of the differences in the correlation between 2005 and 2006, three factors explain the variation of trans-Pacific transport and influences of Asian dust storms on PM levels in western North America. These were identified by modeling results and the re-analysis data. They were 1) Strength of frontal cyclones from Mongolia to north eastern China: The frontal cyclones in East Asia not only bring strong cold air outbreaks, generating dust storms in East Asia, but also lift Asian dust into westerly winds of the free troposphere for trans-Pacific transport; 2) Pattern of transport pathway over the North Pacific: The circulation patterns of westerlies over the North Pacific govern the trans-Pacific transport pattern. Strong zonal airflow of the westerly jet in the free troposphere over the North Pacific favor significant trans-Pacific transport of Asian dust; 3) Variation of precipitation in the North Pacific: The scavenging of Asian dust particles by precipitation is a major process of dust removal on the trans-Pacific transport pathway; therefore, variation of precipitation in the North Pacific could affect trans-Pacific transport of Asian dust.

scholarly journals Source contributions of sulfur and nitrogen deposition – an HTAP II multi model study on hemispheric transport

2018 ◽  
Author(s):  
Jiani Tan ◽  
Joshua S. Fu ◽  
Frank Dentener ◽  
Jian Sun ◽  
Louisa Emmons ◽  
...  
Keyword(s):  
Air Pollution ◽  
North America ◽  
East Asia ◽  
South Asia ◽  
Air Pollutants ◽  
Coastal Regions ◽  
The North ◽  
Source Regions ◽  
Low Emission ◽  
The Impact

Abstract. Abstract. With rising emissions by human activities, enhanced concentrations of air pollutants have been detected in hemispheric air flows in recent years, aggravating the regional air pollution and deposition burden. However, contributions of hemispheric air pollution to deposition at global scale have been given little attention in the literature. In this light, we assess the impact of hemispheric transport on sulfur (S) and nitrogen (N) deposition for 6 world regions: North America, Europe, South Asia, East Asia, Middle East and Russia in 2010, by using the multi-model ensemble results from the 2nd phase of Task Force Hemispheric Transport of Air Pollution (HTAP II) with and without 20 % emission perturbation experiments. About 27–58 %, 26–46 % and 12–23 % of local S, NOx and NH3 emissions are transported and removed by deposition outside of the source regions annually, with 5 % higher fraction of export in winter and 5 % lower in summer. For receptor regions, 20 % emission reduction in source regions affects the deposition in receptor regions by 1–10 % for continental non-coastal regions and 1–15 % for coastal regions and open oceans. Significant influences are found from North America to the North Atlantic Ocean (5–15 %), from South Asia to western East Asia (2–10 %) and from East Asia to the North Pacific Ocean (5–10 %) and western North America (5–8 %). The impact on deposition caused by transport between neighbouring regions (i.e. Europe and Russia) occurs throughout the whole year (slightly stronger in winter), while that by transport over long distances (i.e. from East Asia to North America) mainly takes place in spring and fall, which is consistent with the seasonality found for hemispheric transport of air pollutants. Deposition in emission intense regions such as East Asia is dominated (~ 80 %) by own region emission, while deposition in low emission regions such as Russia is almost equally affected by own region emission (~ 40 %) and foreign impact (~ 23–45 %). We also find that deposition on the coastal regions or near coastal open ocean is twice more sensitive to hemispheric transport than non-coastal continental regions, especially for regions (i.e. west coast of North America) in the downwind location of major emission source regions. This study highlights the significant impact of hemispheric transport on deposition in coastal regions, open ocean and low emission regions. Further research is proposed for improving ecosystem and human health in these regions, with regards to the enhanced hemispheric transport.

scholarly journals Regional characteristics of spring Asian dust and its impact on aerosol chemistry over northern China

2006 ◽  
Vol 6 (6) ◽  
pp. 12825-12864 ◽  
Author(s):  
Y. L. Sun ◽  
G. S. Zhuang ◽  
Z. F. Wang ◽  
Y. Wang ◽  
W. J. Zhang ◽  
...  
Keyword(s):  
Dust Storm ◽  
Fine Particles ◽  
Coastal Region ◽  
Northern China ◽  
Asian Dust ◽  
Aerosol Chemistry ◽  
Transport Pathway ◽  
Regional Characteristics ◽  
Source Regions ◽  
The Impact

Abstract. TSP and PM2.5 aerosol samples were synchronously collected at six sites along the transport pathway of dust storm from desert regions to coastal areas in the spring of 2004. The aerosol concentration and composition were measured to investigate the regional characteristics of spring Asian dust and its impact on aerosol chemistry over northern China. Based on the daily PM10 concentrations in 13 cities, the northern China could be divided into five regions, i.e., Northern Dust Region, Northeastern Dust Region, Western Dust Region, Inland Passing Region, and Coastal Region. Northern Dust Region was characterized by high content of Ca and Northeastern Dust Region was characterized by low one instead. Northeastern Dust Region was a relatively clean area with the lowest concentrations of pollutants and secondary ions among all sites. Inland Passing Region and Coastal Region showed high concentrations of pollutants, of which As and Pb in Inland Passing Region, and Na+, SO42− and NO3− in Coastal Region were the highest, respectively. The impact of dust on air quality was the greatest in the cities near source regions, and this impact decreased in the order of Yulin/Duolun > Beijing > Qingdao/Shanghai as the increase of transport distance. The spring Asian dust was inclined to affect the chemical components in coarse particles near source regions and those in fine particles in the cities far from source regions. Dust storm could mix significant quantities of pollutants on the pathway and carry them to the downwind cities or dilute the pollutants in the cities over northern China. Each dust episode corresponded to a low ratio of NO3−/SO42− with the lowest value appearing after the peak of dust storm. Asian dust played an important role in buffering and neutralizing the acidity of atmosphere in the cities over northern China, which could lead to the pH in the aerosols increase ~1 in spring.

scholarly journals Influence of ENSO on North American subseasonal surface air temperature variability

2021 ◽  
Vol 2 (2) ◽  
pp. 395-412
Author(s):  
Patrick Martineau ◽  
Hisashi Nakamura ◽  
Yu Kosaka
Keyword(s):  
North America ◽  
Air Temperature ◽  
North American ◽  
Surface Air Temperature ◽  
Tropical Pacific ◽  
La Niña ◽  
Western North America ◽  
The North ◽  
Subseasonal Variability ◽  
La Nina

Abstract. The wintertime influence of tropical Pacific sea surface temperature (SST) variability on subseasonal variability is revisited by identifying the dominant mode of covariability between 10–60 d band-pass-filtered surface air temperature (SAT) variability over the North American continent and winter-mean SST over the tropical Pacific. We find that the El Niño–Southern Oscillation (ENSO) explains a dominant fraction of the year-to-year changes in subseasonal SAT variability that are covarying with SST and thus likely more predictable. In agreement with previous studies, we find a tendency for La Niña conditions to enhance the subseasonal SAT variability over western North America. This modulation of subseasonal variability is achieved through interactions between subseasonal eddies and La Niña-related changes in the winter-mean circulation. Specifically, eastward-propagating quasi-stationary eddies over the North Pacific are more efficient in extracting energy from the mean flow through the baroclinic conversion during La Niña. Structural changes of these eddies are crucial to enhance the efficiency of the energy conversion via amplified downgradient heat fluxes that energize subseasonal eddy thermal anomalies. The enhanced likelihood of cold extremes over western North America is associated with both an increased subseasonal SAT variability and the cold winter-mean response to La Niña.

scholarly journals CUACE/Dust – an integrated system of observation and modeling systems for operational dust forecasting in Asia

2007 ◽  
Vol 7 (4) ◽  
pp. 10323-10342 ◽  
Author(s):  
S. L. Gong ◽  
X. Y. Zhang
Keyword(s):  
East Asia ◽  
Atmospheric Chemistry ◽  
Monitoring Network ◽  
Integrated System ◽  
Dust Aerosol ◽  
China Meteorological Administration ◽  
Source Regions ◽  
Operational Forecasts ◽  
Forecasting System ◽  
Aerosol Module

Abstract. An integrated sand and dust storm (SDS) forecasting system – CUACE/Dust (the Chinese Unified Atmospheric Chemistry Environment for Dust) has been developed, which consists of a comprehensive dust aerosol module with emission, dry/wet depositions and other atmospheric dynamic processes, and a data assimilation system (DAS) using observational data from the CMA (China Meteorological Administration) ground dust monitoring network and retrieved dust information from a Chinese geostationary satellite – FY-2C. This is the first time that a combination of surface network observations and satellite retrievals of the dust aerosol has been successfully used in the real time operational forecasts in East Asia through a DAS. During its application for the operational SDS forecasts in East Asia for spring 2006, this system captured the major 31 SDS episodes observed by both surface and satellite observations. Analysis shows that the seasonal mean threat score (TS) for 0–24 h forecast over the East Asia in spring 2006 increased from 0.22 to 0.31 by using the DAS, a 41% enhancement. The time series of the forecasted dust concentrations for a number of representative stations for the whole spring 2006 were also evaluated against the surface PM10 monitoring data, showing a very good agreement in terms of the SDS timing and magnitudes near source regions where dust aerosols dominate. This is a summary paper for a special issue of ACP featuring the development and results of the forecasting system.

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