Research On The Effect Of Shallow Groundwater Table On The Near Heat Island

Based on the soil hydrological experimental data of the typical area in North China, relations between the groundwater environment, soil as well as the effect of the hot island near the ground surface is mainly studied, with the application of data mining technology, statistic theory, catastrophe theory, fractal geometric theory, groundwater and soil water dynamics, stochastic theory, movement interface tracing technology, etc. It is a beneficial supplement to the research of the evolution law of the groundwater environment and climate; also it plays special significance for guiding the recovery of groundwater environment and the ecosystem of North China, for promoting the sustainable development of local economic development. The main contents are as follows,Firstly, based on the massive data of the proving ground of the typical area in North China, relationship between the effect of the hot island near the ground surface and each major influencing factor is studied, with the help of data mining technology, thus it provides that the shallow groundwater is one of the main factors affect the ground temperature near the ground. For the high relationship between the ground temperature and air temperature, it proved that there is a certain relation between the shallow groundwater and the effect of the heat island.Secondly, based on data mining results of the influencing factors, time series model is developed for the effect of the hot island near the ground surface, including statistical model and gray model. According to the non-linear relationship between groundwater component of ground surface temperature and groundwater mining depth, a catastrophe criterion is then established for groundwater mining, which leads to the concept of the critical mining depth influenced by the effect of the groundwater heat island.Thirdly, with the former's research, a unified description of the soil fractal parameters is established in the soil hydrological process numerical simulation. The hydraulic conductivity is included both dynamic and static medium performance, and the soil water characteristic curve is presented, describing both the drying curve and the wetting curve. Considered the fluctuant of the groundwater table, the finite element model by the Galerkin flipped method is established, in which the level set method is used to deal with interface tracing problems in unsaturated/saturated soil hydrology process.Finally, based on the experimental data, the function relation is acquired between the groundwater table and the increased scope of the temperature near the ground surface by the numerical simulation, which leads to the conclusion that the effect of the groundwater heat island is a kind of non-spire heat island, consistent with the criterion by catastrophe model. With the analysis and simulation of the data, the affect content is studied of the groundwater, soil content and the soil property on the ground surface temperature, which can be used to restrain the groundwater heat island.