Article
Meteorology & Atmospheric Sciences
M. J. Alexander, C. C. Liu, J. Bacmeister, M. Bramberger, A. Hertzog, J. H. Richter
Summary: This study examines the relationship between tropical rain cells and small-scale atmospheric waves (gravity waves) in the National Center for Atmospheric Research's Whole Atmosphere Community Climate Model version 6 (WACCM6). Comparisons with high-resolution observations of tropical rain and tropical gravity waves lead to proposed new methods for future simulations with WACCM6, which are likely to improve its representation of interannual wind changes and their impacts on tropical precipitation and winter season weather in the Northern Hemisphere.
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
(2021)
Article
Meteorology & Atmospheric Sciences
Sebastian Buschow
Summary: A recent study shows that the distribution of global precipitation variability in ERA5 has shifted towards smaller spatial scales over the twentieth century, particularly over the tropical oceans. This shift can be explained by the transition from parameterized to explicitly resolved convection in the tropical region. It is induced primarily by changes in the observation system rather than real-world climate change.
QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY
(2023)
Article
Meteorology & Atmospheric Sciences
Rosimar Rios-Berrios, George H. Bryan, Brian Medeiros, Falko Judt, Wei Wang
Summary: This study investigates the effects of resolved deep convection on tropical rainfall and its multi-scale variability. The results show that resolved deep convection leads to a narrower, stronger, and more equatorward intertropical convergence zone, as well as higher precipitation variance and more frequent heavy rainfall rates. Additionally, resolved deep convection results in stronger cold pools and upgradient convective momentum fluxes, while parameterized convection leads to more circular systems, weaker cold pools, and downgradient convective momentum fluxes.
JOURNAL OF ADVANCES IN MODELING EARTH SYSTEMS
(2022)
Article
Mathematics, Applied
Zhe Jiao, Yong Xu, Lijing Zhao
Summary: We study the dynamics of solutions to semilinear wave systems with time-varying damping and nonconvex force potential. Our result reveals the asymptotic stability of the solutions without bifurcation or chaos. We provide numerical simulations of dissipative sine-Gordon equation and dissipative Klein-Gordon equation to illustrate our theoretical findings.
COMMUNICATIONS IN NONLINEAR SCIENCE AND NUMERICAL SIMULATION
(2023)
Article
Meteorology & Atmospheric Sciences
David Leutwyler, Cathy Hohenegger
Summary: The study shows that tropical islands tend to cool rather than warm the troposphere. This is due to the daytime surface warming of the islands pushing convection over land towards a warmer moist adiabat, while drying of the land surface pulls it towards a colder moist adiabat.
QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Evan H. Anders, Adam S. Jermyn, Daniel Lecoanet, Benjamin P. Brown
Summary: Most stars have convection zones, but the behavior of convective boundaries is not well understood. In this study, researchers conducted 3D numerical simulations and discovered the existence of penetration zones. By defining the penetration parameter P and constructing an energy-based theoretical model, they successfully described the simulations. This study is important for understanding convective phenomena in stars.
ASTROPHYSICAL JOURNAL
(2022)
Article
Multidisciplinary Sciences
Ibtisam Aldawish, Mohamed Jleli, Bessem Samet
Summary: We study a semilinear time-fractional damped wave equation in one dimension with a convection term and singular potentials. The equation is defined in a bounded interval and subjected to a Dirichlet boundary condition depending on time. By employing nonlinear capacity estimates, we establish conditions under which weak solutions to the problem do not exist. Specifically, we show the existence of a Fujita-type critical exponent when the boundary condition is independent of time.
Article
Meteorology & Atmospheric Sciences
Daeho Jin, Lazaros Oreopoulos, Dongmin Lee, Jackson Tan, Kyu-myong Kim
Summary: This study applies organization metrics to describe tropical synoptic scale convective activity, and modifies the existing metrics to capture the characteristics of large-scale convective events in such regions.
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
(2022)
Article
Meteorology & Atmospheric Sciences
David S. Nolan, Matthew J. Onderlinde
Summary: Recent studies have examined the dynamics of fine-scale gravity waves radiating from tropical cyclones. Numerical simulations were used to compare with observations as the grid spacing decreased. Different classes of spiral waves and slower-moving waves were observed in satellite images, potentially caused by strong vertically sheared winds in the outflow region of the cyclones.
JOURNAL OF ADVANCES IN MODELING EARTH SYSTEMS
(2022)
Article
Environmental Sciences
Yanmin Lv, Jianping Guo, Jian Li, Lijuan Cao, Tianmeng Chen, Ding Wang, Dandan Chen, Yi Han, Xiaoran Guo, Hui Xu, Lin Liu, Raman Solanki, Gang Huang
Summary: Large-scale in situ observations of atmospheric turbulence in China have been lacking, but high-resolution soundings since 2011 offer a unique opportunity for investigation. Analysis of radiosonde data from 2011-2018 revealed spatial variability in turbulence across China, with more intense turbulence observed over the Tibetan Plateau and neighboring regions characterized by large-amplitude mountain waves. Seasonal and vertical variations in turbulence highlight the importance of understanding and mitigating clear-air turbulence for aviation safety.
ENVIRONMENTAL RESEARCH LETTERS
(2021)
Article
Geosciences, Multidisciplinary
I. Reinares Martinez, S. Evan, F. G. Wienhold, J. Brioude, E. J. Jensen, T. D. Thornberry, D. Heron, B. Verreyken, S. Korner, H. Vomel, J. -M. Metzger, F. Posny
Summary: A nascent in situ cirrus was observed on January 11, 2019 in the tropical tropopause layer over the southwestern Indian Ocean. Data from balloon-borne instruments were used to characterize the cirrus and its environment. Optical modeling was employed to estimate the cirrus microphysical properties, indicating that the formation may have been triggered by a high-frequency gravity wave.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Geosciences, Multidisciplinary
Geet George, Bjorn Stevens, Sandrine Bony, Robert Pincus, Chris Fairall, Hauke Schulz, Tobias Koelling, Quinn T. Kalen, Marcus Klingebiel, Heike Konow, Ashley Lundry, Marc Prange, Jule Radtke
Summary: The study presented the process of deploying dropsondes during the EUREC(4)A field campaign over the tropical North Atlantic and the dataset derived from these measurements, including both raw profiles and gridded data for analyzing the thermodynamic and dynamic environment of clouds in the trade-wind regions.
EARTH SYSTEM SCIENCE DATA
(2021)
Article
Meteorology & Atmospheric Sciences
Chuntao Liu, Joan Alexander, Jadwiga Richter, Julio Bacmeister
Summary: Quantifying the momentum flux transported from the troposphere into the lower stratosphere by gravity waves generated by convection is a challenge due to a lack of observations. This study estimates the geographical distribution of momentum flux at 100 hPa in the tropics and subtropics using observed convective sources, providing insights into the dynamics of general circulation.
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
(2022)
Review
Mechanics
Eric Falcon, Nicolas Mordant
Summary: In the past decade, there has been a significant increase in wave turbulence studies, particularly in the field of water waves. The theoretical modeling of ocean waves, which has driven the development of weak turbulence theory, has been found to be too idealized to capture experimental observations. Laboratory observations have revealed that the waves studied are actually gravity-capillary waves, as opposed to ocean waves. This richer physics has led to various physical effects beyond the theoretical framework, especially in the gravity-capillary crossover region.
ANNUAL REVIEW OF FLUID MECHANICS
(2022)
Article
Meteorology & Atmospheric Sciences
Steven M. Lazarus, Jason Chiappa, Hadley Besing, Michael E. Splitt, Jeremy A. Riousset
Summary: The meteorological characteristics associated with thunderstorm-top turbulence and tropical cyclone gigantic jets have been investigated, with findings including evidence of gravity wave breaking in satellite images and distinguishing features of the TC GJ environment.
JOURNAL OF THE ATMOSPHERIC SCIENCES
(2021)
Article
Meteorology & Atmospheric Sciences
Lewis P. Blunn, Omduth Coceal, Negin Nazarian, Janet F. Barlow, Robert S. Plant, Sylvia Bohnenstengel, Humphrey W. Lean
Summary: Accurate representation of turbulence in urban canopy models is crucial for predicting momentum and scalar distribution. Studies on turbulence characteristics under different conditions revealed similar momentum mixing-length profiles and the significance of dispersive momentum fluxes in real urban settings.
BOUNDARY-LAYER METEOROLOGY
(2022)
Article
Meteorology & Atmospheric Sciences
Douglas J. Parker, Alan M. Blyth, Steven J. Woolnough, Andrew J. Dougill, Caroline L. Bain, Estelle de Coning, Mariane Diop-Kane, Andre Kamga Foamouhoue, Benjamin Lamptey, Ousmane Ndiaye, Paolo Ruti, Elijah A. Adefisan, Leonard K. Amekudzi, Philip Antwi-Agyei, Cathryn E. Birch, Carlo Cafaro, Hamish Carr, Benard Chanzu, Samantha J. Clarke, Helen Coskeran, Sylvester K. Danuor, Felipe M. de Andrade, Kone Diakaria, Cheikh Dione, Cheikh Abdoulahat Diop, Jennifer K. Fletcher, Amadou T. Gaye, James L. Groves, Masilin Gudoshava, Andrew J. Hartley, Linda C. Hirons, Ishiyaku Ibrahim, Tamora D. James, Kamoru A. Lawal, John H. Marsham, J. N. Mutemi, Emmanuel Chilekwu Okogbue, Eniola Olaniyan, J. B. Omotosho, Joseph Portuphy, Alexander J. Roberts, Juliane Schwendike, Zewdu T. Segele, Thorwald H. M. Stein, Andrea L. Taylor, Christopher M. Taylor, Tanya A. Warnaars, Stuart Webster, Beth J. Woodhams, Lorraine Youds
Summary: Africa has the potential to benefit greatly from advancements in weather predictions, and the SWIFT project is playing a significant role in advancing scientific solutions and enhancing forecasting capabilities in the region. By focusing on research, training, and collaboration between academia and operational agencies, SWIFT is helping to build capacity in African meteorology and improve the quality and relevance of weather forecasts.
BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY
(2022)
Article
Meteorology & Atmospheric Sciences
Emma Howard, Simon Thomas, Thomas H. A. Frame, Paula L. M. Gonzalez, John Methven, Oscar Martinez-Alvarado, Steven J. Woolnough
Summary: Two sets of weather patterns in Southeast Asia are presented and compared, showing the ability to capture different modes of tropical circulation variability. The study found that while the patterns can distinguish various climate modes effectively, there are still some modes that are not well captured. The weather patterns show promising potential in extending the useful forecast range for the risk of heavy precipitation.
QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY
(2022)
Article
Meteorology & Atmospheric Sciences
Samson Hagos, Jingyi Chen, Katelyn Barber, Koichi Sakaguchi, Robert S. Plant, Zhe Feng, Heng Xiao
Summary: A machine-learning-assisted stochastic cloud population model is developed and coupled with the WRF model to simulate fluctuations in cloud-base mass flux caused by the life cycles and interactions of cumulus convection cells. The model uses a neural network trained on convective cell size distributions to predict the cell size and cloud-base mass flux distributions. This approach shows promise in simulating realistic precipitation statistics and propagation associated with the Madden-Julian Oscillation, while maintaining realistic depictions of the diurnal cycle over land and ocean.
JOURNAL OF ADVANCES IN MODELING EARTH SYSTEMS
(2022)
Article
Meteorology & Atmospheric Sciences
Masilin Gudoshava, Caroline Wainwright, Linda Hirons, Hussen S. Endris, Zewdu T. Segele, Steve Woolnough, Zachary Atheru, Guleid Artan
Summary: The timing of the rainy season is crucial for various sectors in Eastern Africa. Early onset is associated with increased rainfall and warmer sea surface temperatures, while late onset is associated with rainfall deficit and cooler sea surface temperatures. The variability in onset date is influenced by Indian Ocean sea surface temperatures and circulation.
INTERNATIONAL JOURNAL OF CLIMATOLOGY
(2022)
Article
Meteorology & Atmospheric Sciences
Simon H. H. Lee, Andrew J. J. Charlton-Perez, Steven J. J. Woolnough, Jason C. C. Furtado
Summary: This study investigates the impact of forecast error and uncertainty in the polar vortex on predictions of large-scale weather patterns called regimes over North America. The results provide a framework for interpreting the stratospheric influence on North American regime behavior and can be used to improve weather forecast models.
JOURNAL OF CLIMATE
(2022)
Article
Meteorology & Atmospheric Sciences
Catherine Ivanovich, Weston Anderson, Radley Horton, Colin Raymond, Adam Sobel
Summary: This study investigates the relationship between extreme humid heat events in the Persian Gulf and South Asia and intraseasonal climate variability. The results show that variations in moisture and local circulation anomalies play a crucial role in anomalously high wet-bulb temperatures. This research contributes to the subseasonal prediction of extreme humid heat in regions where it has a significant impact.
JOURNAL OF CLIMATE
(2022)
Article
Geosciences, Multidisciplinary
Shuguang Wang, Adam H. Sobel
Summary: The authors propose a new approximation method to understand the moisture modes in idealized models of tropical intraseasonal oscillations. This method provides physical insights and filters out disturbances, enhancing the understanding of these oscillation patterns.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Meteorology & Atmospheric Sciences
Natalie J. Harvey, Chimene L. Daleu, Rachel A. Stratton, Robert S. Plant, Steven J. Woolnough, Alison J. Stirling
Summary: Despite recent improvements, model simulations using parameterised convection still struggle in accurately capturing the daily cycle of precipitation in tropical regions. Cloud-resolving simulations provide insights into precipitation formation and can serve as benchmarks for evaluating and improving parameterisation schemes.
QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY
(2022)
Article
Meteorology & Atmospheric Sciences
Paula L. M. Gonzalez, Emma Howard, Samantha Ferrett, Thomas H. A. Frame, Oscar Martinez-Alvarado, John Methven, Steven J. Woolnough
Summary: In this study, pattern-conditioned probabilistic rainfall forecasts were produced by combining the horizontal winds from the Met Office GloSea5 prediction system with weather patterns. The results showed that this approach outperformed model-simulated rainfall hindcasts in predicting rainfall for lead times of 10-20 days. This is a fundamental step for the development of subseasonal prediction systems for Southeast Asia.
QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY
(2023)
Article
Meteorology & Atmospheric Sciences
Michael C. Johnston, Christopher E. Holloway, Robert S. Plant
Summary: Convective cloud bands known as cloud trails (CTs) are frequently observed downwind of small islands worldwide. These CTs primarily form in the afternoon due to land-sea contrasts and background flow. Idealized numerical experiments based on observed environmental conditions off Bermuda are conducted to quantify the relationship between island surface forcing and CT circulation strength. The experiments reveal that the integrated excess heating caused by the island determines the strength of the CT circulation, with a linear relationship between CT circulation and island surface heat flux when other factors are constant.
QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY
(2023)
Article
Multidisciplinary Sciences
Beata Latos, Philippe Peyrille, Thierry Lefort, Dariusz B. Baranowski, Maria K. Flatau, Piotr J. Flatau, Nelly Florida Riama, Donaldi S. Permana, Adam V. Rydbeck, Adrian J. Matthews
Summary: In April 2021, tropical cyclone Seroja became one of the first cyclones to hit the near-equatorial regions of Indonesia and East Timor. The unique cyclogenesis close to land was a result of perfect storm conditions caused by multiple wave interactions. This finding suggests that the predictability of tropical cyclones over the Maritime Continent may be increased.
NATURE COMMUNICATIONS
(2023)
Article
Environmental Sciences
Amulya Chevuturi, Nicholas P. Klingaman, Steven J. Woolnough, Conrado M. Rudorff, Caio A. S. Coelho, Jochen Schongart
Summary: Accurate prediction of the maximum water levels of the Negro River in Manaus is crucial for effective mitigation measures. By using dynamical seasonal prediction hindcasts, we were able to extend the lead time of statistical models for earlier forecasts. The developed ensemble forecasts, using input from observations and seasonal hindcasts, perform similarly to the original statistical forecasts and gain one month of lead time.
Article
Geosciences, Multidisciplinary
Philippe Peyrille, Romain Roehrig, Sidiki Sanogo
Summary: This study investigates the sub-seasonal drivers of extreme precipitation events (EPE) in the Central Sahel. A statistical approach is used to analyze the average EPE. It is found that EPEs occur within a large-scale moist anomaly, an upper-level divergence, and at shorter scales an intense vortex. These features are provided by multiple tropical waves, especially an Equatorial Rossby wave (ER) and an African Easterly Wave (AEW). Statistics show that the combination of AEW with ER and/or Kelvin wave increases the probability of EPE. Monitoring these tropical wave combinations could improve EPE forecasts.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Multidisciplinary Sciences
Adam H. Sobel, Chia-Ying Lee, Steven G. Bowen, Suzana J. Camargo, Mark A. Cane, Amy Clement, Boniface Fosu, Megan Hart, Kevin A. Reed, Richard Seager, Michael K. Tippett
Summary: Recent research shows that climate models incorrectly simulate the equatorial Pacific response to greenhouse gas warming, leading to a discrepancy between model predictions and observations of a more La Nina-like state. This could result in incorrect projections of regional tropical cyclone activity and other perils such as severe convective storms and droughts. While these errors may be transient, the transient response is important for climate adaptation in the next several decades. Therefore, it is desirable to develop projections that represent a broader range of possible future tropical Pacific warming scenarios, even if current coupled earth system models cannot produce such projections.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2023)