The Geomorphology And Geometric Change Of Arctic Valley Glaciers

Glaciers, ice caps and ice sheets are the highlights in global changing research. Recent literatures show that the Arctic glaciers are more sensitive to the climate change, and it’s the glaciers that contribute more in the sea level rise in recent years. So there is of importance to monitor and research the Arctic glaciers.This paper summarizes the monitoring methods for the geophysical research in glaciers, including the traditional methds:orientational observation, photogrametry, ice drilling and seismology, and the modern methods:GPS, GPR, satellite observation and so on. With a short introduction of the glacial mass balance, all the methods for mass balance measurement are summarized, including classic glaciological method, process-model method, hydrological method, altimetric methods, flux-gate method, geological methods and satellite gravitational method. The advances and pitfalls for each method is discussed.Based on dual-frequency GPS measurement, the pricise positions of the stakes on two Arctic glaciers are acquired during2005-2010. Based on the point positioning GPS measurement, we got high density GPS survying lines coupled with GPR measurement data. After analysed the altitude difference between different GPS surveying lines and the difference inside one GPS survying line, we find that the relative precision is higher and the accuracy is lower for each surveyed GPS line. So a mathematical algorithm is proposed to adjust the altitude difference between different GPS lines. According to this algorithm all the lines are hramonised to a relative high precise and accurate level. Compared with the high precision GPS position of the stakes then, the adjusted and smoothed lines’data are suitable to produce the glaciers’topography. So the DEM, area, contour maps are all produced in ArcMap software.With a precise model for computing the depth of the section data from GPR survey, software named’GPRead’ has been developed for analysing the data from pulseEKKO GPR. Using this software, we get the depth and position of all the traces acquired on April2004at two glaciers. The deepest position and the depth of two glaciers are presented. Again using the ArcMap software we get the bedrock topography, ice volume and its water equvilent. After compared the ambigious signal with the clear ones, we infer that the bottom of two glaciers is in melting point and the temperate ice is estimated inside.After analyzing the time series position data during2005to2010, we get the surface velocities of the two glaciers. With horizontal velocity comparation we find the highest speed is in the central part of each glacier, and the speed is lower down heading to higher or lower part of the glacier. After slope correction on the vertical velocity, the altitude changing tendency is presented, and we find the retreat and acceleration of the two glaciers, combined with the historical map in1936. With different method for glacial terminal computing, we get different velocities of advances or reteats. After analyzing the discrepancy of considering the altitude or not, we recommend that the altitude should be added into the terminus variation monitoring.Employing the meteorological data in20century at Longyearbyen, the coupling relationship is discussed between glacier and the climate. According to the power law model, the cross section features of the two glaciers’valleys are all classified into V shape rather than U shape. The Austre Lovenbreen is more likely in overdeepning process while the Pedersenbreen is more likely in widening process. Due to the difference in glaciation, we infer that Pedersenbreen will fully grow into U shape at first compared with Austre Lovenbreen.