The earth's climate field is regulated by the balance between incoming solar radiation and outbound heat radiation. The aerosol content of the atmosphere, that is, the proportion of particles in the air, functions as a regulator: cooling off by reflecting incoming light, warming up by absorbing the outbound heat radiation.
But clouds also impact the climate. In various forms-from thin, indiscernible to thick, gray ones-clouds cover roughly half of the earth's surface. Clouds reflect a considerable proportion of solar radiation back into space, but, like greenhouse gases, they can also absorb outbound heat radiation. However, the uncertainties surrounding how clouds affect the climate are great - according to the UN Climate Panel, the greatest single uncertainty when it comes to estimating the sensitivity of the climate.
Now a new field of research is being established at the University of Gothenburg to fill these knowledge gaps.
In his doctoral dissertation, researcher Frans Olofson at the Department of Chemistry presents a new application of a metering technique in which a laser beam is sent up in the air to measure the aerosol content and how light is being reflected in the atmosphere. The study was carried out on cirrus clouds above northern Norway and is the first to be performed in the climate-sensitive Arctic region using this technology. The study establishes that incoming solar radiation is regulated to a great extent by the shape and size of cloud particles.
"Measurements of this type can be used to improve our descriptions of the radiation properties of cirrus clouds, which in turn can enhance the quality of climate models," says Frans Olofson.
In his dissertation Frans Olofson has also studied periodically troublesome temperature inversions, which can be seen in the winter as a lid of yellowish brown emissions over cities. Inversions have serious impacts on people's health, and the longer they are exposed to them, the more they are affected.
Based on his measurements in Gothenburg, Frans Olofson was able to establish that inversions are strongly tied to meteorological phenomena, and that the time it takes for the pollutants to dissolve varies considerably: from a couple of hours in the morning up to several hours in the afternoon. Sometimes an inversion doesn't break up all day.
Title of dissertation: Lidar Studies of Tropospheric Aerosols and Clouds
Krister Svahn | idw
Research sheds new light on forces that threaten sensitive coastlines
24.04.2017 | Indiana University
NASA sees the end of ex-Tropical Cyclone 02W
21.04.2017 | NASA/Goddard Space Flight Center
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
20.04.2017 | Event News
18.04.2017 | Event News
03.04.2017 | Event News
24.04.2017 | Physics and Astronomy
24.04.2017 | Materials Sciences
24.04.2017 | Life Sciences