Abstract:

In this paper, the three years observational data for fog of 39 fog signal stations laid in the Chongqing section of the Yangtze River mountainous waterway are used to investigate the temporal and spatial distribution of fog over the Yangtze River mountainous waterway. Meantime, a neural network is used to simulate the regional fine distribution of fog composite index over the Yangtze River mountainous waterway according to the whole fog and six kinds of geographic information fators such as longitude, latitude, channel width, river bend, river change intensity, river tributaries fork over the whole Yangtze River mountainous waterway (from Yibin to Yichang). The results show that fog of the Yangtze River mountainous waterway increased in winter and decreased in summer overall. Most fog formed from 0 to 8 am and ended from 8 to 12 am, while heavy fog exhibited forming early, ending late and keeping longer time. There were much difference in spatial distribution of fog over the Chongqing section. About 30-50 heavy fogs were occurred in Lanshi to Fengdu section of Peiling and Huanghua section of Wanzhou every year, while less than 5 from Anping to Kuixia section. The simulation results show that we can simulate the distribution of fog over the Chongqing section on the whole by making use of geographic information factors and the neural network. Besides, we can obtain the fine distribution of fog over the whole Yangtze River mountainous waterway when using the neural network further, and the simulation results keep close to the observational results and the field survey in distribution trend. But the simulation results can not represent the actual distribution of fog over the Yangtze River mountainous waterway completely because of local error convergence and limitations of factor selection, thus the simulation test needs more data and impact factors.〖JP〗〖HJ1〗〖HJ〗〖HQ〗