Meteorological Conditions During Snowfall at
Terra Nova Bay (Antarctica)
A. Pellegrini1, A.M. Della Vedova2, P. Grigioni1 and L. De Silvestri1
1 ENEA AMB-GEM-CLIM, Via Anguillarese 301,2 Via M. Bocassini 9, Roma, Italy
Abstract
Changes in the précipitation rate, resulting in a snow cover on sea ice, are not easily monitored by direct observations. Gange déterminations of snowfall are
strongly contamineatd by wind transport of previously deposited snow.
Glaciological accumulation values are a potentially important source of précipitation data, but the requirements for broad areal coverage, the lack of annual time
resolution in many régions and the uncertain impact of wind reworking are problematic. In this paper a method to identify épisodes of snowfall over North
Victoria Land, and particularly over Terra Nova Bay, is described.
1 Introduction
Polar régions play a critical rôle in global change since major interactions
between the atmosphère, ice, océans and biota affect the entire global System
through feedback, biogeochemical cycles, deep océan circulation, atmospheric
transport of energy and pollutants and changes in ice mass balance. Recent studies on the simulated climatic change due to the doubling of atmospheric CO2
show the high altitudes to be one of the most sensitive régions for changes in variables such as température, précipitation, snow and sea-ice coverage [ 1 ]. In particular, the accumulation of snowfall on the Antarctic continent is one of the major
factors determining the response of the ice sheet to climatic change. The Antarctic
ice-sheet net accumulation and the total mass losses are each about 2000 km’
year'1, équivalent to about 6 mm year'1 of sea level change [2], Consequently, a significant change in the major components of the Antarctic mass balance could
influence the current rate of sea-level rise up to 1.5 mm year1 [3]. Despite ail
available measurements of snow accumulation, ice velocities, basal melting and
iceberg discharge, it is still not known for certain whether the ice sheet is growing or shrinking. The uncertainty in the estimate of the total mass balance is at
least 20%, équivalent to a global sea-level change of about 1 mm year 1 [4].
Understanding the response of présent icecaps to climatic fluctuations
dépends on an effective means of modelling mass balance. Ablation can be reasonably well approximated from surface energy-balance calculations, but changes
in snowfall, the primary mass-gain mechanism, are poorly understood. Besides,
the snow can hâve a significant influence on seasonal variation of sea ice [5] and,
Terra Nova Bay (Antarctica)
A. Pellegrini1, A.M. Della Vedova2, P. Grigioni1 and L. De Silvestri1
1 ENEA AMB-GEM-CLIM, Via Anguillarese 301,2 Via M. Bocassini 9, Roma, Italy
Abstract
Changes in the précipitation rate, resulting in a snow cover on sea ice, are not easily monitored by direct observations. Gange déterminations of snowfall are
strongly contamineatd by wind transport of previously deposited snow.
Glaciological accumulation values are a potentially important source of précipitation data, but the requirements for broad areal coverage, the lack of annual time
resolution in many régions and the uncertain impact of wind reworking are problematic. In this paper a method to identify épisodes of snowfall over North
Victoria Land, and particularly over Terra Nova Bay, is described.
1 Introduction
Polar régions play a critical rôle in global change since major interactions
between the atmosphère, ice, océans and biota affect the entire global System
through feedback, biogeochemical cycles, deep océan circulation, atmospheric
transport of energy and pollutants and changes in ice mass balance. Recent studies on the simulated climatic change due to the doubling of atmospheric CO2
show the high altitudes to be one of the most sensitive régions for changes in variables such as température, précipitation, snow and sea-ice coverage [ 1 ]. In particular, the accumulation of snowfall on the Antarctic continent is one of the major
factors determining the response of the ice sheet to climatic change. The Antarctic
ice-sheet net accumulation and the total mass losses are each about 2000 km’
year'1, équivalent to about 6 mm year'1 of sea level change [2], Consequently, a significant change in the major components of the Antarctic mass balance could
influence the current rate of sea-level rise up to 1.5 mm year1 [3]. Despite ail
available measurements of snow accumulation, ice velocities, basal melting and
iceberg discharge, it is still not known for certain whether the ice sheet is growing or shrinking. The uncertainty in the estimate of the total mass balance is at
least 20%, équivalent to a global sea-level change of about 1 mm year 1 [4].
Understanding the response of présent icecaps to climatic fluctuations
dépends on an effective means of modelling mass balance. Ablation can be reasonably well approximated from surface energy-balance calculations, but changes
in snowfall, the primary mass-gain mechanism, are poorly understood. Besides,
the snow can hâve a significant influence on seasonal variation of sea ice [5] and,