COMPILED REPORTS OF THE
U.S. ICE CORE RESEARCH WORKSHOP

NON-CORE STUDIES RELATED TO A GLOBAL ARRAY OF SHALLOW TO INTERMEDIATE DEPTH ICE CORE

(Moderator: R. Borys)

I. Justification

Proper interpretation of ice cores requires an understanding of processes by which contaminants are transported from source regions to their ultimate sink in the glacial ice. Previous work has shown that a number of complex factors influence each step. As a result, using ice core dam to interpret past atmospheric levels of trace constituents is not likely to be straightforward. Research by the atmospheric science community is needed to identify these factors to assist in interpreting the ice cores. Listed below are several scientific objectives which may serve as a guide to what areas of research would be useful in the eventual interpretation of the information obtained from ice core research. 

II. On-Site Scientific Objectives

A. Surface

1. Measure the chemical composition and physical characteristics of the aerosol for use in long-range and atmosphere-to-ice sheet transport and deposition studies.

2. Measure the chemical composition and physical characteristics of the clouds and precipitation for use in cloud-to-ice sheet deposition studies.

3. Conduct post-depositional studies of snow/firn/ice transportation
processes.

4. Determine site representativeness from wet/dry atmospheric deposition studies.

5. Determine site representativeness from an array of snowpits.

6. Monitor year round the basic atmospheric state parameters including accumulation rate.

B. Airborne

1. Determine vertical structure of parameters measured at the surface (A.1, A.2, A.5) concurrently and when surface measurements are not available whenever possible (ground truth studies).

2. Track material through the atmosphere to the ice core site both vertically (stratosphere/troposphere exchange) and horizontally (long range transport).

3. Compare changes in stratosphere/troposphere chemistry with changes in snow pit/ice core chemistry.

4. Radar studies of ice volume, depth, layering.

III. Off-Site Scientific Objectives

Many studies related to the selection of ice coring sites as well as core interpretation can be conducted off-site. These studies could utilize data collected specifically for a given ice core research site as well as the wealth of historical atmospheric data available. These include but are not limited to the following topics:

A. Satellite Remote Sensing

1. Laser altimetry of the ice surface.

2. Vertical aerosol/gas profiling over the core site.

3. Ice movement from successive visual images.

4. Accumulation rates from accurate laser altimetry.

5. SAR data.

6. Transport and circulation patterns from consecutive image analysis and eventual wind profiles.

B. Historical Atmospheric/Biological/Marine/Geological Records

1. Records of atmospheric turbidity derived from aircraft and ground observing stations.

2. Records of atmospheric events such as volcanic eruptions, nuclear accidents, supernovas, ozone anomalies, etc.

3. Known changes in plant pollen sources with time.

4. Use of temperate and tropical tree ring patterns.

5. Use of coral growth patterns in the tropics for glaciers in high altitude/low altitude locations.

6. Use of annual varves in marine sediments.

7. Use of annual varves in lake sediments, in particular, glacier outflow lakes.

C. Modeling

1. Atmospheric/Dynamics models - Global Circulation Models (GCM's) could be used to estimate changes in atmospheric stability, turbulence and predominant airborne transport pathways over the period of time recorded in the ice core.

2. Biogeochemical models - May be applied to describe changes in the composition of the atmosphere and resultant expected changes in ice core chemistry.

3. Chemical/Transport Models - Ongoing studies of the chemistry of the aerosol and the meteorology of transport may be applied to ice core studies (e.g., EUROTRAK, AEROS). Additionally chemical mass balance models, source apportionment models and source receptor models currently in existence could be applied to the interpretation of snowpit and ice core data.

4. Wet Scavenging Models - Microscale models of the physical and chemical scavenging processes that occur within mix phase clouds could be applied to different core sites where the processes of precipitation formation may be significantly different, i.e., between tropical glaciers and the Greenland Ice Sheet.

5. Dry Deposition Models - Given sufficient information about the composition of the atmosphere over a core site, dry deposition rate estimates can be made and compared to the wet process.

6. Trajectory Models - Atmospheric trajectory models could be applied both backward, using historical meteorological data to derive a transport statistic, and forward, from "events", to assist in the description of the causes of observed variability in the composition of ice cores or snow pits with depth. 

IV. Special On-Site Facilities Requirements for Non-Core Related Studies

A separate camp would be required to conduct any on-site special studies of atmospheric chemistry and deposition studies. The basic requirements of such a camp would be:

A. Remote (1 km+) and upwind from the main drilling activities.

B. Self sufficient in accommodations, provisions and power.

C. Living space, clean laboratory, outside working platform and a cold working space needed for personnel, instrumentation, sample collection and sample handling.

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