Measuring Net Snow Accumulation by Miniature Data Loggers

Ole Humlum, The University Courses on Svalbard (UNIS), Norway.

General

Automated measurements of solid precipitation is a difficult task and usually requires complicated instrumentation with internal heating and elaborate wind shielding. As snow moves readily around in the landscape during winter by wind action (picture above), a correct measured value of the amount of precipitation is often of limited use in a geomorphic and biological context. What really matters is the amount of snow accumulated on the ground surface when spring melting commences. The Gemini precipitation loggers offers a simple way of obtaining this information.

Installation of Precipitation Gauge

During installation, due to the drop-contact principle used by the instrument, great care should be taken to ensure that the upper surface of the gauge is horizontal, as satisfactory operation requires water drops to make proper contact in the lower part of the device.

The unit is then left at the measuring site for the winter. This will not damage the gauge by freezing as no liquid water is stored in the instrument and this has no moving parts. While being snow covered, no precipitation will of cause be registered as long as temperatures stay below freezing. However, if properly installed, the unit will record the subsequent melting of the overlying net snow cover present at the measuring site when melt commences. This is illustrated by the diagram below. 

Ground surface temperatures and precipitation gauge readings spring 2001 at head of Qivitut rock glacier, Diskofjord, Disko Island, W. Greenland. 

Latest update: 11. November 2002.