Improved Constraints on Models of
Glacial Isostatic Adjustment
ES0701
Start date: 29/04/2008
End date: 28/04/2012
Year: 3
Johannes Boehm
WG Chair
TU Vienna, Austria
Scientific context and objectives (1/2)
• Background / Problem statement: Our knowledge of presentday ice mass change of the major ice sheets is limited by
inaccuracy of correcting satellite measurements for Glacial
Isostatic Adjustment (GIA)
• [GIA is the result of ongoing adjustment of the solid earth to
deglaciation since Last Glacial Maximum. It involves horizontal
movement on mantle material and results in a surface
displacement which may be measured even now]
• Brief reminder of MoU objectives: The main objective of the
Action is to place improved constraints on models of GIA
• through the development of state-of-the-art surface velocity
measurements
• with the consequent production of new ice mass change estimates
for the major ice sheets
2
Rates of Greenland crustal motion due to GIA
3
Scientific context and objectives (2/2)
• Research directions:
• The objectives will be reached mainly through workshops, bringing
together expert groups. This will be supported by STSMs and a GIA
modelling training school
• The novel aspect of this Action is that geodetic analysts are rarely colocated with GIA modellers and do not interact closely. The same can
be said about geomorphologists. The Action brings those parties
together to open communication and initiate and conduct collaboration
• A further novel aspect is the opportunity to train a new generation of
GIA modellers and broaden the base of already strong European
expertise through a GIA modelling training school
• Bring together those from geography, geodesy, glaciology and solid earth
physics with world expert lecturers
4
Working groups
1.
Geodetic observation-level modelling and
systematic biases
2.
Velocity determination/reference frame
realization
3.
Noise characteristics of station coordinate
time series/velocities
4.
GIA model optimisation and ice mass balance
computations
5
WG 2
6
Working groups
1.
Geodetic observation-level modelling and
systematic biases
2.
Velocity determination/reference frame
realization
3.
Noise characteristics of station coordinate
time series/velocities
4.
GIA model optimisation and ice mass balance
computations
7
Results vs. Objectives
• 2nd GIA training school running as we speak (40 students)
• Due to strong demand following original training school in 2009
• Majority ESR and good gender balance; some international
participants; World-leading lecturers
• 1x first-ever GIA codes benchmarking paper published (+”part B” in
preparation)
• International exposure of Action and results during WG1-4 “vertical
rates” workshop immediately following International GNSS Service
Workshop
• First set of global surface velocity field from GPS soon to be released
via the COST website
8
Significant Highlights in Science or Networking
(1/2)
• DOGEx – The detection of offsets in GPS
experiment – an international community experiment
on offset detection originated in 2008 ESSEM
meeting with ES0601 chair
• Subsequent funding from The Leverhulme Trust for
a 2 year postdoc to work with ES0701 chair (King),
WG3 chair (Williams) and ES0601 chair (Mestre)
• Would not have happened without COST!
9
Significant Highlights in Science or Networking
(2/2)
• GIA codes benchmarking paper
• Several international attempts across 1-2 decades to
cross-compare GIA numerical codes from different groups
commenced but then lost energy
• Some issues with individual codes identified and fixed
• COST WG4 has now published the first such benchmark
and part B of this project is now well advanced
• COST workshop support allowed this to happen and
gives improved confidence in sea level studies using
these codes
10
Challenges
• Release of GPS velocity field has been slowed due to
movement of key WG2 member out of academia
• Need to ensure velocity field is released and Chair’s
group has modified their plans to ensure this
• Action has gone some way to breaking down barriers
between the traditional GIA/geodesy/geomorphology
communities, but still some way to go -> Final
Conference should help
11
Difficulties
• Restrictive budget was a problem to achieving
anything this year other than final conference; now
much improved 
12
Next Work- and Budget Plan
• Final conference and final MC meeting dominates
• 4 STSMs
• Revised plan is yet to be completed but will include
– Increased final conference budget
– Additional STSMs (6-8 in total)
– Previously desired workshop which was not
funded in 2010-11 to look at new sea level rise
indicators in Cyprus for assimilation into GIA
models
13
Action Parties
25
20
18
21
19
18
Grant Holder:
GeoEnvironmental
Institute
Niki Evelpidou
Greece
15
10
5
1
0
YR 1
Parties
1
2
2
YR 2
YR 3
YR 4
Non-COST Countries
14
Action participants
60
50
60
56
50
April 28 start to
Year 4
Total no. of indiv.
Participants
ESRs
40
30
20
25
10
10
16
7
Female
15
7
0
YR 1
YR 2
YR 3
YR 4
15
Use of COST Instruments
Activity (No.)
Year 1
Year 2
Year 3
Year 4
MC/WG Meetings
3
1
1
April 28
start to
year 4
STSMs
1
6
5
Training Schools
0
1
0
Workshops or
Conferences
3
4
5
Joint Publications
1
2
5
1
16