Preprints
Filtering by Subject: Oceanography and Atmospheric Sciences and Meteorology
The NCAR airborne 94-GHz cloud radar: calibration and data processing
Published: 2021-03-30
Subjects: Oceanography and Atmospheric Sciences and Meteorology
The 94-GHz airborne HIAPER Cloud Radar (HCR) has now been deployed in three major field campaigns. NCAR has developed an extensive set of quality assurance and quality control procedures which are applied to all collected data. Engineering measurements performed both in the laboratory and in an antenna measurement chamber yielded calibration characteristics for the antenna, reflector, and radome. [...]
Spatial spectrum of temperature fluctuations in buoyancy driven chaotic and turbulent atmosphere
Published: 2021-03-25
Subjects: Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Planetary Sciences
It is shown, using results of direct numerical simulations, laboratory experiments, measurements in the atmospheric boundary layer, in troposphere, in stratosphere, and the satellite infrared radiances data that in many cases the temperature fluctuations in buoyancy driven chaotic and turbulent atmosphere can be well described by the distributed chaos approach based on the Bolgiano-Obukhov [...]
Crisis at the Salton Sea: The Vital Role of Science
Published: 2021-03-03
Subjects: Atmospheric Sciences, Biogeochemistry, Chemistry, Climate, Earth Sciences, Environmental Chemistry, Environmental Public Health, Environmental Sciences, Environmental Studies, Geochemistry, Geology, Geomorphology, Hydrology, Medicine and Health Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Public Health, Social and Behavioral Sciences
The Salton Sea—a hypersaline, terminal lake in southern California—is in crisis. A combination of mismanagement and competition among federal, state and local agencies has hindered efforts to address declining lake levels and unstable water chemistry. This delay has heightened the public health threat to regional communities as retreating shorelines expose dry lakebed— a source of potentially [...]
Shallow or deep? A reinterpretation of the Rifian Corridor’s unique sandy contourites
Published: 2021-02-25
Subjects: Climate, Earth Sciences, Geology, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Paleontology, Sedimentology, Stratigraphy
This study proposes that sandstone layers exposed in the Fez-Meknes region of Northern Morocco (Ben Allou (Sidi Chaded) and El Adergha localities), have been misinterpreted as unique examples of geostrophically-driven, deep marine (150 - 400 m water depth) sandy contourites. Instead, our independent paleontological, sedimentological, and stratigraphic analyses show that these sandstones represent [...]
High-resolution observations of the North Pacific transition layer from a Lagrangian float
Published: 2021-02-11
Subjects: Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
A crucial region of the ocean surface boundary layer (OSBL) is the strongly-sheared and -stratified transition layer (TL) separating the mixed layer from the upper pycnocline, where a diverse range of waves and instabilities are possible. Previous work suggests that these different waves and instabilities will lead to different OSBL behaviours. Therefore, understanding which physical processes [...]
Reduced High-Latitude Land Seasonality in Climates with Very High Carbon Dioxide
Published: 2021-02-10
Subjects: Atmospheric Sciences, Climate, Oceanography and Atmospheric Sciences and Meteorology
Observations of warm past climates and projections of future climate change show that the Arctic warms more than the global mean, particularly during winter months. Past warm climates such as the early Eocene had above-freezing Arctic continental temperatures year-round. In this paper, we show that a reduced Arctic land seasonality with increased greenhouse gases is a robust consequence of the [...]
Dynamical attribution of North Atlantic interdecadal predictability to oceanic and atmospheric turbulence under realistic and optimal stochastic forcing
Published: 2021-02-01
Subjects: Climate, Environmental Sciences, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Unpredictable variations in the ocean originate from both external atmospheric forcing and chaotic processes internal to the ocean itself, and are a crucial sink of predictability on interdecadal timescales. In a global ocean model, we present i.) an optimisation framework to compute the most efficient noise patterns to generate uncertainty and ii.) a uniquely inexpensive, dynamical method for [...]
Observations of nonlinear momentum fluxes over the inner continental shelf
Published: 2021-01-31
Subjects: Oceanography and Atmospheric Sciences and Meteorology
Nonlinear momentum fluxes over the inner continental shelf are examined using moored observations from multiple years at two different locations in the Middle Atlantic Bight. Inner shelf dynamics are often described in terms of a linear alongshore momentum balance, dominated by frictional stresses generated at the surface and bottom. In this study, observations over the North Carolina inner shelf [...]
The active and passive roles of the ocean in generating basin-scale heat content variability
Published: 2021-01-28
Subjects: Climate, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
The role of ocean circulation in transforming surface forcing into interannual-to-multidecadal oceanic variability is an area of ongoing debate. Here, a novel method, establishing exact causal links, is used to quantitatively determine the role of ocean active and passive processes in transforming stochastic surface forcing into heat content variability. To this end, we use a global ocean model [...]
Vertical fluxes conditioned on vorticity and strain reveal submesoscale ventilation
Published: 2021-01-24
Subjects: Oceanography, Oceanography and Atmospheric Sciences and Meteorology
It has been hypothesized that submesoscale flows play an important role in the vertical transport of climatically important tracers, due to their strong associated vertical velocities. However, the multi-scale, non-linear and Lagrangian nature of transport makes it challenging to attribute proportions of the tracer fluxes to certain processes, scales, regions or features. Here we show that [...]
An idealized 1.5-layer isentropic model with convection and precipitation for satellite data assimilation research. Part II: model derivation
Published: 2021-01-22
Subjects: Applied Mathematics, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
In this part II paper we present the analytical derivation of the isentropic 1.5-layer shallow water model described and used in part I of this study. The mathematical derivation presented here is based on a combined asymptotic and slaved Hamiltonian analysis. The scaling assumptions throughout the paper are supported by real observations based on radiosonde data. Eventually, a fully consistent [...]
An idealized 1.5-layer isentropic model with convection and precipitationfor satellite data assimilation research. Part I: model dynamics
Published: 2021-01-22
Subjects: Applied Mathematics, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
An isentropic 1.5-layer model based on modified shallow water equations is presented, including terms mimicking convection and precipitation. This model is an updated version of the isopycnal single-layer modified shallow water model presented in Kent et al. (2017). The clearer link between fluid temperature and model variables together with a double-layer structure make this revised, isentropic [...]
Decrease in air-sea CO2 fluxes caused by persistent marine heatwaves
Published: 2021-01-21
Subjects: Oceanography and Atmospheric Sciences and Meteorology
Regional processes play a key role in the global carbon budget. Major ocean carbon uptake at mid-latitudes counteracts carbon release in the tropics, which is modulated by episodes of marine heatwaves (MHWs). Yet, we lack essential knowledge on persistent MHWs (PMHWs), and their effect on the carbon sensitive areas. Here, based on a 1985-2017 joint analysis of reconstructions, ocean reanalysis, [...]
Near-inertial dissipation due to stratified flow over abyssal topography
Published: 2021-01-12
Subjects: Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Linear theory for steady stratified flow over topography sets the range for topographic wavenumbers over which freely propagating internal waves are generated, and the radiation and breaking of these waves contribute to energy dissipation away from the ocean bottom. However, previous numerical work demonstrated that dissipation rates can be enhanced by flow over large scale topographies with [...]
Yield estimation of the 2020 Beirut explosion using open access waveform and remote sensing data
Published: 2020-12-22
Subjects: Applied Statistics, Earth Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Physics, Statistics and Probability
We report on a multi-technique analysis using publicly available data for investigating the huge, accidental explosion that struck the city of Beirut, Lebanon, on August 4, 2020. Its devastating shock wave led to thousands of injured with more than two hundred fatalities and caused immense damage to buildings and infrastructure. Our combined analysis of seismological, hydroacoustic, infrasonic [...]