Previous Seminars

Introduction to CMIP6 model data and analysing tools

Speaker: 
Yanchun He (Climate Dynamics and Prediction)
Seminar Date: 
23. June 2020 - 11:15 - 11:45

The seminar will take place on Teams.

Outline of presentation:
- Overview of Coupled Model Intercomparison Project Phase 6 (CMIP6).
- NorESM contribution to CMIP6.
- Access of CMIP6 data on the National e-Infrastructure for Research Data (NIRD).
- Tools to download CMIP6 to NIRD.
- Analysis of the original model output and the standardised (i.e., CMORized) CMIP6 datasets - the NorESM Diagnostic Tool and the ESMValTool.

Postponed: Impact of the North Atlantic Atmospheric Variability on the Northern European Sea Level

Speaker: 
Fabio Mangini (Ocean and Sea Ice Remote Sensing)
Seminar Date: 
17. March 2020 - 11:15 - 11:45

In this project, we analyze the contribution of the winds to the winter-time sea level variability over the Northern European continental shelf at intra-seasonal timescale. Using daily gridded sea level anomaly from altimetry, we relate anomalously high and anomalously low sea level events to the daily winter-time jet clusters. The jet clusters are persistent and recurrent states of the atmospheric circulation in the North Atlantic. They are four in number and capture different configurations of the eddy-driven jet stream. Following this approach, we find two main results.

Detection of the oceanic eddies signature in sea ice drift from synthetic aperture radar images in the Arctic Ocean

Speaker: 
Angelina Cassianides
Affiliation: 
IFREMER, Brest
Seminar Date: 
10. March 2020 - 11:15 - 11:45

Interactions between mesoscale eddies and sea ice could potentially represent an important mechanism, via which the ocean contributes to the on-going and future sea ice retreat. In this study, Synthetic Aperture Radar (SAR) images from Sentinel-1 are used to study the potential signature of these eddies on sea ice drift. The first step is to geolocate oceanic eddies observed from Ice Tethered Profiler data and moorings data deployed over the Arctic Ocean.

Evaluation of Radial Ocean Surface Currents Derived from Sentinel-1 IW Doppler Shift Using Coastal Radar and Lagrangian Surface Drifter Observations

Speaker: 
Artem Moiseev (Ocean and Sea Ice Remote Sensing)
Seminar Date: 
3. March 2020 - 11:15 - 11:45

Ocean surface radial velocities (RVLs) derived from the Sentinel-1 A/B Interferomic Wide (IW) mode Doppler frequency shift observations are regularly acquired over the Norwegian coastal zone. This data can be used to complement existing ocean observation systems with high-resolution (up to 1.5x1.5 km) spatial ocean surface current (OSC) maps. In this study, Sentinel-1 IW Level 2 OSC retrievals were obtained from two months (October-November 2017) of raw Doppler shift observations acquired over the Norwegian Coastal Current (NCC).

Student Participation in the Coordinated Arctic Acoustic Thermometry Experiment (CAATEX)

Speaker: 
Bjørnar Hallaråker Røsvik and Henrik Hellem (bachelor students in Polar Acoustics and Oceanography)
Seminar Date: 
14. February 2020 - 13:15 - 13:45

As part of the Ocean Technology program at the University of Bergen (UiB) we, Bjørnar Hallaråker Røsvik and Henrik Hellem, were invited by the NERSC Acoustics Group to participate in the CAATEX cruise. Our roles on board was among other to help facilitate the mooring deployments and assist in optical experiments carried out by doctorate student H. Sandven from UiB. We also participated in reporting sea ice conditions into the Arctic Shipbourne Sea Ice Standardization Tool (ASSIST) software.

Ensemble filtering with displacement errors

Speaker: 
Michael Ying
Affiliation: 
NCAR, Boulder, Colorado
Seminar Date: 
12. February 2020 - 13:00 - 14:00

An outstanding issue for multiscale weather prediction is the choice of data assimilation methods. Since small scale features rapid error growth that gives rise to nonlinearity, data assimilation methods based on linearization, such as the ensemble Kalman filter (EnKF), performs suboptimally. Position error of convective clouds among ensemble members is one of the common causes of nonlinearity and has been a major challenge for data assimilation. Previous studies have made some progress in developing nonlinear optimization methods to reduce position errors.

Introduction of AGCM experiments in Blue-Action project and preliminary results

Speaker: 
Lingling Suo (Climate Dynamics and Prediction)
Seminar Date: 
17. December 2019 - 11:15 - 11:45

Four groups of the AGCM experiments are conducted to isolate the relative role of the Arctic sea ice, PDO and AMO in Arctic warming. One is a historical experiment and the other three adopt the boundary conditions with climatological Arctic sea ice, removal of PDO / AMO signals in SST, respectively.
The preliminary results show that the Arctic sea ice trend contributes to the majority of Arctic near-surface warming while PDO suppresses Arctic tropospheric warming in recent several decades. The contribution of AMO is uncertain.

The Angola-Benguela Upwelling system: interannual and decadal variability (two talks)

Speaker: 
Marie-Lou Bachelery and Folly Serge Tomety
Affiliation: 
University of Cape Town
Seminar Date: 
26. November 2019 - 13:00 - 14:00

Title 1: Impacts and characteristics of the interannual Coastal Trapped Waves in the Angola-Benguela Upwelling System

Marie-Lou Bachelery, Serena Illig, and Mathieu Rouault

Investigating the variability and dynamics of the Beaufort Gyre from satellite observations and a high-resolution model

Speaker: 
Heather Regan (visitor to the Sea Ice Modelling group)
Affiliation: 
LOPS, Ifremer, Brest, France
Seminar Date: 
19. November 2019 - 13:15 - 13:45

Authors: Heather Regan (LOPS, Ifremer, Brest, France), in collaboration with Camille Lique and Claude Talandier (LOPS), Thomas Armitage (JPL) and Gianluca Meneghello (MIT)

Are ice shelf fronts a topographic barrier for barotropic currents?

Speaker: 
Nadine Steiger (Ocean Modeling)
Seminar Date: 
29. October 2019 - 11:15 - 11:45

Ice shelves in West Antarctica are thinning at an increasing rate due to the inflow of relatively warm Circumpolar Deep Water into the ice shelf cavities. This warm water from off the continental shelf flows southward towards the ice shelves through submarine troughs incised into the continental shelf. Observations in front of Getz Ice Shelf suggest that 90% of the volume transport and 65% of the temperature transport is linked to the barotropic component of the southward current which follows f/H-contours.