Greenland Ice Sheet mass balance and climate interactions

Speaker: 
Prof. Edward Hanna

Affiliation: 
School of Geography and Lincoln Centre for Water and Planetary Health, College of Science, University of Lincoln, UK

Seminar Date: 
30. August 2018 - 11:15 - 12:00

The rate of mass loss from the Greenland Ice Sheet (GrIS) has tripled over the last 20 years, reflecting strong climate warming over the region. Here I will present a review of some of the Greenland mass-balance evaluations that I have been involved with over the last 15 years. We will also review other recent estimates of GrIS mass change, including some very recent observational updates from satellite data, noting the impacts on global sea-level rise.

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Arctic Amplification and mid-latitude extreme weather

Speaker: 
Prof. Edward Hanna

Affiliation: 
School of Geography and Lincoln Centre for Water and Planetary Health, College of Science, University of Lincoln, UK

Seminar Date: 
29. August 2018 - 11:15 - 12:00

Recently there has been a significant increase in some types of extreme weather over the UK and other northern mid-latitudes: for example winters 2013/14 & 2015/16 in the UK were exceptionally mild, wet and stormy, while large parts of winters 2009/10 and 2010-11 were unusually cold and had record deep snows. Snowmageddon hit the eastern seaboard of the USA in the last few winters. Meanwhile several recent summers, most notably 2007 and 2012, experienced record UK rainfall and widespread flooding.

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Creating a Madden-Julian oscillation (MJO) without convection

Speaker: 
Dr Jun-Ichi Yano

Affiliation: 
Meteo France

Seminar Date: 
12. July 2018 - 12:15 - 13:00

The Madden--Julian oscillation (MJO), a planetary--scale eastward propagating coherent structure with periods of 30--60 days, is a prominent manifestation of intraseasonal variability in the tropical atmosphere.
It is widely presumed that small--scale moist cumulus convection is a critical part of its dynamics.
However, the recent results from high--resolution modeling as well as data analysis suggest that the MJO may be understood by dry dynamics to a leading--order approximation.

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Introductory Course On Statistical Modeling Of Extreme Values

Speaker: 
Hans Wackernagel

Affiliation: 
Equipe de GEOSTATISTIQUE - MINES ParisTech - PSL

Seminar Date: 
31. May 2018 - 10:15 - 1. June 2018 - 15:00

Extreme value theory is based on different principles than those
of conventional statistics as it is designed to study and model
exceptional events rather than the average characteristics of
natural phenomena.

This two-day introductory course will start by presenting
exploratory tools to analyze the behavior of extreme values in
geophysical data. This will help to motivate the basic principles
of the statistical modeling of extreme values and the
distributions that characterize them. The two common approaches
for assessing the risk of extreme events at a given level, i.e.

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Impact of Winter Storms in a Thinner Arctic Sea-ice Regime

Speaker: 
Polona Itkin

Affiliation: 
Norwegian Polar Institute

Seminar Date: 
5. June 2018 - 10:00 - 11:00

The integrative effects of increased winter storm activity in the Arctic's Atlantic sector were studied using a collection of field observations and analyses. In early 2015, during the six-month N-ICE2015 expedition in the pack ice north of Svalbard, we observed a chain of events in the atmosphere-ice-ocean system that was triggered by several powerful winter storms. Our unique, interdisciplinary observations show that these winter storms entail significant effects that last much longer than the short-lived storm events themselves.

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Liouville solutions for low complexity systems: characterisation of PDF evolutions

Speaker: 
Alejandro Hermoso

Affiliation: 
University of Balearic Islands.

Seminar Date: 
13. July 2018 - 11:00 - 11:30

The prediction of weather and climate is one of the most challenging problems faced nowadays by the scientific community, not only for its incalculable value for macroevolution planning but also for civil protection and man- agement of a myriad of socioeconomic assets. One of the main causes why numerical weather forecasts made with dynamical models are uncertain is the lack of knowledge about the state of the atmosphere with infinite preci- sion.

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Ocean Acoustic Tomography in the North Atlantic

Speaker: 
Brian Dushaw

Affiliation: 
Nansen Center, Bergen, Norway

Seminar Date: 
15. May 2018 - 13:00 - 14:00

An objective mapping exercise was used to assess the resolution capabilities of ocean acoustic tomography in combination with Argo floats. Basis functions for a basin-wide area are derived from a covariance computed using an ocean state estimate. As is demonstrated by the formal uncertainty estimates from this computation, Argo and tomography are complementary measurements. In several examples, each separately gives results with comparable uncertainty, while when both are employed, uncertainties are reduced by O(50%).

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