Previous Seminars

Validation and Environmental Application of Ocean General Circulation Model

Speaker: 
Yonqi gao
Seminar Date: 
14. February 2013 - 12:30 - 13:00

Bjerknes Compensation in the Bergen Climate Model

Speaker: 
Stephen Outten
Seminar Date: 
7. February 2013 - 12:30 - 13:00

The meridional transport of heat, through both the ocean and atmosphere, is a basic component for maintaining Earth’s climate. Understanding the decadal to multi-decadal changes of these transports provides an insight into the natural variability of the climate system. In 1964, Jacob Bjerknes proposed that large anomalies in the oceanic heat transport should be balanced by opposing variations in the atmospheric heat transport; a process later named Bjerknes Compensation.

Acoustic Communication and Navigation for Gliders and Drifters in the Marginal Ice Zone

Speaker: 
Lee Freitag
Affiliation: 
Woods Hole Oceanographic Institution
Seminar Date: 
21. January 2013 - 11:15 - 12:00

Abstract – Navigation of gliders operating under Arctic ice is important for geo-referencing subsea data with that collected by above-ice sensors. However, bottom-mounted navigation beacons cannot be used to support ice-based experiments because the sensors field will move with the natural drift of the ice. Navigation signals transmitted by sources suspended from the ice solves the movement problem, but creates another: the sources must broadcast their locations so that a real-time position can be calculated by the receivers.

Retrieval of Arctic Sea Ice Parameters by Satellite Passive Microwave Sensors: A Comparison of Different Sea Ice Algorithms

Speaker: 
Natalia Ivanova
Seminar Date: 
17. January 2013 - 12:30 - 13:15

Eleven different passive microwave sea ice algorithms were implemented and inter-compared. The algorithms computing the sea ice concentration are using the same input of SMMR (1978-1987) and SSM/I (1987- ) daily brightness temperatures for the period 1979 – 2010 for low-frequency algorithms and 1992 – 2010 for high-frequency algorithms. Daily, monthly and yearly Arctic sea ice concentration, area and extent were calculated by the algorithms. The differences between the eleven sea ice concentration estimates sometimes called structural uncertainties were analyzed spatially and seasonally.

Planetary boundary layer in the Earth's climate system

Speaker: 
Igor Esau
Affiliation: 
GC Rieber
Seminar Date: 
10. January 2013 - 12:15 - 13:15

The discussion will address the effects caused by the vertical turbulent mixing in the stratified atmosphere on climatologically significant time scales. It will be demonstrated that the planetary boundary layer (PBL) is an important amplifier of natural and anthropogenic disturbances of the equilibrium climate. Since this amplifier is asymmetric with respect to external heating/cooling forcing, it produce significant statistical effect on the climate variability and trends.

Arctic Oscillation and Precipiation over the North Pacific

Speaker: 
Miao HU
Affiliation: 
Beijing Normal University
Seminar Date: 
6. December 2012 - 12:30 - 13:00

The relationships between the winter (January-March) Arctic Oscillation and precipitation over the tropical Northern Pacific during the period of 1979 to 2011 is presented based on the monthly GPCP (Global Precipitation Climatology Project) data and NCEP/NCAR Reanalysis, after subtracting ENSO signals from all datasets. The sliding correlation analysis demonstrates there is a prominent weakening in the AO-precipitation relation around the year 1990.

Greenland ice sheet elevation changes from satellite altrimetry

Speaker: 
Kirill Khvorostosky
Affiliation: 
NERSC
Seminar Date: 
22. November 2012 - 12:30 - 13:00

A change in surface elevation is an important characteristic of the ice sheet behavior, which is used in mass balance studies. Analysis of the Greenland ice sheet (GrIS) elevation time series (1992-2010) derived from ERS-1, ERS-2 and Envisat satellite radar altimeter measurements will be presented. Problems of the ice-sheet elevation change estimation from satellite radar altimetry will be discussed.

Changes in ice thickness, ice freeboard and snow depth from measurements at North Pole drifting stations.

Speaker: 
Vitaly Alexandrov
Affiliation: 
NIERSC
Seminar Date: 
29. October 2012 - 12:30 - 13:00

Estimating the change in global sea levels: Bayesian methods in inverse problems

Speaker: 
Patrick Raanes
Affiliation: 
Oxford University, UK
Seminar Date: 
22. October 2012 - 11:15 - 11:45

Patrick Raanes is applying for the PhD position in data assimilation and oil reservoir. He will present his 1st year PhD and his summer internship:

"Estimating the change in global sea levels:
Bayesian methods in inverse problems"
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Abstract:

A Realtime Monitoring and Dynamical Forecasting System for Floods and Landslides in China

Speaker: 
Jun Wang
Affiliation: 
Nansen-Zhu International Research Center
Seminar Date: 
11. October 2012 - 12:15 - 12:45