Preprints
Filtering by Subject: Atmospheric Sciences
Enhanced secondary pollution offset reduction of primary emissions during COVID-19 lockdown in China
Published: 2020-04-13
Subjects: Atmospheric Sciences, Environmental Health and Protection, Environmental Monitoring, Environmental Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
To control the spread of the 2019 novel coronavirus (COVID-19), China imposed nationwide restrictions on the movement of its population (lockdown) after the Chinese New Year of 2020, leading to large reductions in economic activities and associated emissions. Despite such large decreases in primary pollution, there were nonetheless several periods of heavy haze pollution in East China, raising [...]
Seasonal Rainfall Forecasts for the Yangtze River Basin in Summer 2019 from an Improved Climate Service
Published: 2020-03-18
Subjects: Atmospheric Sciences, Climate, Meteorology, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Rainfall forecasts for the summer monsoon season in the Yangtze River Basin allow decision-makers to plan for possible flooding, which can affect the lives and livelihoods of millions of people. A trial climate service was developed in 2016, producing a prototype seasonal forecast product for use by stakeholders in the region, based on forecasting rainfall directly using a dynamical model. Here [...]
Plant Physiology Increases the Magnitude and Spread of the Transient Climate Response in CMIP6 Earth System Models
Published: 2020-02-20
Subjects: Atmospheric Sciences, Climate, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Increasing concentrations of CO2 in the atmosphere not only influence climate through CO2’s effect as a greenhouse gas but also through its impact on plants. Plants respond to atmospheric CO2 concentrations in several ways that can alter surface energy and water fluxes and thus surface climate, including changes in stomatal conductance, water use, and canopy leaf area. These plant physiological [...]
A Shallow Water Model for Convective Self-Aggregation
Published: 2020-02-02
Subjects: Atmospheric Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Convective self-aggregation is proposed to be fundamental to the development of tropical cyclones and the Madden-Julian Oscillation, both of which are long-term mysteries in tropical meteorology. Therefore, understanding self-aggregation is key to deciphering how convection works in the tropical atmosphere. Here we present a 1D shallow water model that simulates the dynamics of the planetary [...]
Spatially distributed chaos and turbulence in clouds
Published: 2020-01-22
Subjects: Atmospheric Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Spatially distributed chaos (turbulence) in the cumulus, stratocumulus, stratiform, cirrus and cirrus mammatus clouds have been studied using results of direct numerical simulations and measurements in the cloudy atmosphere. It is shown that in the considered cases the second order moment of helicity distribution (the Levich-Tsinober invariant) dominates the kinetic energy spectra.
Uncertainty in the response of sudden stratospheric warmings and stratosphere-troposphere coupling to quadrupled CO2 concentrations in CMIP6 models
Published: 2020-01-09
Subjects: Atmospheric Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Major sudden stratospheric warmings (SSWs), vortex formation and final breakdown dates are key highlight points of the stratospheric polar vortex. These phenomena are relevant for stratosphere-troposphere coupling, which explains the interest in understanding their future changes. However, up to now, there is not a clear consensus on which projected changes to the polar vortex are robust, [...]
Feedback between drought and deforestation in the Amazon
Published: 2020-01-09
Subjects: Atmospheric Sciences, Climate, Earth Sciences, Environmental Sciences, Hydrology, Natural Resources and Conservation, Natural Resources Management and Policy, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics, Sustainability
Deforestation and drought are among the greatest environmental pressures on the Amazon rainforest, possibly destabilizing the forest-climate system. Deforestation in the Amazon reduces rainfall regionally, while this deforestation itself has been reported to be facilitated by droughts. Here we quantify the interactions between drought and deforestation spatially across the Amazon during the early [...]
Detection Uncertainty Matters for Understanding Atmospheric Rivers
Published: 2020-01-02
Subjects: Atmospheric Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
The 3rd ARTMIP Workshop What: Over 30 participants from multiple universities and research insititutions met to discuss new results from the Atmospheric River Tracking Method Intercomparison Project. Where: Lawrence Berkeley National Lab, Berkeley, CA, USA When: 16-18 October 2019
Evaluation and comparison of a machine learning cloud identification algorithm for the SLSTR in polar regions
Published: 2019-12-04
Subjects: Atmospheric Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
A Feed Forward Neural Net (NN) approach to distinguish between clouds and the surface has been applied to the Sea and Land Surface Temperature Radiometer in polar regions. The masking algorithm covers the Arctic, Antarctic and regions typically classified as the cryosphere such as northern hemisphere permafrost. The mask has been trained using collocations with the CALIOP active lidar, which in [...]
Gulf Stream and Kuroshio Current are synchronized
Published: 2019-11-05
Subjects: Atmospheric Sciences, Climate, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Observational records show that sea surface temperatures along the Gulf Stream and Kuroshio tend to synchronize at decadal time scales. This synchronization, which we refer to as the Boundary Current Synchronization (BCS), is reproduced in global climate models with high spatial resolution. Both in observations and model simulations, BCS is associated with meridional migrations of the atmospheric [...]
Pre-deliquescent water uptake in deposited nanoparticles observed with in situ ambient pressure X-ray photoelectron spectroscopy
Published: 2019-10-31
Subjects: Atmospheric Sciences, Chemistry, Oceanography and Atmospheric Sciences and Meteorology, Physical Chemistry, Physical Sciences and Mathematics
In this work we study the adsorption, or uptake, of water onto deposited inorganic sodium chloride and organic malonic acid and sucrose nanoparticles at low relative humidities from 0 to 16%. We employ the surface sensitive ambient pressure x-ray photoelectron spectroscopy technique, which has a detection sensitivity from parts per thousand. Our results show that water is adsorbed on sodium [...]
Non-stationary teleconnection between the Pacific Ocean and Arctic sea ice
Published: 2019-10-08
Subjects: Atmospheric Sciences, Climate, Oceanography and Atmospheric Sciences and Meteorology, Other Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Over the last 40 years observations show a teleconnection between summertime Pacific Ocean sea-surface temperatures and September Arctic sea-ice extent. However, the short satellite observation record has made it difficult to further examine this relationship. Here, we use 30 fully-coupled general circulation models (GCMs) participating in Phase 5 of the Coupled Model Inter-comparison Project to [...]
Analog forecasting of extreme-causing weather patterns using deep learning
Published: 2019-07-31
Subjects: Artificial Intelligence and Robotics, Atmospheric Sciences, Computational Engineering, Computer Sciences, Engineering, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Numerical weather prediction (NWP) models require ever-growing computing time/resources, but still, have difficulties with predicting weather extremes. Here we introduce a data-driven framework that is based on analog forecasting (prediction using past similar patterns) and employs a novel deep learning pattern-recognition technique (capsule neural networks, CapsNets) and impact-based [...]
Evidence against a general positive eddy feedback in atmospheric blocking
Published: 2019-07-04
Subjects: Atmospheric Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
The eddy straining mechanism of Shutts (1983; S83) has long been considered a main process for explaining the maintenance of atmospheric blocking. As hypothesized in S83, incoming synoptic eddies experience a meridional straining effect when approaching a split jetstream, and as a result, enhanced PV fluxes reinforce the block. A two-layer QG model is adopted here as a minimal model to conduct [...]
Reducing uncertainties in climate projections with emergent constraints: Concepts, Examples and Prospects
Published: 2019-06-28
Subjects: Atmospheric Sciences, Climate, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics
Models disagree on a significant number of responses to climate change, such as climate feedback, regional changes, or the strength of equilibrium climate sensitivity. Emergent constraints aim to reduce these uncertainties by finding links between the inter-model spread in an observable predictor and climate projections. In this paper, the concepts underlying this framework are recalled with an [...]