Science Daily May 26, 2021 In recent years, however, a growing body of experimental evidence has shown that EMIC waves can cause the scattering loss of electrons down to sub-MeV energies. Using measurements of trapped electron flux from the GPS satellite constellation, an international team of researchers (New Zealand, UK, USA – Los Alamos National Laboratory) investigated the ability of EMIC waves to cause significant depletions of radiation belt electron populations. They presented statistical evidence demonstrating global decreases in sub-MeV trapped electron flux in response to EMIC wave activity. Although they found that electron losses extend down to sub-MeV energies, […]
Tag Archives: Atmospheric science
Lightning and subvisible discharges produce molecules that clean the atmosphere
Phy.org April 29, 2021 Lightning increases the atmosphere’s ability to cleanse itself by producing nitric oxide (NO), leading to atmospheric chemistry that forms ozone (O3) and the atmosphere’s primary oxidant, the hydroxyl radical (OH). A team of researchers (Pennsylvania State University, Texas Tech University, NOAA, University of Oklahoma, University of Maryland, University of Alaska, University of Colorado) analyzed data from their 2012 airborne study of deep convection and chemistry which showed that lightning also directly generates the oxidants OH and the hydroperoxyl radical (HO2). Extreme amounts of OH and HO2 were discovered and linked to visible flashes occurring in front […]
Aerosol formation in clouds
Science Daily March 24, 2021 Cloud processing is potentially important for secondary organic aerosol (SOA) formation, a major aerosol component: however, laboratory experiments fail to mimic this process under atmospherically relevant conditions. An international team of researchers (Switzerland, UK, USA – Carnegie Mellon University, industry) developed a wetted-wall flow reactor to simulate aqueous-phase processing of isoprene oxidation products (iOP) in cloud droplets. They found that 50 to 70% (in moles) of iOP partition into the aqueous cloud phase, where they rapidly react with OH radicals, producing SOA. Integrating their experimental results into a global model, they showed that clouds effectively […]
Researchers explore using light to levitate discs in the mesosphere
Phys.org February 15, 2021 To improve weather prediction sensors need to be sent to mesosphere. The satellites and rockets currently used have problems as the air is too thick and friction and heat would make long-duration flights impractical. Researchers at the University of Pennsylvania constructed and demonstrated light-driven levitation of macroscopic polymer films with nanostructured surface as candidates for long-duration near-space flight. The disks were made of 0.5-micron-thick mylar film coated with carbon nanotubes on one side. When illuminated with light intensity comparable to natural sunlight, the polymer disk heats up and interacts with incident gas molecules differently on the […]
Scientists Detect ‘Superbolts’ 1,000 Times Brighter Than Typical Lightning Strikes
Science Alert November 24, 2020 Researchers at the Los Alamos National Laboratory used Fast On-Orbit Detection of Transient Events (FORTE) satellite observations to identify superbolt-class optical lightning events and evaluate their origins. Superbolts have been defined as lightning pulses whose peak optical power exceeds 1011 W. However, it has been unclear whether superbolts resulted from particular types of high-energy lightning process or whether they were the result of measurement bias. According to their 12-year analysis of FORTE superbolt detections indicates that the lower optical superbolt energy range (~100 GW) is dominated by normal lightning, but brighter cases are predominantly strong […]
Shift in atmospheric rivers could affect Antarctic sea ice, glaciers
Science Daily November 23, 2020 Researchers at UCLA investigated the atmospheric river (AR) frequency trends over the Southern Hemisphere using three reanalyses and two Community Earth System Model (CESM) ensembles. Their results show that AR frequency has been increasing over the Southern Ocean and decreasing over lower latitudes in the past four decades and that ARs have been shifting poleward. While the observed trends are mostly driven by the poleward shift of the westerly jet, the experiments indicate anthropogenic forcing would result in positive AR frequency trends over the Southern Ocean due mostly to moisture changes. They conclude that the […]
Atlantic hurricanes linked to weather system in East Asia
Science Daily August 7, 2020 A team of researchers in the US (University of Iowa, Princeton University) has identified an association between the East Asian Subtropical Jet Stream (EASJ) during July–October and the frequency of Atlantic tropical cyclones during August–November based on observations for 1980–2018. According to the researchers the Rossby waves hitch a ride on the EASJ to the North Atlantic when tropical cyclones in the Atlantic are most likely to form. The waves affect wind shear, a key element in the formation of tropical storms. Rossby waves form within the Earth’s oceans and atmosphere because of the planet’s […]
Deep learning accurately forecasts heat waves, cold spells
EurekAlert February 4, 2020 Researchers at Rice University have created a deep learning computer system called “capsule neural network”. During training, it examines hundreds of pairs of maps. Each map shows surface temperatures and air pressures at five-kilometers height, and each pair shows those conditions several days apart. The training includes scenarios that produced extreme weather — extended hot and cold spells that can lead to deadly heat waves and winter storms. Once trained, the system was able to examine maps it had not previously seen and make five-day forecasts of extreme weather with 85% accuracy…read more. Open Access TECHNICAL ARTICLE
Atmospheric river storms create $1 billion-a-year flood damage
Science Daily December 4, 2019 Researchers found that flooding has caused nearly $51 billion in damages to western states in the last 40 years. More than 84 percent of these damages were caused by atmospheric rivers (ARs), long narrow corridors of water vapor in the atmosphere, capable of carrying more than twice the volume of the Amazon river through the sky. A team of researchers in the US (UC San Diego, US Army) used 40 years of data from the National Flood Insurance Program to show that ARs are the primary drivers of flood damages in the western United States. […]
Researchers uncover key reaction that influences growth of potentially harmful particles in atmosphere
Phys.org November 25, 2019 An international team of researchers (USA – University of Nebraska, University of Pennsylvania, Finland, China) has identified a catalytic reaction between methanol and SO3, catalyzed by SA, DMA, or water that was previously overlooked. The catalytic reaction between methanol and SO3 can convert methanol into a methyl hydrogen sulfate (MHS). Their simulation results suggest that the formation of MHS consumes an appreciable amount of atmospheric SO3, disfavoring further reactions of SO3 with H2O. They show that MHS formation can cause a reduction of SA concentration up to 87%. Hence, a high abundance of methanol in the […]