scholarly journals Observation and modeling of a historic African dust intrusion into the Caribbean Basin and the southern U.S. in June 2020

2021 ◽  
Author(s):  
Hongbin Yu ◽  
Qian Tan ◽  
Lillian Zhou ◽  
Yaping Zhou ◽  
Huisheng Bian ◽  
...  
Keyword(s):  
Air Quality ◽  
West Africa ◽  
Transport Model ◽  
Satellite Observations ◽  
Moist Convection ◽  
Caribbean Basin ◽  
Dust Emissions ◽  
African Dust ◽  
The Caribbean ◽  
The U.S

Abstract. This study characterizes a massive African dust intrusion into the Caribbean Basin and southern U.S. in June 2020, which is nicknamed the Godzilla dust plume, using a comprehensive set of satellite and ground-based observations (including MODIS, CALIOP, SEVIRI, AERONET, and EPA Air Quality network) and the NASA GEOS global aerosol transport model. The MODIS data record registered this massive dust intrusion event as the most intense episode over the past two decades. During this event, the aerosol optical depth observed by AERONET and MODIS peaked at 3.5 off the coast of West Africa and 1.8 in the Caribbean Basin. CALIOP observations show that the top of dust plume reached altitudes of 6–8 km in West Africa and descended to about 4 km altitude over the Caribbean Basin and 2 km over the U.S. Gulf coast. The dust plume degraded the air quality in Puerto Rico to the hazardous level, with maximum daily PM10 concentration of 453 μg m−3 recorded on June 23. The dust intrusion into the U.S. raised the PM2.5 concentration on June 27 to a level exceeding the EPA air quality standard in about 40 % of the stations in the southern U.S. Satellite observations reveal that dust emissions from convection-generated haboobs and other sources in West Africa were large albeit not extreme on a daily basis. However, the anomalous strength and northern shift of the North Atlantic Subtropical High (NASH) together with the Azores low formed a closed circulation pattern that allowed for accumulation of the dust near the African coast for about four days. When the NASH was weakened and wandered back to south, the dust outflow region was dominated by a strong African Easterly Jet that rapidly transported the accumulated dust from the coastal region toward the Caribbean Basin, resulting in the record-breaking African dust intrusion. In comparison to satellite observations, the GEOS model well reproduced the MODIS observed tracks of the meandering dust plume as it was carried by the wind systems. However, the model substantially underestimated dust emissions from haboobs and did not lift up enough dust to the middle troposphere for ensuing long-range transport. Consequently, the model largely missed the satellite-observed elevated dust plume along the cross-ocean track and underestimated the dust intrusion into the Caribbean Basin by a factor of more than 4. Modeling improvements need to focus on developing more realistic representations of moist convection, haboobs, and the vertical transport of dust.

scholarly journals Observation and modeling of the historic “Godzilla” African dust intrusion into the Caribbean Basin and the southern US in June 2020

2021 ◽  
Vol 21 (16) ◽  
pp. 12359-12383
Author(s):  
Hongbin Yu ◽  
Qian Tan ◽  
Lillian Zhou ◽  
Yaping Zhou ◽  
Huisheng Bian ◽  
...  
Keyword(s):  
Air Quality ◽  
West Africa ◽  
Satellite Observations ◽  
Moist Convection ◽  
Caribbean Basin ◽  
Dust Emissions ◽  
African Dust ◽  
Southern Us ◽  
The Us ◽  
The Caribbean

Abstract. This study characterizes a massive African dust intrusion into the Caribbean Basin and southern US in June 2020, which is nicknamed the “Godzilla” dust plume, using a comprehensive set of satellite and ground-based observations (including MODIS, CALIOP, SEVIRI, AERONET, and EPA Air Quality network) and the NASA GEOS global aerosol transport model. The MODIS data record registered this massive dust intrusion event as the most intense episode over the past 2 decades. During this event, the aerosol optical depth (AOD) observed by AERONET and MODIS peaked at 3.5 off the coast of West Africa and 1.8 in the Caribbean Basin. CALIOP observations show that the top of the dust plume reached altitudes of 6–8 km in West Africa and descended to about 4 km altitude over the Caribbean Basin and 2 km over the US Gulf of Mexico coast. The dust intrusion event degraded the air quality in Puerto Rico to a hazardous level, with maximum daily PM10 concentration of 453 µg m−3 recorded on 23 June. The dust intrusion into the US raised the PM2.5 concentration on 27 June to a level exceeding the EPA air quality standard in about 40 % of the stations in the southern US. Satellite observations reveal that dust emissions from convection-generated haboobs and other sources in West Africa were large albeit not extreme on a daily basis. However, the anomalous strength and northern shift of the North Atlantic Subtropical High (NASH) together with the Azores low formed a closed circulation pattern that allowed for accumulation of the dust near the African coast for about 4 d. When the NASH was weakened and wandered back to the south, the dust outflow region was dominated by a strong African easterly jet that rapidly transported the accumulated dust from the coastal region toward the Caribbean Basin, resulting in the record-breaking African dust intrusion. In comparison to satellite observations, the GEOS model reproduced the MODIS observed tracks of the meandering dust plume well as it was carried by the wind systems. However, the model substantially underestimated dust emissions from haboobs and did not lift up enough dust to the middle troposphere for ensuing long-range transport. Consequently, the model largely missed the satellite-observed elevated dust plume along the cross-ocean track and underestimated the dust intrusion into the Caribbean Basin by a factor of more than 4. Modeling improvements need to focus on developing more realistic representations of moist convection, haboobs, and the vertical transport of dust.

scholarly journals A record-breaking trans-Atlantic African dust plume associated with atmospheric circulation extremes in June 2020

2021 ◽  
pp. 1-41
Author(s):  
Bing Pu ◽  
Qinjian Jin
Keyword(s):  
Air Quality ◽  
Atmospheric Circulation ◽  
Long Range ◽  
North Africa ◽  
North Atlantic ◽  
Caribbean Basin ◽  
Dust Emissions ◽  
African Dust ◽  
The Caribbean ◽  
The U.S

AbstractHigh concentrations of dust can affect climate and human health, yet our understanding of extreme dust events is still limited. A record-breaking trans-Atlantic African dust plume occurred during June 14–28, 2020, greatly degrading air quality over large areas of the Caribbean Basin and U.S. Daily PM2.5 concentrations exceeded 50 μg m−3 in several Gulf States, while the air quality index reached unhealthy levels for sensitive groups in more than 11 States. The magnitude and duration of aerosol optical depth over the tropical North Atlantic Ocean were the greatest ever observed during summer over the past 18 years based on satellite retrievals. This extreme trans-Atlantic dust event is associated with both enhanced dust emissions over western North Africa and atmospheric circulation extremes that favor long-range dust transport. An exceptionally strong African easterly jet and associated wave activities export African dust across the Atlantic toward the Caribbean in the middle to lower troposphere, while a westward extension of the North Atlantic subtropical high and a greatly intensified Caribbean low-level jet further transport the descended, shallower dust plume from the Caribbean Basin into the U.S. Over western North Africa, increased dust emissions are associated with strongly enhanced surface winds over dust source regions and reduced vegetation coverage in the western Sahel. While there are large uncertainties associated with assessing future trends in African dust emissions, model-projected atmospheric circulation changes in a warmer future generally favor increased long-range transport of African dust to the Caribbean Basin and the U.S.

scholarly journals The Impact of African Dust on Air Quality in the Caribbean Basin

Eos ◽  
2016 ◽  
Vol 97 ◽  
Author(s):  
Joseph Prospero ◽  
Henry Diaz
Keyword(s):  
Climate Change ◽  
Air Quality ◽  
Human Health ◽  
Caribbean Basin ◽  
Airborne Dust ◽  
African Dust ◽  
The Caribbean ◽  
The Impact

Symposium on Airborne Dust, Climate Change, and Human Health; Miami, Florida, 19–21 May 2015

scholarly journals Homogeneized modeling of mineral dust emissions over Europe and Africa using the CHIMERE model

2014 ◽  
Vol 7 (3) ◽  
pp. 3441-3480 ◽  
Author(s):  
R. Briant ◽  
L. Menut ◽  
G. Siour ◽  
C. Prigent
Keyword(s):  
Air Quality ◽  
Main Part ◽  
Roughness Length ◽  
Mineral Dust ◽  
Satellite Observations ◽  
Production Model ◽  
Dust Production ◽  
Dust Emissions ◽  
Sahel Region ◽  
Agricultural Areas

Abstract. In the region including Africa and Europe, the main part of mineral dust emissions is observed in Africa. The particles are thus transported towards Europe and constitute a non-negligible part of the surface aerosols measured and controlled in the framework of the European air quality legislation. The modelling of these African dust emissions fluxes and transport is widely studied and complex parameterizations are already used in regional to global model for this Sahara-Sahel region. In a lesser extent, mineral dust emissions occur locally in Europe, mainly over agricultural areas. Their modelling is generally poorly done or just ignored. But in some cases, this contribution may be important and may impact the European air quality budget. In this study, we propose an homogeneized calculations of mineral dust fluxes for Europe and Africa. For that, we extended the CHIMERE dust production model (DPM) by using new soil and surface datasets, and the global aeolian roughness length dataset provided by GARLAP from microwave and visible satellite observations. This DPM is detailed along with academic tests case results and simulation on a real case results.

Soviet Interests in Latin America: New Opportunities and Old Constraints

1984 ◽  
Vol 26 (2) ◽  
pp. 163-198 ◽  
Author(s):  
W. Raymond Duncan
Keyword(s):  
Latin America ◽  
Caribbean Basin ◽  
Soviet Policy ◽  
Policy Responses ◽  
The Future ◽  
The Caribbean ◽  
The U.S

The October 1983 crisis in Grenada left little doubt that the Soviet and Cuban presence had been expanding in the Caribbean basin. But the October crisis did not answer questions regarding the extent of their actual influence there, nor the direction it might take in the future, nor even what the most appropriate U.S. policy responses should be to that influence elsewhere in the region. Therefore, in the wake of the U.S. occupation of Grenada and the evidence it uncovered about the degree of Soviet and Cuban activity there, it is useful to examine the kind of situations that have encouraged the Soviets to expand their presence and/or influence in Latin America. At the same time, it equally is useful to examine the limitations or constraints on such an expanded presence or influence.Clearly, Soviet policy in Latin America has been the product of two conflicting forces or tendencies.

scholarly journals Response of dust emissions in southwestern North America to 21st century trends in climate, CO<sub>2</sub> fertilization, and land use: Implications for air quality

2020 ◽  
Author(s):  
Yang Li ◽  
Loretta J. Mickley ◽  
Jed O. Kaplan
Keyword(s):  
Land Use ◽  
New Mexico ◽  
Air Quality ◽  
North America ◽  
21St Century ◽  
Transport Model ◽  
Co2 Fertilization ◽  
Dust Emissions ◽  
Northern Mexico ◽  
Northern Border

Abstract. Climate models predict a shift toward warmer and drier environments in southwestern North America. However, the projected dust trends under climate change are sometimes contradictory. Here we link a dynamic vegetation model (LPJ-LMfire) to a chemical transport model (GEOS-Chem) to assess the impacts of future changes in climate, CO2 fertilization, and land use practices on dust mobilization, and to investigate the consequences for surface air quality. Considering all factors in the most extreme future warming scenario, we find decreasing trends of fine dust emissions over Arizona and New Mexico but increasing emissions along Mexico's northern border in the late-21st century during springtime, the season of maximum dust emissions. These trends result from more densely vegetated environments in the arid southwestern U.S. under future climate, but sparser vegetation in northern Mexico. The two main drivers of dust trends in this region – CO2 fertilization and land use intensification – play opposing roles, with the first driver enhancing vegetation and thus decreasing dust in the southwestern U.S. and the second driver increasing dust in northern Mexico. In the absence of CO2 fertilization, the RCP8.5 scenario places an upper bound on increases in dust, with elevated concentrations widespread over the southwestern North America by 2100 in spring, especially in southeastern New Mexico (up to ~2.0 µg m−3) and along the border between New Mexico and Mexico (up to ~2.5 µg m−3).

scholarly journals Air Quality Degradation by Mineral Dust over Beijing, Chengdu and Shanghai Chinese Megacities

Atmosphere ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 708 ◽  
Author(s):  
Mathieu Lachatre ◽  
Gilles Foret ◽  
Benoit Laurent ◽  
Guillaume Siour ◽  
Juan Cuesta ◽  
...  
Keyword(s):  
Air Quality ◽  
Transport Model ◽  
Mineral Dust ◽  
Dust Emission ◽  
Dust Storms ◽  
Three Dimensions ◽  
Anthropogenic Sources ◽  
Dust Emissions ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Pm 10

Air pollution in Chinese megacities has reached extremely hazardous levels, and human activities are responsible for the emission or production of large amounts of particulate matter (PM). In addition to PM from anthropogenic sources, natural phenomena, such as dust storms over Asian deserts, may also emit large amounts of PM, which lead episodically to poor air quality over Chinese megacities. In this paper, we quantify the degradation of air quality by dust over Beijing, Chengdu and Shanghai megacities using the three dimensions (3D) chemistry transport model CHIMERE, which simulates dust emission and transport online. In the first part of our work, we evaluate dust emissions using Moderate Resolution Imaging Spectroradiometer (MODIS) and Infrared Atmospheric Sounding Interferometer (IASI) satellite observations of aerosol optical depth, respectively, in the visible and the thermal infrared over source areas. PM simulations were also evaluated compared to surface monitoring stations. Then, mineral dust emissions and their impacts on particle composition of several Chinese megacities were analyzed. Dust emissions and transport over China were simulated during three years (2011, 2013 and 2015). Annual dust contributions to the PM 10 budget over Beijing, Chengdu and Shanghai were evaluated respectively as 6.6%, 9.5% and 9.3%. Dust outbreaks largely contribute to poor air quality events during springtime. Indeed it was found that dust significantly contribute for 22%, 52% and 43% of spring PM 10 events (for Beijing, Chengdu and Shanghai respectively).

scholarly journals NO<sub><i>x</i></sub> emission estimates during the 2014 Youth Olympic Games in Nanjing

2015 ◽  
Vol 15 (16) ◽  
pp. 9399-9412 ◽  
Author(s):  
J. Ding ◽  
R. J. van der A ◽  
B. Mijling ◽  
P. F. Levelt ◽  
N. Hao
Keyword(s):  
Air Quality ◽  
Olympic Games ◽  
Transport Model ◽  
Satellite Observations ◽  
Strong Increase ◽  
Nox Emissions ◽  
Chemical Transport Model ◽  
Ozone Monitoring Instrument ◽  
Spring Festival ◽  
Emission Estimate

Abstract. The Nanjing Government applied temporary environmental regulations to guarantee good air quality during the Youth Olympic Games (YOG) in 2014. We study the effect of those regulations by applying the emission estimate algorithm DECSO (Daily Emission estimates Constrained by Satellite Observations) to measurements of the Ozone Monitoring Instrument (OMI). We improved DECSO by updating the chemical transport model CHIMERE from v2006 to v2013 and by adding an Observation minus Forecast (OmF) criterion to filter outlying satellite retrievals due to high aerosol concentrations. The comparison of model results with both ground and satellite observations indicates that CHIMERE v2013 is better performing than CHIMERE v2006. After filtering the satellite observations with high aerosol loads that were leading to large OmF values, unrealistic jumps in the emission estimates are removed. Despite the cloudy conditions during the YOG we could still see a decrease of tropospheric NO2 column concentrations of about 32 % in the OMI observations when compared to the average NO2 columns from 2005 to 2012. The results of the improved DECSO algorithm for NOx emissions show a reduction of at least 25 % during the YOG period and afterwards. This indicates that air quality regulations taken by the local government have an effect in reducing NOx emissions. The algorithm is also able to detect an emission reduction of 10 % during the Chinese Spring Festival. This study demonstrates the capacity of the DECSO algorithm to capture the change of NOx emissions on a monthly scale. We also show that the observed NO2 columns and the derived emissions show different patterns that provide complimentary information. For example, the Nanjing smog episode in December 2013 led to a strong increase in NO2 concentrations without an increase in NOx emissions. Furthermore, DECSO gives us important information on the non-trivial seasonal relation between NOx emissions and NO2 concentrations on a local scale.

scholarly journals NO<sub>x</sub> emission estimates during the 2014 Youth Olympic Games in Nanjing

2015 ◽  
Vol 15 (5) ◽  
pp. 6337-6372 ◽  
Author(s):  
J. Ding ◽  
R. J. van der A ◽  
B. Mijling ◽  
P. F. Levelt ◽  
N. Hao
Keyword(s):  
Air Quality ◽  
Olympic Games ◽  
Transport Model ◽  
Satellite Observations ◽  
Strong Increase ◽  
Nox Emissions ◽  
Chemical Transport Model ◽  
Ozone Monitoring Instrument ◽  
Spring Festival ◽  
Emission Estimate

Abstract. The Nanjing Government has taken temporary environmental regulations to guarantee good air quality during the Youth Olympic Games (YOG) in 2014. We study the effect of those regulations by applying the emission estimate algorithm DECSO (Daily Emission estimates Constrained by Satellite Observations) to measurements of the Ozone Monitoring Instrument (OMI). We improved DECSO by updating the chemical transport model CHIMERE from v2006 to v2013 and by adding an Observation minus Forecast (OmF) criterion to filter outlying satellite retrievals due to high aerosol concentrations. The comparison of model results with both ground and satellite observations indicates that CHIMERE v2013 is better performing than CHIMERE v2006. After filtering the satellite observations with high aerosol loads that were leading to large OmF values, unrealistic jumps in the emission estimates are removed. Despite the cloudy conditions during the YOG we could still see a decrease of tropospheric NO2 column concentrations of about 32% in the OMI observations as compared to the average NO2 concentrations from 2005 to 2012. The results of the improved DECSO algorithm for NOx emissions show a reduction of at least 25% during the YOG period. This indicates that air quality regulations taken by the local government were successful. The algorithm is also able to detect an emission reduction of 10% during the Chinese Spring Festival. This study demonstrates the capacity of the DECSO algorithm to capture the change of NOx emissions on a monthly scale. We also show that the observed concentrations and the derived emissions show different patterns that provide complimentary information. For example, the Nanjing smog episode in December 2013 led to a strong increase in NO2 concentrations without an increase in NOx emissions. Furthermore, DECSO gives us important information of the non-trivial seasonal relation between NOx emissions and NO2 concentrations on a local scale.

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