Population Vertical Distribution Research Articles

The Correlation Analysis of Henan Population Distribution Evolution and Terrain Characteristics

Aiming at the relationship between population distribution evolution and terrain characteristics, based on 30m × 30m DEM and 1km2×1km2 population density raster data, and using spatial analysis methods, this paper studies the evolution characteristics of the population spatial distribution, the population vertical distribution and the population slope distribution in Henan province from 1995 to 2015. The results show that, there are significant imbalances in the population development in the province, the population aggregation in urban built-up area is very obvious. The gradually decreasing regions with the density of 500-1000 person/km2 are still the main density distribution characteristics of the province's population. With the rapid increase of population, many people are migrating out from complex terrain. With rapid urbanization, major cities in the province have attracted a large number of immigrants. Excluding the natural population growth factors, the relative growth rate of population is inversely proportional to elevation and slope, there are a lot of people above 6°slope migrating out.

Bubble size distribution in surface wave breaking entraining process

From the similarity theorem, an expression of bubble population is derived as a function of the air entrainment rate, the turbulent kinetic energy (TKE) spectrum density and the surface tension. The bubble size spectrum that we obtain has a dependence of \(a^{ - 2.5 + n_d } \) on the bubble radius, in which nd is positive and dependent on the form of TKE spectrum within the viscous dissipation range. To relate the bubble population with wave parameters, an expression about the air entrainment rate is deduced by introducing two statistical relations to wave breaking. The bubble population vertical distribution is also derived, based on two assumptions from two typical observation results.