scholarly journals The impact of waves and sea spray on modelling storm track and development

2015 ◽  
Vol 67 (1) ◽  
pp. 27967 ◽  
Author(s):  
Lichuan Wu ◽  
Anna Rutgersson ◽  
Erik Sahlée ◽  
Xiaoli Guo Larsén
Keyword(s):  
Storm Track ◽  
Sea Spray ◽  
The Impact

scholarly journals The Influence of Air–Sea Roughness, Sea Spray, and Storm Translation Speed on Waves in North Atlantic Storms

2008 ◽  
Vol 38 (4) ◽  
pp. 817-839 ◽  
Author(s):  
Weiqing Zhang ◽  
William Perrie
Keyword(s):  
Wave Height ◽  
Significant Wave Height ◽  
Storm Track ◽  
Wave Drag ◽  
Sea Spray ◽  
Wave Spectra ◽  
Translation Speed ◽  
Significant Wave ◽  
Directional Wave ◽  
The Impact

Abstract A coupled atmosphere–wave–sea spray model system is used to evaluate the impact of sea spray and wave drag on storm-generated waves, their height variations, and directional wave spectra in relation to the storm location and translation speed. Results suggest that the decrease or increase of significant wave height due to spray and wave drag is most significant in high-wind regions to the right of the storm track. These processes are modulations on the maximum-wave region and tend to occur several hours after the peak wind events, depending on the storm translation velocity. The translation speed of the storm is important. The directional variation between local winds and wind-generated waves within rapidly moving storms that outrun the waves is notably different from that of trapped waves, when the dominant waves’ group velocity approximates the storm translation speed. While wave drag and spray can increase or reduce the magnitudes of wind and significant wave height, their nondirectional formulations allow them to have little apparent effect on the directional wave spectra.

scholarly journals Gaseous chemistry and aerosol mechanism developments for version 3.5.1 of the online regional model, WRF-Chem

2014 ◽  
Vol 7 (6) ◽  
pp. 2557-2579 ◽  
Author(s):  
S. Archer-Nicholls ◽  
D. Lowe ◽  
S. Utembe ◽  
J. Allan ◽  
R. A. Zaveri ◽  
...  
Keyword(s):  
Gas Phase ◽  
Chemical Mechanism ◽  
Reduced Form ◽  
Sea Spray ◽  
Wind Fields ◽  
Aerosol Composition ◽  
Aerosol Emission ◽  
Sea Spray Aerosol ◽  
The Impact ◽  
Phase Chemical

Abstract. We have made a number of developments to the Weather, Research and Forecasting model coupled with Chemistry (WRF-Chem), with the aim of improving model prediction of trace atmospheric gas-phase chemical and aerosol composition, and of interactions between air quality and weather. A reduced form of the Common Reactive Intermediates gas-phase chemical mechanism (CRIv2-R5) has been added, using the Kinetic Pre-Processor (KPP) interface, to enable more explicit simulation of VOC degradation. N2O5 heterogeneous chemistry has been added to the existing sectional MOSAIC aerosol module, and coupled to both the CRIv2-R5 and existing CBM-Z gas-phase schemes. Modifications have also been made to the sea-spray aerosol emission representation, allowing the inclusion of primary organic material in sea-spray aerosol. We have worked on the European domain, with a particular focus on making the model suitable for the study of nighttime chemistry and oxidation by the nitrate radical in the UK atmosphere. Driven by appropriate emissions, wind fields and chemical boundary conditions, implementation of the different developments are illustrated, using a modified version of WRF-Chem 3.4.1, in order to demonstrate the impact that these changes have in the Northwest European domain. These developments are publicly available in WRF-Chem from version 3.5.1 onwards.

A nonlinear multi-scale theory of atmospheric blocking: Structure and evolution of blocking linked to meridional and vertical structures of storm tracks

2021 ◽  
Author(s):  
Dehai Luo ◽  
Wenqi Zhang
Keyword(s):  
Storm Track ◽  
Interaction Model ◽  
Maximum Amplitude ◽  
Transient Eddy ◽  
Baroclinic Mode ◽  
Upper Troposphere ◽  
Multi Scale ◽  
The North ◽  
Baroclinic Modes ◽  
The Impact

AbstractThis paper examines the impact of the meridional and vertical structures of a preexisting upstream storm track (PUST) organized by preexisting synoptic-scale eddies on eddy-driven blocking in a nonlinear multi-scale interaction model. In this model, the blocking is assumed, based on observations, to be comprised of barotropic and first baroclinic modes, whereas the PUST consists of barotropic, first baroclinic and second baroclinic modes. It is found that the nonlinearity (dispersion) of blocking is intensified (weakened) with increasing amplitude of the first baroclinic mode of the blocking itself. The blocking tends to be long-lived in this case. The lifetime and strength of blocking are significantly influenced by the amplitude of the first baroclinic mode of blocking for given basic westerly winds (BWWs), whereas its spatial pattern and evolution are also affected by the meridional and vertical structures of the PUST.It is shown that the blocking mainly results from the transient eddy forcing induced by the barotropic and first baroclinic modes of PUST, whereas its second baroclinic mode contributes little to the transient eddy forcing. When the PUST shifts northward, eddy-driven blocking shows an asymmetric dipole structure with a strong anticyclone/weak cyclone in a uniform BWW, which induces northward-intensified westerly jet and storm track anomalies mainly on the north side of blocking. However, when the PUST has no meridional shift and is mainly located in the upper troposphere, a north-south anti-symmetric dipole blocking and an intensified split jet with maximum amplitude in the upper troposphere form easily for vertically varying BWWs without meridional shear.

Nature-Based Solutions: Dependency of Effectiveness on Spatial Configuration

2020 ◽  
Author(s):  
Ian Pattison
Keyword(s):  
Flood Risk ◽  
Critical Infrastructure ◽  
Spatial Configuration ◽  
Storm Track ◽  
Spatial Location ◽  
Flood Management ◽  
Clear Understanding ◽  
Storm Events ◽  
Catchment Scale ◽  
The Impact

<p>Several recent large flood events have had severe economic and social impacts. The winter 2015-16 UK floods resulted in 16,000 properties flooding and damage to critical infrastructure. It is increasingly being recognised that traditional approaches of flood defence are not sustainable due to the pressures of climate change and economic constraints. The solution to the flood risk problem in cities is no longer seen as being just on-site, and thinking is shifting upstream and to the catchment/landscape scales, known as Nature-Based Solutions or Natural Flood Management (NFM). The approach consists of measures that “Work with Natural Processes”, such as storing water in ponds, and slowing the flow in rivers. The evidence for the impacts is strong at the local scale, but the larger spatial scale impact is highly uncertain due to the cumulative impacts resulting from amplifying/mitigating effects of different interventions, controlled by spatial location and storm-track interaction.</p><p>To date, Nature-Based Solution schemes have proceeded on an opportunistic basis, without a clear design strategy (which measure and where to implement it). However, if schemes are implemented without clear understanding of their impacts, they may, at best, fail to achieve the optimum flood reduction benefit downstream, or, at worst, make flooding more severe (if implemented in inappropriate locations, when tributaries’ flows are synchronised).  </p><p><span>Impacts of NFM measures are spatially and temporally dependent i.e. the same intervention in two locations will have different effects on flows, and the same intervention will have different impacts during different storm events. Therefore, it is essential that when strategically designing NFM schemes for catchments, that WHERE? and WHAT? are answered together to optimise the impact, as it is possible that whilst upstream NFM may be beneficial locally it may make tributary peaks coincide and make flood magnitudes worse downstream. Here we demonstrate the importance of the spatial configuration of Nature-Based Solutions on their catchment scale effectiveness in reducing flood risk.</span></p>

Drivers of biases in the extratropical storm tracks in CMIP6

2020 ◽  
Author(s):  
Matthew Priestley ◽  
Duncan Ackerley ◽  
Jennifer Catto ◽  
Kevin Hodges ◽  
Ruth McDonald ◽  
...  
Keyword(s):  
Large Scale ◽  
Climate Models ◽  
Storm Track ◽  
Storm Tracks ◽  
Extratropical Cyclones ◽  
Ocean Coupling ◽  
Coupled Climate Models ◽  
The Mean ◽  
The Impact

<p>Extratropical cyclones are the leading driver of the day-to-day weather variability and wintertime losses for Europe. In the latest generation of coupled climate models, CMIP6, it is hoped that with improved modelling capabilities come improvements in the structure of the storm track and the associated cyclones. Using an objective cyclone identification and tracking algorithm the mean state of the storm tracks in the CMIP6 models is assessed as well as the representation of explosively deepening cyclones. Any developments and improvements since the previous generation of models in CMIP5 are discussed, with focus on the impact of model resolution on storm track representation. Furthermore, large-scale drivers of any biases are investigated, with particular focus on the role of atmosphere-ocean coupling via associated AMIP simulations and also the influence of large-scale dynamical and thermodynamical features.</p>

scholarly journals Impact of Coupling an Ocean Model to WRF Nor’easter Simulations

2015 ◽  
Vol 143 (12) ◽  
pp. 4997-5016 ◽  
Author(s):  
Stephen D. Nicholls ◽  
Steven G. Decker
Keyword(s):  
Storm Track ◽  
Wrf Model ◽  
Ocean Model ◽  
Weather Research And Forecasting ◽  
Model Coupling ◽  
Sea Level Pressure ◽  
Model Simulations ◽  
Simulated Precipitation ◽  
Ocean Atmosphere ◽  
The Impact

Abstract The impact of ocean–atmosphere coupling and its possible seasonal dependence upon Weather Research and Forecasting (WRF) Model simulations of seven, wintertime cyclone events was investigated. Model simulations were identical aside from the degree of ocean model coupling (static SSTs, 1D mixed layer model, full-physics 3D ocean model). Both 1D and 3D ocean model coupling simulations show that SSTs following the passage of a nor’easter did tend to cool more strongly during the early season (October–December) and were more likely to warm late in the season (February–April). Model simulations produce SST differences of up to 1.14 K, but this change did not lead to significant changes in storm track (<100 km), maximum 10-m winds (<2 m s−1), or minimum sea level pressure (≤5 hPa). Simulated precipitation showed little sensitivity to model coupling, but all simulations did tend to overpredict precipitation extent (bias > 1) and have low-to-moderate threat scores (0.31–0.59). Analysis of the storm environment and the overall simulation failed to reveal any statistically significant differences in model error attributable to ocean–atmosphere coupling. Despite this result, ocean model coupling can reduce dynamical field error at a single level by up to 20%, and this was slightly greater (1%–2%) with 3D ocean model coupling as compared to 1D ocean model coupling. Thus, while 3D ocean model coupling tended to generally produce more realistic simulations, its impact would likely be more profound for longer-term simulations.

scholarly journals The Basic Ingredients of the North Atlantic Storm Track. Part I: Land–Sea Contrast and Orography

2009 ◽  
Vol 66 (9) ◽  
pp. 2539-2558 ◽  
Author(s):  
David James Brayshaw ◽  
Brian Hoskins ◽  
Michael Blackburn
Keyword(s):  
North Atlantic ◽  
Rocky Mountains ◽  
Large Scale ◽  
Storm Track ◽  
Storm Tracks ◽  
Cold Pool ◽  
North American Continent ◽  
The North ◽  
The North Atlantic ◽  
The Impact

Abstract Understanding and predicting changes in storm tracks over longer time scales is a challenging problem, particularly in the North Atlantic. This is due in part to the complex range of forcings (land–sea contrast, orography, sea surface temperatures, etc.) that combine to produce the structure of the storm track. The impact of land–sea contrast and midlatitude orography on the North Atlantic storm track is investigated through a hierarchy of GCM simulations using idealized and “semirealistic” boundary conditions in a high-resolution version of the Hadley Centre atmosphere model (HadAM3). This framework captures the large-scale essence of features such as the North and South American continents, Eurasia, and the Rocky Mountains, enabling the results to be applied more directly to realistic modeling situations than was possible with previous idealized studies. The physical processes by which the forcing mechanisms impact the large-scale flow and the midlatitude storm tracks are discussed. The characteristics of the North American continent are found to be very important in generating the structure of the North Atlantic storm track. In particular, the southwest–northeast tilt in the upper tropospheric jet produced by southward deflection of the westerly flow incident on the Rocky Mountains leads to enhanced storm development along an axis close to that of the continent’s eastern coastline. The approximately triangular shape of North America also enables a cold pool of air to develop in the northeast, intensifying the surface temperature contrast across the eastern coastline, consistent with further enhancements of baroclinicity and storm growth along the same axis.

scholarly journals Atmospheric Blocking: The Impact of Topography in an Idealized General Circulation Model

2020 ◽  
Author(s):  
Veeshan Narinesingh ◽  
James F. Booth ◽  
Spencer K. Clark ◽  
Yi Ming
Keyword(s):  
High Pressure ◽  
General Circulation ◽  
Storm Track ◽  
Circulation Model ◽  
Wave Activity ◽  
Stationary Waves ◽  
Atmospheric Blocking ◽  
The Pacific ◽  
The Impact ◽  
Wave Activity Flux

Abstract. Atmospheric blocking can have important impacts on weather hazards, but the fundamental dynamics of blocking are not yet fully understood. As such, this work investigates the influence of topography on atmospheric blocking in terms of dynamics, spatial frequency, duration and displacement. Using an idealized GCM, an aquaplanet integration, and integrations with topography are analyzed. Block-centered composites show midlatitude aquaplanet blocks exhibit similar wave activity flux behavior to those observed in reality, whereas high-latitude blocks do not. The addition of topography significantly increases blocking and determines distinct regions where blocks are most likely to occur. These regions are found near high-pressure anomalies in the stationary waves and near storm track exit regions. Focusing on block duration, blocks originating near topography are found to last longer than those that are formed without or far from topography but have qualitatively similar evolutions in terms of nearby geopotential height anomalies and wave activity fluxes in composites. Integrations with two mountains have greater amounts of blocking compared to the single mountain case, however, the longitudinal spacing between the mountains is important for how much blocking occurs. Comparison between integrations with longitudinally long and short ocean basins show that more blocking occurs when storm track exits spatially overlap with high-pressure maxima in stationary waves. These results have real-world implications, as they help explain the differences in blocking between the Northern and Southern Hemisphere, and the differences between the Pacific and Atlantic regions in the Northern Hemisphere.

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