NB new date!!
DMI/NBI Bimonthly meeting to keep updated on ice2ice activities within and between the NBI and DMI groups. Norwegian colleagues are more than welcome. Contact Vasileios Gkinis and Ida Ringgaard for more information.
Isotopes in Greenland precipitation: Isotope-enabled AGCM modelling and a new Greenland database of observations and ice core measurements
ABSTRACT Greenland ice cores offer a unique opportunity to investigate the climate system behaviour. The objective of this PhD project is to investigate isotope modelling of present- day conditions and conduct model-data comparison using Greenland ice cores. Thus this thesis investigates how the integration of model and data can be used to improve the understanding of climate changes. This is done through analysis of isotope modelling, observations and ice core measurements. This dissertation comprises three projects: (1) Modelling the isotopic response to changes in Arctic sea surface conditions, (2) Constructing a new Greenland database of observations and present-day ice core measurements, and (3) Performance test of isotope-enabled CAM5 for Greenland.
The recent decades of rapid Arctic sea ice decline are used as a basis for an observational-based model experiment using the isotope-enabled CAM model 3, isoCAM3. Results show that δ18O of precipitation is sensitive to local changes of sea ice concentration and sea surface conditions. It is found that the distribution of the sea ice cover and sea surface conditions is essential for the spatial distribution of the simulated changes in δ18O over the Arctic Ocean.
A comprehensive database is created based on ice core and weather station data from Greenland within the period 1890-2014. Present day annual and seasonal mean values are computed for 326 locations in Greenland. Parameterization of the spatial distribution of temperature and δ18O are used to create the first observational-based gridded map of δ18O of precipitation for Greenland and the first gridded map of Greenland temperature, where ice core borehole temperatures are included. The database and gridded maps create a framework for conducting model-data comparison of isotope-enabled GCMs.
The simulation of Greenland isotopes is tested for the isotope-enabled model CAM5. Here the importance of model resolution is investigated. A positive bias of 6-10 ‰ is found for the annual mean δ18O on the central part of the Greenland Ice Sheet. The amplitude of the seasonal cycle of Greenland δ18O is highly dependent on model resolution. This is attributed to a complex interaction of local and large scale processes associated with changes in the intensity and position of large scale atmospheric circulation and synoptic systems in the North Atlantic.
SUPERVISORS
Bo M. Vinther, Centre for Ice and Climate
Jesper Sjolte, Dept. of Geology, Lund -S
COMMITTEE
Chairman:
Christine Hvidberg, Centre for Ice and Climate
Members:
Kerim Nisancioglu, Bjerknes Centre for Climate Research, Bergen – N
Martin Werner, Alfred Wegener Institute, Bremerhaven – D
If interested please contact Anne-Katrine Faber for a copy of the thesis.
akfaber @nbi.ku.dk
PI meeting in Bergen
Martin Miles will visit Copenhagen (CIC) between the 7 and 10th of June.
On the 10th he will give a Friday lunch talk at CIC- all ice2ice members are very welcome.
The East Greenland Ice: New history of the past millennium
ABSTRACT The East Greenland Ice (Koch, 1945) is the immense belt of Arctic sea ice transported along the East Greenland Current (EGC) and its downstream extension along SW Greenland, where it is termed Storis. This represents the Earth’s largest pathway of sea ice and freshwater transport, with linkages to ocean circulation and climate-system variability. Here we synthesize historical and paleo proxy records to study two aspects of the natural variability of the East Greenland Ice: (1) multidecadal variability of sea ice in a multi-century context, and (2) constraining and understanding modulations during the past millennium, focused on the onset of the Little Ice Age.
First, we integrate and synthesize a set of multi-century historical records of sea ice, and establish a signal of pervasive and persistent multidecadal (60–90 year) fluctuations that is most pronounced in the Greenland Sea, and weakens further away. We highlight evidence for co-variability between sea ice and the Atlantic Multidecadal Oscillation (AMO) during the instrumental and historical record; similar covariability through previous centuries is evident from comparison of the longest historical records and proxy reconstructions of sea ice and the AMO.
Second, we present a multi-proxy study focused on constraining and understanding modulations during the past millennium. This is addressed through a synthesis of data records spanning the length of the extended EGC pathway. These are derived from marine sediment cores and are indicative of sea-ice and ocean conditions based on multiple proxies, including direct sea-ice proxies (IP 25 ) and indirect indicators (mineralogical and biological indicators, e.g., foraminifera and diatoms). We find reasonable coherence between the disparate records, particularly in the early 1300s – around the abrupt onset of the Little Ice Age in this region. Markedly enhanced export of sea ice from the Arctic Ocean can be inferred as a statistically extreme anomaly apparent not only along SW Greenland, but also upstream through the entire EGC pathway from the Arctic Ocean.
Finally, we compare the sea ice–ocean records with atmospheric (temperature and circulation indices) and other reconstructions. It is apparent that the changes in the East Greenland ice–ocean conditions occurred decades before well-documented changes in large-scale atmospheric circulation around
the early 1400s.
The East Greenland Ice: New history of the past millennium
Martin Miles
ABSTRACT The East Greenland Ice (Koch, 1945) is the immense belt of Arctic sea ice transported along the East Greenland Current (EGC) and its downstream extension along SW Greenland, where it is termed Storis. This represents the Earth’s largest pathway of sea ice and freshwater transport, with linkages to ocean circulation and climate-system variability. Here we synthesize historical and paleo proxy records to study two aspects of the natural variability of the East Greenland Ice: (1) multidecadal variability of sea ice in a multi-century context, and (2) constraining and understanding modulations during the past millennium, focused on the onset of the Little Ice Age.
First, we integrate and synthesize a set of multi-century historical records of sea ice, and establish a signal of pervasive and persistent multidecadal (60–90 year) fluctuations that is most pronounced in the Greenland Sea, and weakens further away. We highlight evidence for co-variability between sea ice and the Atlantic Multidecadal Oscillation (AMO) during the instrumental and historical record; similar covariability through previous centuries is evident from comparison of the longest historical records and proxy reconstructions of sea ice and the AMO.
Second, we present a multi-proxy study focused on constraining and understanding modulations during the past millennium. This is addressed through a synthesis of data records spanning the length of the extended EGC pathway. These are derived from marine sediment cores and are indicative of sea-ice and ocean conditions based on multiple proxies, including direct sea-ice proxies (IP 25 ) and indirect indicators (mineralogical and biological indicators, e.g., foraminifera and diatoms). We find reasonable coherence between the disparate records, particularly in the early 1300s – around the abrupt onset of the Little Ice Age in this region. Markedly enhanced export of sea ice from the Arctic Ocean can be inferred as a statistically extreme anomaly apparent not only along SW Greenland, but also upstream through the entire EGC pathway from the Arctic Ocean.
Finally, we compare the sea ice–ocean records with atmospheric (temperature and circulation indices) and other reconstructions. It is apparent that the changes in the East Greenland ice–ocean conditions occurred decades before well-documented changes in large-scale atmospheric circulation around
the early 1400s.
Applications are invited to attend the 2016 Advanced Climate Dynamics Course – this will be the 8th in a series of very exiting summer schools focusing on climate dynamics and aiming to mix students and faculty from different backgrounds to exchange and discuss current topics in the field.
Topic: Role of High Latitudes in Centennial to Millennial Scale Climate Variability
Date: August 8th – August 20th, 2016
Where: Bonne Bay Research Station on Newfoundland
Goal: To mix students and lecturers with empirical/proxy and dynamical training within climate science and focus on understanding the basic principles and dynamics behind centennial to millennial scale climate variability and their link to past, present and future changes to high latitude climate.
Confirmed lecturers:
David Battisti – University of Washington
Anne Jennings – Institute of Arctic and Alpine Research
Ray Bradley – University of Massachusetts Amherst
Alan Condron – University of Massachusetts Amherst
Julie Bringham Grette – University of Massachusetts Amherst
Tore Furevik – University of Bergen
Jake Gebbie – Woods Hole Oceanographic Institution
Patrick Heimbach – The University of Texas at Austin / Massachusetts Institute of Technology
Kerim H. Nisancioglu – University of Bergen
Øyvind Paasche – University of Bergen
Lev Tarasov – Memorial University of Newfoundland
Applications:
deadline is the 10th of March and we aim to send decision letters by early April. The application form is found here: http://www.resclim.no/2158.aspx
For further details of this (and info on earlier) summer courses, go to:
Note that local expenses will be covered by the summer school. There will also be an opportunity to apply for a travel grant, which will cover part of the costs of travel to Newfoundland. If you have any questions, please contact: acdc@uib.no
PS! Flyer: http://www.uib.no/sites/w3.uib.no/files/attachments/acdc2016flyer_0.pdf
How to register: The number of participants is limited to about 40 participants. There is no registration fee, but if you would like to participate please register at: http://mform.imr.no/view.php?id=55316
Proposed date for first Monthly meeting fall 2016.
Aim is to keep updated on ice2ice activities within and between the Bergen groups. Copenhagen colleagues are more than welcome. Contact Erik.
Agenda:
- Short (10 min) summary from small meetings since May:
- Workshop on proxy uncertainties for State estimates in MIS3 held in Bergen (May)-Christian Rodehacke
- Proxy/model interaction -Helen/Bo?
- Warm arctic Ocean (Sept)- Peter/Shuting
- Paul and Marius on RECAP Holocene discussions in June
- Discussion on how to produce back-trajectory maps of the source regions of aerosols reaching the Renland ice cap -Jens/Paul
- Upcoming meetings:
- DO event workshop (Emilie)
If you have items for the agenda please let Hellek@fys.ku.dk know. And as always we would love to see also some of our Norwegian colleagues.
More info contact Erwin Lambert <Erwin.Lambert@uib.no>