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

A GLOBAL ARRAY OF SHALLOW AND UNTERMEDIATE ICE CORES AND SITE SELECTION

(Moderator L. T'hompson)

Climatic and environmental variability over the last 2000 years is poorly documented and yet this period will represent the conditions prevailing over the next 200 years.

It is widely recognized that ice core information can be used to address problems which are of concern to a wide sector of the scientific community.

The problems include:
     - Large scale climatic events such as El Nino-Southern Oscillation and Monsoonal variability
     - The long term variations in greenhouse gases (e.g., C02, Methane, etc.)
     - The timing and abruptness of climatic events.
     - A calibration of the deep polar ice core records with high resolution ice core records on a global scale.

The paleoclimatic information extracted from the polar ice sheets is insufficient to provide a completely global perspective. Much of the important climatic activity in the world does not affect the polar ice caps and thus, is lost if the polar regions are the only places where ice cores are recovered.

The successful execution of ice core recovery programs on a global scale requires detailed planning and coordination with institutions within the countries where the field site is located. Field site selection requires snow pit and shallow core studies, ice temperature measurements and radar depth determinations for location of the drilling site. Once a site is selected, a detailed strain network for ice deformation and accumulation measurements is essential. Even though the basic components of ice core drills remain the same, they must be modified for the conditions of the site. Emphasis must be placed on logistical considerations for getting personnel, drilling equipment and supplies in and out of the field. Transportation of frozen ice core samples out of these remote field sites must receive special attention.

Issues which must be considered include percolation and the need to insure that the particular property being studies is properly preserved in the ice. The processing/handling must be more sophisticated, especially when gas studies are planned. For chemistry there are two choices: (a) a more sophisticated transport system for samples or (b) analyses conducted in the field which requires a long lead time for equipment development.

A global array of ice core studies is essential to establish the linkages between hemispheres in order to study the synchroneity of specific events and the regional, hemispheric and/or global extent of climatic and environmental perturbations. These types of ice core studies which focus on problems affecting man on present time scales e.g., monsoons and El Nino-Southern Oscillation events) open up new areas of research for which ice cores are a unique tool. Understanding the global climate system requires a multidisciplinary approach through the study of high resolution records not only from ice cores, but also from tree rings, corals, marine and lake sediments, and historical documentation. On the longer time scales, comparisons can be made with glacial geologic and palynology studies. Sites for future study include Alaska, Arctic Canada, the Soviet Union, Africa and high resolution records from Greenland and Antarctica. Reconstruction of past environments and the global network role of ice cores have been recognized as priority items for the U.S. Global Change Program. Similarly, these objectives are entirely consistent with the goals of the NSF Global Geosciences Initiative. A sufficient number of such programs have been conducted to indicate that the goals of the global array of ice cores can be reached within the existing capability of drilling and laboratory analyses.

Recommendations are that the research projects aimed at recovery of a global array of shallow and intermediate cores should continue simultaneously with polar drilling activities.

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