The Observation, Diagnosis And Analysis For The Climate In The Coastal Region Of Bohai Bay

Along with the booming economy, the economic belt of Bohai Coastal Ring in China has become an important developing point for the north China. As the core of this Ring, the coastal region of Bohai Bay includes the industrial center of Tianjin City and the national political center of Beijing City. In addition, the construction of new developing districts titled'Binhai'in Tianjin city and'Bohai'in Hebei Province, has stimulated the local economy with new energy. In addition, Chinese government has setup national project to exploit the sea ice in Bohai Sea as a resource of fresh water to solve the local fresh water shortage problem. Therefore, the local climate background information is strategically important either for the local economic development or for of sea ice exploitation. This paper treated the climate in the Bohai Bay Coastal Region as the object. The temporal and spatial climate patterns for the study region were deeply studied by combining statistical analysis of the field observed data and long time officially observed data in recent 50 years.The data from the field observed data showed that the Sea Land Breeze is in existence in the Western Coast of Bohai Bay, The observation dates could be separated as Sea Land Breeze Day and Non Sea Land Breeze Day according to the wind direction changes in the observation dates. The impact area of the Sea Land Breeze could penetrate 74km inland in a Sea Land Breeze Day. The generation and intensity of the Sea Land Breeze were closely related to the distance of the station to the coastline, the season that the observation was in and the instant climate then. Near coast region, summers and sunny day were favorable to the development of Sea Land Breeze.In the three observations, the daily temperature in the near coast rose and fell more rapidly than that in regions inland. The daily temperature changed faster in fall and winter in comparison with that in summer. The daily average temperature and daily extreme low temperature decreased from the coast to inland, while daily extreme high temperature and daily temperature difference increased from the coast to inland. The spatial temperature difference from near coast to inland was comparatively greater at Sea Land Breeze Day than that in Non Sea Land Breeze Day.In the 150km region within the Bohai Bay Coastline, the annual average temperature increased with a vibrating pattern in recent 150 years, and the annual temperature difference to average has kept positive since 1990. The seasonal temperatures also surged with different degrees, however, the winter temperature slowed down its increasing rate after it entered the 21st century. Spatially, the annual and seasonal temperature both followed the latitude law and the pattern of Sea-Land difference. The annual temperature of the 75-150km region was significantly higher than that within the 75km range. The spring and summer temperature increased when it moved from near coast to inland, but inversed in autumn and winter. It was greater in spring and autumn than summer and winter for absolute value of temperature difference between near land and far land.The annual precipitation has dropped by 150mm in recent 50 years. 1998-2007 had the most significant rainfall decreasing rate in recent 50 years, which showed a probable drought tendency in the study area. The seasonal precipitation showed a most significant falling in summer, which has been behaving lower than -100mm below average values constantly since 2000. Spatially, the range within 75km to the coastline had more precipitation than the 75-150km range either for annual or seasonal value. Because there are mountains existing in 40-75km range, it had the most annual, summer and autumn precipitation. The Standardized Precipitation Index (SPI) showed that this region was frequently attacked by severe spring and summer droughts. It has been displayed that the region within 75km to the coastline tended to have much more severe drought in severe spring and summer drought cases. Fortunately, it has been verified that the drought problem could be solved perfectly and well in time by the proposed large scale exploitation of the sea ice in Bohai Bay.