OIB Land Ice Meeting
June 16, 2011
Minutes (Day 2)
Jezek began by reminding the team that the objective of the morning session was to provide an
assessment of OIB acquisition, data collections, and products from a science perspective. Larour and
Nowicki then gave an overview of modeling activities. This included a summary of comments solicited
from the modeling community during weekly telecons. The plans is to continue the telecons to
encourage modelers to become more involved with using OIB data. Highlights included Larour’s use of
ice thickness data and error estimates to show that ice fluxes are more sensistive to ice thickness than to
basal drag or hardness parameter.
Fahnestock gaven an overview of dh/dt analysis and illustrated that OIB is targeting the key areas of
thickness change. Smith provided a nice assessement of how coverage over select areas is changed
from ICESat to OIB but nevertheless showed how OIB is continuing the record of dh/dt over key areas of
Antarctica. Csatho summarized recent ICESAT OIB analyses of dh/dt over Greenland which show that
there are important spatial and TEMPORAL variabilities that must be captured in order to meaningfully
bridge the dh/dt records. Luthcke also reviewed how the altimeter dh/dt could be integrated with
GRACE. An action is to assess seasonal/spatial coverage/and platform requirements as part of the
long term OIB strategy. Tagg followed up with a request for an estimate of seasonal flight hour required
to assess interseasonal variations in ice behavior.
Bell illustrated how the integration of OIB data lead to a better understanding of basal processes and the
influence of basal processes on surface topography. She demonstrated how OIB is providing a unique
data ensemble that is only achievable using airborne data.
Fahnestock reviewed approaches for estimating subglacial water from internal layer deformation. He
illustrated internal layer picking procedures and showed how combination of surface features from
MOA could be used to constrain layer picking strategies. An action is to move basal water layer
detection using internal layers from a research to operational product.
Csatho presented improved DEMS using integration of SPOT and OIB data. She also presented improved
basal topography maps which showed a complicated network of subglacial drainage channels that feed
into the main Jacobshavn glacier channel.
Young summarized Totten Glacier data collected as part of ICECAP. Correspondence with Rignot’s
grounding line were very good but he also showed how other products such as flotation maps enriched
the interpretation.
Rignot reviewed his grounding line map and then went on to assess mass balance estimates improved
using OIB data. He also showed results of modeling studies to assess basal melting beneath ice shelves
as well as how improved bathymetry changed interpretation of oceanic transport beneath ice shelves. A
discussion followed of how mass balance could be successfully used to improve ice thickness DEMS in a
fashion better than simple kriging.
Paden gave a brief review of picking approaches for MCORDS data. Larour noted that a detailed
description of MCORDS error statistics are crucial for modeling and an action Is to provide same. Paden
noted that earlier KU thickness data sets do not necessarily have a consistent wave speed or firn
correction model and that metadata to document same are probably no longer available. The approach
is to reprocess the data to a common standard. Paden requested feedback from the science team on
data formats.
Sonntag began the discussion of flight planning and provided a draft of potential flight lines for the
coming season. Tagg recommended that flight lines be planned for the maximum flight duration. Tagg
also inquired whether mission duration could be extended past end of November but Jezek circulated
information showing that surface melt at low elevations could complicate dh/dt after late November.
Hofton then summarized the strategy for G-5 LVIS acquisitions. Tagg asked whether it was more
desirable to fly the G-5 in 2011 or use the money to speed delivery of a Global Hawk system. Smith
noted that by waiting we approach the launch of ICESAT-2 and lesson the value of a later data set.
The Bindschadler data request was discussed and a recommendation to fly a portion of the area was
past on to Sonntag for further discussion with Bindschadler. Other flight line options were then
discussed and Jezek concluded with a summary of level 1 requirements vs the current flight line
portfolio.
Activities for Thursday include a summary of planned ICECAP activities, long range OIB strategy and
additional flight requests from modelers.