Cloud-Aerosol Transport System (CATS) on Board ISS – NASA/SVS (2017)

NASA’s Cloud-Aerosol Transport System is a remote-sensing instrument installed on the International Space Station (ISS) in 2015. Using LIDAR technology it scans a vertical slice of the atmosphere for natural as well as human made aerosols and clouds. The near-real-time data transmitted from the ISS enables CATS team to process it within six hours.

One of the natural aerosol sources is volcanoes. In April 2015, the CATS instrument provided a detailed profile of the south Chilean volcano Calbuco when it erupted in multiple episodes. The ash column reached the upper troposphere. This is the type of eruption that affects the global heat budget since the aerosols that reach troposphere get to disperse evenly to far reaches of the globe deflecting the incoming sunlight.

CATS measurements help scientists incorporate the structure of dust plumes and other atmospheric features into climate models and forecasting calculations. Being able to track suspended particles and clouds and their interactions with each other over time is very useful for predicting intermediate range events such as the Atlantic hurricanes. Climate scientists knew that the desert dust plumes from the Sahara can suppress hurricane formation in the Atlantic. These plumes also form nuclei for cloud formation and affect rainfall patterns in the Amazon basin. In October 2016, CATS measurements helped understand characteristic anvil cirrus and convective clouds on the periphery of the core of the Hurricane Matthew.

NASA’s satellite fleet continues to monitor aerosol abundance, diversity and transport. At any given time 80 percent of our skies are covered by diverse cloud formations. Cloud formation and its interaction with aerosols is crucial to understand large scale global events such as the El Niño Southern Oscillation.

Smoke generated by wildfires is another source of aerosols. In August 2015, smoke from wildfires in Oregon reached to a height of 5 km. The vertical structure of smoke plumes is very useful in understanding the interactions with low altitude clouds. Low altitude clouds have a cooling effect while the high altitude clouds trap heat.

CATS – NASA Wildfire from Nature Documentaries on Vimeo.

All together, a global synthesis of aerosol dynamics is a necessity to predict what could be brewing in the next century. The following animation which is featured as a close-up version in the last section of the visualizations in the main video does that by visualizing aerosol emissions and transport from September 1, 2006 to April 10, 2007. Black and organic carbon (green), dust (red-orange), sulfates (white), and sea salt (blue) as well as locations of wildfires and human-initiated burning (red dots) are detected by the MODIS instrument on NASA’s Terra and Aqua satellites.

In the first 45 seconds of the animation, fires burning over South America and Africa can be seen emitting large amounts of black carbon into the atmosphere. At the same time, dust from the Sahara and the Middle East is picked up by winds and transported west, where it becomes wrapped up in two tropical cyclones over the Atlantic in early to mid September. Sulfur emissions from Europe, Asia, and North America are also pulled into the flow and advected eastward and poleward, and are occasionally pulled into cyclones. Mount Nyiragongo, in the Democratic Republic of the Congo, continuously erupts throughout the animations. The Tibetan Plateau is like an obstacle course against the westerly winds that have swept across the Gobi desert in Asia and picked up dust.

NASA Global Dust and Aerosol Simulation from Nature Documentaries on Vimeo.

After 45 seconds into the simulation, fires in Indonesia intensify and emit large amounts of black carbon into the atmosphere in October and November. This corresponds to reduction of biomass burning in South America hidden on the other side of our planet. At the same time, several strong cyclones in the western Pacific can be seen lifting sea salt aerosols and entraining dust, sulfates, and black carbon. In December, fires in southeastern Australia ignite and emit black carbon that mixes with dust from the Australian deserts. These aerosols then get drawn into the westerlies of the southern hemisphere. Aerosol travel around the Antarctica in southern mid-to-high latitudes. Undisturbed by land, the aerosols interact with the polar easterlies to form large cyclones that can easily be seen in the distribution of sea salt aerosols. Simultaneous with Australian fires biomass burning in Africa intensifies (not visible in visualization).

At 1 minute 45 seconds into the visualization (January 2007), the eruption of the Karthala volcano on Grand Comore Island off Africa’s eastern coast can be seen. The eruption began on January 12 and lasted for a few days. The sulfate aerosols disperse, mixing with the emissions from biomass burning in central Africa, and are pulled in two directions by opposing wind belts. By February, sulfate emissions from Mount Karthala decreases, but dust and black carbon continue to drift off the Africa and make their way to the Americas or to Europe.

In North America, (at around after 2 minutes into the visualization) winter weather systems can be periodically seen spinning up over the center of the continent and pushing sulfate emissions as well as advected dust, black carbon, and sea salt aerosols away from the landmass into the Atlantic and the Gulf of Mexico.

Later in February, biomass burning in Thailand and neighboring countries increases. Black carbon emissions quickly mix with dust from the Middle East and the Gobi and with sulfates from industry in China. These aerosols are then transported eastward, are pulled into mid-latitude cyclones that churn up sea salt, and eventually cross the Pacific to reach North America.



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