There is a significant palaeo-environmental resource in the existing firn/ice core and surface snow data collected on previous oversnow traverses. This data is also valuable in the planning of future traverses and drill sites. The data includes: spatial and temporal accumulation patterns; stable oxygen ∂ 18O and deuterium ∂D isotopes; snow chemistry; and borehole temperatures. All existing data on these parameters which was collected prior to 1990 will be compiled by the ITASE programme into a series of environmental baseline maps. These maps will act as a basis for the inclusion of post-1990 data collected by ITASE traverses. Discussion below focuses on existing data.
Spatial Accumulation Map
A spatial accumulation map will be prepared by updating previous compilations by Giovinetto and Bentley (1985) and the more recent compilation by Vaughan et al. (in prep) (Figure 5) These previous compilations include accumulation data interpreted from cane markers, snow pits and ice cores over a wide range of measurement time intervals. To maximise the use of the ITASE map for ground truthing modelled precipitation patterns, it is intended that the accumulation data will first be scaled for a common epoch, 1980-90, using the previously obtained time series where these occur. The sites of all previously retrieved ice cores will be used to progressively upgrade Figure 1 of this document.
Spatial Oxygen ∂ 18O and Deuterium ∂D Stable Isotopes Map
A spatial map of oxygen ∂ 18 O and deuterium ∂D isotope data will be prepared by adding data contributed by ITASE national programmes to the previous compilations of Morgan (1982) and more recently, Giovinetto et al. (submitted). Locations where oxygen ∂ 18 O and deuterium ∂D isotopes time series have been measured will also be mapped.
Spatial Snow Chemistry Map
A spatial map of snow chemistry data will be prepared by adding data contributed by ITASE national programmes to the previous compilation of Kreutz and Mayewski (in prep). This compilation includes spatial distribution maps divided by period of sample coverage for all major ions (Ca, Na, Mg, K, NH4, Cl, NO3, SO4) and MSA.
Spatial Borehole Temperatures Map
The 10 m snow temperature approximates the mean annual surface air temperature. A spatial map of 10 m snow temperatures previously measured in boreholes along existing traverse routes will be compiled. This map will be valuable as ground truth for the satellite derived passive microwave brightness temperature distribution. Mean annual air temperatures at each of the AWS sites will also be mapped.