scholarly journals Assimilating realistically simulated wide-swath altimeter observations in a high-resolution shelf-seas forecasting system

Ocean Science ◽  
2021 ◽  
Vol 17 (6) ◽  
pp. 1791-1813
Author(s):  
Robert R. King ◽  
Matthew J. Martin
Keyword(s):  
Mean Squared Error ◽  
Surface Current ◽  
Surface Currents ◽  
Correlated Errors ◽  
North West ◽  
Forecasting System ◽  
Negative Impacts ◽  
Ocean Topography ◽  
The Impact ◽  
Wide Swath

Abstract. The impact of assimilating simulated wide-swath altimetry observations from the upcoming Surface Water and Ocean Topography (SWOT) mission is assessed using observing system simulation experiments (OSSEs). These experiments use the Met Office 1.5 km resolution North West European Shelf analysis and forecasting system. In an effort to understand the importance of future work to account for correlated errors in the data assimilation scheme, we simulate SWOT observations with and without realistic correlated errors. These are assimilated in OSSEs along with simulated observations of the standard observing network, also with realistic errors added. It was found that while the assimilation of SWOT observations without correlated errors reduced the RMSE (root mean squared error) in sea surface height (SSH) and surface current speeds by up to 20 %, the inclusion of correlated errors in the observations degraded both the SSH and surface currents, introduced an erroneous increase in the mean surface currents and degraded the subsurface temperature and salinity. While restricting the SWOT data to the inner half of the swath and applying observation averaging with a 5 km radius negated most of the negative impacts, it also severely limited the positive impacts. To realise the full benefits in the prediction of the ocean mesoscale offered by wide-swath altimetry missions, it is crucial that methods to ameliorate the effects of correlated errors in the processing of the SWOT observations and account for the correlated errors in the assimilation are implemented.

scholarly journals Assimilating realistically simulated wide-swath altimeter observations in a high-resolution shelf-seas forecasting system

2021 ◽  
Author(s):  
Robert R. King ◽  
Matthew J. Martin
Keyword(s):  
Surface Current ◽  
Surface Currents ◽  
Correlated Errors ◽  
North West ◽  
Shelf Seas ◽  
Forecasting System ◽  
Negative Impacts ◽  
Future Work ◽  
The Impact ◽  
Wide Swath

Abstract. The impact of assimilating simulated wide-swath altimetry observations from the upcoming SWOT mission is assessed using Observing System Simulation Experiments (OSSEs). These experiments use the Met Office 1.5 km resolution North-West European Shelf analysis and forecasting system. In an effort to understand the importance of future work to account for correlated errors in the data assimilation scheme, we simulate SWOT observations with and without realistic correlated errors. These are assimilated in OSSEs along with simulated observations of the standard observing network, also with realistic errors added. It was found that while the assimilation of SWOT observations without correlated errors reduced the RMSE in sea surface height (SSH) and surface current speeds by up to 20 %, the inclusion of correlated errors in the observations degraded both the SSH and surface currents, introduced an erroneous increase in the mean surface currents, and degraded the sub-surface temperature and salinity. While restricting the SWOT data to the inner half of the swath and applying observation averaging with a 5 km radius negated most of the negative impacts, it also severely limited the positive impacts. To realise the full benefits in the prediction of the ocean mesoscale offered by wide-swath altimetry missions it is crucial that methods to ameliorate the effects of correlated errors in the processing of the SWOT observations and to account for the correlated errors in the assimilation are implemented.

scholarly journals The impact of a new high-resolution ocean model on the Met Office North-West European Shelf forecasting system

2019 ◽  
Author(s):  
Marina Tonani ◽  
Peter Sykes ◽  
Robert R. King ◽  
Niall McConnell ◽  
Anne-Christine Pequignet ◽  
...  
Keyword(s):  
High Resolution ◽  
Superior Performance ◽  
North West ◽  
Resolution System ◽  
Basin Scale ◽  
European Shelf ◽  
Forecasting System ◽  
The Impact ◽  
New System ◽  
West European

Abstract. The North-West European shelf ocean forecasting system has been providing oceanographic products for the European continental shelf seas for more than fifteen years. In that time several different configurations have been implemented, updating the model and the data assimilation components. The latest configuration to be put in operations, an eddy resolving model at 1.5 km (AMM15), replaces the 7 km model (AMM7) that has been used for a number of years. This has improved the ability to resolve the mesoscale variability in this area. An overview of this new system and its initial validation is provided in this paper, highlighting the differences with the previous version. Validation of the model is based on the results of two years (2016–2017) trial experiments run with the low and high resolution systems in their operational configuration. The 1.5 km system has been validated against observations and the low resolution system, trying to understand the impact of the high resolution on the quality of the products delivered to the users. Although the number of observations is a limiting factor, especially for the assessment of model variables like currents and salinity, the new system has been proven to be an improvement in resolving fine scale structures and variability and provides more accurate information on the major physical variables, like temperature, salinity and horizontal currents. AMM15 improvements are evident from the validation against high-resolution observations, available in some selected areas of the model domain. However, validation at the basin scale and using daily means penalised the high-resolution system and does not reflect its superior performance. This increment in resolution also improves the capabilities to provide marine information closer to the coast even if the coastal processes are not fully resolved by the model.

scholarly journals The impact of COVID-19 social distancing and isolation recommendations for Muslim communities in North West England

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Shaima M. Hassan ◽  
Adele Ring ◽  
Naheed Tahir ◽  
Mark Gabbay
Keyword(s):  
Psychological Distress ◽  
Qualitative Interviews ◽  
Muslim Community ◽  
North West ◽  
Low Mood ◽  
The North ◽  
Negative Impacts ◽  
Muslim Communities ◽  
The Uk ◽  
The Impact

Abstract Introduction People from Minority Ethnic backgrounds living in the UK are at greater risk of not only contracting COVID-19, but also experiencing serious consequences of the virus. These emerging health inequalities mirror those already evident in UK society. Aim The aim of this study was to understand how COVID-19 and the associated imposed restrictions affected the lives of people from the Muslim community living in the North West of England. Method Twenty-five in-depth qualitative interviews and four focus groups (n = 22) explored individual experiences of COVID-19 and imposed restrictions. Data were analysed thematically. Findings The virus and associated imposed restrictions had negative impacts on the psychological wellbeing of participants, their families and the wider community. Worry and low mood were particular features of participant’s pandemic stories. Main concerns were those of contracting and transmitting the virus to others and employment-related difficulties. Low mood was particularly linked to the impact of restrictions on fundamental interactions embedded within cultural and religious practices. These practices are central to feelings of belonging and connectedness within the Muslim community. Religious beliefs were important in helping to mitigate psychological distress for some participants. Conclusion Psychological distress was associated with COVID-19 virus and impact of COVID-19 restrictions on livelihoods and fundamental human interactions. Better provision of culturally appropriate information, improving local channels of communication and practical support are important during times of pandemic when usual support systems may be disrupted.

scholarly journals High-Frequency radar measurements with CODAR in the region of Nice: improved calibration and performance

2021 ◽  
Author(s):  
Charles-Antoine Guérin ◽  
Dylan Dumas ◽  
Anne Molcard ◽  
Céline Quentin ◽  
Bruno Zakardjian ◽  
...  
Keyword(s):  
Surface Current ◽  
Surface Currents ◽  
Calibration Technique ◽  
North West ◽  
High Frequency Radar ◽  
Self Calibration ◽  
The North ◽  
First Results ◽  
And Performance ◽  
Long Term Observation

AbstractWe report on the installation and first results of one compact oceanographic radar in the region of Nice for a long-term observation of the coastal surface currents in the North-West Mediterranean Sea. We describe the specific processing and calibration techniques that were developed at the laboratory to produce high-quality radial surface current maps. In particular, we propose an original self-calibration technique of the antenna patterns, which is based on the sole analysis of the database and does not require any shipborne transponder or other external transmitters. The relevance of the self-calibration technique and the accuracy of inverted surface currents have been assessed with the launch of 40 drifters that remained under the radar coverage for about 10 days.

scholarly journals The impact of a new high-resolution ocean model on the Met Office North-West European Shelf forecasting system

Ocean Science ◽  
2019 ◽  
Vol 15 (4) ◽  
pp. 1133-1158 ◽  
Author(s):  
Marina Tonani ◽  
Peter Sykes ◽  
Robert R. King ◽  
Niall McConnell ◽  
Anne-Christine Péquignet ◽  
...  
Keyword(s):  
High Resolution ◽  
Data Assimilation ◽  
Superior Performance ◽  
North West ◽  
Resolution System ◽  
European Shelf ◽  
Forecasting System ◽  
The Impact ◽  
New System ◽  
West European

Abstract. The North-West European Shelf ocean forecasting system has been providing oceanographic products for the European continental shelf seas for more than 15 years. In that time, several different configurations have been implemented, updating the model and the data assimilation components. The latest configuration to be put in operation, an eddy-resolving model at 1.5 km (AMM15), replaces the 7 km model (AMM7) that has been used for 8 years to deliver forecast products to the Copernicus Marine Environment Monitoring Service and its precursor projects. This has improved the ability to resolve the mesoscale variability in this area. An overview of this new system and its initial validation is provided in this paper, highlighting the differences with the previous version. Validation of the model with data assimilation is based on the results of 2 years (2016–2017) of trial experiments run with the low- and high-resolution systems in their operational configuration. The 1.5 km system has been validated against observations and the low-resolution system, trying to understand the impact of the high resolution on the quality of the products delivered to the users. Although the number of observations is a limiting factor, especially for the assessment of model variables like currents and salinity, the new system has been proven to be an improvement in resolving fine-scale structures and variability and provides more accurate information on the major physical variables, like temperature, salinity, and horizontal currents. AMM15 improvements are evident from the validation against high-resolution observations, available in some selected areas of the model domain. However, validation at the basin scale and using daily means penalized the high-resolution system and does not reflect its superior performance. This increment in resolution also improves the capabilities to provide marine information closer to the coast even if the coastal processes are not fully resolved by the model.

scholarly journals Impact of currents on surface flux computations and their feedback on dynamics at regional scales

Ocean Science ◽  
2015 ◽  
Vol 11 (4) ◽  
pp. 657-666 ◽  
Author(s):  
A. Olita ◽  
I. Iermano ◽  
L. Fazioli ◽  
A. Ribotti ◽  
C. Tedesco ◽  
...  
Keyword(s):  
Surface Current ◽  
Surface Flux ◽  
Power Input ◽  
Western Mediterranean ◽  
Surface Fluxes ◽  
Surface Currents ◽  
Qualitative Comparison ◽  
Satellite Sst ◽  
Ocean Surface Currents ◽  
The Impact

Abstract. A twin numerical experiment was conducted in the seas around the island of Sardinia (Western Mediterranean) to assess the impact, at regional and coastal scales, of the use of relative winds (i.e., taking into account ocean surface currents) in the computation of heat and momentum fluxes through standard (Fairall et al., 2003) bulk formulas. The Regional Ocean Modelling System (ROMS) was implemented at 3 km resolution in order to well resolve mesoscale processes, which are known to have a large influence in the dynamics of the area. Small changes (few percent points) in terms of spatially averaged fluxes correspond to quite large differences of such quantities (about 15 %) in spatial terms and in terms of kinetics (more than 20 %). As a consequence, wind power input P is also reduced by ~ 14 % on average. Quantitative validation with satellite SST suggests that such a modification of the fluxes improves the model solution especially in the western side of the domain, where mesoscale activity (as suggested by eddy kinetic energy) is stronger. Surface currents change both in their stable and fluctuating part. In particular, the path and intensity of the Algerian Current and of the Western Sardinia Current (WSC) are impacted by the modification in fluxes. Both total and eddy kinetic energies of the surface current field are reduced in the experiment where fluxes took into account the surface currents. The main dynamical correction is observed in the SW area, where the different location and strength of the eddies influence the path and intensity of the WSC. Our results suggest that, even at local scales and in temperate regions, it would be preferable to take into account such a contribution in flux computations. The modification of the original code, substantially cost-less in terms of numerical computation, improves the model response in terms of surface fluxes (SST validated) and it also likely improves the dynamics as suggested by qualitative comparison with satellite data.

scholarly journals Impact of currents on surface fluxes computation and their feedback on coastal dynamics

2015 ◽  
Vol 12 (1) ◽  
pp. 1-30
Author(s):  
A. Olita ◽  
I. Iermano ◽  
L. Fazioli ◽  
A. Ribotti ◽  
C. Tedesco ◽  
...  
Keyword(s):  
Coastal Upwelling ◽  
Surface Current ◽  
Ocean Surface ◽  
Western Mediterranean ◽  
Surface Fluxes ◽  
Heat Fluxes ◽  
Ocean Modeling ◽  
Surface Currents ◽  
Regional Ocean Modeling System ◽  
The Impact

Abstract. A twin numerical experiment was conducted in the seas of Sardinia (Western Mediterranean) to assess the impact, at coastal scales, of the use of relative winds (i.e. taking into account ocean surface currents) in the computation of heat and momentum fluxes through bulk formulas. The model, the Regional Ocean Modeling System (ROMS), was implemented at 2 km of resolution in order to well resolve (sub-)mesoscale dynamics. Small changes (1–2%) in terms of spatially-averaged fluxes correspond to quite large spatial differences of such quantities (up to 15–20%) and to comparably significant differences in terms of mean velocities of the surface currents. Wind power input of the wind stress to the ocean surface P results also reduced by a 15%, especially where surface currents are stronger. Quantitative validation with satellite SST suggests that such a modification on the fluxes improves the model solution especially in areas of cyclonic circulation, where the heat fluxes correction is predominant in respect to the dynamical correction. Surface currents changes above all in their fluctuating part, while the stable part of the flow show changes mainly in magnitude and less in its path. Both total and eddy kinetic energies of the surface current field results reduced in the experiment where fluxes took into account for surface currents. Dynamically, the largest correction is observed in the SW area where anticyclonic eddies approach the continental slope. This reduction also impacts the vertical dynamics and specifically the local upwelling that results diminished both in spatial extension as well in magnitude. Simulations suggest that, even at local scales and in temperate regions, it is preferable to take into account for such a component in fluxes computation. Results also confirm the tight relationship between local coastal upwelling and eddy-slope interactions in the area.

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