- professor in Glaciology at The Geologic Survey of Denmark and Greenland (GEUS)
- Greenland ice climatologist; list of publications
- more than 20 expeditions to Greenland since 1994, more than 1 year camping on ice
- installed and maintained a network of more than 20 automatic weather stationson Greenland's inland ice in expeditions spanning 1994-present.
- university teaching 2003-2010 with emphasis on atmosphere-surface interactions, physical climatology at local to global scales, and environmental problems.
- scholar at Byrd Polar Research Center 2002-2012
- contributor to the Danish Polar Portal web site providing realtime climate and ice sheet mass balance info and end of melt season reports since 2013 at, see polarportal.org
- led the Greenland entry for The Bulletin of the American Meteorological Society's annual State of the Climatereports 2003-2012.
- 2004-2012 led composition of the Greenland entry to NOAA's Arctic Report Card, published since 2006 by The US National Oceanic and Atmospheric Administration .
- contributing author to Intergovernmental Panel on Climate Change (IPCC) fourth and fifth assessment reports.
awarded a NASA grant to support the installation and maintenance of Greenland time lapse cameras. Jason is active in Greenland field work for the Extreme Ice Survey (EIS)and is using EIS photos from Greenland to measure glacier speed changes, putting precise numbers on glacier flow and studying glacier flow sensitivity to climate.
Expeditions involved traversing 100s of km by snow mobile, as in the Arctic Circle Traverse April-May 2010.
Most of the inland ice camps are accessed by helicopter and ski-equipped airplane.
Instrumenting glaciers flowing out from the inland ice sheet has involved using ships and sail boating.
organizing Greenland inland ice expeditions in 2013 and 2014 part of the Dark Snow project, see darksnow.org/