Nav: Home

Thin tropical clouds cool the climate

August 17, 2016

Thin clouds at about 5 km altitude are more ubiquitous in the tropics than previously thought and they have a substantial cooling effect on climate. This is shown in a recent study by researchers from Stockholm University and the University of Miami published in Nature Communications. The cooling effect of mid-level clouds is currently missing in global climate models.

"Using the satellite observations and high-resolution numerical modelling, we find that thin mid-level clouds are frequently formed in the tropics in the vicinity of deep convective clouds and that their cooling effect could be as large as the warming induced by high cirrus clouds", says lead author of the study Quentin Bourgeois, postdoctoral associate at the Department of Meteorology (MISU) and the Bolin Centre for Climate Research, Stockholm University.

Clouds play a pivotal role in determining the Earth's climate and radiation budget, yet we still have a lot to learn about them. In particular, little is known about mid-level clouds, i.e. clouds located at approximately 5 km altitude, as these clouds are challenging to study.

"To bridge our gaps in knowledge about thin mid-level clouds we used space-borne lidar instruments that provide detailed information on the vertical distribution of clouds", says Quentin Bourgeois.

The scientists anticipate that their study will trigger further interest in thin mid-level clouds, which have been neglected for too long. In particular, the mechanism of their formation is not well understood yet. The authors also hope that the climate research community will factor in clouds in climate models more often in the future so that projections of climate change will become more accurate.

Clouds effects on global climate


Clouds cover about 70% of the Earth's surface at any time. Different types of clouds affect the Earth's climate differently: low liquid clouds, such as the cotton-like cumulus, cool the Earth while high altitude ice clouds, such as the wispy cirrus, warm the climate. Overall, clouds cool the climate by about 20 W m-2. In contrast, the Earth receives on average about 340 W m-2 energy from the sun every day and our current emissions of anthropogenic greenhouse gases warm the climate by about 3 W m-2.
-end-
For more information

Quentin Bourgeois, Department of Meteorology (MISU) and the Bolin Centre for Climate Research, Stockholm University, email: quentin.bourgeois@misu.su.se, phone +46(0)8-16 42 36, cell phone +46 (0)707 40 57 12

Annica Ekman, Department of Meteorology (MISU) Stockholm University, email: annica@misu.su.se, phone/cellphone +46(0)8-16 23 97

Matthew Igel, University of Miami, email: migel@rsmas.miami.edu, phone +1 828 493 05 07

Radovan Krejci, Department of Environmental Science and Analytical Chemistry, Stockholm University, email: radovan.krejci@aces.su.se, phone +46(0)8-674 72 24 This work is supported by the Swedish National Space Board (Rymdstyrelsen). M. Igel is supported by the National Science Foundation under Award No. 1433164. We thank T. Corti and T. Peter for their help with the cloud radiative forcing model. We acknowledge the ICARE Data Services and Center for providing access to the CALIOP data used in this study and tools to process them.

Stockholm University

Related Climate Change Articles:

The black forest and climate change
Silver and Douglas firs could replace Norway spruce in the long run due to their greater resistance to droughts.
For some US counties, climate change will be particularly costly
A highly granular assessment of the impacts of climate change on the US economy suggests that each 1°Celsius increase in temperature will cost 1.2 percent of the country's gross domestic product, on average.
Climate change label leads to climate science acceptance
A new Cornell University study finds that labels matter when it comes to acceptance of climate science.
Was that climate change?
A new four-step 'framework' aims to test the contribution of climate change to record-setting extreme weather events.
It's more than just climate change
Accurately modeling climate change and interactive human factors -- including inequality, consumption, and population -- is essential for the effective science-based policies and measures needed to benefit and sustain current and future generations.
Climate change scientists should think more about sex
Climate change can have a different impact on male and female fish, shellfish and other marine animals, with widespread implications for the future of marine life and the production of seafood.
Climate change prompts Alaska fish to change breeding behavior
A new University of Washington study finds that one of Alaska's most abundant freshwater fish species is altering its breeding patterns in response to climate change, which could impact the ecology of northern lakes that already acutely feel the effects of a changing climate.
Uncertainties related to climate engineering limit its use in curbing climate change
Climate engineering refers to the systematic, large-scale modification of the environment using various climate intervention techniques.
Public holds polarized views about climate change and trust in climate scientists
There are gaping divisions in Americans' views across every dimension of the climate debate, including causes and cures for climate change and trust in climate scientists and their research, according to a new Pew Research Center survey.
The psychology behind climate change denial
In a new thesis in psychology, Kirsti Jylhä at Uppsala University has studied the psychology behind climate change denial.

Related Climate Change Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Digital Manipulation
Technology has reshaped our lives in amazing ways. But at what cost? This hour, TED speakers reveal how what we see, read, believe — even how we vote — can be manipulated by the technology we use. Guests include journalist Carole Cadwalladr, consumer advocate Finn Myrstad, writer and marketing professor Scott Galloway, behavioral designer Nir Eyal, and computer graphics researcher Doug Roble.
Now Playing: Science for the People

#529 Do You Really Want to Find Out Who's Your Daddy?
At least some of you by now have probably spit into a tube and mailed it off to find out who your closest relatives are, where you might be from, and what terrible diseases might await you. But what exactly did you find out? And what did you give away? In this live panel at Awesome Con we bring in science writer Tina Saey to talk about all her DNA testing, and bioethicist Debra Mathews, to determine whether Tina should have done it at all. Related links: What FamilyTreeDNA sharing genetic data with police means for you Crime solvers embraced...