RESPONSE OF A TEMPERATE ALPINE VALLEY GLACIER TO CLIMATE CHANGE AT THE DECADAL SCALE          下载免费PDF全文

CHRYSTELLE GABBUD  NATAN MICHELETTI  STUART N. LANE 《Geografiska Annaler: Series A, Physical Geography》2016,98(1):81-95

Glacier advance and recession are considered key indicators of climate change. Understanding the relationship between climatic variations and glacial responses is crucial. Here, we apply archival digital photogrammetry to reconstruct the decadal scale glacial history of an unmonitored Alpine valley glacier, the Haut Glacier d'Arolla, Switzerland, and we use the data generated to explore the linkages between glacier recession and climate forcing. High precision digital elevation models were derived. They show continual recession of the glacier since 1967, associated with long‐term climatic amelioration but only a weak reaction to shorter‐term climatic deterioration. Glacier surface velocity estimates obtained using surface particle tracking showed that, unlike for most Swiss glaciers during the late 1970s and early 1980s, ice mass flux from the accumulation zone was too low to compensate for the effects of glacier thinning and subsequent snout recession, especially during the rapid warming that occurred through the 1980s. The results emphasise the dangers of inferring glacier response to climate forcing from measurements of the terminus position only and the importance of using remote sensing methods as an alternative, especially where historical imagery is available.  相似文献   

Assessment of the Jason-1 and TOPEX/Poseidon Microwave Radiometer Performance Using GPS from Offshore Sites in the North Sea     

STUART EDWARDS  PHILIP MOORE  MATT KING 《Marine Geodesy》2013,36(3-4):717-727

The accuracy and drift of atmospheric path delay due to water vapor as derived from satellite microwave radiometers (MWR) is vital to altimetric measures of sea-level change. In this study a continuous time series of dual frequency GPS data from a number of offshore sites is used to examine the long term stability of the TOPEX/Poseidon radiometer and investigate initial performance of that of Jason-1. The location offshore eliminates the problems associated with land based/coastal locations where extrapolation of the GPS tropospheric correction to subsatellite points offshore are required to avoid background surface heat emissions contaminating the MWR delay measurement.  相似文献   

ALIGNMENT OF NEAR-SURFACE INCLUSIONS AND APPROPRIATE CRACK GEOMETRIES FOR GEOTHERMAL HOT-DRY-ROCK EXPERIMENTS1     

STUART CRAMPIN 《Geophysical Prospecting》1990,38(6):621-631

Ubiquitous splitting of seismic shear-waves indicates that most rocks in the upper half of the crust are pervaded by stress-aligned fluid-filled inclusions, called EDA-cracks. These inclusions are expected to be aligned perpendicular to the minimum compressional stress by stress relationships similar to those aligning industrial hydraulic fractures. At depths where the overburden stress is sufficiently large (typically below a few hundred metres), this minimum stress is usually horizontal, so that the EDA-cracks and hydraulic fractures are typically aligned vertically, striking parallel, or subparallel, to the direction of maximum compression. This is confirmed by the polarizations of the split shear-waves along raypaths at depth in the crust. At the free surface, however, the vertical stress is zero (or approximately zero) and cracks (and hydraulic fractures) at shallow depths in intact rock tend to be horizontal. Thus, the directions of minimum stress, and the orientations of hydraulic fractures, are likely to swing through 90° near the surface of the Earth. Since the behaviour of cracks and stress is often crucial to drilling operations, the rotation of the crack- and stress-geometry near-surface has important implications, particularly for optimizing hydrocarbon production and geothermal reservoir management. Consequently, evidence gained from experiments, for example in hot-dry-rock geothermal heat extraction, in inappropriate crack geometries at shallow depths, may not be valid when applied to other crack- and stress-geometries at depth in hot rock.  相似文献   

ANISOTROPY AND TRANSVERSE ISOTROPY*     

S. CRAMPIN 《Geophysical Prospecting》1986,34(1):94-99

A number of authors in the exploration literature have written about anisotropy, but have restricted their discussions to wave propagation through rock having transverse isotropy with a vertical symmetry axis. This note shows that there are fundamental differences between transverse isotropy when the symmetry axis is vertical (normal to the free surface) and more general anisotropy with an azimuthal variation of properties. These differences are important now that effective azimuthal shear-wave anisotropy resulting from aligned cracks and pores is becoming recognized as a significant property of crustal rocks.  相似文献   

WATER QUALITY AND ITS CONTROL edited by M. Hino,A. A. Balkema,Rotterdam, 1994, No. of pages: ix + 262. Price: £72.00 (hb). ISBN 90-5410-123-7.     

STUART LANE 《地球表面变化过程与地形》1996,21(6):584-585

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