Previous Seminars

Improving the sea ice thickness of TOPAZ by the merged weekly product from Cryosat2 and SMOS

Speaker: 
Jiping Xie from Ocean Modeling
Seminar Date: 
30. May 2017 - 11:15 - 11:45

A merged measurements of Sea Ice Thickness (SIT) from CryoSat2 and SMOS has been distributed in recent years. This product is weekly during the cold season and available since October 2010. As a potential operational SIT observation in Arctic, the quantitative evaluation of its impact on the performance of TOPAZ, which represents the Arctic component of the Copernicus Marine Environment Monitoring Service (CMEMS), is an essential issue due to the well-known SIT errors in most marine forecast systems.

Assimilation of non-conventional observations. Application to the estimating of ocean surface currents.

Speaker: 
Julien Brajard
Affiliation: 
LOCEAN/IPSL, Sorbonne Université, Paris, France
Seminar Date: 
29. May 2017 - 11:00 - 11:30

Data assimilation consists in optimally combining observations of a system with
outputs of a numerical model. In the traditional approaches, observations are
are considered to be eulerian and scalar. Recently, in the field
of earth and ocean observations, there is an increasing number of observations
that are fundamentally non-eulerian and/or non scalars:
Drifters and floats are advected by currents and bring a Lagrangian observation through their successive positions,
satellite data are measuring images that contains structured patterns.

Data assimilation of sea ice concentration: a twin experiment within the Norwegian Climate Prediction Model

Speaker: 
Madlen Kimmritz from Climate Dynamics and Prediction
Seminar Date: 
16. May 2017 - 11:15 - 11:45

A method capable of constraining the sea ice of a coupled climate system in a dynamically consistent manner would be of crucial societal importance.
It would allow for more accurate and reliable reconstruction of the climate that would improve the understanding of the sensitivity of our climate to anthropogenic forcing and enhance the skill of climate prediction on seasonal-to-decadal time scale.

Urban heat island effect in the Arctic

Speaker: 
Victoria Miles from Climate Processes
Seminar Date: 
2. May 2017 - 11:15 - 11:45

Urbanization in the Arctic and sub-Arctic is an increasingly important anthropogenic influence on climate, and has significantly affected terrestrial ecosystems. One of the most evident effects associated with urbanization is the urban heat island (UHI), when urban and suburban areas are warmer then rural areas. The effect is more pronounced in the high latitudes.

Wave-ice interactions in the neXtSIM sea-ice model

Speaker: 
Timothy Williams
Affiliation: 
NERSC
Seminar Date: 
27. April 2017 - 12:30 - 13:00

We have added a waves-in-ice model (WIM) into the new sea ice model neXtSIM. The physical effects included so far are the effect of the wave radiation stress (WRS) on the ice drift. Specifically, as waves travel into the ice, they are attenuated and lose momentum. This momentum could go into the ocean or the ice (or the atmosphere), but we transfer it entirely to the ice. The WRS, which is the flux of momentum from the waves to the ice, is relatively high at the ice edge but decays exponentially into the ice (like the wave energy).

Decadal Changes in Salinity in the Oceanic Subtropical Gyres

Speaker: 
Subrahmanyam (Subra) Bulusu
Affiliation: 
Satellite Oceanography Laboratory,School of the Earth, Ocean and Environment, University of South Carolina
Seminar Date: 
19. April 2017 - 11:00 - 12:00

There is evidence that the global water cycle has been undergoing an intensification over several decades as a response to increasing atmospheric temperatures, particularly in regions with skewed evaporation – precipitation (E-P) patterns such as the oceanic subtropical gyres. Moreover, observational data (rain gauges, etc.) are quite sparse over such areas due to the inaccessibility of open ocean regions. We analyzed spatial and temporal salinity trends in five subtropical gyre regions over the past six decades using Simple Ocean Data Assimilation (SODA) reanalysis.

Influence of Madagascar Ridge on ocean mesoscale eddies in a regional ocean model

Speaker: 
Issufo Halo
Affiliation: 
1) Department of Conservation and Marine Sciences, Cape Peninsula University of Technology, Cape Town, South Africa, 8000 2) Nansen-Tutu Centre for Marine Environmental Research, Oceanography Department, University of Cape Town, South Africa, 7700
Seminar Date: 
5. April 2017 - 13:00 - 13:30

The topography of the world's ocean basins are among the least studied oceanographic environments. However, they are fundamental for understanding the oceanic circulation. In this study the role of the Madagascar Ridge on modulating the mesoscale circulation, more specifically the eddy field is being investigated using two climatological solutions derived from a regional ocean model, ROMS. In the first experiment the model runs with an ordinary GEBCO-01 topography, whereas in the second, it runs with a modified topography, where the Madagascar Ridge has been removed.

Dynamically constrained uncertainty for the Kalman filter covariance in the presence of model error

Speaker: 
Colin James Grudzien
Affiliation: 
NERSC
Seminar Date: 
4. April 2017 - 11:15 - 11:45

The forecasting community has long understood the impact of dynamic instability on the uncertainty of predictions in physical systems and this has led to innovative filtering design to take advantage of the knowledge of process models. The advantages of this combined approach to filtering, including both a dynamic and statistical understanding, have included dimensional reductions and robust feature selection in the observational design of filters.

Observability of long term Kuroshio variability through four dimensional ocean data assimilation

Speaker: 
Tsuyoshi Wakamatsu
Affiliation: 
JAMSTEC
Seminar Date: 
9. March 2017 - 14:15 - 15:00

Eddy resolved (1/10 degree), long term (1982-current) ocean reanalysis data, FORA-WNP30, covering the Western North Pacific Ocean (117E-160W, 15N-65N) is newly produced using cycled 4DVar data assimilation system with quasi 10 day assimilation period. The reanalysis project was led by joint research group of Japan Agency for Marine-Earth Science and Technology (JAMSTEC) and Meteorological Research Institute (MRI), Japan.

Dynamical systems and transport processes in the ocean: an application to a marine oil spill.

Speaker: 
Ana Mancho
Affiliation: 
ICMAT, Consejo Superior de Investigaciones Científicas, Mardid, Spain.
Seminar Date: 
7. March 2017 - 11:15 - 12:00

The goal of this presentation is to provide evidence on how tools from
dynamical systems theory may help to understand transport processes in the ocean surface.
The role of these techniques will be illustrated through the description of a recent marine oil-spill,
produced after the sinking of the Oleg Naydenov fishing ship, in Spain, close to the
Canary Islands, in April 2015.