Circumpolar safety, search and rescue collaboration - Forecasting and monitoring for Arctic S&R Part 1
- 09:10 FEATURED TALK: Finnmark ocean currents field experiment
Authors: Kai H. Christensen ( Norwegian Meteorological Institute ); Harald Johnsen ( NORUT ); Ann Kristin Sperrevik ( Norwegian Meteorological Institute ); Johannes Röhrs ( Norwegian Meteorological Institute ); Breivik Øyvind ( Norwegian Meteorological Institute )
We report from a field experiment that will take place in Northern Norway in October 2017. During the experiment, several methods for measuring ocean currents will be compared: (i) radial velocity components from High Frequency (HF) radar, (ii) drift of floats with and without drogues, (iii) currents from moored acoustic Doppler velocity profilers (ADCPs), and (iv) radial velocity components derived from satellite Synthetic Aperture Radar (SAR). The analysis of the data will focus on the vertical and horizontal variability of the currents, and validation and improvements of the geophysical model function for deriving the radial surface current from the radial velocity measurement of SAR. We will also comment on the potential for using the various observation types in ocean data assimilaton.
- 09:40 Norshelf: A data assimilative ocean model for the prediction of surface currents on the Norwegian Shelf
Authors: Johannes Röhrs ( Norwegian Meteorological Institute ); Ann Kristin Sperrevik ( Norwegian Meteorological Institute ); Kai Håkon Christensen ( Norwegian Meteorological Institute )
Ocean circulation models are commonly used to study oceanic transport and as forecasting tool for contingency preparedness. We will release the “Norshelf reanalysis”, a new ocean circulation model simulation for the Norwegian Sea with a 4D-var data assimilation scheme on 2.4km resolution. Therein, satellite and in-situ observations of the oceanic state in terms of temperature and salinity are used to constrain the ocean circulation model. We will present a validation of the model and the performance of the data assimilation scheme, and show some of the key dynamic processes that appear in this region with focus on surface currents.
The Norshelf model covers the shelf sea around Norway, i.e. the Skagerak, the northern parts of the North Sea, the shelf slope off western Norway and the southern parts of the Barents Sea. In this domain, the model resolves the hydrodynamics and hydrography of the the Norwegian Coastal Current, the Atlantic Current, and mesoscale fronts and eddies permitted by the intermediate resolution of 2.4km. In addition to the reanalysis, an operational forecast with daily analysis of the ocean’s state is run at the Norwegian Meteorological Institute. Both the reanalysis and forecast are open available data sets.
- 09:55 Towards ensemble forecasting and data assimilation in the Arctic using a Lagrangian sea-ice model
Authors: Ali Aydoğdu ( Nansen Environmental and Remote Sensing Center ); Matthias Rabatel ( Nansen Environmental and Remote Sensing Center ); Alberto Carrassi ( Nansen Environmental and Remote Sensing Center ); Pierre Rampal ( Nansen Environmental and Remote Sensing Center ); Laurent Bertino ( Nansen Environmental and Remote Sensing Center )
neXtSIM is a novel sea-ice model designed to tackle the challenges in modelling the extreme fracturing events and acceleration of the sea-ice drift associated with the drastic changes in the Arctic sea ice cover. It is a continuous Lagrangian numerical model that uses an Maxwell-Elasto Brittle rheology to simulate the ice response to external forces. We present first a sensitivity analysis and the probabilistic forecast capabilities of neXtSIM as a response of the model to the uncertainty on winds using probabilistic forecasts of ice trajectories. The performance is also evaluated using the IABP buoys' trajectories, and compared to the free-drift model formulation, in which the rheology of the ice does not play any role on the modelled physics of the ice. An assessment of the model for search-and-rescue (S&R) operations has been performed. We will discuss then our ongoing efforts and some preliminary results for the development of an ensemble-based data assimilation system with neXtSIM. The nature of the Lagrangian mesh of neXtSIM, which also includes the possibility of re-meshing, constitutes the main issue related to the use of data assimilation, and particularly ensemble-based, methods. While this property is essential to the skill of the model in describing the mechanics of the sea ice with great details, it brings a challenge in developing compatible data assimilation schemes, as the dimension of the state space can change over time when these re-meshing occur. Some solution to overcome this challenge and its outcomes for better forecasting, which will directly serve to improved S&R operations, will also be discussed.
- 10:10 Drifting path prediction and search for missing vessels
Authors: Tor Einar Berg ( SINTEF Ocean ); Ã˜rjan Selvik ( SINTEF Ocean ); Raymond Prestøy ( JRCC Bodoe ); Øyvind Bech ( Norwegian Coast Guard )
In Arctic waters it will be important to have a good starting point and efficient search patterns in the search phase of a SAR operation. Time is a critical factor for all Arctic SAR operations. It is thus necessary to have reliable tools for prediction of drifting patterns based on the last confirmed position of the drifting vessel. This paper will investigate the following topics that influence the reliability of tools for defining the search area and search patterns for missing vessels in Arctic waters:
- Uncertainty in the last reported position of a missing vessel
- Quality of metocean data for Arctic waters
- Quality of motion models for drifting vessels
- Optimized search patterns based on estimation of vessel drifting motion
The first part will discuss existing systems for position reporting from different types of vessels operating in Arctic waters. Late information of abnormal operational conditions for commercial vessels has in many cases resulted in emergency situations needing SAR operations to save crew members.
The second part will review quality of metocean data for Arctic waters. As an example the findings from a study done by Øyvind Bech as part of his MSc thesis in nautical science will be presented to highlight difference between estimated and observed position of a drifting object i a SAR scenario.
The third part presents experience from use of a specific drifting vessel model in SAR like operations involving smaller fishing vessels. Further this part will present a comparison of estimated drifting tracks for a modern 120 m cargo vessel (generated by different simulation tools). The need for better prediction of paths of drifting vessels will be discussed.
The final part of the paper will discuss how drifting path prediction outcomes can be used to optimize search patterns in Arctic maritime search and rescue operations.
- 10:25 10 years of fixed-wing unmanned aircraft (UAV) operations operations in Norway - history, status and future.
Authors: Vegard Evjen Hovstein ( Maritime Robotics AS ); Rune Storvold ( NORUT )
The presentation can be helt as a joint presentation between Maritime Robotics (Vegard Evjen Hovstein) and NORUT (Rune Storvold)
Both NORUT and Maritime Robotics have been the national pioneers within fixed-wing unmanned aircraft (UAV) beyond-line-of-sight (BLOS) operations in Norway. The presenters met already in 2005 and start fixed-wing operations in their respective environments. It is now over 10 years since we started the first fixed-wing operations in Norway, at a time when the civil aviation authoritires had barely started its work on regulations. We can look back at RnD and scientific missions in coastal and arctic climate over more than 10 years. The evolution has taken place and the lecture will look back on this with some examples highlighting important lessons. We will also consider how we believe that fixed-wing BLOS operations in the high-north and arctic areas will develop over the next 10 years.
Wednesday 24th January 2018
09:10 - 10:40