Mysterious, Upside-Down Lightning May Not Be a Freak Phenomenon After All

Science Alert  January 21, 2021 Lightning-like blue jets of atmospheric electric discharges fan into cones as they propagate from the top of thunderclouds into the stratosphere. They are thought to initiate in an electric breakdown between the positively charged upper region of a cloud and a layer of negative charge at the cloud boundary and in the air above. The breakdown forms a leader that transitions into streamers when propagating upwards. An international team of researchers (Denmark, Norway, Spain) report that they observed five intense, approximately 10-microsecond blue flashes from a thunderstorm cell. One flash initiated a pulsating blue jet […]

New tractor beam has potential to tame lightning

Phys.org  November 11, 2020 Numerous experiments utilizing powerful pulsed lasers with peak-intensity above air photoionization and photo-dissociation have demonstrated excitation and confinement of plasma tracks in the wakes of laser field. An international team of researchers (Australia, USA – UCLA) developed and demonstrated an efficient approach for triggering, trapping, and guiding electrical discharges in air. It is based on the use of a low-power continuous-wave vortex beam that traps and transports light-absorbing particles in mid-air. They found a 30% decrease in discharge threshold mediated by optically trapped graphene microparticles with the use of a laser beam of a few hundred […]

Turbulence affects aerosols and cloud formation

Science Daily  September 16, 2020 Traditionally the mechanics of cloud formation have not accounted for turbulence. Researchers at the Michigan Technological University investigated the aspects of cloud formation under controlled conditions including the effects of fluctuations, produced by turbulence. The measurements show a clear transition from a regime in which the mean saturation ratio dominates to one in which the fluctuations determine cloud properties. Measurements in the chamber show that turbulence can mimic the behaviors that have been attributed to particle variation, primarily size and composition. According to the researchers their model will help forecasters predict the fluctuations Planet Ocean-Cloud […]

Volcanic activity and changes in Earth’s mantle were key to rise of atmospheric oxygen

Science Daily  June 9, 2020 A team of researchers in the US (University of Washington, Scripps Institution of Oceanography, University of Maryland, Arizona State University) combined data with evidence from ancient sedimentary rocks to show a tipping point sometime after 2.5 billion years ago, when oxygen produced by microbes overcame its loss to volcanic gases and began to accumulate in the atmosphere during the Great Oxidation Event. The data demonstrates that an evolution of the mantle of the Earth could control an evolution of the atmosphere of the Earth, and possibly an evolution of life as multicellular life needs a […]

Nanoparticles of Fungal Spores Have Been Detected Floating in Our Atmosphere

Science Alert  January 26, 2020 Aerosol nanoparticles play an important role in the climate system by affecting cloud formation and properties, as well as in human health because of their deep reach into lungs and the circulatory system. The sudden appearance of large numbers of atmospheric nanoparticles is commonly attributed to secondary formation from gas-phase precursors. Researchers at UC Irvine have detected a mode of fungal fragments with a mobility diameter of roughly 30 nm released in episodic bursts in ambient air over an agricultural area in northern Oklahoma. These events reached concentrations orders of magnitude higher than other reports […]

Researchers preserve and release trove of public, low-frequency radio data

EurekAlert  December 9, 2019 At AGU’s 2019 Fall Meeting researchers unveiled the world’s largest open-access database of ELF/VLF data, Worldwide Archive of Low-frequency Data and Observations (WALDO). Researchers will be able to access nearly 1000 terabytes (TB) of data to further scientific efforts in fields like space weather, ionospheric remote sensing, earthquake forecasting, and subterranean prospecting. This is a joint project of Stanford University, Georgia Institute of Technology and the University of Colorado Denver with support from the National Science Foundation and Department of Defense. Most data are from the last 20 years, some recordings date back to the 1970s […]

A missing link in haze formation

Science Daily  November 25, 2019 Particles in the atmosphere that are 2.5 to 10 micrometers in size, can be inhaled, are potentially harming the heart and lungs. Alcohols in general and methanol in particular are believed to play a small role in atmospheric new particle formation (NPF) largely due to the weak binding abilities of alcohols with the major nucleation precursors. An international team of researchers (USA – University of Nebraska, University of Pennsylvania, Finland, China) has identified a catalytic reaction between methanol and sulfur trioxide (SO3) which can have unexpected quenching effects on the NPF process, particularly in dry […]

Rarely Seen Gravity Waves Captured Rippling in Earth’s Atmosphere

Science Alert  October 28, 2019 Gravity waves, also known as buoyancy waves, are a physical phenomenon where waves are generated in any fluid medium, such as waves at the beach, or ripples in a glass of water. They also take place in gases, like our atmosphere, and are called gravity waves because gravity is the force that restores equilibrium. In the atmosphere, they are generally created by obstructions to airflow, such as mountain ranges (on Venus, this creates enormous atmospheric waves), and by collisions between air masses of different temperatures. The latter is what caused the waves over Western Australia. […]

Researchers rise to challenge of predicting hail, tornadoes three weeks in advance

Science Daily  November 28, 2018 A team of researchers in the US (Colorado State University, Stoney Brook University) used a reliable tropical weather pattern called the Madden-Julian Oscillation, which can influence weather in distant parts of the Earth, to demonstrate the ability to make skillful predictions of severe weather across the Plains and southeastern United States, including hail and tornadoes, in 2-to-5-weeks-in-advance period. They validated their predictions using available datasets looking at what the Madden-Julian Oscillation was doing about three weeks ahead of severe weather in these areas during the typical severe-weather months of March through June. Although forecasting weeks […]