Phys.org July 12, 2024 New particle formation in the free troposphere is a major source of cloud condensation nuclei globally. The prevailing view is that in the free troposphere, new particles are formed predominantly in convective cloud outflows. An international team of researchers (USA -Washington University, NASA Langley Research Center (VA), University of Colorado, NOAA (Boulder), National Center for Atmospheric Research, Boulder, Washington University in St. Louis, Austria) presented another mechanism using global observations. They found that during stratospheric air intrusion events, the mixing of descending ozone-rich stratospheric air with more moist free tropospheric background resulted in elevated hydroxyl radical […]
Category Archives: Atmospheric science
New twists on tornadoes: Earth scientist studies why U.S. has so many tornadoes
Phys.org June 27, 2024 Central North America is the global hotspot for tornadoes, fueled by elevated terrain of the Rockies to the west and a source of warm, moist air from equatorward oceans. Based on this theory central South America, with the Andes to the west and Amazon basin to the north, should have a “tornado alley” at least as active as central North America. Central South America has frequent severe thunderstorms yet relatively few tornadoes. According to a team of researchers in the US (Purdue University, National Center for Atmospheric Researchers, (Boulder, CO), Stony Brook University, Colorado State University) […]
New insights into the formation of tiny cloud particles in the Arctic
Phys.org June 21, 2024 Vertical particle distributions are required to study aerosol–cloud interaction over sea ice comprehensively. An international team of researchers (Germany, USA – University of Colorado) presented vertically resolved measurements of aerosol particle number concentrations and sizes using tethered balloons with the data collected during the Multidisciplinary drifting Observatory for the Study of Arctic Climate expedition in the summer of 2020. Radiosoundings, cloud remote sensing data, and 5-day back trajectories supplemented the analysis of thirty-four profiles of aerosol particle number concentration observed in 2 particle size ranges above 150 nm (N>150). The majority of aerosol profiles showed more […]
Quantum data assimilation: A quantum leap in weather prediction
Science Daily June 13, 2024 In the context of numerical weather prediction (NWP), data assimilation is particularly vital for improving initial conditions and subsequent predictions. However, the computational demands imposed by conventional approaches, pose notable challenges in computational time. Researchers in Japan proposed quantum data assimilation approach which solves the data assimilation problem using quantum annealers. Their experiments using the 40-variable Lorenz model were highly promising, showing that the quantum annealers produced an analysis with comparable accuracy to conventional data assimilation approaches. In particular, the D-Wave Systems physical quantum annealing machine achieved a significant reduction in execution time… read more. […]
Simple equations clarify cloud climate conundrum
Phys.org April 1, 2024 Changes in anvil clouds with warming remain a leading source of uncertainty in estimating Earth’s climate sensitivity. An international team of researchers (France, UK) developed a feedback analysis that decomposes changes in anvil clouds and creates testable hypotheses for refining their proposed uncertainty ranges with observations and theory. They derived a simple but quantitative expression for the anvil area feedback, which depended on the present-day measurable cloud radiative effects and the fractional change in anvil area with warming. Satellite observations suggested an anvil cloud radiative effect of about ±1 W m−2, which requires the fractional change in anvil […]
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 […]