Preprints
Filtering by Subject: Oceanography and Atmospheric Sciences and Meteorology
A comparison of Bayesian inference and gradient-based approaches for friction parameter estimation
Published: 2020-06-30
Subjects: Applied Mathematics, Numerical Analysis and Computation, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Numerical tidal models are essential to the study of a variety of coastal ocean processes, but typically rely on uncertain inputs, including a bottom friction parameter which can in principle be spatially varying. Here we employ an adjoint-capable numerical ocean model, Thetis, and apply it to the Bristol Channel and Severn Estuary, using a spatially varying Manning coefficient within the bottom [...]
Terrestrial evaporation and global climate: lessons from Northland, a planet with a hemispheric continent
Published: 2020-06-22
Subjects: Climate, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
From a climate perspective, land differs from the ocean in several fundamental physical ways, including albedo, heat capacity, amount of water storage, and differences in resistance to evaporation. These differences alter the surface energy and water budgets over land compared to ocean, with implications for both surface climate and atmospheric circulation. In this study, we use an idealized [...]
Tropical cyclone response to anthropogenic warming as simulated by a mesoscale-resolving global coupled earth system model
Published: 2020-06-19
Subjects: Atmospheric Sciences, Climate, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Tropical cyclones (TCs) are extreme storm systems that form over warm tropical oceans. Along their track TCs can mix up cold water which can further impact their development. Due to the adoption of lower ocean model resolutions, previous modeling studies on the TC response to greenhouse warming underestimate such oceanic feedbacks. To address the robustness of TC projections in the presence of [...]
Seasonal impact-based mapping of compound hazards
Published: 2020-06-17
Subjects: Applied Mathematics, Atmospheric Sciences, Climate, Earth Sciences, Environmental Sciences, Hydrology, Mathematics, Multivariate Analysis, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Statistics and Probability
Impact-based, seasonal mapping of compound hazards is proposed. It is pragmatic, identifies phenomena to drive the research agenda, produces outputs relevant to stakeholders, and could be applied to many hazards globally. Illustratively, flooding and wind damage can co-occur, worsening their joint impact, yet where wet and windy seasons combine has not yet been systematically mapped. Here, [...]
Global wave-driven beach evolution; consequences for observation strategies
Published: 2020-06-12
Subjects: Civil and Environmental Engineering, Earth Sciences, Engineering, Life Sciences, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
It is an illusion to think that one can observe monthly beach behaviour with monthly surveys. Current coastal observation strategies restrict understanding of beach evolution, preventing effective risk mitigation. In this article, we quantify the global spatiotemporal scales of coastal wave changes, which are the known dominant driver of beach evolution. Consequences and recommendations for beach [...]
Decomposing the Drivers of Polar Amplification with a Single Column Model.
Published: 2020-06-10
Subjects: Atmospheric Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
The precise mechanisms driving Arctic amplification are still under debate. Previous attribution methods based on top-of-atmosphere energy budgets have assumed all forcings and feedbacks lead to vertically-uniform temperature changes, with any departures from this collected into the lapse-rate feedback. We propose an alternative attribution method using a single column model that accounts for the [...]
Is Net Zero by 2050 Possible?
Published: 2020-06-10
Subjects: Climate, Earth Sciences, Engineering, Environmental Indicators and Impact Assessment, Environmental Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Achieving Net Zero 2050 does not assure complying with a global warming temperature ceiling. The U.S. might achieve NZ(2050); the world almost certainly will not. For the U.S. to achieve NZ(2050) requires a massive transition of the economy, which is extremely unlikely.
Large model parameter and structural uncertainties in global projections of urban heat waves
Published: 2020-06-10
Subjects: Atmospheric Sciences, Civil and Environmental Engineering, Computer Sciences, Earth Sciences, Engineering, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Risk Analysis, Statistics and Probability
Urban heat waves (UHWs) are strongly associated with socioeconomic impacts. Reliable projections of these extremes are pressingly needed for local actions in the context of extreme event preparedness and mitigation. Such information, however, is not available because current multi-model projections largely lack a representation of urban areas. Here, we use a newly-developed urban climate emulator [...]
Sediment redox dynamics in an oligotrophic deep-water lake in Tierra del Fuego: insights from Fe isotopes
Published: 2020-06-10
Subjects: Earth Sciences, Fresh Water Studies, Geochemistry, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Sedimentology
Fe speciation and Fe isotopes have been widely used to reconstruct past basin dynamics and water redox conditions. However, sedimentation and early diagenesis of such proxies eventually alter any primary climate signal. In this work, we disentangled the processes occurring at the redox front below the sediment-water interface of a ventilated deep-water lake (Lago Fagnano, Argentina/Chile). A [...]
Heat does not physically flow in the ways assumed by greenhouse-warming theory
Published: 2020-06-07
Subjects: Climate, Earth Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Volcanology
Heat is currently defined as an amount of thermal energy flowing each second per unit area. Temperature is assumed to result from the net amount of heat flowing—the sum of all radiative forcings. Yet direct and unambiguous observations of Nature show that macroscopic temperature of solid matter results from a very broad spectrum of sub-microscopic oscillations of all the bonds holding matter [...]
Antarctic elevation drives hemispheric asymmetry in polar lapse-rate climatology and feedback
Published: 2020-06-07
Subjects: Climate, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
The lapse-rate feedback is the dominant driver of stronger warming in the Arctic than the Antarctic in simulations with increased CO2. While Antarctic surface elevation has been implicated in promoting a weaker Antarctic lapse-rate feedback, the mechanisms in which elevation impacts the lapse-rate feedback are still unclear. Here we suggest that weaker Antarctic warming under CO2 forcing stems [...]
A novel rules-based shoreface translation model for predicting future coastal change: ShoreTrans
Published: 2020-06-05
Subjects: Earth Sciences, Engineering, Geomorphology, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Other Engineering, Physical Sciences and Mathematics
Predicting change to global shorelines presents an increasing challenge as sea-level rise (SLR) accelerates. Many shoreline prediction models use variations of the ‘Bruun-rule’, failing to account for relevant processes and morphologic complexity. To address this, we introduce a simple rules-based model (ShoreTrans) designed for complex, real-world profiles that predicts change across a wide [...]
Atmospheric thermal convection and strong chaotic fluctuations of global temperature on Earth and on Mars
Published: 2020-06-05
Subjects: Atmospheric Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
It is shown that the atmospheric thermal (buoyancy driven) convection plays the main role in generation of the strong chaotic fluctuations of the global temperature through the Kolmogorov-Bolgiano-Obukhov mechanism (in the frames of the distributed chaos approach). It is valid for the planets with substantial atmosphere such as the Earth and Mars. Direct numerical simulations, the Berkeley Earth [...]
Observation-based Simulations of Humidity and Temperature Using Quantile Regression
Published: 2020-05-29
Subjects: Atmospheric Sciences, Climate, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Statistics and Probability
The human impacts of changes in heat events depend on changes in the joint behavior of temperature and humidity. Little is currently known about these complex joint changes, either in observations or projections from general circulation models (GCMs). Further, GCMs do not fully reproduce the observed joint distribution, implying a need for simulation methods that combine information from GCMs [...]
Advective sorting of silt by currents: a laboratory study
Published: 2020-05-28
Subjects: Earth Sciences, Geomorphology, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Sedimentology
Accumulations of fine sediments along continental shelf and deep-sea bathymetric contours, known as contourite drifts, form a sedimentary record that is dependent on oceanographic processes such as ocean-basin-scale circulation. A tool used to aid in interpretation of such deposits is the sortable silt hypothesis, which suggests that the mean size of the sortable silt (silt from 10-63 µm) within [...]