Preprints
Filtering by Subject: Oceanography and Atmospheric Sciences and Meteorology
Unsupervised clustering of Southern Ocean Argo float temperature profiles
Published: 2018-04-19
Subjects: Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
The Southern Ocean has complex spatial variability, characterized by sharp fronts, steeply tilted isopycnals, and deep seasonal mixed layers. Methods of defining Southern Ocean spatial structures traditionally rely on somewhat ad-hoc combinations of physical, chemical, and dynamic properties. As a step towards an alternative approach for describing spatial variability in temperature, here we [...]
Detecting lightning infrasound using a high-altitude balloon
Published: 2018-04-17
Subjects: Atmospheric Sciences, Earth Sciences, Geophysics and Seismology, Meteorology, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Acoustic waves with a wide range of frequencies are generated by lightning strokes during thunderstorms, including infrasonic waves (0.1 to 20 Hz). The source mechanism for these low frequency acoustic waves is still debated and studies have so far been limited to ground-based instruments. Here we report the first confirmed detection of lightning generated infrasound with acoustic instruments [...]
The role of upper level diffluence in the Tropical Easterly Jet in the formation of the recent strongest Atlantic hurricanes
Published: 2018-04-08
Subjects: Atmospheric Sciences, Meteorology, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
In this paper we report the evidence of the potential role of diffluence in the 200hPa wind field off the coast of West Africa in the formation of a significant number of Category 4 and Category 5 hurricanes in the recent decade. It is shown that on an average of 65% cases of hurricanes at Category 4 and above is preceded by upper level diffluence in the Tropical Easterly Jet (TEJ) by 0–3 days. [...]
Could machine learning break the convection parametrization deadlock?
Published: 2018-03-16
Subjects: Atmospheric Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Physics, Planetary Sciences
Modeling and representing moist convection in coarse-scale climate models remains one of the main bottlenecks of current climate simulations. Many of the biases present with parameterized convection are strongly reduced when convection is explicitly resolved (in cloud resolving models at high spatial resolution ~ a kilometer or so). We here present a novel approach to convective parameterization [...]
The Extraordinary Mediocrity of the Holocene
Published: 2018-03-15
Subjects: Climate, Computer Sciences, Earth Sciences, Environmental Sciences, Oceanography and Atmospheric Sciences and Meteorology, Other Physical Sciences and Mathematics, Physical Sciences and Mathematics, Planetary Sciences
The extinction of multiple genera of large-bodied mammals during the Holocene interglacial transition has been attributed to three hypothesized causes: human migration, climate change, and an extra-terrestrial impact. Two of these hypotheses, climate change and extra-terrestrial impactor, would predict that the Holocene interglacial transition was uniquely stressful for large-bodied mammals. To [...]
The effect of wind stress anomalies and location in driving Pacific Subtropical cells and tropical climate
Published: 2018-03-12
Subjects: Climate, Oceanography, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
The importance of subtropical and extratropical zonal wind stress on Pacific Subtropical Cells (STCs) strength is assessed through several idealized numerical experiments performed with a global ocean model. Different zonal wind stress anomalies are employed, and their intensity is strengthened or weakened with respect to the climatological value throughout a suite of simulations. Strengthened [...]
Disagreement among global cloud distributions from CALIOP, passive satellite sensors and general circulation models
Published: 2018-03-09
Subjects: Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Cloud detection is the first step of any complex satellite-based cloud retrieval. No instrument detects all clouds, and analyses that use a given satellite climatology can only discuss a specific subset of clouds. We attempt to clarify which subsets of clouds are detected in a robust way by passive sensors, and which require active sensors. To do so, we identify where retrievals of Cloud Amounts [...]
Uncertainty in sea level rise projections due to the dependence between contributors
Published: 2018-03-08
Subjects: Applied Statistics, Climate, Earth Sciences, Environmental Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Probability, Statistical Models, Statistics and Probability
Sea level rises at an accelerating pace threatening coastal communities all over the world. In this context sea level projections are key tools to help risk mitigation and adaptation. Sea level projections are often made using models of the main contributors to sea level rise (e.g. thermal expansion, glaciers, ice sheets...). To obtain the total sea level these contributions are added, therefore [...]
Radiative feedbacks from stochastic variability in surface temperature and radiative imbalance
Published: 2018-03-02
Subjects: Climate, Earth Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Estimates of radiative feedbacks obtained by regressing fluctuations in top-of-atmosphere (TOA) energy imbalance and surface temperature depend critically on assumptions about the nature of the stochastic forcing and on the sampling interval. Here we develop an energy-balance framework that allows us to model the different contributions of stochastic atmospheric and oceanic forcing on feed- back [...]
On the reduction of trend errors by the ANOVA joint correction scheme used in homogenization of climate station records
Published: 2018-02-16
Subjects: Climate, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Inhomogeneities in climate data are the main source of uncertainty for secular warming estimates. To reduce the influence of inhomogeneities in station data statistical homogenization compares a candidate station to its neighbors to detect and correct artificial changes in the candidate. Many studies have quantified the performance of statistical break detection tests used in this comparison. [...]
Multi-scale modeling of the urban meteorology: integration of a new canopy model in the WRF model
Published: 2018-02-16
Subjects: Atmospheric Sciences, Climate, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Urban parametrizations have been recently proposed and integrated in mesoscale meteorological models for a better reproduction of urban heat islands and to compute building energy con- sumption. The objective of the present study is to evaluate the value of the use of a module able to produce highly resolved vertical profiles of these variables. For this purpose, the Canopy Interface Model (CIM) [...]
Application of discrete-element methods to approximate sea-ice dynamics
Published: 2018-02-14
Subjects: Earth Sciences, Glaciology, Oceanography and Atmospheric Sciences and Meteorology, Other Physical Sciences and Mathematics, Physical Sciences and Mathematics
Lagrangian models of sea-ice dynamics have several advantages over Eulerian continuum models. Spatial discretization on the ice-floe scale are natural for Lagrangian models and offer exact solutions for mechanical non-linearities with arbitrary sea-ice concentrations. This allows for improved model performance in ice-marginal zones. Furthermore, Lagrangian models can explicitly simulate jamming [...]
An estimate of equilibrium climate sensitivity from interannual variability
Published: 2018-02-03
Subjects: Climate, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Estimating the equilibrium climate sensitivity (ECS; the equilibrium warming in response to a doubling of CO2) from observations is one of the big problems in climate science. Using observations of interannual climate variations covering the period 2000 to 2017 and a model-derived relationship between interannual variations and forced climate change, we estimate ECS is likely 2.4-4.6 K (17-83% [...]
Description of the COST - HOME monthly benchmark dataset and the submitted homogenized contributions
Published: 2018-02-02
Subjects: Climate, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
As part of the COST Action HOME a dataset has been generated that will serve as a benchmark for homogenisation algorithms. Members of the Action and third parties have been invited and are still welcome to homogenise this dataset. The results of this exercise was analysed to obtain recommendations for a standard homogenisation procedure and are described in Venema et al. (Climate of the Past, [...]
Facies architecture of submarine channel deposits on the western Niger Delta slope: Implications for grain-size and density stratification in turbidity currents
Published: 2018-01-28
Subjects: Earth Sciences, Geology, Geomorphology, Mathematics, Oceanography and Atmospheric Sciences and Meteorology, Other Mathematics, Physical Sciences and Mathematics, Sedimentology, Stratigraphy
High-resolution bathymetry, seismic reflection, and piston core data from a submarine channel on the western Niger Delta slope demonstrate that thick, coarse-grained, amalgamated sands in the channel thalweg/axis transition to thin, fine-grained, bedded sands and muds in the channel margin. Radiocarbon ages indicate that axis and margin deposits are coeval. Core data show that bed thickness, [...]