渤海冰期的基本水文气象参量研究

A Study of Basic Hydrologic and Meteorological Parametersin the Ice-covered Bohai Sea

渤海是一个中纬度的超浅海,每年都会产生不同程度的结冰现象,这给海上生产和作业带来了很大的威胁.而冰情的严重程度则由该年冬季的水文气象条件决定.本文应用1997年1月辽东湾冰调资料和锦州20—2平台的部分资料,比较详尽地研究了渤海冰期的基本水文气象参量,其中包括太阳短波辐射、长波辐射、风速和风向、湿度,海冰导热率和比热等.研究发现:(1)太阳短波辐射是影响渤海海面热量平衡的重要因子,是引起海面能量失衡的重要因子.应用Laevastu(1960)公式的简化形式可以基本满足计算渤海区域太阳短波辐射的需要,(2)根据观测,冰面上的大气相对湿度约为50%,而水面上的相对湿度约为90%;(3)风速和海面气温是引起海面热量失衡的另两个重要因子.气温越低,风速越大,海面损失的热量就越多,低温和大风是造成1997年1月期间海冰迅速发展的最直接原因;(4)海面长波辐射比较稳定,冬季时一般在100W/m^2左右,随气温和海面温度会有一些变化,但变化幅度一般小于30W/m^2.(5)由于海冰随存在时间的延长其盐度会逐渐减小,因此会对海冰的比热、导热率和凝结潜热等产生影响.在渤海,海冰的导热率和凝结潜热变化很小,可以看作是常量;而比热则变化较大,应引起足够的重视.

Based on the sea ice investigation in the Liaodong Bay and observations on Platform JZ20 -2 in January, 1997, the basic hydrologic and meteorological parameters in the Bohai Sea are studied. These parameters consist of sonar short wave radiation, long wave radiation, wind velocity and direction, air humidity and some thermal properties of the sea ice. And some results are obtained as follows: (1)Sonar short wave radiation is an important factor affecting the energy balance in the Bohai Sea, and the simplified form of Laevastu (1960) formula can be used to calculate it in the Bohai Sea; (2) According to the observations, the air humidity is about 50% above the sea ice surface, and about 90% above sea water surface in the winter; (3) Wind velocity and air temperature are another two important factors affecting energy balance, and the stronger the wind is,the lower the temperature is, the more energy the sea surface loses; (4) Sea surface net long wave loss is almost static in winter; (5) In the Bohai Sea, the thermal conductivity and latent heat of sea water condensation can be regarded as being constant, but the specific heat is varying within a sizable range.