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Immediate report of Victoria University of Wellington Antarctic Expedition 1988-89: VUWAE 33

Abstract

Abstract

This project involves a three year hydrological, glaciological, and sediment transport monitoring programme in the Miers Valley.

Information required to study and quantify the energy and mass balances of the glacier-river-lake system will be collected.

The data will permit:
1.The evaluation of the seasonal variability of glacier behaviour and surface water hydrology.
2.An improved understanding of the energy and mass balances of the glacier-river-lake system in the Miers Valley, which typifies such systems in the Dry Valleys region.
3.The development of a water balance for the Miers Valley hydrologic system.
4.The determination of the importance of temperature in controlling viscosity, and therefore the transportational potential, of both air and water "fluid" media.
5.The quantification of sediment sources, the relative importance of sediment transporting media, and how these vary both spatially and temporally.

During the 1988-89 season three automated hydrometric sites were installed together with climate monitoring equipment. All the equipment and software was fully tested and functioned well during December and January. Quarter hourly data values of fourteen different variables at 3 sites were recorded. Networks of ablation poles were installed on the Miers and Adams glaciers and a considerable amount of survey control was established. The sedimentary facies of the valley were mapped and the aeolian sediment transport processes monitored.

An initial examination of the hydrologic and climatic data indicates that:
1.Stream flow is directly controlled by the amount, and intensity, of solar radiation striking the glaciers. Such is the level of this control that clouds passing in front of the sun can be identified in the hydrographs.
2.Temperature has only a minor affect on stream flow, determining to a slight degree the "baseflow" when there is no direct sunlight.
3.There is a maximum amount of melt able to be generated, if there is no cloud, when the sun is at a particular azimuth. This is indicated by "flat" peaks on the hydrographs.
4.The maximum amount of melt possible on any day during the season (if there is no cloud) is cyclic and increases as the angle of the sun gets higher. Essentially, maximum stream flows should be cyclic around the "longest day".
5.Higher than average temperatures early in the 1988-89 season led to higher humidity levels, more cloud, more snow fall and as a consequence, less stream flow during the season.page 13
6.The 1988-89 season was, however, in many ways a typical. There were very few fine days; temperatures (on average) were higher than usual; more snowfall and higher humidity were experienced. The data must therefore be interpreted with some degree of caution.

The sediment samples are currently being analysed and this must be completed before any definitive comments can be made. However, it would appear that the average, "long term", sedimentation rates are slow but that periods with extremely high rates occur periodically to produce a disjoint stratigraphy.