青岛沿海风应力和海气交换研究

Study on Wind Stress and Air-sea Exchange over Coastal Waters of Qingdao

利用实测的海洋气象资料研究了青岛沿海海气间能通量和水汽交换情况,分析了青岛沿海40a间(1961-2000)海面风应力、海-气热通量、水汽通量的大小以及时变特征。结果表明:青岛沿海风应力冬夏季大,春秋季小,6月和12月出现峰值,分别为2.9×10-3N/m2和5.8×10-3N/m2。海面净热通量全年呈单峰变化,7月份最大,为140.4W/m2;11月份最小,为-115.0W/m2;年平均海表净热通量为23.5W/m2。海面热量收支的季节分布特征是:海面吸收的太阳短波辐射夏季大、冬季小;海表有效辐射冬季大、夏季小;海-气潜热交换季节变化呈双峰分布,极大值出现在5月和9月;海-气感热交换受海气温差控制,冬季为正,热量由海洋传向大气,夏季为负,热量由大气传向海洋。受云量影响,海面吸收的太阳短波辐射从上世纪90年代以来有所增加;海-气潜热交换的年际变化显著,40a间变动范围达33.7W/m2。海-气净热通量的年际变化也很明显,40a间变动范围达41.7W/m2,且自80年代以来呈现上升的趋势。青岛沿海年平均蒸发量大于降水量,量值分别为888.0mm和677.2mm,年平均净水汽通量为-210.8mm;蒸发量的季节分布呈双峰变化,5月和9月达极大值;多年平均7,8两个月份降水多于蒸发,其余月份蒸发多于降水。

The observed meteoocean data were used to study the airsea energy flux and moisture exchanges over coastal waters of Qingdao, and the variation characteristics of sea surface wind stress, airsea heat and moisture fluxes in the area during 1961 to 2000 were analysed. It is shown from the analysis results that the wind stress is big in winter and summer and small in spring and autumn with peak values of 2.9×10-3 N/m2 and 5.8×10-3 N/m2 occurring in June and December, respectively. The variations in surface net heat flux in a year are unimodal with a maximum of 140.4 W/m2 in July and a minimum of -115.0 W/m2 in November, and the annual mean surface net heat flux is 23.5 W/m2. It is shown from the seasonal distributions of surface heat budget that the solar shortwave radiation absorbed by sea surface is big in summer and small in winter; the effective radiation of sea surface is big in winter and small in summer; the seasonal variation in airsea latent heat exchange show a bimodal distribution with the maximum values occurring in May and September; the airsea sensible heat exchange is controlled by the difference between sea and air temperatures, it is positive in winter with the heat transferred from sea to air and negative with the heat transferred from air to sea. Influenced by the cloud cover, the solar shortwave radiation absorbed by sea surface shows an increasing trend since the 1990s. The interannual variations in airsea latent heat exchange are significant with a variation range of 33.7 W/m2 in the 40 years. The interannual variations in airsea net heat flux are also significant with a variation range of 41.7 W/m2 in the 40 years, and the net heat flux shows an increasing trend since the 1980s. The annual mean amount of evaporation is larger than that of precipitation, and their values are 888.0 mm and 677.2 mm, respectively, so the annual mean net moisture flux is -210.8mm; the seasonal distribution of amount of evaporation shows a bimodal variation with the maxima occurring in May and September; the multiyear mean amounts of precipitation in July and August are larger than those of evaporation, and those of precipitation in the other months are smaller than those of evaporation.