That's because aerosols, fine particles such as smoke and dust that form droplets in clouds and change cloud thickness, affect how much sun is able to pass through the cloud to Earth, as well as the amount of moisture that's returned to Earth. Both moisture and sunlight play significant roles in climate change.
"Think of it as having two clouds--one made of cotton and the other of Styrofoam," Penner said. "More sunlight and moisture will pass through a cloud of cotton as opposed to the denser cloud of Styrofoam. This difference is becoming more critical in terms of modeling future changes in the climate as we continue to produce more and more aerosols that form thicker and thicker clouds." Penner will present a talk on this topic, "Aerosol-Cloud Interactions and Climate Projections" during panel at a meeting of the American Association for the Advancement of Science in San Francisco on Feb. 17.
By comparing the observed temperature change record since 1850 with two different climate models, one that has low climate sensitivity and small amounts of aerosols and one that has high climate sensitivity and high amounts of aerosols, Penner's group showed that both models follow almost identical predictive paths in the past, but diverge significantly when predicting the temperature in the future
Penner's presentation also looks at the predictive capability of three climate models, a US NCAR-Oslo model, a French model and a Japanese model, and shows that differences are large, especially when the models predict both aerosols and their cloud effects in the assumed level of aerosols at the time, significantly changes the results. The differences are large partly because these models do not have high enough resolution to reproduce observations.
"We know that aerosol effects on clouds need to be included in climate models," Penner said, "but we need more research to reach optimum predictive properties for climate models."
NASA examines Peru's deadly rainfall
24.03.2017 | NASA/Goddard Space Flight Center
Steep rise of the Bernese Alps
24.03.2017 | Universität Bern
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
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24.03.2017 | Physics and Astronomy