Article
Geosciences, Multidisciplinary
A. Gunn, M. Wanker, N. Lancaster, D. A. Edmonds, R. C. Ewing, D. J. Jerolmack
Summary: Research shows that sand and dust in desert areas experience a daily rhythm of nonequilibrium atmospheric boundary layer convection, leading to significant sand transport phenomena. A global analysis reveals a connection between surface wind speed and diurnal temperature cycles, contributing to climate feedback mechanisms that may impact desert expansion and dune activity on Mars.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Geosciences, Multidisciplinary
Lu Zhang, Hongsheng Zhang, Qianhui Li, Wei Wei, Xuhui Cai, Yu Song, Ali Mamtimin, Minzhong Wang, Fan Yang, Yu Wang, Chenglong Zhou
Summary: The deep convective boundary layer in the Taklimakan Desert plays a vital role in the climate system in East Asia. This study used observation experiments and large-eddy simulation to uncover the turbulent mechanisms behind its formation. It was revealed that the daily maximum depth of the boundary layer was independent of surface heating, and a weak temperature inversion and a near-neutral residual layer existed above the CBL in the late-morning. The distinct boundary-layer process was found to entrain free-tropospheric air and warm the residual layer, which contributed to the growth of the CBL.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Meteorology & Atmospheric Sciences
Liming Zhou, Yuhong Tian, Nan Wei, Shu-Peng Ho, Jing Li
Summary: Turbulent mixing in the planetary boundary layer plays a critical role in the vertical exchange of heat, moisture, momentum, trace gases, and aerosols. This study examines the spatial patterns of long-term PBLH trends over land and finds consensus on increasing PBLH over the Sahara Desert and Arabian Peninsula and declining PBLH in India. The changes in PBLH are significantly correlated with changes in surface heating and moisture at the global scale.
JOURNAL OF CLIMATE
(2021)
Article
Mechanics
Michael Heisel, Charitha M. de Silva, Nicholas Hutchins, Ivan Marusic, Michele Guala
Summary: The statistical properties of prograde spanwise vortex cores and internal shear layers in high-Reynolds-number turbulent boundary layers are evaluated. Results show the importance of the local large-eddy turnover time in determining the strain rate confining the size of the vortex cores and shear layers. The study highlights the relevance of the turnover time and the Taylor microscale in explaining the interaction of coherent velocity structures in the boundary layer flows.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Meteorology & Atmospheric Sciences
Fan Yang, Qing He, Jianping Huang, Ali Mamtimin, Xinghua Yang, Wen Huo, Chenglong Zhou, Xinchun Liu, Wenshou Wei, Caixia Cui, Minzhong Wang, Hongjun Li, Lianmei Yang, Hongsheng Zhang, Yuzhi Liu, Xinqian Zheng, Honglin Pan, Lili Jin, Han Zou, Libo Zhou, Yongqiang Liu, Jiantao Zhang, Lu Meng, Yu Wang, Xiaolin Qin, Yongjun Yao, Houyong Liu, Fumin Xue, Wei Zheng
Summary: DECON, established in the Taklimakan Desert, is a comprehensive environmental and climate observation network covering a wide range of areas, providing in-depth understanding of meteorological and environmental conditions in the region. It helps evaluate and mitigate desert environmental issues, promoting sustainable development in Central Asia.
BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY
(2021)
Article
Meteorology & Atmospheric Sciences
Qingfang Jiang, Qing Wang
Summary: The study focused on the characteristics of a stable internal boundary layer (SIBL) offshore of Duck, North Carolina under the influence of offshore winds. The analysis showed that the offshore area can be divided into three zones, with local similarity theory applicable only in the nearshore zone. The advection of turbulence from land plays a significant role in the momentum and scalar budgets over the NSZ, while becoming less important but still non-negligible in the IOZ.
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
(2021)
Article
Environmental Sciences
Ulrike Egerer, Andre Ehrlich, Matthias Gottschalk, Hannes Griesche, Roel A. J. Neggers, Holger Siebert, Manfred Wendisch
Summary: Specific humidity inversions (SHIs) above low-level cloud layers in the Arctic are often associated with large-scale advection of humid air masses. This study analyzes the coupling of SHIs with cloud layers through turbulent processes, showing that SHIs supply moisture to the cloud layer via turbulent mixing. Large-eddy simulations demonstrate that in the presence of a SHI, the cloud layer remains thicker and the temperature inversion height is elevated.
ATMOSPHERIC CHEMISTRY AND PHYSICS
(2021)
Article
Geosciences, Multidisciplinary
Bing Liu, Hui Zhao, Sheng-Hua Li, Heling Jin, Yu Li, Haipeng Wang, Aijun Sun, Yujie Xu, Keqi Wang
Summary: This study reviews the patterns of palaeosol development, precipitation/moisture evolution, and lake level fluctuations in the Asian summer monsoonal boundary (ASMB) region of northern China. The results show an asynchronous pattern of palaeosol development, with different dominant climatic factors in different sub-regions, highlighting the diverse responses of palaeosol development to regional climate change.
EARTH-SCIENCE REVIEWS
(2022)
Article
Environmental Sciences
Chenglong Zhou, Yuzhi Liu, Qing He, Xinjie Zhong, Qingzhe Zhu, Fan Yang, Wen Huo, Ali Mamtimin, Xinghua Yang, Yu Wang, Lu Meng
Summary: This study investigates the vertical distribution of dust with different particle sizes, dust concentration changes, temperature stratification, and other meteorological factors in the Taklimakan Desert using observations from unmanned aerial vehicles, an environmental particulate matter analyzer, and GPS sounding balloons. The results show that the dust concentration increases sharply during dust pollution over the Taklimakan Desert, with larger-sized particles being more easily entrained into the air. Additionally, dust pollution leads to a weakening of total solar radiation and modifications in temperature stratification. On clear days, the convective boundary layer height is negatively correlated with dust pollution levels, while the stable boundary layer height shows a positive correlation.
Article
Meteorology & Atmospheric Sciences
Yu Wang, Hajigul Sayit, Ali Mamtimin, Jun Zhu, Chenglou Zhou, Wen Huo, Fan Yang, Xinghua Yang, Jiacheng Gao, Xueshang Zhao
Summary: This study evaluated the applicability of five PBL parameterization schemes in China's Gurbantunggut Desert, with the ACM2 model showing the best simulation ability and highest universality.
ATMOSPHERIC RESEARCH
(2021)
Article
Engineering, Marine
Congfang Ai, Yuxiang Ma, Changfu Yuan, Guohai Dong
Summary: A non-hydrostatic model is developed using a semi-implicit algorithm and immersed boundary method to predict internal wave generations and propagations over uneven bottoms. By combining z-level vertical coordinate and immersed boundary method, the model effectively avoids numerical errors and considers stratification effects. The model accurately captures waveform evolution characteristics in laboratory-scale test cases, providing an alternative for simulating internal wave phenomena.
Article
Geosciences, Multidisciplinary
Zhanshan Ma, Chuanfeng Zhao, Jiandong Gong, Jin Zhang, Zhe Li, Jian Sun, Yongzhu Liu, Jiong Chen, Qingu Jiang
Summary: The study analyzed the characteristics of spin-ups under different initial fields in the global forecast system (GRAPES_GES2.3.1) and discussed the influence of cloud-field information on the spin-up and forecast results of the GRAPES model.
GEOSCIENTIFIC MODEL DEVELOPMENT
(2021)
Article
Mathematics, Applied
Noureddine Igbida, Fahd Karami, Driss Meskine
Summary: The aim of this paper is to introduce and study a mathematical model for traveling sand dunes, which describes the surface flow process of sand under the influence of wind and gravity. The model is based on a nonlinear diffusion-transport equation that couples the transportation of sand by wind with avalanches due to gravity and the repose angle. The avalanche flow is governed by the surface evolution model, with a nonlocal term used to handle sand transport in the direction of the wind.
NONLINEAR ANALYSIS-REAL WORLD APPLICATIONS
(2021)
Article
Physics, Multidisciplinary
Tom Dror, Ilan Koren, Huan Liu, Orit Altaratz
Summary: Shallow cloud fields exhibit different patterns that have significant impacts on their radiative effects and climate change. It has been found that these organized patterns are derived from the steady state of convection cells, and can be better simulated in climate models through parameterization to capture their feedback in a warming climate.
PHYSICAL REVIEW LETTERS
(2023)
Article
Mechanics
Jiyang He, Benjamin Favier, Michel Rieutord, Stephane Le Dizes
Summary: This study examines the internal shear layers generated by the longitudinal libration of the inner core in a rotating spherical shell. By using asymptotic and numerical analysis, the researchers provide insights into the behavior of these shear layers and compare the asymptotic predictions with direct numerical results. The study demonstrates that, with decreasing Ekman numbers, the agreement between the asymptotic predictions and numerical results improves.
JOURNAL OF FLUID MECHANICS
(2022)
Article
Geochemistry & Geophysics
Mathieu G. A. Lapotre, Ryan C. Ewing, Michael P. Lamb
Summary: This study investigates the climate indication role of large ripples formed in fine sand on Mars, and synthesizes the debate on the mechanism of ripple formation. Despite remaining knowledge gaps, it is clear that large ripples are larger under thinner atmospheres.
JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS
(2021)
Article
Geosciences, Multidisciplinary
A. Gunn, M. Wanker, N. Lancaster, D. A. Edmonds, R. C. Ewing, D. J. Jerolmack
Summary: Research shows that sand and dust in desert areas experience a daily rhythm of nonequilibrium atmospheric boundary layer convection, leading to significant sand transport phenomena. A global analysis reveals a connection between surface wind speed and diurnal temperature cycles, contributing to climate feedback mechanisms that may impact desert expansion and dune activity on Mars.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Geosciences, Multidisciplinary
Yoni Teitelbaum, Tomer Shimony, Edwin Saavedra Cifuentes, Jonathan Dallmann, Colin B. Phillips, Aaron Packman, Scott K. Hansen, Shai Arnon
Summary: The study presents a novel simulation framework to model hyporheic exchange induced by mobile bedforms within a stationary reference frame, successfully reproducing observations of clay deposition in sand beds. Increased bedform celerity and filtration both lead to shallower depth of clay deposition and a more compact deposition layer.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Environmental Sciences
S. Retelletti Brogi, G. Cossarini, G. Bachi, C. Balestra, E. Camatti, R. Casotti, G. Checcucci, S. Colella, V. Evangelista, F. Falcini, F. Francocci, T. Giorgino, F. Margiotta, M. Ribera d'Alcala, M. Sprovieri, S. Vestri, C. Santinelli
Summary: The rapid spread of the SARS-CoV-2 virus in Italy led to a 3-month lockdown of the entire country, resulting in a marked decrease in dissolved organic carbon concentration in the Arno River and coastal areas affected by its input. Additionally, the optical properties of DOM showed a shift towards smaller and less aromatic molecules during the lockdown period.
SCIENCE OF THE TOTAL ENVIRONMENT
(2022)
Article
Environmental Sciences
Federica Braga, Daniele Ciani, Simone Colella, Emanuele Organelli, Jaime Pitarch, Vittorio E. Brando, Mariano Bresciani, Javier A. Concha, Claudia Giardino, Gian Marco Scarpa, Gianluca Volpe, Marie-Helene Rio, Federico Falcini
Summary: During the COVID-19 lockdown, Earth-Observation data were used to monitor and diagnose water quality changes. Analysis of the North Adriatic Sea showed negative anomalies in Chlorophyll-a concentration, possibly due to a secondary anthropogenic effect in addition to natural environmental causes.
SCIENCE OF THE TOTAL ENVIRONMENT
(2022)
Article
Multidisciplinary Sciences
Andrew Gunn, Giampietro Casasanta, Luca Di Liberto, Federico Falcini, Nicholas Lancaster, Douglas J. Jerolmack
Summary: Aeolian dunes can form in areas with strong winds and loose sand, and their growth is initially predictable. However, as dunes mature and coarsen, their growth becomes more complex and influenced by various factors such as wind variability and sand supply. This study shows that there is no evidence of a size limit for dunes determined by atmospheric boundary layer height, indicating that dunes can potentially continue growing indefinitely, although sand supply may ultimately limit their growth.
NATURE COMMUNICATIONS
(2022)
Article
Multidisciplinary Sciences
George D. McDonald, Joshua Mendez Harper, Lujendra Ojha, Paul Corlies, Josef Dufek, Ryan C. Ewing, Laura Kerber
Summary: This study suggests that surface modification on Jupiter's moon Io may not only be attributed to lava emplacement and volcanic plume deposits, but also to wind-blown transport of sediment. Interactions between lava and sulfur dioxide frost may produce vapor flows dense enough to mobilize sand grains, with saltation potentially occurring if frost temperatures surpass 155 K. Ridge-like features on Io could be evidence of aeolian sediment transport.
NATURE COMMUNICATIONS
(2022)
Article
Multidisciplinary Sciences
Giovanni La Forgia, Davide Cavaliere, Stefania Espa, Federico Falcini, Guglielmo Lacorata
Summary: This article presents a review and a new assessment of the Lagrangian dispersion properties of a 2D model of chaotic advection and diffusion. The study examines absolute and relative Lagrangian dispersion for a kinematic flow, a hydrodynamic model, and a laboratory experiment, using dynamical system techniques. The main results include experimental verification of the scale-dependent dispersion properties of the considered model and a qualitative and quantitative assessment of the hydro-dynamical Lagrangian simulations.
SCIENTIFIC REPORTS
(2022)
Article
Chemistry, Physical
Giampietro Casasanta, Federico Falcini, Roberto Garra
Summary: Obtaining a reliable formulation of the Beer-Lambert law in photochemistry requires understanding the role of space and time dependence of absorbance in the system. This study presents a generalized Beer-Lambert law based on Mittag-Leffler extinction of radiation, derived through probabilistic arguments and applied in a mathematical model in photochemistry.
JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY
(2022)
Article
Astronomy & Astrophysics
Don R. Hood, S. F. Sholes, S. Karunatillake, C. Fassett, R. C. Ewing, J. Levy
Summary: In this study, a tool called Martian Boulder Automatic Recognition System (MBARS) is developed to automatically locate and measure boulders on the surface of Mars. This tool enables rapid and accurate assessments of boulder populations, providing insights into the processes that have operated on the Martian surface.
EARTH AND SPACE SCIENCE
(2022)
Article
Engineering, Marine
Ilya V. Buynevich, Hannes Tonisson, Alar Rosentau, Tiit Hang, Are Kont, Toru Tamura, Sten Suuroja, Valdeko Palginomm, Sophia F. S. Doering
Summary: Coastal archives provide records of changing hydrometeorological conditions, including mineralogical anomalies. This study presents a database of magnetic susceptibility measurements from beach and dune lithosomes in the Western Estonian archipelago, which can be used to assess the impact of wave and wind climate changes as well as extreme events.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2023)
Article
Geosciences, Multidisciplinary
L. Rubanenko, A. Gunn, S. Perez-Lopez, L. K. Fenton, R. C. Ewing, A. Soto, M. G. A. Lapotre
Summary: The morphology of dunes on Mars can be used to investigate its atmosphere. A convolutional neural network was used to characterize over 700,000 barchans globally, revealing that their migration aligns with known atmospheric circulation patterns and is affected by topographic roughness. This study provides insights into aeolian processes on Mars and can aid in predicting future missions.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Environmental Sciences
T. Shimony, Y. Teitelbaum, E. Saavedra Cifuentes, J. Dallmann, C. B. Phillips, A. I. Packman, S. Arnon
Summary: Clogging of streambeds due to clay deposition affects stream-subsurface exchange flux and has implications for hyporheic ecological and biogeochemical processes. This study investigated the combined effect of moving bedforms and losing or gaining flows on kaolinite deposition and streambed clogging. The results showed that bedform movement had a greater influence on kaolinite deposition patterns than the flow conditions, and deposition occurred faster under losing flow conditions. The study highlights the importance of considering bedform dynamics in understanding the hydrology of catchments.
WATER RESOURCES RESEARCH
(2023)
Article
Geography, Physical
Hossein Hosseiny, Claire C. Masteller, Jedidiah E. Dale, Colin B. Phillips
Summary: Prediction of bed load sediment transport rates in rivers is difficult due to variability in river hydraulics and channel morphology. A neural network model using 8117 measurements from 134 rivers was developed to predict bed load transport rates based on river discharge, flow width, bed slope, and bed surface sediment sizes. The model showed good performance in estimating bed load flux and reproducing sediment rating curves without site-specific calibration. This neural network model has the potential to broadly predict bed load fluxes based on discharge and reach properties alone.
EARTH SURFACE DYNAMICS
(2023)
Article
Environmental Sciences
Colin B. Phillips, Claire C. Masteller, Louise J. Slater, Kieran B. J. Dunne, Simona Francalanci, Stefano Lanzoni, Dorothy J. Merritts, Eric Lajeunesse, Douglas J. Jerolmack
Summary: This Perspective examines how the size and shape of alluvial river channels are controlled and adjusted by the flow of water and sediment. The feedback between flow and form modulates flood risk and the impacts of climate and land-use change. Despite variations in hydro-climates, sediment supply, geology, and vegetation, rivers follow remarkably consistent hydraulic geometry scaling relations.
NATURE REVIEWS EARTH & ENVIRONMENT
(2022)