Climate models

Scientist analyzes cloud data to improve climate models

Paquita Zuidema, a professor at the Rosenstiel School of Marine and Atmospheric Science, is a researcher on a multi-year NASA-led project that will advance the short- and long-term accuracy of climate modeling.

This is one of the remaining challenges for weather and climate modellers: understanding how variations in spatial cloud patterns affect weather patterns over time.

Now, a University of Miami atmospheric scientist is part of a multi-year NASA-led field campaign that uses synchronized aircraft flights to unravel some of the mysteries surrounding cloud evolution. during cold air surges-from thick, covered with fluffy cumulus clouds resembling cotton balls.

“Sampling during cold air outbreaks is one of the key elements of this project. We’re looking at how clouds at low altitude change shape as cold air heads offshore,” said Paquita Zuidema, a professor at the University’s Rosenstiel School of Marine and Atmospheric Science, who is a researcher. on the interactions of aerosol cloud meteorology over the Western Atlantic. Experiment, or ACTIVATE. “The models often under-represent the ‘streets’ of shallow clouds and the often dramatic change from more overcast clouds to more broken clouds,” she explained.

“Critical uncertainty arises because even at subzero temperatures, most of a cloud’s composition is usually liquid,” Zuidema added. “If, how and when the liquid becomes ice, and what this does to the organization of the cloud field remains a major research question. We observe similar cloud evolutions in fully liquid clouds at warmer temperatures, but we know less what to expect when ice may also be present. Knowing how much of a cloud is made up of liquid and how much is made up of snow and ice is a key question for weather and climate modelling.

For the past two years, ACTIVATE researchers have deployed on two aircraft from NASA’s Langley Research Center in Hampton, Virginia, flying over the western North Atlantic Ocean to collect critical data. on atmospheric structure, aerosols and cloud physics not available by other means.

“The two small planes fly relatively slowly, allowing them to increase their sample time and stay coordinated with each other,” Zuidema said.

Planes fly in sync. While a plane flies through clouds to take atmospheric measurements, the second cruises directly overhead, to assembleing remote sensing measurements and broadcastsing probes that record vertical structure readings.

The western North Atlantic is an ideal location for study due to its proximity to cloud transitions. “It’s also interesting to note that continental air carries a wide range of aerosol loads, primarily East Coast industrial pollution. This can then mix with much cleaner air from higher up and to spray aerosols from the ocean, so there’s a whole range of complexities to consider,” Zuidema noted.

The data collected by the two NASA planes is uploaded to a web server, which gives Seethala Chellappan, a science assistant at the Zuidema and Rosenstiel school, the opportunity to analyze the relationship between the microphysical characteristics of clouds. and the wider environment.

“We published an initial paper that looked at the effectiveness of reanalysis data, that is, data provided by models after they assimilate satellite measurements, capturing changes in atmospheric temperature, humidity and vertical wind patterns as the air moved over the Gulf Stream,” Zuidema revealed. In this studypublished on September 8, 2021, AGU online numberGeophysical Research Letters, Zuidema and his team found that reanalysis data is adequate to initialize higher-resolution modeling of cold air outbreak clouds.

The project, she said, has the potential to provide atmospheric scientists with decades of important information about the processes that dictate the life cycle of clouds, from their formation and maintenance to their eventual dissipation. .

ACTIVATE research flights will continue through September, augmenting data from previous missions.

The University of Arizona is the lead academic institution for the project, which is one of five NASA Earth Venture Suborbital campaigns investigating little-understood aspects of our planet’s system processes.

The study is another example of Zuidema’s ongoing work in cloud exploration. His research focuses on the relationship between warm, shallow clouds and the large-scale environment, with an emphasis on the connection to radiation.

She was principal investigator of the five-year NASA-funded ORACLES (ObseRvations of Aerosols above CLouds and their intEractionS) project, studying the climate impact of biomass burning of aerosol particles produced by fires in Africa. southern.

Born in the Netherlands, Zuidema grew up speaking Dutch. She was only 4 years old when her father, a cultural anthropologist, moved his family to Peru for a university teaching job. She earned a Bachelor of Science in Physics from the University of Illinois at Urbana-Champaign, and later a Ph.D. in Atmospheric and Oceanic Sciences from the University of Colorado-Boulder.

She became fascinated with clouds as a graduate student, writing a thesis on a satellite characterization project that involved low, shallow clouds.

“I love looking at the clouds,” she said, “and wondering why they are.”

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