An approach to the verification of high-resolution ocean models using spatial methods

Abstract. The Met Office currently runs two operational ocean forecasting configurations for the North West European Shelf: an eddy-permitting model with a resolution of 7 km (AMM7) and an eddy-resolving model at 1.5 km (AMM15). Whilst qualitative assessments have demonstrated the benefits brought by the increased resolution of AMM15, particularly in the ability to resolve finer-scale features, it has been difficult to show this quantitatively, especially in forecast mode. Applications of typical assessment metrics such as the root mean square error have been inconclusive, as the high-resolution model tends to be penalised more severely, referred to as the double-penalty effect. This effect occurs in point-to-point comparisons whereby features correctly forecast but misplaced with respect to the observations are penalised twice: once for not occurring at the observed location, and secondly for occurring at the forecast location, where they have not been observed. An exploratory assessment of sea surface temperature (SST) has been made at in situ observation locations using a single-observation neighbourhood-forecast (SO-NF) spatial verification method known as the High-Resolution Assessment (HiRA) framework. The primary focus of the assessment was to capture important aspects of methodology to consider when applying the HiRA framework. Forecast grid points within neighbourhoods centred on the observing location are considered as pseudo ensemble members, so that typical ensemble and probabilistic forecast verification metrics such as the continuous ranked probability score (CRPS) can be utilised. It is found that through the application of HiRA it is possible to identify improvements in the higher-resolution model which were not apparent using typical grid-scale assessments. This work suggests that future comparative assessments of ocean models with different resolutions would benefit from using HiRA as part of the evaluation process, as it gives a more equitable and appropriate reflection of model performance at higher resolutions.

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An approach to the verification of high-resolution ocean models using spatial methods

10.5194/os-2020-12 ◽

2020 ◽

Author(s):

Ric Crocker ◽

Jan Maksymczuk ◽

Marion Mittermaier ◽

Marina Tonani ◽

Christine Pequignet

Keyword(s):

High Resolution ◽

Model Performance ◽

Evaluation Process ◽

In Situ Observation ◽

Single Observation ◽

North West ◽

The North ◽

Resolution Model ◽

Ocean Models ◽

Ocean Forecasting

Abstract. The Met Office currently runs two operational ocean forecasting configurations for the North West European Shelf, an eddy-permitting model with a resolution of 7 km (AMM7), and an eddy-resolving model at 1.5 km (AMM15). Whilst qualitative assessments have demonstrated the benefits brought by the increased resolution of AMM15, particularly in the ability to resolve fine-scale features, it has been difficult to show this quantitatively, especially in forecast mode. Application of typical assessment metrics such as the root mean square error have been inconclusive, as the high-resolution model tends to be penalised more severely (double-penalty effect). An assessment of SST has been made at in-situ observation locations using a single-observation-neighbourhood-forecast (SO-NF) spatial method known as the High-Resolution Assessment (HiRA) framework, which utilises ensemble and probabilistic forecast verification metrics such as the Continuous Ranked Probability Score (CRPS). It is found that through the application of HiRA it is possible to identify improvements in the higher resolution model which were not apparent using typical grid scale assessments. This work suggests that future comparative assessments of ocean models with different resolutions would benefit from using HiRA as part of the evaluation process, as it gives a more equitable and appropriate reflection of model performance at higher resolutions.

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Estimate hydrodynamic connectivity and probability of contamination through Lagrangian experiments in a high resolution shelf sea model

10.5194/egusphere-egu2020-20673 ◽

2020 ◽

Author(s):

Michele Bendoni ◽

Carlo Brandini ◽

Maria Fattorini ◽

Chiara Lapucci ◽

Carlo Pretti

Keyword(s):

High Resolution ◽

Initial Conditions ◽

Low Resolution ◽

Reanalysis Dataset ◽

North West ◽

The North ◽

Port Area ◽

Shelf Sea ◽

Resolution Model ◽

One Year

Coastal areas are experiencing an increasing anthropic pressure worldwide, especially due to port activities. In addition, valuable ecosystems such as Marine Protected Areas (MPA) might be located close to ports and be potentially subject to pollutant driven by the local current pattern. It is then fundamental to develop tools to analyze and quantify the tendency of a MPA to be affected by generic pollutant released from a port. Present work is based on a series of Lagrangian experiments carried out on a domain containing the port of Livorno and the Meloria Sholas MPA, located in the Tuscany Archipelago (Italy). The flow field employed to force the experiments is obtained from a downscaling modelling chain implemented with the 3D ROMS software. The top level is a 1.2 km low-resolution model covering the North-West portion of the Mediterranean basin which feeds with a one-way nesting algorithm a 400 m mid-resolution model for the Tuscany Archipelago, extending West of Corsica Island and up to the Gulf of Genova. The inner level of the modelling chain is a 50 m high-resolution coastal model (offline nesting) which covers the area of Meloria Shoals, the port, and their surroundings. Hydrodynamic simulations are carried out for one year. Initial conditions are provided by the CMEMS (1/24&#176; res) model Analysis, as well as boundary conditions for the low-resolution model. Atmospheric forcing comes from the downscaling of the ERA-5 reanalysis dataset, consisting on the BOLAM model implemented on a 7 km grid of the Med-CORDEX domain, in which the MOLOCH model is nested on a 2.5 km spaced grid. Lagrangian numerical experiments are carried out considering the consecutive release of passive particles in the port area, at finite intervals for one year, following the trajectories for ten days. To estimate the degree of hydrodynamic connectivity between the port and the MPA and give a measure of the probability of contamination, the &#8220;oceanographic distance&#8221; is computed in several ways from the calculated trajectories. Preliminary results show the main transport pattern is mostly distributed alongshore, making the MPA less connected to the port compared to areas placed at the same distance.

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Seismic structure of the Cheb Basin from high resolution surveying – data quality assessment and first results

10.5194/egusphere-egu21-10124 ◽

2021 ◽

Author(s):

Natalia Banasiak ◽

Florian Bleibinhaus

Keyword(s):

High Resolution ◽

Earthquake Activity ◽

Seismic Structure ◽

North West ◽

The North ◽

Eger Rift ◽

First Results ◽

Ground Roll ◽

Variscan Granites ◽

Cheb Basin

In this study we present data and preliminary results from several shallow high-resolution seismic surveys in the Cheb Basin, CR, a small intracontinental basin in the North-West Bohemian Massif, located at the Western end of the Cenozoic Eger Rift. The area is well known for its intense earthquake activity, with the largest instrumentally recorded magnitude of ML=4.6. Macroseismic reports of local seismicity date back to the early 19th century, with magnitudes possibly above 5. Quaternary volcanoes, CO2-rich moffettes, and the swarm-like occurrence of the earthquakes suggest they are being triggered by crustal fluids. In contrast, most focal mechanisms show a dominant strike-slip component, indicative of tectonics. Investigating the role of fluids in triggering those earthquakes is one of the objectives of an ongoing ICDP program.We expect high-resolution images of the basin structure to provide additional constraints regarding the importance of tectonic faulting. To that end, we surveyed several up to 3-km-long reflection and refraction profiles in the basin center across the putative Po&#269;&#225;tky-Plesn&#225; Fault, and at its edge, across the basin-bounding Mari&#225;nsk&#233; L&#225;zn&#283; Fault. The up to 350-m-thick basin sediments are mostly of Miocene and Quaternary origin, overlying Paleozoic Variscan units and post-Variscan granites. The main reflectors are around 200-400 ms. The data were collected with a 500-m-long split-spread of single geophones at 2 m spacing, and the raw shots are dominated by ground roll. In this presentation, we will show an overview of the field campaigns and present first results.

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Effects of High Resolution and Spinup Time on Modeled North Atlantic Circulation

Journal of Physical Oceanography ◽

10.1175/jpo-d-18-0141.1 ◽

2019 ◽

Vol 49 (5) ◽

pp. 1159-1181 ◽

Cited By ~ 4

Author(s):

Christopher Danek ◽

Patrick Scholz ◽

Gerrit Lohmann

Keyword(s):

High Resolution ◽

North Atlantic ◽

Horizontal Resolution ◽

Quasi Equilibrium ◽

Low Resolution ◽

The North ◽

Resolution Model ◽

High Horizontal Resolution ◽

High Resolution Model ◽

The North Atlantic

AbstractThe influence of a high horizontal resolution (5–15 km) on the general circulation and hydrography in the North Atlantic is investigated using the Finite Element Sea Ice–Ocean Model (FESOM). We find a stronger shift of the upper-ocean circulation and water mass properties during the model spinup in the high-resolution model version compared to the low-resolution (~1°) control run. In quasi equilibrium, the high-resolution model is able to reduce typical low-resolution model biases. Especially, it exhibits a weaker salinification of the North Atlantic subpolar gyre and a reduced mixed layer depth in the Labrador Sea. However, during the spinup adjustment, we see that initially improved high-resolution features partially reduce over time: the strength of the Atlantic overturning and the path of the North Atlantic Current are not maintained, and hence hydrographic biases known from low-resolution ocean models return in the high-resolution quasi-equilibrium state. We identify long baroclinic Rossby waves as a potential cause for the strong upper-ocean adjustment of the high-resolution model and conclude that a high horizontal resolution improves the state of the modeled ocean but the model integration length should be chosen carefully.

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DEMETER HIGH RESOLUTION 3D SEISMIC SURVEY—REVITALISED DEVELOPMENT AND EXPLORATION ON THE NORTH WEST SHELF, AUSTRALIA

The APPEA Journal ◽

10.1071/aj05007 ◽

2006 ◽

Vol 46 (1) ◽

pp. 101 ◽

Cited By ~ 1

Author(s):

K.J. Bennett ◽

M.R. Bussell

Keyword(s):

High Resolution ◽

Seismic Data ◽

New Technologies ◽

Seismic Survey ◽

Future Application ◽

3D Seismic ◽

Gas Field ◽

North West ◽

The North ◽

Exploration And Development

The newly acquired 3,590 km2 Demeter 3D high resolution seismic survey covers most of the North West Shelf Venture (NWSV) area; a prolific hydrocarbon province with ultimate recoverable reserves of greater than 30 Tcf gas and 1.5 billion bbls of oil and natural gas liquids. The exploration and development of this area has evolved in parallel with the advent of new technologies, maturing into the present phase of revitalised development and exploration based on the Demeter 3D.The NWSV is entering a period of growing gas market demand and infrastructure expansion, combined with a more diverse and mature supply portfolio of offshore fields. A sequence of satellite fields will require optimised development over the next 5–10 years, with a large number of wells to be drilled.The NWSV area is acknowledged to be a complex seismic environment that, until recently, was imaged by a patchwork of eight vintage (1981–98) 3D seismic surveys, each acquired with different parameters. With most of the clearly defined structural highs drilled, exploration success in recent years has been modest. This is due primarily to severe seismic multiple contamination masking the more subtle and deeper exploration prospects. The poor quality and low resolution of vintage seismic data has also impeded reservoir characterisation and sub-surface modelling. These sub-surface uncertainties, together with the large planned expenditure associated with forthcoming development, justified the need for the Demeter leading edge 3D seismic acquisition and processing techniques to underpin field development planning and reserves evaluations.The objective of the Demeter 3D survey was to re-image the NWSV area with a single acquisition and processing sequence to reduce multiple contamination and improve imaging of intra-reservoir architecture. Single source (133 nominal fold), shallow solid streamer acquisition combined with five stages of demultiple and detailed velocity analysis are considered key components of Demeter.The final Demeter volumes were delivered early 2005 and already some benefits of the higher resolution data have been realised, exemplified in the following:Successful drilling of development wells on the Wanaea, Lambert and Hermes oil fields and identification of further opportunities on Wanaea-Cossack and Lambert- Hermes;Dramatic improvements in seismic data quality observed at the giant Perseus gas field helping define seven development well locations;Considerably improved definition of fluvial channel architecture in the south of the Goodwyn gas field allowing for improved well placement and understanding of reservoir distribution;Identification of new exploration prospects and reevaluation of the existing prospect portfolio. Although the Demeter data set has given significant bandwidth needed for this revitalised phase of exploration and development, there remain areas that still suffer from poor seismic imaging, providing challenges for the future application of new technologies.

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Mesoscale eddy statistics and implications for parameterization refinements from a diagnosis of a high resolution model of the North Pacific

Ocean Modelling ◽

10.1016/j.ocemod.2010.02.004 ◽

2010 ◽

Vol 33 (3-4) ◽

pp. 205-223 ◽

Cited By ~ 7

Author(s):

Hiroyuki Tsujino ◽

Shiro Nishikawa ◽

Kei Sakamoto ◽

Hideyuki Nakano ◽

Hiroshi Ishizaki

Keyword(s):

High Resolution ◽

North Pacific ◽

Mesoscale Eddy ◽

The North ◽

Resolution Model ◽

High Resolution Model ◽

The North Pacific

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Evaluation of trends in extreme temperatures simulated by HighResMIP models across Europe

10.5194/egusphere-egu2020-21769 ◽

2020 ◽

Author(s):

Gerard van der Schrier ◽

Antonello Squintu ◽

Else van den Besselaar ◽

Eveline van der Linden ◽

Enrico Scoccimarro ◽

...

Keyword(s):

High Resolution ◽

Western Europe ◽

Extreme Values ◽

Maximum Temperature ◽

Western Balkans ◽

North West ◽

The Balkans ◽

The North ◽

Summer Maximum ◽

Maximum Temperatures

The comparison of simulated climate with observed daily values allows to assess their reliability and the soundness of their projections on the climate of the future. Frequency and amplitude of extreme events are fundamental aspects that climate simulations need to reproduce. In this work six models developed within the High Resolution Model Intercomparison Project are compared over Europe with the homogenized version of the observational E-OBS gridded dataset. This is done by comparing averages, extremes and trends of the simulated summer maximum temperature and winter minimum temperatures with the observed ones.Extreme values have been analyzed making use of indices based on the exceedances of percentile-based thresholds. Winter minimum temperatures are generally underestimated by models in their averages (down to -4 deg. C of difference over Italy and Norway) while simulated trends in averages and extreme values are found to be too warm on western Europe and too cold on eastern Europe (e.g. up to a difference of -4% per decade on the number of Cold Nights over Spain). On the other hand the models tend to underestimate summer maximum temperatures averages in Northern Europe and overestimate them in the Mediterranean areas (up to +5 deg. C over the Balkans). The simulated trends are too warm on the North West part and too cold on the South East part of Europe (down to -3%/dec. on the number of Warm Days over Italy and Western Balkans).These results corroborate the findings of previous studies about the underestimation of the warming trends of summer temperatures in Southern Europe, where these are more intense and have more impacts. &#160;A comparison of the high resolution models &#160;with the corresponding version in CMIP5 has been performed comparing the absolute biases of extreme values trends. This has shown a slight improvement for the simulation of winter minimum temperatures, while no signs of significant progresses have been found for summer maximum temperatures.

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Towards Direct Simulation of Future Tropical Cyclone Statistics in a High-Resolution Global Atmospheric Model

Advances in Meteorology ◽

10.1155/2010/915303 ◽

2010 ◽

Vol 2010 ◽

pp. 1-13 ◽

Cited By ~ 23

Author(s):

Michael F. Wehner ◽

G. Bala ◽

Phillip Duffy ◽

Arthur A. Mirin ◽

Raquel Romano

Keyword(s):

High Resolution ◽

Radiative Forcing ◽

General Circulation ◽

Circulation Model ◽

Atmospheric Model ◽

Tropical Storm ◽

Model Studies ◽

The North ◽

Resolution Model ◽

High Resolution Model

We present a set of high-resolution global atmospheric general circulation model (AGCM) simulations focusing on the model's ability to represent tropical storms and their statistics. We find that the model produces storms of hurricane strength with realistic dynamical features. We also find that tropical storm statistics are reasonable, both globally and in the north Atlantic, when compared to recent observations. The sensitivity of simulated tropical storm statistics to increases in sea surface temperature (SST) is also investigated, revealing that a credible late 21st century SST increase produced increases in simulated tropical storm numbers and intensities in all ocean basins. While this paper supports previous high-resolution model and theoretical findings that the frequency of very intense storms will increase in a warmer climate, it differs notably from previous medium and high-resolution model studies that show a global reduction in total tropical storm frequency. However, we are quick to point out that this particular model finding remains speculative due to a lack of radiative forcing changes in our time-slice experiments as well as a focus on the Northern hemisphere tropical storm seasons.

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AMM15: a new high-resolution NEMO configuration for operational simulation of the European north-west shelf

Geoscientific Model Development ◽

10.5194/gmd-11-681-2018 ◽

2018 ◽

Vol 11 (2) ◽

pp. 681-696 ◽

Cited By ~ 28

Author(s):

Jennifer A. Graham ◽

Enda O'Dea ◽

Jason Holt ◽

Jeff Polton ◽

Helene T. Hewitt ◽

...

Keyword(s):

High Resolution ◽

Horizontal Resolution ◽

Bias Reduction ◽

Small Scale ◽

Operational System ◽

North West ◽

The North ◽

European North ◽

The Mean ◽

Mean State

Abstract. This paper describes the next-generation ocean forecast model for the European north-west shelf, which will become the basis of operational forecasts in 2018. This new system will provide a step change in resolution and therefore our ability to represent small-scale processes. The new model has a resolution of 1.5 km compared with a grid spacing of 7 km in the current operational system. AMM15 (Atlantic Margin Model, 1.5 km) is introduced as a new regional configuration of NEMO v3.6. Here we describe the technical details behind this configuration, with modifications appropriate for the new high-resolution domain. Results from a 30-year non-assimilative run using the AMM15 domain demonstrate the ability of this model to represent the mean state and variability of the region.Overall, there is an improvement in the representation of the mean state across the region, suggesting similar improvements may be seen in the future operational system. However, the reduction in seasonal bias is greater off-shelf than on-shelf. In the North Sea, biases are largely unchanged. Since there has been no change to the vertical resolution or parameterization schemes, performance improvements are not expected in regions where stratification is dominated by vertical processes rather than advection. This highlights the fact that increased horizontal resolution will not lead to domain-wide improvements. Further work is needed to target bias reduction across the north-west shelf region.

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