Clouds play a prominent role in moderating Earth’s climate, but their role is still poorly understood. Generally, clouds cool the Earth by reflecting incoming sunlight back out into space. Reducing the clouds’ reflectivity—with a layer of pollution, for example—reduces the cooling effect. However, new research in Proceedings of the National Academy of Sciences by Zhibo Zhang, associate professor of atmospheric physics at UMBC, two of his students, and collaborators from University of Wyoming, University of Science and Technology of China, Universities Space Research Association, and University of Michigan adds another level of complexity to this model.

Every fall, fires race across central and southern Africa. Many are wildfires; others are intentionally set by humans to clear farmland. They create so much smoke that it’s clearly visible from space. Wind sweeps the smoke westward over the Atlantic Ocean, where it rises above the largest semi-permanent gathering of clouds in the world. For years, scientists believed that overall, the smoke diminishes the clouds’ cooling effect by absorbing light that the clouds beneath otherwise would reflect. The new study by Zhang and colleagues doesn’t dispute the existence of this effect, but introduces a new mechanism that counteracts it by making the clouds more reflective.

“The purpose of this paper is to look at these competing processes. Which one is more important?” asks Zhang. A previous paper by Chamara Rajapakshe, a Ph.D. candidate in Zhang’s group (the UMBC ACROS group) and co-author on the new paper, was crucial to answering that question. Using data from a LiDAR system on the International Space Station, Rajapakshe found that the smoke and cloud layers are much closer to each other than previously observed. That means the smoke, which is in the form of tiny particles known as aerosols, can physically interact with the clouds, affecting how they form at the microscopic level. Previous studies usually overlooked these microphysical changes caused by aerosols’ interactions with the clouds.

Clouds need “seeds” to grow. A seed can be any tiny particle around which cloud droplets condense. Aerosols are perfect for seeding clouds, and with more seeds, many small cloud droplets replace fewer large droplets, which then collectively reflect more light and increase the cooling effect.

The team found that in smoky conditions, there are almost twice as many “seeds” per cubic centimeter. By running computer simulations under different conditions, they determined that overall, “The seeding effect is winning,” Zhang says. So, contrary to long-held understanding, the overall effect of the hovering smoke on the clouds near Africa appears to be a cooling one.

Zhang is quick to point out that this result is not an argument in favor of fires. “Aerosols are a very local phenomenon, and they are also short-lived,” he says, so their cooling effects are short-lived, too. “The lifetime of carbon dioxide and other greenhouse gases,” which are released in abundance when plant material burns, “is hundreds of years.”

The team’s ultimate goal is to refine global climate models by improving how they account for clouds. Zhang’s other Ph.D. student and another co-author, Zhifeng Yang, has contributed to that effort by analyzing data collected by a satellite that stays put in the sky (rather than orbiting Earth) to get a more accurate sense of how cloud cover changes in daily cycles.

The next step is to evaluate existing climate models against the team’s new finding. “Now that we know there are two competing mechanisms, and the seeding effect is winning, we can see whether climate models consider these processes properly when they predict the weather and climate in this area,” explains Zhang.

Zhang, Rajapakshe, and Yang are excited to present their findings to the atmospheric physics community in their new paper, and to continue working in this area to further improve climate models—but the more they learn about the complexity of the processes involved, the harder it gets.

“First we had to simulate the clouds correctly. Then we had to simulate the aerosols correctly, and now we have to also simulate the interactions between them correctly,” says Zhang. “It’s becoming a much harder question to address.”

Still, they are up for the challenge. A new NASA mission called PACE is expected to launch in 2020. It will be able to detect polarized light, in addition to everything LiDAR can do.

“With the new satellite you can look at things from different perspectives,” says Zhang, and develop three-dimensional models of the interactions between aerosols and clouds. “Hopefully we can look at this phenomenon even better.”

Beyond the upcoming NASA mission, what really excites Zhang and his team is the opportunity to play a role in making sure communities around the world have the best information available as they prepare for the effects of climate change.

Image: View from a data-collecting aircraft over the Atlantic Ocean, where a layer of smoke is visible above the clouds. (NASA/Kirk Knobelspiesse)

The UMBC Admissions office has made an official statement on Feb. 26 stating that participating in peaceful protests will not affect admission chances.

“Participation in peaceful protests and demonstrations in support of important social issues will not negatively affect admissions decisions,” UMBC said.

The statement is in response to threats of suspension if high schoolers choose to demonstrate during school hours. High schools have the right to punish students if they protest during school hours.

Many prospective college students raised concerns over whether disciplinary action would affect their chances of admission at UMBC. Many high schoolers have contacted UMBC asking if a demonstration could harm their admission chances.

“We have people calling the front office and wanting to know. These students wanted to understand the implications if any disciplinary action was taken against them,” said Assistant Vice Provost Dale Bittinger.

The announcement that peaceful protest will not harm admission chances does not reflect a change in UMBC’s admissions policy. The admission’s office has always accounted for the extenuating circumstances behind any disciplinary action.

“No, it’s not a change in our policy,” said Bittinger. “We always had a policy that allowed us to look at individual circumstances surrounding any disciplinary action issued against a student.”

In assuring prospective college students, UMBC has joined 236 other colleges across the country. UMBC published the statement on the official Facebook page, undergraduate website and the UMBC Admissions & Orientation Twitter account. The stance UMBC has taken has garnered positive reception, with 48 likes on Facebook and 14 likes on Twitter.

“I think it speaks to the characteristics UMBC wants to see in their upcoming class of students,” said Jackson Pugliese, a freshman physics major. ”It is noble that schools are sending the message that it is okay to stand up for what they believe.”

UMBC’s statement comes before several protest walkouts that aim to raise awareness. On March 14, “Enough” will occur, where at least 33,000 students have planned to walk out of school for 17 minutes. At 1,965 high schools, students plan to leave class and make their voices heard.

“The recent events in Florida have really led to students wanting to take action, [to] have a voice through protest and demonstrations,” said Bittinger. “And so quite simply, it’s important for us to support our students who want to be change agents.That’s really what this is about, too.”

Walkouts and marches are not the only ways students are making their voice heard. On social media, students are posting with the hashtag “NeverAgain.” Cameron Kasky, a survivor of the parkland shooting, created the #neveragain movement. The goal of the movement is to raise awareness and increase gun regulations to prevent future school shootings.

“UMBC is committed to inclusive excellence, social justice and freedom of expression,” according to the statement. These values hold true as no student will lose their spot here at UMBC because they were disciplined in school for choosing to peacefully protest for what they believed in.

“We value different thoughts and perspectives and matters, and we really believe in social justice,” said Bittinger.

After years of indifference to the music of pop singer Joni Mitchell, Zadie Smith suddenly found herself in love with Mitchell’s music. In her lecture, Rita Felski uses Smith’s change in preference to explain why art captivates us.

Felski’s lecture “Attunement: How We Become Enthralled by Art” kicked off the Spring 2018 Dresher Center Humanities Forum series in the AOK library gallery. Surrounded by ambient lighting and exhibition artwork, Felski delivered a powerful speech on her research.

Felski defines Attunement as the unpredictable nature of how experiences and social influences can shape the perception of art. Attunement is the reason why art captivates people. It is also the focus of the research that Felski, an English professor at the University of Virginia, is currently conducting. Her work focuses on literary theory and aesthetics— the science behind why people enjoy art.

Felski’s lecture introduces the idea behind why some works of art are captivating while others bore people. She attunes the audience to how people’s perceptions shift as they go through life. “There’s also this other side to it, not just appreciating it, but being aware of how it works on us,” said Dresher Center Director Jessica Berman.

At UMBC, the Dresher Center has been striving to make the humanities accessible to all students. The Humanities Forum series aims to bring ideas and perspectives from around the country to UMBC. According to Berman, the series hopes to change how students view the humanities and provide a meaningful experience to students, no matter what major they are.

“What we’re hoping will happen is some sort of connecting with people, pushing them a little in new directions and adding something new to the way they might approach the issues facing [sic] in their lives,” Berman said.

In the following months, the Dresher Center plans to bring many other speakers to UMBC. Next week Jennifer Stoever, an associate professor of English at Binghamton University, will be speaking on the relationship between race and sound in her lecture “Listening To Racism in the US – Or Why Sound Matters.”

“A really good lecture like this can really jolt you out your habits,” said Berman. When students hear new ideas, it has the potential to make a difference in their lives.

The Humanities Forum is one of many lecture series UMBC students can attend. Most departments host a lecture series to educate students outside of the classroom.

Felski’s lecture gave students insight into the mystery of human mental processes and why certain information, including what students hear in extracurricular lectures, makes a lasting impression. “Our senses are trained to distinguish and indistinguish,” said Felski.

After successfully competing for four years as part of the Coastal Collegiate Sports Association, UMBC men’s swimming and diving returned to the America East for the 2017-18 season with a hunger for victory. Their vision became a reality when the Retrievers emerged with the America East championship trophy after four days of grueling competition in Worcester, Massachusetts. With a final score of 1,113 points, UMBC blew second-place team Binghamton out of the water by nearly 300 points.

UMBC’s women’s team also made huge strides, bridging a nearly 100-point gap after the first day of competition. Their tenacity paid off, landing them in second place by the end of the meet, only 4.5 points behind New Hampshire.

Over the course of the championship, both teams cemented their legacy by breaking multiple UMBC and America East records. Tunisian national champion Haythem Abdelkhalek ‘19, computer science, bested the former men’s 1650 record of 15:31.99 (set by a Retriever in 2006) by staggering 10 seconds, setting a new record of 15:21.41. Emily Vance ‘20, health administration and policy, set a new UMBC women’s 100 back record of 54.50, while also swimming the 200 back in 1:57.61, beating her own previous UMBC record, as well as the America East’s record set in 2011.

Danish national champion Alexander Gliese ‘19, mechanical engineering, brought home gold and, in the process, set a new men’s 200 back record with a time of 1:45.27. With a solid showing throughout the weekend, Luis Galvan ‘20, health administration and policy and financial economics, set new America East records in both the 100 and 200 breast. Philip Adejumo ‘18, biochemistry and molecular biology, finished his career with a UMBC team record in the 100 fly, clocking a 47.43 to eclipse a record from 2014. The Retrievers posted the only relay record broken during the weekend when the team of Gliese, Jared Vance ‘18, business technology administration, Adejumo and Rattsev, posted a 1:31.11 to break the 2011 Boston University record in the 200 medley relay.

The accolades continued as Natalija Marin ‘21, mechanical engineering, and Kai Wisner ‘21, mechanical engineering, received Most Outstanding Rookie awards. Ilia Rattsev ‘20, bioinformatics and computational biology, was named Male Most Outstanding Swimmer and Nikola Trajkovic ‘18, financial economics, was awarded the Dave Alexander Coaches Award for accumulating the most points in the championships as a senior.

In additional to purely athletic achievements, Allison Atkinson ‘18, biological sciences, and Connor Ganley ‘18, chemical engineering, were recognized as having the highest GPAs among competing student-athletes and were named the America East Elite 18 recipients. Coach Chad Cradock ’97, psychology, and his staff were named the men’s and women’s Coaching Staff of the Year.

“I want to thank our coaching staff for doing such a great job. To be voted coaching staff of the year for both men and women is a such a compliment and a product of their dedication to our program,” Cradock said.

Coming off their record-breaking showing at America East, UMBC men’s and women’s swimming and diving traveled to Rutgers University for the Eastern College Athletic Conference Championships on February 15, 2018. Gliese again earned first in both the 100 and 200 men’s back, breaking the pool record in the 200 backstroke, and Vance reset her own school record in the women’s 100 back.
For more UMBC Swimming and Diving news, see UMBC Athletics.

Image: UMBC’s men’s swimming and diving team celebrate a first place win at America East Championships; photo by Greg Cooper. Inset: UMBC men’s and women’s swimming and diving teams; photo by Gail Burton.

Clouds play a prominent role in moderating Earth’s climate, but their role is still poorly understood. Generally, clouds cool the Earth by reflecting incoming sunlight back out into space. Reducing the clouds’ reflectivity—with a layer of pollution, for example—reduces the cooling effect. However, new research in Proceedings of the National Academy of Sciences by Zhibo Zhang, associate professor of atmospheric physics at UMBC, two of his students, and collaborators from University of Wyoming, University of Science and Technology of China, Universities Space Research Association, and University of Michigan adds another level of complexity to this model.

Every fall, fires race across central and southern Africa. Many are wildfires; others are intentionally set by humans to clear farmland. They create so much smoke that it’s clearly visible from space. Wind sweeps the smoke westward over the Atlantic Ocean, where it rises above the largest semi-permanent gathering of clouds in the world. For years, scientists believed that overall, the smoke diminishes the clouds’ cooling effect by absorbing light that the clouds beneath otherwise would reflect. The new study by Zhang and colleagues doesn’t dispute the existence of this effect, but introduces a new mechanism that counteracts it by making the clouds more reflective.

“The purpose of this paper is to look at these competing processes. Which one is more important?” asks Zhang. A previous paper by Chamara Rajapakshe, a Ph.D. candidate in Zhang’s group (the UMBC ACROS group) and co-author on the new paper, was crucial to answering that question. Using data from a LiDAR system on the International Space Station, Rajapakshe found that the smoke and cloud layers are much closer to each other than previously observed. That means the smoke, which is in the form of tiny particles known as aerosols, can physically interact with the clouds, affecting how they form at the microscopic level. Previous studies usually overlooked these microphysical changes caused by aerosols’ interactions with the clouds.

Clouds need “seeds” to grow. A seed can be any tiny particle around which cloud droplets condense. Aerosols are perfect for seeding clouds, and with more seeds, many small cloud droplets replace fewer large droplets, which then collectively reflect more light and increase the cooling effect.

The team found that in smoky conditions, there are almost twice as many “seeds” per cubic centimeter. By running computer simulations under different conditions, they determined that overall, “The seeding effect is winning,” Zhang says. So, contrary to long-held understanding, the overall effect of the hovering smoke on the clouds near Africa appears to be a cooling one.

Zhang is quick to point out that this result is not an argument in favor of fires. “Aerosols are a very local phenomenon, and they are also short-lived,” he says, so their cooling effects are short-lived, too. “The lifetime of carbon dioxide and other greenhouse gases,” which are released in abundance when plant material burns, “is hundreds of years.”

The team’s ultimate goal is to refine global climate models by improving how they account for clouds. Zhang’s other Ph.D. student and another co-author, Zhifeng Yang, has contributed to that effort by analyzing data collected by a satellite that stays put in the sky (rather than orbiting Earth) to get a more accurate sense of how cloud cover changes in daily cycles.

The next step is to evaluate existing climate models against the team’s new finding. “Now that we know there are two competing mechanisms, and the seeding effect is winning, we can see whether climate models consider these processes properly when they predict the weather and climate in this area,” explains Zhang.

Zhang, Rajapakshe, and Yang are excited to present their findings to the atmospheric physics community in their new paper, and to continue working in this area to further improve climate models—but the more they learn about the complexity of the processes involved, the harder it gets.

“First we had to simulate the clouds correctly. Then we had to simulate the aerosols correctly, and now we have to also simulate the interactions between them correctly,” says Zhang. “It’s becoming a much harder question to address.”

Still, they are up for the challenge. A new NASA mission called PACE is expected to launch in 2020. It will be able to detect polarized light, in addition to everything LiDAR can do.

“With the new satellite you can look at things from different perspectives,” says Zhang, and develop three-dimensional models of the interactions between aerosols and clouds. “Hopefully we can look at this phenomenon even better.”

Beyond the upcoming NASA mission, what really excites Zhang and his team is the opportunity to play a role in making sure communities around the world have the best information available as they prepare for the effects of climate change.

Image: View from a data-collecting aircraft over the Atlantic Ocean, where a layer of smoke is visible above the clouds. (NASA/Kirk Knobelspiesse)

Related Articles:  https://phys.org/news/2018-03-physicists-interactions-clouds-unexpected-cooling.html

http://www.uwyo.edu/uw/news/2018/03/uw-researchers-lead-study-that-discovers-south-african-wildfires-create-climate-cooling.html