VELMAP: Introduction

Ice flow and its temporal changes are among the most fundamental parameters of the Antarctic Ice Sheet, essential to mass balance studies, modeling, and the impact the continent may have on sea level. A tremendous amount of data already exist on ice motion in the Antarctic, reaching back to the beginning of the 20th century and the heroic expeditions, and in the present with large regions mapped to accuracies of hundreds of millimeters per year using interferometric SAR methods, and point measurements to better than centimeter per year accuracies using GPS.

With the advent of the the second and third Radarsat Antarctic Mapping Missions (AMM-2 and -3), missions designed to acquire two highly accurate snapshots of ice motion for all regions north of 80 degrees South, it seems appropriate to initiate an effort to gather all existing ice velocity data, from all well-documented and accurate sources available.

The National Snow and Ice Data Center would like to begin to compile these data under a project we hope will evolve much like the British Antarctic Survey's BEDMAP Project ( This project is initially funded at a modest level as part of several ongoing efforts at NSIDC, specifically, the Antarctic Glaciological Data Center (funded by NSF-OPP), the NSIDC portion of the RadarSat Antarctic Mapping Project (funded by NASA), Landsat 7 ice velocity mapping work (funded by NASA), and the NSIDC Snow and Ice DAAC (Distributed Active Archive Center), providing mostly infra- structure for data storage and handling. We anticipate proposals for future funding specific to VELMAP in the next year. The work will be led by Mr. Bruce Raup and Dr. Ted Scambos of NSIDC.

Our initial efforts will be focussed on gathering and uniformly presenting existing data sets in tabular form. We will compile the data as ASCII tables of latitude, longitude, speed, bearing, elevation*, slope*, date range, and errors for each parameter (*=optional). A variety of derived, gridded products are envisioned for eventual distribution. NSIDC will build on its existing compilation of velocity data, viewable and downloadable through this Velmap site.

There are many data sets available in the community right now, in just this format or easily convertible to it. We can assist you in converting your data, even if it is not in digital form, if you can provide us with information to generate the listed parameters. Contributors will be acknowledged and cited for each data set.

No data set is too old, small, or large.

Unpublished or unreleased data may be submitted under a 'hold' until the contributing investigator is ready to release it. We have several data sets in this status already.

The objective of this message is make the community aware of our effort, and to begin to solicit data contributions. If you have, or are aware of, ice motion data covering the Antarctic ice sheet please inform us at

If you would simply like to be on our 'velmap' e-mail list, just send us a message with a short message expressing interest in the project.