Previous Seminars

An Empirical Model for Mode-1 Internal Tides Derived from Satellite Altimetry: Computing Accurate Tidal Predictions at Arbitrary Points Over the World Oceans

Speaker: 
Brian Dushaw
Affiliation: 
NERSC and the Applied Physics Laboratory, University of Washington, Seattle
Seminar Date: 
31. March 2016 - 12:30 - 13:30

A global estimate for harmonic constants of mode-1 internal tides is described, enabling accurate predictions of internal tide amplitude and phase in most regions of the world's oceans. The estimates are derived from TOPEX/POSEIDON altimetry, building on a frequency-wavenumber tidal analysis technique described by Dushaw et al. (2011) [B. D. Dushaw, P. F. Worcester, and M. A. Dzieciuch, 2011. On the predictability of mode-1 internal tides, Deep-Sea Res. 58, 677-i698].

The Brazilian Oceanographic Modeling and Observation Network (REMO): Status and Plans

Speaker: 
Prof. Clemente A. S. Tanajura
Affiliation: 
Instituto de Física, Universidade Federal da Bahia (UFBA), Brasil
Seminar Date: 
30. March 2016 - 12:00 - 12:45

This talk will present a general view of the Brazillian REMO group in physical oceanography and operational oceangraphy in the South Atlantic. It will focus on the REMO ocean data assimilation system (RODAS) based on the Ensemble Optimal Interpolation method and the work by researchers from NERSC and the Institute of Atmospheric Physics (IAP/CAS). Some preliminary results will be also presented in an attempt to improve the current system.

The GAIA-CLIM project: Characterizing satellite measurements using in-situ, ground-based and sub-orbital capabilies

Speaker: 
Anna Christina Mikalsen
Seminar Date: 
30. March 2016 - 11:00 - 11:30

This presentation will provide an overview on the H2020 project "Gap Analysis for Integrated Atmospheric ECV CLimate Monitoring (GAIA-CLIM)".

The GAIA-CLIM project aims to improve our ability to use (ground-based and sub-orbital) non-satellite observations to characterise satellite observations for a number of atmospheric Essential Climate Variables (ECVs). The key outcomes will be a “Virtual Observatory” facility of co-locations and their uncertainties and a report on gaps in capabilities or understanding, which shall be used to inform subsequent Horizon 2020 activities.

The Wind-Driven Ocean Circulation: Bifurcations, Simulations and Observations

Speaker: 
Michael Ghil
Affiliation: 
Ecole Normale Supérieure, Paris, and University of California, Los Angeles
Seminar Date: 
18. March 2016 - 14:00 - 15:00

The large-scale, near-surface flow of the mid-latitude oceans is dominated by the presence of a larger, anticyclonic and a smaller, cyclonic gyre. The two gyres share the eastward extension of western boundary currents, such as the Gulf Stream or Kuroshio, and are induced by the shear in the winds that cross the respective ocean basins. The boundary currents and eastward jets carry substantial amounts of heat and momentum; the jets also contribute to mixing in the oceans by their "whiplashing" oscillations and the detachment of eddies from them.

PhD defence: ensemble data assimilation

Speaker: 
Patrick Nima Raanes
Affiliation: 
NERSC and Oxford maths
Seminar Date: 
16. March 2016 - 13:00 - 14:00

1. Intro to data assimilation
2. Intro to the ensemble Kalman filter (EnKF)
3. The 'square root' method in the EnKF
4. Adaptive inflation in the EnKF
5. The equivalence of two ensemble smoothers

This is a dry run before the actual defence. There will be no celebrating. Bring questions.

Does the variation in strength and position of the Agulhas Current induce sea level variation?

Speaker: 
Bernardino Nhantumbo
Affiliation: 
PhD candidate at UCT, Department of Oceanography
Seminar Date: 
14. March 2016 - 13:15 - 14:00

Research on sea level variability has been carried out worldwide from tide gauge records in order to ascertain the current rates of sea level rise (SLR). These rates of change vary from place to place due to several different local phenomena. A first goal of our study is to determine the SL trend at specific tide gauge locations along the south and east coast of southern Africa, and to determine the important forcing mechanisms behind the changes.

All Quiet on the Arctic Front?

Speaker: 
Jenny Ullgren
Seminar Date: 
3. March 2016 - 11:30 - 12:00

In the Fram Strait, the Atlantic gateway to the Arctic Ocean, an oceanic front marks the boundary between the warm, saline Atlantic Water transported northward by the West Spitsbergen Current and the colder, fresher waters further east. The front is important both because of the heat and freshwater exchanges across it and because it affects the conditions for marine life. The research ship Håkon Mosby crossed this front from the north-west to the south-east in September 2011.

Changes in the Arctic cloudiness

Speaker: 
Dr. Alexander Chernokulsky
Affiliation: 
Institute for Atmospheric Physics, Moscow
Seminar Date: 
1. March 2016 - 14:00 - 14:45

Part of the special event group day of the GC Rieber Climate Institute and “Climate Processes” Group at NERSC.