Article
Geosciences, Multidisciplinary
Geet George, Bjorn Stevens, Sandrine Bony, Raphaela Vogel, Ann Kristin Naumann
Summary: Understanding the drivers of cloud organization is crucial for accurately estimating cloud feedbacks and their contribution to climate warming. Shallow mesoscale circulations, which have not been observed before, are found to exist and play an important role in cloud organization. These circulations are associated with large variability in mesoscale vertical velocity and amplify moisture variance at the cloud base. The ubiquity of these circulations suggests their integral role in determining how clouds respond to climate change.
Article
Physics, Fluids & Plasmas
G. R. Vybhav, S. Ravichandran
Summary: This study investigates the entrainment in dry and moist thermals using direct numerical simulations in neutral and unstably stratified ambients. The results show that turbulence plays a minor role in entrainment in dry thermals in neutral ambients. However, the net entrainment rate increases with higher buoyancy of the thermals due to condensation heating or an unstably stratified ambient. In addition, the role of turbulence is greater in moist thermals, and the combination of condensation heating and turbulence leads to the destruction of coherent vortex rings observed in dry and moist laminar thermals. Fully resolved simulations at Reynolds numbers larger than the mixing transition Reynolds number are necessary to understand the role of turbulence in entrainment in growing cumulus clouds.
PHYSICAL REVIEW FLUIDS
(2022)
Article
Environmental Sciences
Florian Tornow, Andrew S. Ackerman, Ann M. Fridlind
Summary: The study investigates the impact of frozen hydrometeors on transitions during marine cold air outbreaks. It is found that ice particles can accelerate the transition speed, shortening the overcast state. Ice particles affect the boundary layer evolution by reducing cloud liquid water, consuming cloud condensation nuclei, and leading to early precipitation cooling and moistening below cloud.
ATMOSPHERIC CHEMISTRY AND PHYSICS
(2021)
Article
Meteorology & Atmospheric Sciences
Chun-Yian Su, Chien-Ming Wu, Wei-Ting Chen, Jen-Her Chen
Summary: This study implements the unified parameterization in the global forecast system and investigates its impacts on simulated precipitation variability and organized convective systems through short-term hindcasts. The results show that the unified parameterization can adapt better to convective development, reduce parameterized convection, and increase spatial variation of moisture, leading to improved precipitation spectrum and the relationship between precipitation and convective system scale.
MONTHLY WEATHER REVIEW
(2021)
Article
Environmental Sciences
B. Poujol, P. A. Mooney, S. P. Sobolowski
Summary: As the climate warms, precipitation becomes more intense, especially in the autumn. The increase in convective precipitation frequency and intensity dominates the climate change signal, but there are deviations in the precipitation response in autumn and spring.
ENVIRONMENTAL RESEARCH LETTERS
(2021)
Article
Meteorology & Atmospheric Sciences
John M. Peters, Daniel R. Chavas
Summary: This study evaluates alternative variables to moist static energy (MSE) and suggests that MSE - IB and MSE + KE are better conserved than MSE in large-eddy simulations of deep convection. The combination of MSE with buoyancy and kinetic energy variables provides more accurate predictions along trajectories in different types of convection.
JOURNAL OF THE ATMOSPHERIC SCIENCES
(2021)
Article
Meteorology & Atmospheric Sciences
Gorm G. Jensen, Romain Fievet, Jan O. Haerter
Summary: Research shows that simulating the diurnal cycle can enable convective self-aggregation (CSA) at fine resolutions, and that this process can be accelerated by even finer resolutions. The emergence of vigorous combined cold pools with mesoscale convective systems is believed to be one of the reasons for these findings.
JOURNAL OF ADVANCES IN MODELING EARTH SYSTEMS
(2022)
Article
Meteorology & Atmospheric Sciences
Zhe Feng, L. Ruby Leung, Nana Liu, Jingyu Wang, Robert A. Houze, Jianfeng Li, Joseph C. Hardin, Dandan Chen, Jianping Guo
Summary: A new methodology is developed to track mesoscale convective systems (MCS) globally using satellite data, providing insights into MCS characteristics and seasonal variations. The study confirms the superiority of the new method over previous T-b-only approaches and validates MCS statistics across the globe.
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
(2021)
Article
Meteorology & Atmospheric Sciences
Martin Janssens, Jordi Vila-guerau De Arellano, Chiel C. Van Heerwaarden, Stephan R. De Roode, A. Pier Siebesma, Franziska Glassmeier
Summary: Condensation in cumulus clouds plays a key role in structuring the mean trade wind boundary layer. Small anomalies in condensation power circulations that transport moisture and reinforce the condensation anomaly. The positive feedback of mesoscale moisture fluctuations in cumulus clouds is explained as a linear instability, motivating further research into its relevance.
JOURNAL OF THE ATMOSPHERIC SCIENCES
(2023)
Article
Meteorology & Atmospheric Sciences
Todd Emmenegger, Yi-Hung Kuo, Shaocheng Xie, Chengzhu Zhang, Cheng Tao, J. David Neelin
Summary: A set of diagnostics is used to assess the behavior of the Coupled Model Intercomparison Project (CMIP6) models with respect to precipitation. The models show significant errors in the relationship between precipitation and column water vapor (CWV). Models also exhibit biases in column relative humidity (CRH) statistics, with compensating biases often occurring.
JOURNAL OF CLIMATE
(2022)
Article
Meteorology & Atmospheric Sciences
C-C Chen, J. H. Richter, C. Liu, M. W. Moncrieff, Q. Tang, W. Lin, S. Xie, P. J. Rasch
Summary: The study investigated the impact of mesoscale organization of convection on global circulation models, and found that MCSP heating can improve climate simulations and reduce precipitation biases in the tropical Pacific region.
JOURNAL OF ADVANCES IN MODELING EARTH SYSTEMS
(2021)
Article
Geosciences, Multidisciplinary
Xingchao Chen, L. Ruby Leung, Zhe Feng, Qiu Yang
Summary: Based on satellite observations, this study reveals that precipitation over tropical oceans rapidly increases when the environmental column saturation fraction exceeds the critical value of 0.7. Non-deep convection, deep convection, and mesoscale convective systems (MCS) play sequential roles in the precipitation-moisture interactions, with MCS becoming the major contributor to total rain above the critical CSF value.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Meteorology & Atmospheric Sciences
T. Connor Nelson, James Marquis, Adam Varble, Katja Friedrich
Summary: The study deployed a high-spatiotemporal-resolution radiosonde network to examine environments supporting deep convection in the complex terrain of central Argentina. Through spatiotemporal autocorrelation analysis, it was found that there are large statistical differences between environments supporting convective precipitation and Null events. This study also presents evidence that flow-terrain interactions may affect convective initiation outcomes through gravity wave activity.
MONTHLY WEATHER REVIEW
(2021)
Article
Meteorology & Atmospheric Sciences
James N. Marquis, Zhe Feng, Adam Varble, T. Connor Nelson, Adam Houston, John M. Peters, Jake P. Mulholland, Joseph Hardin
Summary: By analyzing radiosonde profiles collected during several hundred CI events in central Argentina, researchers found that the depth and strength of background ascent, as well as the component of low-level flow oriented parallel to the ridgeline, can accurately distinguish the depth of clouds formed by updraft convection. Meanwhile, the low to mid-level relative humidity can strongly differentiate between events with and without updraft convection.
MONTHLY WEATHER REVIEW
(2023)
Article
Meteorology & Atmospheric Sciences
Da Fan, Steven J. Greybush, Xingchao Chen, Yinghui Lu, Fuqing Zhang, George S. Young
Summary: This study investigates the role of deep moist convection in atmospheric kinetic energy and brightness temperature spectra through simulations and observations. Moist convection can energize the mesoscale kinetic energy and the brightness temperature spectra show dependence on convective systems at different scales.
JOURNAL OF THE ATMOSPHERIC SCIENCES
(2022)
Article
Meteorology & Atmospheric Sciences
Robert S. Arthur, Timothy W. Juliano, Bianca Adler, Raghavendra Krishnamurthy, Julie K. Lundquist, Branko Kosovic, Pedro A. Jimenez
Summary: In this article, we demonstrate how a new framework for modeling atmospheric turbulence improves cold pool predictions, using a case study from January 2017 in the Columbia River basin (U.S. Pacific Northwest). Cold pools are regions of cold, stagnant air that form within valleys or basins, and improved forecasts could help to mitigate the risks they pose to air quality, transportation, and wind energy production. For the chosen case study, our tests show a reduction in temperature and wind speed errors by up to a factor of 2-3 relative to standard model options. These results strongly motivate continued development of the framework as well as its application to other complex weather events.
JOURNAL OF APPLIED METEOROLOGY AND CLIMATOLOGY
(2022)
Review
Geochemistry & Geophysics
N. C. Pepin, E. Arnone, A. Gobiet, K. Haslinger, S. Kotlarski, C. Notarnicola, E. Palazzi, P. Seibert, S. Serafin, W. Schoener, S. Terzago, J. M. Thornton, M. Vuille, C. Adler
Summary: This comprehensive analysis examines the relationship between elevation and temperature/precipitation changes in mountain regions. The study finds that while some regions show increased warming at higher elevations, there is no universal amplification of warming in mountains on a global scale. Additionally, the increase in mountain precipitation is weaker compared to low elevations, indicating reduced elevation-dependency of precipitation.
REVIEWS OF GEOPHYSICS
(2022)
Article
Meteorology & Atmospheric Sciences
Mathias W. Rotach, Stefano Serafin, Helen C. Ward, Marco Arpagaus, Ioana Colfescu, Joan Cuxart, Stephan F. J. De Wekker, Vanda Grubisic, Norbert Kalthoff, Thomas Karl, Daniel J. Kirshbaum, Manuela Lehner, Stephen Mobbs, Alexandre Paci, Elisa Palazzi, Adriana Bailey, Jurg Schmidli, Christoph Wittmann, Georg Wohlfahrt, Dino Zardi
Summary: This essay discusses the challenges faced by the atmospheric community in adequately treating flows over mountains and their implications for numerical weather prediction, climate simulations, and impact modeling. It emphasizes the need for further research and understanding of the mountain boundary layer (MoBL), as the current parameterizations overlook its many differences from the boundary layer over flat terrain, potentially leading to inaccurate model outputs.
BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY
(2022)
Article
Meteorology & Atmospheric Sciences
Daniel J. Kirshbaum
Summary: Large-eddy simulations conducted in this study reveal the impacts of heterogeneous, low terrain on deep-convection initiation. The terrain plays a significant role in determining the size of incipient cumulus clouds and their subcloud support. Enhanced subcloud circulations and more vigorous clouds penetrating deeper into the troposphere are observed due to the influence of terrain. Larger-scale terrains are more effective in promoting deep-convection initiation.
JOURNAL OF THE ATMOSPHERIC SCIENCES
(2022)
Article
Meteorology & Atmospheric Sciences
Florian Baur, Christian Keil, Christian Barthlott
Summary: The combined impact of soil moisture and microphysical perturbations on convective clouds and precipitation over Central Europe was studied. Homogeneous soil-moisture bias primarily controls the timing of convection initiation and the amount of surface rainfall, while the number of cloud condensation nuclei and width of the cloud droplet size distribution mainly control the number, size, and lifetime of convective clouds. Positive couplings are observed under moisture-limited conditions. Wetter soils and more polluted conditions result in fewer, but larger, cloud clusters.
QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY
(2022)
Article
Meteorology & Atmospheric Sciences
Lukas Strauss, Stefano Serafin, Manfred Dorninger
Summary: This study explores the potential of a multiphysics regional ensemble prediction system to improve wind turbine icing forecasts. It found that the multiphysics ensemble is less underdispersive compared to the global ensemble without significantly decreasing forecast accuracy. Probability forecasts enhance the potential economic value, but the improvement of the multiphysics ensemble seems modest compared to a simple neighbourhood ensemble approach. Icing forecasts are affected by overconfidence and require calibration for users to benefit from them. Overall, the findings suggest that a computationally cheap neighbourhood method can provide a large portion of the skill improvement obtained through the use of probabilistic icing forecasts.
QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY
(2022)
Article
Multidisciplinary Sciences
Martin Kohler, Geoffrey Bessardon, Barbara Brooks, Norbert Kalthoff, Fabienne Lohou, Bianca Adler, Oluwagbemiga Olawale Jegede, Barbara Altstaedter, Leonard Kofitse Amekudzi, Jeffrey Nii Armah Aryee, Winifred Ayinpogbilla Atiah, Muritala Ayoola, Karmen Babic, Konrad Baerfuss, Yannick Bezombes, Guillaume Bret, Pierre-Etienne Brilouet, Fred Cayle-Aethelhard, Sylvester Danuor, Claire Delon, Solene Derrien, Cheikh Dione, Pierre Durand, Kwabena Fosu-Amankwah, Omar Gabella, James Groves, Jan Handwerker, Corinne Jambert, Norbert Kunka, Astrid Lampert, Jeremy Leclercq, Marie Lothon, Patrice Medina, Arnaud Miere, Falk Paetzold, Xabier Pedruzo-Bagazgoitia, Irene Reinares Martinez, Steven Sharpe, Victoria Smith, Andreas Wieser
Summary: This article provides an overview of extensive in-situ measurements conducted as part of the DACCIWA project to study the southern West African atmospheric boundary layer. The measurements aimed to improve our understanding of the formation and influence of low-level clouds in this region. Scientific findings based on the dataset analyses are briefly summarized.
Article
Meteorology & Atmospheric Sciences
J. Sedlar, L. D. Riihimaki, D. D. Turner, J. Duncan, B. Adler, L. Bianco, K. Lantz, J. Wilczak, E. Hall, C. Herrera, Gary B. Hodges
Summary: This study analyzed detailed observations of the surface energy budget and daytime boundary layer properties in a heterogeneous forested landscape in northern Wisconsin using data from the CHEESEHEAD19 field campaign. The study found that the redistribution efficiency of radiative energy by surface turbulent heat fluxes was highly dependent on sky conditions. The depth of the daytime mixed layer varied with the sky condition, with deeper mixed layers occurring during low cumulus periods. Additionally, vertical velocity profiles had enhanced variance under low cumulus conditions compared to clear sky periods, suggesting potential cloud feedbacks on boundary layer structure and surface energy fluxes.
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
(2022)
Article
Meteorology & Atmospheric Sciences
Bianca Adler, James M. M. Wilczak, Laura Bianco, Ludovic Bariteau, Christopher J. J. Cox, Gijs de Boer, Irina V. V. Djalalova, Michael R. R. Gallagher, Janet M. M. Intrieri, Tilden P. P. Meyers, Timothy A. A. Myers, Joseph B. B. Olson, Sergio Pezoa, Joseph Sedlar, Elizabeth Smith, David D. D. Turner, Allen B. B. White
Summary: This study investigates the structure and evolution of the atmospheric boundary layer (ABL) under clear-sky conditions over mountainous terrain, using data from ground-based infrared spectrometers in Colorado's Rocky Mountains. The results show that the ABL structure strongly depends on surface snow cover, with a convective boundary layer forming during low snow cover and a shallow convective boundary layer forming during high snow cover. Comparison with a numerical model reveals large warm biases, indicating the model's inability to simulate nocturnal inversions and daytime stability when there is snow on the ground.
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
(2023)
Article
Geosciences, Multidisciplinary
Bianca Adler, James M. Wilczak, Jaymes Kenyon, Laura Bianco, Irina V. Djalalova, Joseph B. Olson, David D. Turner
Summary: Accurately forecasting orographic cold-air pools is crucial for integrating wind energy into the electrical grid. Model developments during WFIP2 have improved the simulation of a persistent cold-air pool, enhancing the representation of low-level clouds and reducing temperature biases. However, further improvements are needed for clearing low-level clouds during the day and refining the decay process of the cold-air pool.
GEOSCIENTIFIC MODEL DEVELOPMENT
(2023)
Article
Environmental Sciences
Christian Barthlott, Amirmahdi Zarboo, Takumi Matsunobu, Christian Keil
Summary: In order to improve the accuracy of precipitation prediction in convective-scale ensemble prediction systems, this study investigates the impact of microphysical and land-surface uncertainties on convective-scale predictability. By using a novel perturbation strategy, the researchers analyze the response of convective precipitation to different soil moisture fields, cloud condensation nuclei concentrations, and cloud droplet size distribution shape parameters. The results reveal that these uncertainties significantly influence the quantitative precipitation forecasting of summertime convection in central Europe.
ATMOSPHERIC CHEMISTRY AND PHYSICS
(2022)
Article
Meteorology & Atmospheric Sciences
James B. Jr Jr Duncan, Laura Bianco, Bianca Adler, Tyler Bell, Irina Djalalova, Laura Riihimaki, Joseph Sedlar, Elizabeth N. Smith, David D. Turner, Timothy J. Wagner, James M. Wilczak
Summary: During the CHEESEHEAD19 field campaign, various ground-based remote sensing instruments were used to investigate the response of the planetary boundary layer to heterogeneous land surface forcing. The study found that different instruments have their strengths and limitations under different conditions, highlighting the need for comprehensive analysis.
ATMOSPHERIC MEASUREMENT TECHNIQUES
(2022)
Article
Environmental Sciences
Christian Barthlott, Amirmahdi Zarboo, Takumi Matsunobu, Christian Keil
Summary: This study investigates the response of convective clouds and precipitation over central Europe to varying cloud condensation nuclei (CCN) concentrations and different shape parameters of the cloud droplet size distribution (CDSD). The results show that increasing CCN concentrations and narrowing CDSDs lead to an increase in the total cloud water content and a reduction in the total rain water content. These findings have important implications for quantitative precipitation forecasting.
ATMOSPHERIC CHEMISTRY AND PHYSICS
(2022)
Article
Meteorology & Atmospheric Sciences
Irina Djalalova, David D. Turner, Laura Bianco, James M. Wilczak, James Duncan, Bianca Adler, Daniel Gottas
Summary: In this study, a physical iterative method is used to retrieve temperature and humidity profiles from XPIA data. The combination of MWR and RASS observations improves the accuracy of low-level temperature inversions and matches radiosonde observations better than using only MWR in the atmosphere layer between the surface and 3 km above ground level.
ATMOSPHERIC MEASUREMENT TECHNIQUES
(2022)
Article
Geosciences, Multidisciplinary
Matthias Goebel, Stefano Serafin, Mathias W. Rotach
Summary: This paper introduces an open-source software called WRFlux, which allows precise budget evaluation for numerical weather prediction models. WRFlux incorporates new capabilities compared to similar existing tools, such as transforming the model's terrain-following grid to the Cartesian coordinate system for simplified interpretation of budgets obtained from simulations over non-uniform orography. It also decomposes resolved advection into mean advective and resolved turbulence components, which is useful for analyzing large-eddy simulation outputs. The performance and a possible application of WRFlux are demonstrated through an idealized simulation. Results show that WRFlux provides high precision in budget evaluations compared to inconsistent approximations.
GEOSCIENTIFIC MODEL DEVELOPMENT
(2022)