Expressions of Intent for International Polar Year 2007-2008 Activities

Expression of Interest Details

PROPOSAL INFORMATION

Mass Balance of the Greenland Ice Sheet from InSAR in 2007-2008.  (GRISSPY)

Outline
The mass balance of the Greenland Ice Sheet has been estimated in the 1990’s using repeat –pass airborne laser altimetry and satellite radar altimetry data from changes in surface elevation. The results showed that the interior of the ice sheet is in balance with snow accumulation, but thinning dominates along the coast and is concentrated along the narrow channels occupied by outlet glaciers. The airborne data, however, do not cover all outlet glaciers, and satellite radar altimetry does not cover coastal ranges where most changes take place. As a result, published estimates of the mass balance of the Greenland Ice Sheet are underestimates. Moreover, recent analysis suggests that changes in velocity of the glaciers contribute for more than half of the observed mass loss, but such velocity changes cannot be measured with altimetry. Another approach to mass balance is the mass budget or component method where mass outflow at the grounding line - calculated combined information on ice velocity and thickness - is compared with net accumulation upstream. We have successfully applied this method to glaciers of northern and eastern Greenland using ERS-1/2 InSAR from 1992-1996 and radio echo sounding data, combined with snow accumulation maps produced by NASA’s PARCA program. We have now extended this velocity mapping to the rest of Greenland using Radarsat-1 InSAR, yet ice thickness data are remain too sparse to measure outflow on all glaciers. In the next two years, we will collect the necessary thickness data using the NASA P3 to estimate 2000 ice fluxes from Radarsat-1. During IPY, we will not re-measure ice thickness but we will re-measure ice velocity using either Radarsat-1 new acquisitions, or new acquisitions with ALOS or Envisat, around the entire periphery of Greenland, except local ice caps. These new and old data will be used to estimate mass balance of all the major Greenland glaciers and changes between 1992, 1996, 2000, and 2008. This is be important to determine the contribution to sea level rise of Greenland as well as identify the contribution to mass imbalance from changes in ice velocity of the glaciers. It will also identify the glaciers that are contributing the most to the imbalance of the Greenland ice sheet. Analysis of the results will be done jointly with colleagues in Denmark.

What significant advance(s) in relation to the IPY themes and targets can be anticipated from this project?
This project is relevant to IPY themes 1-2-4. We will quantify the temporal and spatial variability in ice discharge of the entire island of Greenland.We will establish a benchmark of ice discharge data for studying the evolution of the Greenland ice sheet in a warming climate. We will improve current estimates of the mass balance of the Greenland Ice Sheet, which has an important impact on sea level rise.

What international collaboration is involved in this project?
This project combines teams from NASA Wallops, NASA JPL, and the TU of Denmark

FIELD ACTIVITY DETAILS

Geographical location(s) for the proposed field activities:
The field operation will take along the west coast of Greenland via the NASA P3 aircraft

Approximate timeframe(s) for proposed field activities:
Arctic: 05/06 – 06/06 (ice thickness)            
Antarctic: n/a

Significant facilities will be required for this project:
We will rely on the NASA P3 aircraft for collecting ice thickness data, or a smaller aircraft (twin otter) is the P3 is not available. Ice thickness data are typically acquired for more than a single research project during NASA campaigns.

Will the project leave a legacy of infrastructure?
No.

How is it envisaged that the required logistic support will be secured?
Consortium
National agency
Other sources of support

We will seek a combination of funds from NASA and NSF Arctic Program for this project.

Has the project been "endorsed" at a national or international level?
No - We plan to submit a proposal to NASA in 2005

PROJECT MANAGEMENT AND STRUCTURE

Is the project a short-term expansion (over the IPY 2007-2008 timeframe) of an existing plan, programme or initiative or is it a new autonomous proposal?


This project has potential links with several other IPY projects dealing with the mass balance of the Greenland Ice Sheet.

How will the project be organised and managed?
Project leaders will be determined by activities (airborne deployment, remote sensing, GPS, science). We will participate in science meetings to coordinate activities, deployments, with other research groups, at the national and international levels. Our project will involve students at University of Kansas and one graduate student at JPL.Scientific analysis of the results will be done jointly with colleagues in Denmark

What are the initial plans of the project for addressing the education, outreach and communication issues outlined in the Framework document?
The program will involve the participation of students in the airborne deployment (radar data collection over glaciers) and at the laboratory (processing and analysis of InSAR data).

What are the initial plans of the project to address data management issues (as outlined in the Framework document?
Airborne/spaceborne remote sensing data and field data collected and analyzed in this project will be public domain per NASA and NSF’s policy. Airborne radar sounding data are posted on the web since the early 1990s. Glacier velocity data will be distributed to NSIDC.

How is it proposed to fund the project?
We propose to combine funds from NASA (cryospheric science program), and international partners (TUD). A research proposal will be submitted to NASA in 2005 to request funds for the P3 campaign. This instrument has been flown over Grenland nearly every year since 1993.

Is there additional information you wish to provide?
None

PROPOSER DETAILS

Dr Eric Rignot
Jet Propulsion Laboratory
MS 300-321
4800 Oak Grove Drive
Pasadena CA 91109-8099
USA

Tel: +1 818 354 1640
Mobile: +1 818 653 2531
Fax: +1 818 393 5184
Email:

Other project members and their affiliation