ACOM

CAM-chem simulation of the 2020 lockdown

Gaubert 2020 Figure 1.

With the unprecedented global reduction in economic activities following the COVID-19 pandemic outbreak in early 2020, most emissions of air pollutants (i.e., nitrogen oxides (NOx), carbon monoxide (CO), sulfur dioxide (SO2), volatile organic carbon (VOC), black carbon (BC), organic carbon (OC)) have decreased substantially throughout the first half of the year. This unintended global experiment has given insight on some of the processes that control air quality and offered a glimpse into a potential future in which air quality would be improved.

A First Look at Air quality in Central Asia

Janyl Madykova 2020, Figure 1.

Air pollution is a major societal and environmental threat that is occurring in many places across the world including Central Asia (CA). Yet this region is significantly understudied, which motivated Janyl Madykova to make this a topic for her research. Janyl is from Kyrgyzstan and came to the USA in 2018 as a Fulbright Scholar. In summer 2020 she virtually visited NCAR under a Muskie Internship Program collaborating with ACOM on exploring air quality in CA. Here is a brief summary of the work Janyl performed.

COVID-19 impact on Asian emissions: Insight from space observations

MOPITT total tropospheric CO column values
During February and March 2020, ACOM scientists looked into the perturbation to atmospheric composition due to the large scale curtailing of human activities in response to COVID-19, in addition to operational issues of the ACCLIP field campaign planned for summer 2020 out of Okinawa. In this short briefing, we report on the large signature in atmospheric composition from spaceborne observations for the time period of lockdown in China during February to early March, 2020.

Massive Smoke Plume from Siberian Fires Reaches North America

CO fire emissions measured by TROPOMI on July 29, 2019.

A continental-scale plume of carbon monoxide (CO) and other air pollutants from active fires in Siberia is being mapped in near real-time by ACOM scientists, based on data provided by TROPOMI (the TROPOspheric Monitoring Instrument, on board ESA's Sentinel-5P platform). Figures 1 and 2 illustrate the magnitude of CO emissions during this fire season (summer 2019) compared to the same period last year (2018).

Photolysis of Organic Aerosols

A multitude of recent atmospheric observations show that organic aerosols are ubiquitous and often more abundant than other particles such as sulfate, nitrate, soot, and dust.  These large amounts of organic particles contribute to the health impacts of air pollution, to regional visibility reductions, to both cooling and warming tendencies of radiative forcing, and to modified cloud properties and precipitation patterns.  Uncertainties remain in all aspect of their lifecycle, i.e., their formation, transformations and properties, and especially their removal.

Gas-Phase Dry Deposition as a Major Removal Mechanism for Secondary Organic Aerosols (SOA)

Water droplets on a leaf, by Siddharth Patil at Wikimedia Commons

Removal of secondary organic aerosols (SOA) from the atmosphere has been studied far less than its equal, production.  In current regional and global chemistry models rainout is the dominant loss of SOA. Here we show the importance of a less direct pathway, in which large scale evaporation of SOA particles occurs as a re-adjustment to gas-particle partitioning when semi-volatile organic gases are lost by dry deposition to the Earth’s surface.

The CONvective TRansport of Active Species in the Tropics (CONTRAST) Experiment

UTLS, convective transport in the tropics

ACD scientists in collaboration with colleagues from seven universities successfully sampled atmospheric composition over the Western Pacific warm pool region during the season characterized by massive convective storms.  The CONvective TRansport of Active Species in the Tropics (CONTRAST) experiment successfully concluded its field phase during January-February 2014. 

Secondary Organic Aerosols (SOA)

Secondary Organic Aerosol (SOA) formation in aqueous particles

Recent research suggests that in-cloud and in-particle chemistry could contribute substantially to the formation of SOA. Glyoxal is one of the precursors proposed to be important. In Knote et al. (2013) we included the state of knowledge on SOA formation from glyoxal into WRF-chem and conducted simulations over California as well as the continental United States for summer 2010.

Drought-Amplified CO Emissions in Amazonia

http://commons.wikimedia.org/wiki/File:ISS029-E-008032_Fires_along_the_Rio_Xingu_-_Brazil.jpg

Fires in Amazonia principally occur during the dry season lasting roughly from July to October and are concentrated in the 'arc of deforestation' spanning across the southern and eastern basin margins.  While much of the biomass burning activity in Amazonia follows directly from deforestation associated with agricultural practices, human-caused fires often escape from deforested areas into neighboring standing forests.  These fires typically burn below the forest canopy and cause long-term dama

WACCM Model Simulates Global Environmental Effects of a Regional Nuclear War

A closeup of the fireball and mushroom cloud from the Upshot-Knothole Grable atomic bomb; National Nuclear Security Administration

A regional nuclear conflict between India and Pakistan would not only inflict immediate damage in the subcontinent, including massive loss of life and destruction of built infrastructure; severe long-term environmental damage would also spread globally, lasting decades, researchers have found.

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