Results 1 to 10 of about 18,018 (92)
Study of Temperature Field Distribution in Topographic Bias Tunnel Based on Monitoring Data [PDF]
Symmetry, 2021 In recent decades, numerous tunnels have been built in the cold region of China. However, the temperature field of topographically biased tunnels in the monsoon freeze zone has not been sufficiently studied. In this study, we monitored the temperature of the surrounding rock in two topographic bias sections of the Huitougou Tunnel and analyzed the ...
Tao Zhang, Lei Nie, Yan Xu
exaly +2 more sources
The topographic bias in gravimetric geoid determination revisited [PDF]
Journal of Geodetic Science, 2019 Abstract The topographic potential bias at geoid level is the error of the analytically continued geopotential from or above the Earth’s surface to the geoid. We show that the topographic potential can be expressed as the sum of two Bouguer shell components, where the density distribution of one is spherical symmetric and the other is ...
Lars E Sjoberg
exaly +3 more sources
A numerical test of the topographic bias
Journal of Geodetic Science, 2018 Abstract In 1962 A. Bjerhammar introduced the method of analytical continuation in physical geodesy, implying that surface gravity anomalies are downward continued into the topographic masses down to an internal sphere (the Bjerhammar sphere). The method also includes analytical upward continuation of the potential to the surface of the
Lars E Sjoberg
exaly +3 more sources
The topographic control on land surface energy fluxes: A statistical approach to bias correction [PDF]
Journal of Hydrology, 2020 Abstract Subsurface hydrodynamics are an important component of the hydrological cycle and a key factor in the partitioning of land surface water and energy fluxes. Because of computational reasons they are often neglected, or strongly simplified, in numerical weather prediction and climate models.
Stefan Kollet, Mostaquimur Rahman
exaly +2 more sources
On the topographic bias and density distribution in modelling the geoid and orthometric heights
Journal of Geodetic Science, 2018 AbstractIt is well known that the success in precise determinations of the gravimetric geoid height (N) and the orthometric height (H) rely on the knowledge of the topographic mass distribution. We show that the residual topographic bias due to an imprecise information on the topographic density is practically the same for N and H, but with opposite ...
Lars E Sjoberg
exaly +3 more sources
Locality of Topographic Ground Truth Data for Salt Marsh Lidar DEM Elevation Bias Mitigation
IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 2022 Lidar-derived digital elevation models (DEMs) are crucial for modeling salt marsh evolution, forecasting inundation depth, frequency, and duration, and simulating sea level rise. Advances in lidar acquisition and data processing techniques have led to increased accuracy; however, in densely vegetated coastal salt marsh areas, lidar-derived DEMs are ...
Stephen C Medeiros
exaly +3 more sources
Journal of Geodetic Science, 2015 Abstract Geoid determination below the topographic surface in continental areas using analytical continuation of gravity anomaly and/or an external type of solid spherical harmonics determined by an Earth GravitationalModel (EGM) inevitably leads to a topographic bias, as the true disturbing potential at the geoid is not harmonic in ...
exaly +3 more sources
Journal of Geodetic ScienceAbstract Topography is a problem in geoid determination by the Stokes formula, a high degree Earth Gravitational Model (EGM), or for a combination thereof. Herein, we consider this problem in analytical/harmonic downward continuation of the external potential at point P to a geocentric spherical sea level approximation in geoid ...
Lars E Sjoberg
exaly +3 more sources
Geoid model validation and topographic bias
Journal of Geodetic Science, 2022 Abstract Recently a number of geoid campaigns were performed to verify different types of geoid and quasigeoid modeling techniques. Typically, GNSS-leveling was employed as an independent method, but in some cases zenith camera astronomic deflection data were also used in astrogeodetic determinations of the geoid and/or quasigeoid ...
openaire +4 more sources
Grid overlays reduce bias in mental representations of topographic maps [PDF]
Abstracts of the ICA, 2019 Abstract. Reading spatial information from topographic maps to form mental representations that guide spatial orientation and navigation is a rather complex cognitive process. Perceptual and knowledge-driven processes interact to support the map reader in building these mental representations. The resulting cognitive maps are not one-to-one mappings of
Lars Kuchinke +4 more
openaire +3 more sources