Previous Seminars

Lagrangian ocean analysis to study the physical mechanisms driving the processes occurring in the Greater Agulhas Current System

Speaker: 
Michael Hart-Davis
Seminar Date: 
13. August 2019 - 11:15 - 11:45

Lagrangian ocean analysis is a powerful way to study ocean processes from in-situ observations and numerical model simulations. As numerical modelling capabilities develop and physical mechanisms of the ocean are better understood, the importance of particle trajectory modelling continues to increase. Therefore, developing cross-disciplinary particle trajectory model applications for the Greater Agulhas System is highly relevant due to its potential contribution to scientific studies and operational applications.

Cloud Computing Needs for Earth Observation Data Analysis: EGI and the European Open Science Cloud

Speaker: 
Bjørn Backeberg
Affiliation: 
Björn Backeberg (1), Yin Chen (1), *Tiziana Ferrari (1), Pedro Gonçalves (4), Paolo Mazzetti (3), Anabela Oliveira (2), Diego Scardaci (1), Gergely Sipos (1) 1. EGI Foundation, 2. LNEC, 3. CNR, 4. Terradue
Seminar Date: 
27. June 2019 - 11:15 - 12:00

Over recent years, the vision of Open Science has emerged as a new paradigm of transparent, data-driven science capable of accelerating competitiveness and innovation. The embodiment of this vision in Europe is the European Open Science Cloud (EOSC), first proposed by the European Commission in April 2016 as part of the Communication on the ‘European Cloud Initiative’, one of the pillars of the Digital Single Market Strategy.

Data assimilation using adaptive, non-conservative, moving mesh models

Speaker: 
Ali Aydoğdu (Data Assimilation)
Seminar Date: 
25. June 2019 - 11:15 - 11:45

Numerical models solved on adaptive moving meshes have become increasingly prevalent in recent years. Motivating problems include the study of fluids in a Lagrangian frame and the presence of highly localized structures such as shock waves or interfaces. In the former case, Lagrangian solvers move the nodes of the mesh with the dynamical flow; in the latter, mesh resolution is increased in the proximity of the localized structure. Mesh adaptation can include remeshing, a procedure that adds or removes mesh nodes according to specific rules reflecting constraints in the numerical solver.

Explore dynamical information with Pseudo-orbit Data Assimilation

Speaker: 
HAILIANG DU
Affiliation: 
Durham University
Seminar Date: 
13. June 2019 - 11:00 - 12:00

Physical processes such as the weather are usually modeled using nonlinear dynamical systems. Traditional statistical approaches are found to be difficult to draw dynamical information from the nonlinear dynamics. This talk is focusing on exploring dynamical information with Pseduo-orbit data assimilation to address various problems encountered in analyzing and modeling nonlinear dynamical systems. The talk will start with solving an “impossible” challenge pointed out by Berliner (1991) when applying the Bayesian paradigm to state estimation in chaotic systems.

High-resolution assessments at NERSC – overview and current developments in ReSIS

Speaker: 
Tobias Wolf (Climate Dynamics and Prediction)
Seminar Date: 
21. May 2019 - 11:15 - 11:45

In the first part of this presentation I will give an overview over the high-resolution studies and capabilities, the Climate Prediction and Dynamics Group has been working with so far. This part will highlight results from projects during the last years. Among these are the successful studies for the Bergen harbour authority, the TRAKT-2018 project and the study on the mitigation of domestic-wood-heating related pollution.

Is it really getting younger? Sea ice type and age in model simulations and satellite remote sensing products

Speaker: 
Polona Itkin (Sea Ice Modelling)
Seminar Date: 
16. April 2019 - 11:15 - 11:45

Sea ice type and age are one of the basic indicators of Arctic sea ice state. For a sea ice model to simulate sea ice type or age faithfully, both sea ice dynamics and thermodynamics need to be represented well. In contrast to sea ice thickness, ice age and type have been able to be retrieved from satellite observations relatively reliably for more than a decade. In this study we are using neXtSIM – ‘next generation sea ice model’ that uses Maxwell-elasto-brittle rheology to simulate sea ice motion and a thermodynamical model that accounts for healing of damaged ice through freezing.

The challenge of bounded, non-Gaussian, non-linear and multi-scale variables

Speaker: 
Craig Bishop
Affiliation: 
School of Earth Sciences and ARC Centre of Excellence for Climate Extremes University of Melbourne
Seminar Date: 
8. April 2019 - 11:00 - 12:00

Current state estimation or data assimilation techniques assume Gaussian uncertainties for both forecasts and observations. However, unbiased observations of bounded variables can be shown to have highly non-Gaussian uncertainties and observation error standard deviations that depend on the value of the unknown true state. In particular, the observation error variance of such observations must tend to zero as the unknown true state tends to zero.

Using climate reanalysis products to identify ecological memory patterns in drylands

Speaker: 
Erik Kusch
Seminar Date: 
29. March 2019 - 12:30 - 13:00

Repeated climate stress events may cause fundamental shifts in species compositions or ecosystem functioning. However, few studies document such shifts. One reason for higher stability of ecosystems than previously expected may be ecological stress memory of vegetation. The study of memory effects of large-scale vegetation may therefore aid in predictions of future changes in biome distributions and resilience assessments on ecosystem or even species level. Such information is invaluable for management oriented decision support systems.

Korea Satellite Remote Sensing of the Arctic

Speaker: 
Hyun-Cheol Kim
Affiliation: 
Korea Polar Research Institute (KOPRI)
Seminar Date: 
28. March 2019 - 15:00 - 15:30

Dr. Hyun-Cheol Kim is the director of Unit of Arctic Sea-Ice Prediction, Korea Polar Research Institute (KOPRI).
As a remote sensing scientist, he will give us a talk regarding the research activities of KOPRI.
After the seminar, NERSC and KOPRI will sign a MoU.

Sea Ice Parameter Retrieval with Physical Synergy of Active and Passive Satellite Data

Speaker: 
Dr. Shiming Xu
Affiliation: 
Department of Earth System Science, Tsinghua University, China
Seminar Date: 
27. March 2019 - 13:00 - 13:45

Sea ice is a key component in the global climate system. Satellite remote sensing is the major approach to the basin-scale observation of sea ice, informing the community of key findings including accelerated shrinkage and drastic thinning of the sea ice cover. As the major method for the estimation of sea ice thickness, satellite altimetry is hindered by the snow cover over the sea ice, which introduces large uncertainty to the sea ice thickness retrieval. Meanwhile, the snow over is a direct indicator of polar hydrological cycle, and a key modulating factor of air-ice-sea interaction.