Analysis Of Hydrothermal Condition Variations In Bohai Coastal Cities

Under the background of global climate change, the coastal cities were influenced by land and sea for its special position. So with the urbanization level has been improved, the main meteorological elements and hydrothermal condition in coastal cities appeared its particularity.Using the values of main meteorology elements(temperature,rainfall,wind speed) during 1951-2009 and 1980-2009 in Bohai coastal cities, we get the variation trends of seasonal and year values. The outcome manifests: during the 60 years (1951-2009), the temperature in the coastal cities is becoming warmer, Spring and Winter's contribution rate is larger than other season; The rainfall is reduced periodically; And the wind speed is also becoming weak. Applying Surfer 8.0 get the contour map for meteorology elements change at the different stage during 1980-2009. We can conclude that the temperature differs in different cities is shorted under the warming condition, the rainfall variations differed for its position in Bohai. Wind speed has not changed obviously, and its spatial construction looks alike at the different period. The changes in temperature,rainfall and wind speed were evident in Liaoning coastal cities. This character is related to the changes in underlying surface. The speedy urbanization in the area has changed the quantity and the structure of the underlying surface, through this course, it affected the exchange state of water and heat between atmosphere and ground.In measuring hydrothermal condition changes of city, choose the human comfort index which can reflect the human feeling of humidity and heat as a standard, and to figure out the hydrothermal condition index(H). From this outcome, the value of H is on a declining trend in Dalian,Yingkou,Weifang and Jinzhou. The fluctuation of H in Qinhuangdao is lessen, but in Tianjin the index became high during the study time. In order to further the conclusion, we counted the seasonal H values in each city, utilizing the Mann-kendall test methods to analysis the direction and remarkable degree of the trend in different season of studying cities. The results indicated that hydrothermal condition in spring,summer and autumn is dropped notably except Tianjin. In summer, the condition is improved except Qinhuangdao.