How many measurements are necessary to accurately assess the mass balance of a glacier?
To identify the impact of sampling density on determination of a glaciers annual mass balance, the North Cascade Glacier Climate Project utilized a varying density of measurements to determine annual mass balance on Columbia Glacier, Washington and Lemon Creek Glacier, Alaska. Mass balance was determined solely from field measurements. The density of the mass balance networks ranged from 1 to 375 points/km2. The lesser density networks were sub-samples of the highest measurement density network. The highest density network is probably the highest measurement density ever used in mass balance observations. The point simply to see if an absurdly high density helped improve accuracy. The results on both glaciers indicate significant improvement in accuracy resulting from increasing the total number of measurements from 1 to 4 points/km2 on Lemon Creek Glacier and 12 to 46 points/km2 on Columbia Glacier. There was no significant improvement in accuracy on the smaller Columbia Glacier for u
