Researchers provide unprecedented view into aerosol formation in Earth’s lower atmosphere

Phys.org  March 6, 2024 Criegee intermediates are reactive intermediates that are implicated in transforming the composition of Earth’s troposphere and in the formation of secondary organic aerosol, impacting Earth’s radiation balance, air quality and human health. Direct identification of their signatures in the field are not available. An international team of researchers (USA – Argonne National Laboratory, NASA Jet Propulsion Laboratory, Sandia National Laboratory, Caltech, Princeton University, Princeton Plasma Physics Laboratory, UC Davis, UK, Turkey, Brazil, France) has identified sequences of masses consistent with the expected signatures of oligomerization of the CH2OO Criegee intermediate, a process implicated in ozonolysis-driven aerosol […]

Ocean system that moves heat gets closer to collapse, which could cause weather chaos, study says

Phys.org  February 10, 2024 One of the most prominent climate tipping elements is the Atlantic meridional overturning circulation (AMOC), which can potentially collapse because of the input of fresh water in the North Atlantic. Although AMOC collapses have been induced in complex global climate models by strong freshwater forcing, the processes of an AMOC tipping event have so far not been investigated. Researchers in the Netherlands have shown results of the first tipping event in the Community Earth System Model, including the large climate impacts of the collapse. Using these results, they developed a physics-based and observable early warning signal […]

Biological particles play crucial role in Arctic cloud ice formation

Science Daily  September 28, 2023 Primary biological aerosol particles (PBAP) play an important role in the climate system, facilitating the formation of ice within clouds, consequently PBAP may be important in understanding the rapidly changing Arctic climate. An international team of researchers (Sweden, Switzerland, Japan, Norway) used single-particle fluorescence spectroscopy to identify and quantify PBAP at an Arctic mountain site, with transmission electronic microscopy analysis supporting the presence of PBAP. They found that PBAP concentrations ranged between 10−3–10−1 L−1 and peak in summer. Evidence suggested that the terrestrial Arctic biosphere was an important regional source of PBAP, given the high […]

Superbolts: Scientists figure out what causes Earth’s strongest lightning

Phys.org   September 28, 2023 Exceptionally high-energy lightning strokes >106 J (X1000 stronger than average) in the very low-frequency band between 5 and 18 kHz, also known as superbolts (SB), occur mostly during winter over the North-East Atlantic, the Mediterranean Sea, and over the Altiplano in South America. An international team of researchers (Israel, USA- University of Washington) compared the World-Wide Lightning Location Network database with meteorological and aerosol data to examine the causes of lightning stroke high energies. Their results showed that the energy per stroke increases sharply as the distance between the cloud’s charging zone (where the cloud electrification […]

Thunderstorms clumping together: How understanding water vapor helps scientists predict future climate change

Phys.org  October 2, 2023 Convective clouds in the atmosphere can aggregate in a variety of ways, from individual cells to larger systems like tropical cyclones and squall lines. An international team of researchers (USA – University of New Mexico, MIT, Germany, Ethiopia, France) used remote sensing datasets of water vapor isotopic composition along with objective measures of convective aggregation to better understand the impact of convective aggregation on the atmospheric hydrologic cycle in the global tropics for the period 2015–2020. When convection was unaggregated, vertical velocity profiles were top-heavy, mixing ratios increased and water vapor δD decreased as the mean […]

Exploring just how extreme future storms could get

Phys.org   September 18, 2023 Due to the lack of long homogenous climate data and methodological frameworks, it is challenging to estimate how extreme precipitation could get and what the physical drivers are. Researchers in Switzerland developed two complementary strategies to extrapolate beyond the precipitation records: (a) statistical estimates based on fitting generalized extreme value distributions, providing their probabilistic information on return periods and, (b) ensemble boosting, a model-based re-initialization of heavy precipitation in large ensembles, providing a physical coherent storyline in space and time, however, with no direct quantification of its probability. Both show that 3-day accumulated precipitation maxima can […]

In dust and clouds over Africa, scientists find clues to how hurricanes form

Phys.org  May 25, 2023 When the dust that wafts off the Sahel and Sahara regions of Africa mixes with tropical clouds, it creates rainy “disturbance” in the eastern Atlantic which are hurricanes in their youngest form. To study these infant storms, a group of NASA scientists spent a month flying off the northwestern coast of Africa aboard NASA’s research plane logging roughly 100 hours. The campaign encountered and measured one of the largest dust events the Airborne Laboratory capturing data with its instruments. Onboard remote sensing instruments captured detailed profiles of Saharan dust, wind speed and direction, temperature, moisture, and […]

Extended-range forecasts to be recast in next model upgrade

Phys.org  May 18, 2023 In the next upgrade of European Centre for ECMWF’s (Medium-Range Weather Forecasts) Integrated Forecasting System (IFS), extended-range forecasts will have 101 instead of 51 ensemble members and will run more frequently than before, at a consistent horizontal resolution of 36 km. The upgrade will lead to improvements in forecast performance across all parameters. The extended-range forecasts provide predictions up to 46 days ahead. The 51‑member ensemble in the current configuration cannot always properly capture small shifts in forecast probabilities. Doubling the ensemble size to 101 ensemble members will provide a more accurate representation of the forecast […]

Initial wind field structure: A crucial factor in determining tropical cyclone size and intensity

Phys.org  May 15, 2023 Researchers in China conducted experiments by varying the radius of maximum wind (RMW) and shape parameter b of the initial vortices. The size–intensity relationship was quantified by the linear regression coefficient of the azimuthally-averaged gale-force wind radius against the maximum wind during the development stage, reflecting the degree of size expansion at the same intensity increment. The regression coefficient increased with increased RMW and decreased b, with the RMW being the primary constraint. Enlarging the RMW led to a secondary circulation with a horizontally elongated structure, which retards the intensification while expanding the size. Broadening the […]

Scientists develop Earth system models with clouds and ocean submesoscale eddies

Phys.org  April 26, 2023 Researchers in China developed a series of high-resolution coupled Earth system models (SW-HRESMs) with up to 5 km of atmosphere and 3 km of ocean which can meet the needs of multiscale interaction studies with different computational costs. They described the progress of SW-HRESMs development, with an overview of the major advancements made by the international Earth science community in HR-ESMs. They showed the preliminary results of SW-HRESMs regarding capturing major weather-climate extremes in the atmosphere and ocean, stressing the importance of permitted clouds and ocean submesoscale eddies in modeling tropical cyclones and eddy-mean flow interactions, […]