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Jürgen Kurths

Renowned German mathematical physicist Jürgen Kurths is the current Sydney Chapman Endowed Chair of Physical Sciences. He developed this schedule with an eye to interdisciplinary research and hopes that mathematicians, biologists, climate scientists, geoscientists, and scientists from many other disciplines will attend. The seminars are open to all levels from undergraduates to faculty.

Extreme Events from Climate to Power Grids

These seminars will bring in some of the field’s leading researchers to talk about extreme events in the complex systems of ecosystems, climate and power grids.

Many complex systems have extreme events as one of their characteristics. What the extreme event is depends on the system. Climate has large storms or very large floods as extreme events. Power grids have large blackouts. Ecosystems have large die offs or population explosions.

Theme: Climate

Power transmission grid as a complex system

Complex systems span the range from solid state systems through human social systems to engineered systems. Modern societies depend crucially on a web of engineered complex critical infrastructures such as power transmission networks, communication systems, transportation networks in addition to many others.  These infrastructure systems display a number of the characteristic properties of complex systems. Important among these characteristics, they exhibit infrequent large cascading failures that often obey a power law distribution in their probability versus size and long time correlations (memory). This power law behavior and memory effect suggests that conventional risk analysis does not apply to these systems.

In this talk, infrastructure systems as complex dynamical systems will be introduced and some of their properties explored. Much of the talk will then be focused on the characteristics and scalings of such systems using the electric power transmission grid as the exemplar, though many of the results can be easily applied to other infrastructures (and other general complex systems). General properties of the grid will be discussed and results from a dynamical complex systems power transmission model will be compared with real world data. Then we will look at a variety of uses for and results from this type of model. As examples, we will discuss the impact of size and network homogeneity on the grid robustness, the change in risk of failure as generation mix (more distributed vs centralized for example) changes, as well as the effect of operational changes such as the changing the operational risk aversion or grid upgrade strategies. Among the important counter intuitive outcomes from this work is the realization that “improvements” in the system components and operational efficiency do not always improve the system robustness, while another is there may be an optimal size for systems.

3:15 pm | Elvey Aud., Elvey Bldg.
David Newman
Physics Professor at UAF

David Newman received an undergraduate degree in physics and math in 1983. He married his wife, Uma Bhatt, (who is now chair of UAF’s Dept. of Atmospheric Sciences). After they married, they then served in the U.S. Peace Corps (the toughest honeymoon you’ll ever love), teaching in a rural secondary school in Kenya from 1983 to 1985. He graduated with a Ph.D. in physics from the University of Wisconsin Madison in 1993. He became a Wigner Fellow and then staff scientist at Oak Ridge National Lab in the Fusion Energy Division from 1993 to 1998. During this time, he received the 1997 residential Early Career Award for Scientists and Engineers. Newman joined the University of Alaska Fairbanks physics faculty in 1998 and is now a professor and the Director of the Center for Complex Systems Studies. His current research explores complex systems ranging from turbulence in fusion plasmas to power transmission grids and general infrastructure systems. He and Uma have a 13-year-old son named Tilahun.

Power systems integration for high penetration renewables

Description coming soon

4:15 pm | Elvey Aud., Elvey Bldg.
Marc Mueller-Stoffels, Program Director, H&D, Power Systems Integration, AK Center for Energy and Power

Theme: Power Grids

Methods for Evaluating Dynamic Stability in Power Grids

In Power Grids, strong, nonlocal Perturbations may lead to non-trivial transient phenomena where the nonlinear effects have to be considered. Basin Stabilty demonstrates how sampling-based metrics can be used to account for such effects. Extension have been developed: Survivability considering boundaries in the phase space that should not be transgressed, and Timing of Transient including the time information to approach the attractor.

3:15 pm | Globe Room, Elvey Bldg.

Tim Kittel is a PhD candidate in Physics within the DFG funded IRTG 1740 “Dynamical Phenomena in Complex Networks: Fundamentals and Applications” in the research group of Prof. Kurths at the Potsdam Institute for Climate Impact Research and at Humboldt University Berlin.

His focus is developing mathematical tools to analyze the transient phase within complex, dynamical systems. Strong perturbations or imminent transitions, e.g. in Power Grids, Energy Transition, Sustainability Science, demand a better understanding of a trajectory’s transient and his tools are designed to evaluate them from a quantitative and qualitative point of view.

Resilience and Robustness of Power Grids with High Shares of Renewables

In the face of climate change related extreme weather events makes the resilience of power grid infrastructure one of the key challenges for grid operators worldwide. At PIK we developed stability methods to evaluate a system’s reaction towards large local perturbations and found empiric evidence of the relationship between structural and dynamic properties.

Next to the grid’s resilience towards large perturbations the increasing share of renewable energy sources (RES) asks for a better understanding of its robustness being subject to stochastic power infeed. Ireland restricts its renewable power penetration to 55% fearing serious dynamic stability issues related to the rate of change of frequency. The new power grid dynamics introduced by RES are manifold. The power production by RES is intermittent and thus fluctuating on time scales from seconds to hours. Also, the nature of generation changes from physical machines to power electronic systems that show delays caused by measurement times and interact with each other in an often unknown manner.

We investigate the topology influence on stochastic stability measures for single-node intermittent power infeed from Renewables Energy Sources in lossy microgrids and Mid-Voltage (MV) grids.  In order to balance frequency fluctuations we suggest an Electric Vehicle (EV) control scheme that effectively ensures grid stability and safe battery operation at the same time.

4:15 pm | Globe Room, Elvey Bldg.

Sabine Auer is a PhD candidate in Physics within the BMBF funded Condynet (Collective Nonlinear Dynamics of complex Networks) Project in the research group of Prof. Kurths at the Potsdam Institute for Climate Impact Research and at Humboldt University Berlin. Prior, she studied physics at TU Ilmenau, TU Berlin and worked for Siemens AG, Yale University in New Haven and the Institute of Photonic Sciences (ICFO) In Barcelona as a working student or intern.

In a broader sense in her dissertation, Sabine is interested in modeling future power system dynamics. Her personal focus is the investigation of the novel dynamics intermittent power fluctuations induce into distribution grids. Besides, she is also interested in concepts of decentral control for grid stabilization, e.g. with electric vehicles, and in power market modeling.

Theme: Climate

Critical phenomena and downscaling criticality in tipping elements in the Earth system

Tipping elements (TE) are large-scale components of the Earth System. A rapid and often irreversible qualitative change its state might have dramatic consequences on the system as a whole. Despite recent advances in developing the early warning indicators, which show that transition is coming, they are unable to predict when it will happen in advance. Hence, predicting the future abrupt transitions remains an outstanding scientific challenge.

In our study, we make a step forward in this direction by proposing a new method of downscaling criticality.  In particular, it allows identifying local-scale TEs in the large-scale tipping element. We use the critical phenomena as precursors of impending transition. In contrast to traditional approaches, which use precursors for prediction of the time of the critical transition (which in fact work retrospectively only), we discovered how to use precursors in a new way – to find regions where the critical conditions for a transition originate. We use the phenomenon of critical growth of fluctuations to detect such regions. Then we reveal a teleconnection between the TEs that allows as predicting the timing of the upcoming critical transition.

We show that the downscaling criticality might lead to improving predictability of impending abrupt transitions. The proposed approach is applicable for systems of different nature, thereby offers a general framework for predicting critical transitions in spatial-temporal systems.

4 PM | Elvey Aud., Elvey Bldg.
Elena Surovyatkina, Academy of Sciences, Moscow, Russia

Elena Surovyatkina is a visiting Professor at the Potsdam Institute for Climate Impact Research, Germany, and a Leading Researcher at Space Research Institute of Russian Academy of Sciences, Moscow, Russia. Her research connects theoretical insights of bifurcations to puzzles in our current understanding of the properties of spatially organized critical transitions in climate.

Theme: Ecosystems

Synchronized life-cycles - an underestimated a driver of ecological oscillations

Synchronization is a fundamental process in coupled dynamical systems, with applications in many natural and biological systems – it has however rarely been applied to capture the collective dynamics of interacting life cycles of organisms. Here we develop a framework to describe phase synchronization in an ensemble of oscillators with non-conserved number of particles. Our novel approach can readily by applied to capture entrained life cycles, giving rise to oscillatory dynamics even in unstructured populations.

We demonstrate our approach in in two case studies. First, we study synchronization-driven cycles in single-species phytoplankton
populations. Thereby, algae cells become synchronized by interacting via a common nutrient pool, causing periodic modulation in the size spectra and oscillations at the population level, in accord to experimental observations.

In our second application we model the 5-6 year population cycle of Antarctic krill (Euphausia superba), possibly the world largest population cycle in absolute biomass. Previous studies have postulated that the krill cycle is induced by periodic climatological factors, but these postulated drivers neither show consistent agreement, nor are they supported by quantitative models. Here, using data analysis complemented with modeling of krill ontogeny and population dynamics, we identify synchronization of the krill life cycle in the extreme seasonality of the Antarctic environment as the main driver of the krill cycle, with many consequences for the entire Southern Ocean ecosystem.

3:15 pm | Elvey Aud., Elvey Bldg.
Bernd Blasius, University of Oldenburg, Germany

Physicist Bernd Blasius, professor for mathematical modeling, has been teaching and researching at the Institute for Chemistry and Biology of the Marine Environment (ICBM) at the University of Oldenburg since 2007. He is also the Vice director of the ICBM and a founding member of the new Helmholtz Institute for Functional Marine Biodiversity in Oldenburg. He studied physics at Darmstadt Technical University, where he was awarded his doctorate in 1997. Following this, he worked for three years at Tel Aviv University before returning to Germany 2001 as a junior group leader at the University of Potsdam, where in 2004 he took up an appointment as junior professor at the Institute for Physics. Blasius is an expert in the modeling of complex natural systems at the interface between physics, biology and theoretical ecology. His research covers a large range of scientific areas, ranging from bioinvasions, global transport routes, to complex
networks and theory of biodiversity.

4:15 pm | Elvey Aud., Elvey Bldg.
TBA Biologist

Theme: Extreme Power Grids

Tipping Elements Approach for Long-Term Seasonal Prediction: Observational Evidence

Seasonal variability implies two aspects: first, the seasons do not begin at fixed dates but must be determined by observation and are known only after the fact; and second, a new season begins at different dates in different parts of the country and over the world. Seasonal variability strongly affects different aspects of human life such as agricultural productivity and food security, economic growth and political stability. Numerical Weather Prediction has a limit to forecast the weather for up to approximately 10 days in the future. Other long-term prediction numerical models provide the statistical summary only such as whether the temperature averaged over the next summer will be warmer or colder than average over some number of years before. Hence, the seasonal prediction is a considerable scientific challenge with great importance for society.

In our study of the Indian monsoon season, we have found the evidence in observational data that we can consider the onset of monsoon as a critical transition – a sudden transition to the monsoon when critical thresholds (in particular, in near-surface air temperature, relative humidity) are reached. This finding allows us using the critical transition theory for developing the Tipping elements approach for prediction of onset and withdrawal dates of the summer monsoon.

Our prediction relies on observations of near-surface air temperature and relative humidity from both the ERA-40 and NCEP/NCAR reanalyzes. Our results show that our method allows predicting the monsoon not only retrospectively (over the period 1951-2015) but also in the future. In 2016 we successfully predicted of the onset and withdrawal dates of the Southwest monsoon over the central part of India for 40 and 70 days in advance respectively. In 2017 our prediction the onset date was successful as well. Currently, we are waiting for confirmation of our prediction of withdrawal between 7th and 17th October 2017. Hence, in 2016 and 2017 we proved that such early prediction of season timing is possible.

Proposed approach is applicable for different kind of season, which exhibits properties of critical transition. Our prediction is based on observational data only when the model cannot accurately anticipate the transition or does not exist yet.

 

[1] Stolbova, V., E. Surovyatkina, B. Bookhagen, and J. Kurths (2016): Tipping elements of the Indian monsoon: Prediction of onset and withdrawal. GRL 43, 1–9 [doi:10.1002/2016GL068392]
[2] https://www.pik-potsdam.de/services/infodesk/forecasting-indian-monsoon

3:15 pm | Elvey Aud., Elvey Bldg.
Elena Surovyatkina, Academy of Sciences, Moscow, Russia

Elena Surovyatkina is a visiting Professor at the Potsdam Institute for Climate Impact Research, Germany, and a Leading Researcher at Space Research Institute of Russian Academy of Sciences, Moscow, Russia. Her research connects theoretical insights of bifurcations to puzzles in our current understanding of the properties of spatially organized critical transitions in climate.

Rapid “Atlantification” of the eastern Arctic Ocean

In the last decade, sea-ice cover in the Arctic Ocean has experienced dramatic changes. The most pronounced sea-ice loss during the two record breaking years of 2007 and 2012 occurred in the Canadian Basin; however, during the two most recent years of 2014 and 2015, sea-ice decline in the eastern Eurasian Basin (EEB) was also impressive, and at least comparable to or even exceeding that of the western Arctic. 2013–2015 observations using moorings and drifting Ice-Tethered Buoys (ITP) provided strong evidence that the EEB is in transition to the conditions previously uniquely identified in the western Nansen Basin. For example, shoaling of the intermediate-depth (~150-900 m) Atlantic Water layer and weakening of stratification in the halocline in the EEB in recent years has provided means for unprecedented winter ventilation of the ocean interior, making this region similar to the western Eurasian Basin. An associated enhanced release of oceanic heat has reduced winter sea-ice formation at a rate comparable to sea-ice loss due to local atmospheric thermodynamic forcing, explaining the observed recent reduction in sea-ice cover in the eastern Arctic. This “atlantification” of the eastern Arctic Ocean represents an essential step toward a new Arctic climate state.

In our study of the Indian monsoon season, we have found the evidence in observational data that we can consider the onset of monsoon as a critical transition – a sudden transition to the monsoon when critical thresholds (in particular, in near-surface air temperature, relative humidity) are reached. This finding allows us using the critical transition theory for developing the Tipping elements approach for prediction of onset and withdrawal dates of the summer monsoon.

Our prediction relies on observations of near-surface air temperature and relative humidity from both the ERA-40 and NCEP/NCAR reanalyzes. Our results show that our method allows predicting the monsoon not only retrospectively (over the period 1951-2015) but also in the future. In 2016 we successfully predicted of the onset and withdrawal dates of the Southwest monsoon over the central part of India for 40 and 70 days in advance respectively. In 2017 our prediction the onset date was successful as well. Currently, we are waiting for confirmation of our prediction of withdrawal between 7th and 17th October 2017. Hence, in 2016 and 2017 we proved that such early prediction of season timing is possible.

Proposed approach is applicable for different kind of season, which exhibits properties of critical transition. Our prediction is based on observational data only when the model cannot accurately anticipate the transition or does not exist yet.

 

[1] Stolbova, V., E. Surovyatkina, B. Bookhagen, and J. Kurths (2016): Tipping elements of the Indian monsoon: Prediction of onset and withdrawal. GRL 43, 1–9 [doi:10.1002/2016GL068392]
[2] https://www.pik-potsdam.de/services/infodesk/forecasting-indian-monsoon

4:15 pm | Elvey Aud., Elvey Bldg.
Rapid “Atlantification” of the eastern Arctic Ocean
Igor Polyakov, IARC/CNSM

Igor Polyakov is a Professor with the International Arctic Research Center and Atmospheric Sciences Dept/College of Natural Sciences and Mathematics, University of Alaska Fairbanks. His primary research areas are:

  • Role of ocean in shaping Arctic sea ice changes
  • Mechanisms of heat delivery from the ocean interior to the upper ocean and sea ice
  • Modes of upper ocean and sea ice variability in the Arctic
  • Role of fresh water in changing Arctic climate
  • Polar amplification of global warming
  • Multi-decadal climate variability in the Arctic and North Atlantic

Theme: Ecosystems

Marine bioinvasion in the network of global shipping connections

Transportation networks play a crucial role in human mobility, the exchange of goods, and the spread of invasive species. With 90% of world trade carried by sea, global shipping provides one of the most important modes of transportation. Shipping also constitutes the world largest transportation vector for marine bioinvasion, transferring accidentally numerous species around the world.
Here, we use information about the itineraries of 16,363 cargo ships during the year 2007 to construct a network of shipping connections between ports.  We perform a statistical analysis of the network topology and reveal marked differences to standard gravity models. Coupling the shipping network with port environmental conditions and biogeography, we develop a model for marine bioinvasion by world-wide ballast water exchange. The model allows to identify high risk invasion routes, hot spots of bioinvasion, and major source regions from which bioinvasion is likely to occur, and it can be used to classify coastal ecoregions with respect to total invasion risk and risk composition from other regions. Our model predictions agree with observations in the field and reveal a pattern of maximal invasion risk at intermediate geographic distances. We apply the model to investigate strategies for risk reduction by ballast water treatment. Finally, we project changes in worldwide shipping intensity due to the predicted opening of Arctic sea passages.

4 pm | Elvey Aud., Elvey Bldg. 
Bernd Blasius, University of Oldenburg, Germany

Physicist Bernd Blasius, professor for mathematical modeling, has been teaching and researching at the Institute for Chemistry and Biology of the Marine Environment (ICBM) at the University of Oldenburg since 2007. He is also the Vice director of the ICBM and a founding member of the new Helmholtz Institute for Functional Marine Biodiversity in Oldenburg. He studied physics at Darmstadt Technical University, where he was awarded his doctorate in 1997. Following this, he worked for three years at Tel Aviv University before returning to Germany 2001 as a junior group leader at the University of Potsdam, where in 2004 he took up an appointment as junior professor at the Institute for Physics. Blasius is an expert in the modeling of complex natural systems at the interface between physics, biology and theoretical ecology. His research covers a large range of scientific areas, ranging from bioinvasions, global transport routes, to complex
networks and theory of biodiversity.

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