Phys.org November 4, 2024 Poleward water vapor transport in the midlatitudes mainly occurs in meandering filaments of intense water vapor transport, spanning thousands of kilometers long and hundreds of kilometers wide and moving eastward. The water vapor filaments, known as atmospheric rivers (ARs), can cause extreme wind gusts, intense precipitation, and flooding along densely populated coastal regions. Many recent studies about ARs focused on the statistical analyses of ARs, but a process-level understanding of ARs remains elusive. A team of researchers in the US (Argonne National Laboratory, University of Chicago) showed that ARs are streams of air with enhanced vapor […]
Tag Archives: Atmospheric science
New study unveils 16,000 years of climate history in the tropical Andes
Phys.org August 12, 2024 Understanding tropical South America’s climate history can provide valuable insight into the water cycle, ecosystems, and future climate change, yet past temperature changes are not well-known. An international team of researchers (USA – Brown University, Florida Institute of Technology, the Netherlands) reconstructed temperature and rainfall since ~16,800 y ago in the tropical Andes Mountains. In addition to warming driven by rising atmospheric CO2 concentrations, they observed rapid temperature changes linked to changes in the deep ocean circulation. Their findings suggested that Amazonia’s ecosystems may be challenged by rapid temperature changes superposed on warming from sharply increasing […]
Earth and space share the same turbulence
Phys.org June 7, 2024 The dynamics of upper atmosphere winds differ significantly from those at lower altitudes, with larger magnitudes and increased sensitivity to solar events. An international team of researchers (Germany, Japan) used multi-year observations of cross-track winds (u) from the CHAllenging Minisatellite Payload (CHAMP) and the Gravity Field and Steady State Ocean Circulation Explorer (GOCE) to calculate third-order structure functions in the thermosphere as a function of horizontal separation (s). They presented two main characteristics – they are consistently positive, predicting a preferential cyclonic rotational motion (counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere) and, […]
Cloud engineering could be more effective ‘painkiller’ for global warming than previously thought
Phys.org April 11, 2024 Marine cloud brightening is a proposed method to tackle warming through injecting aerosols into marine clouds. However, it is unclear how aerosols influence clouds. An international team of researchers (USA – University of Birmingham, NASA GSFC, Greenbelt, MD, University of Maryland Baltimore County, UK, Switzerland) used satellite observations of volcanic eruptions in Hawaii to quantify the aerosol fingerprint on tropical marine clouds. They observed a large enhancement in reflected sunlight, mainly due to an aerosol-induced increase in cloud cover. This suggested that the current level of global warming is driven by a weaker net radiative forcing […]
Clouds disappear quickly during a solar eclipse, shows study
Phys.org February 12, 2024 Clouds affected by solar eclipses could influence the reflection of sunlight back into space and might change local precipitation patterns. Satellite cloud retrievals have so far not taken into account the lunar shadow, hindering a reliable spaceborne assessment of the eclipse-induced cloud evolution. Researchers in the Netherlands used satellite cloud measurements during three solar eclipses between 2005 and 2016 that have been corrected for the partial lunar shadow together with large-eddy simulations to analyze the eclipse-induced cloud evolution. The corrected data revealed that, over cooling land surfaces, shallow cumulus clouds start to disappear at very small […]
Detecting atmospheric rivers with satellite observations
Phys.org February 19, 2024 Atmospheric rivers (ARs) are filaments of enhanced horizontal moisture transport in the atmosphere. They play a prominent role in the meridional moisture transport and regional weather extremes. But the representations of ARs and their associated precipitation on a global scale remains largely unknown. A team of researchers in the US (UCLA, NCAR, Caltech) developed an AR detection algorithm specifically for satellite observations using moisture and the geostrophic winds derived from 3D geopotential height field from the combined retrievals of the Atmospheric Infrared Sounder and the Advanced Microwave Sounding Unit on NASA Aqua satellite. The algorithm enabled […]
Earth’s ‘third pole’ and its role in global climate
Phys.org August 25, 2023 Researchers in China reviewed recent advances in research regarding land–atmosphere coupling processes over the Tibetan Plate (TP) and concluded that climate warming has caused glacier retreat, permafrost degradation, and a general increase in vegetation density, while climate wetting has led to a significant increase in the number of major lakes, primarily through increased precipitation. The TP drives surface pollutants to the upper troposphere in an Asian summer monsoon (ASM) anticyclone circulation before spreading to the lower stratosphere. The thermal forcing of the TP plays an essential role in the ASM. TP forcing can modulate hemispheric-scale atmospheric […]
Scientists improve the accuracy of weather and climate models
Phys.org March 1, 2023 Researchers in Switzerland have developed a new modelling framework for atmospheric flow simulations for cryospheric regions called CRYOWRF. CRYOWRF couples the state-of-the-art and used atmospheric model WRF (the Weather Research and Forecasting model) with the detailed snow cover model SNOWPACK. CRYOWRF makes it feasible to simulate the dynamics of a large number of snow layers governed by grain-scale prognostic variables with online coupling to the atmosphere for multiscale simulations from the synoptic to the turbulent scales. They also introduced a scheme for blowing snow in CRYOWRF. They described the technical design goals, model capabilities and the […]
Scientists can now map lightning in 3D
Phys.org February 15, 2023 A team of researchers in the US (Los Alamos National Laboratory, New Mexico Institute of Mining and Technology) developed and deployed a new 3-dimensional broadband radio frequency interferometric mapping and polarization system (BIMAP-3D) which provides an unprecedented capability in high-resolution, time-evolving 3D lightning source mapping and 3D source polarization detection for detailed study of lightning discharge physics. In this article they described the BIMAP-3D system design, a generalized and analytical 2D interferometry technique for noncoplanar antenna array, a two-stage 3D mapping technique based on geometric triangulation and baseline-based differential time of arrival, and a technique to […]
Deflecting lightning with a laser lightning rod
Phys.org January 16, 2023 An international team of researchers (France, Switzerland, Germany, USA – New Mexico Institute of Mining and Technology, Sweden) conducted the first field-result that experimentally demonstrated lightning guided by lasers. They conducted an experimental campaign on the Säntis mountain in north-eastern Switzerland during the summer of 2021 with a high-repetition-rate terawatt laser. The guiding of an upward negative lightning leader over a distance of 50 m was recorded by two separate high-speed cameras. It was corroborated in three other instances by very-high-frequency interferometric measurements, and the number of X-ray bursts detected during guided lightning events greatly increased. According […]