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Bathymetry: Features and Hypsography
Published in Yeqiao Wang, Coastal and Marine Environments, 2020
Heidi M. Dierssen, Albert E. Theberge
Taken from the Greek word “hypsos,” meaning height, hypsography is the study of the distribution of elevations on Earth and is used to relate bathymetry to the projected two-dimensional surface area of a region or feature. The “hypsographic curve” of Earth shows the cumulative percentage of the Earth surface area at different elevations from above and below sea level (Figure 18.5). As shown, the ocean represents ~71% of the Earth’s surface and most of this surface area is quite deeply submerged at close to 4 km below sea level. Based on our current and still limited knowledge of bathymetry, the average depth of the oceans is calculated to be 3.7 km. The prevalence of deep seafloor is related to the heavier elemental composition of oceanic crust that makes it much denser than terrestrial crust. Along the perimeters of the ocean basins, the ocean slopes rapidly and very little of the Earth’s surface occurs between the continental shelves (<500 m) and the deep sea (4 km). Metaphorically, the ocean basins can be considered like deep bowls with thin rims and steep sides. However, the bowl bottoms are not smooth, but littered with abyssal hills and seamounts, as well as spreading ridges that appear as jagged seams laced across a baseball.
Battle damage-oriented spare parts forecasting method based on wartime influencing factors analysis and ε-support vector regression
Published in International Journal of Production Research, 2020
Xiong Li, Xiaodong Zhao, Wei Pu
Battlefield environment is the joint name of battlefield and surrounding conditions that will influence the combat activities, including natural conditions, human conditions, battlefield construction situations, information, network and electromagnetism conditions, et al. Different battlefield environments not only require different combat modes, but also can influence performance of equipments significantly. Battlefield environment can be described by geographical-meteorological conditions (natural environment) and defensive position settings (artificial environment). They can be respectively quantified by the following coefficients. Geographical-meteorological comprehensive influencing coefficient (G). Terrain types are mainly divided according to natural conditions like hypsography and vegetation density. The geographical and meteorological factors are considered together in this paper. Their influences on combat operation are mainly reflected by march velocity, attack formation, usage of equipments, target location, and fire. G can be determined by combining Delphi technique and fuzzy comprehensive evaluation method.
Sea level rise exposure assessment of U.S. East Coast cargo container terminals
Published in Maritime Policy & Management, 2022
Thomas R. Allen, George McLeod, Sheila Hutt
Each terminal’s area-elevation statistics is plotted as a hypsography with superimposed 2050 and 2100 MHHW elevation heights. Plotted as a set of hypsographs for each port, individual terminals can be compared to assess general susceptibility to tidal flooding with sea level rise. In addition, each port and terminal analyzed generates an elevation map of potential tidal flooding.