北冰洋及其邻近海域极昼期间大气边界层结构特征试验研究

EXPERIMENT RESEARCH ON THE CHARACTERISTICS OF ABL STRUCTURE OVER THE ARCTIC OCEAN AND ADJACENT SEA AREA DURING THE POLAR DAY PERIOD

1999年 7— 9月中国“雪龙”号破冰船首航北极科学考察期间 ,利用TMT(系留式气象塔 )大气边界层探测系统 ,对北冰洋及其邻近海域不同下垫面进行较长时间的连续多次观测 .观测到的大气边界层廓线 ,其中包括比湿廓线的多层、逆湿结构 (逆湿强度最强为 0 .7g/(1 0m·kg) ) ;风向、风速廓线的切变结构 (风向切变为 1 .1°/m ,风速切变为 0 .1 1 (m·s- 1 ) /m .特别是持续数日、厚达几百米、其平均逆温强度有时高达 1 .4℃ /1 0m的逆温结构 ,这种北冰洋海域特有的大气边界层结构 ,与地球气候系统中其他圈层的大气边界层结构有明显差别 .据此 ,提出了对该海域大气 -海冰 -海洋间动量、感热和潜热等湍流通量垂直交换以及热量平衡等有重要影响的大气逆温的屏障过程 .这为研究北极地区对全球气候影响、模拟北极地区现代气候和未来气候等提供一条新的思路 .此外 ,文中还给出该海域不同下垫面稳定大气边界层的高度 .

The ABL profiles were produced by using TMT (the tethered meteorological tower) ABL sounding system on different underlying surfaces over the Arctic Ocean during a long-term continuous observation,carried out when Chinese 'Xue Long' breaker made its first voyage to the Arctic Ocean for scientific expedition from Jul. to Sept.,1999. The profiles include the humidity inversion structure (with the strongest intensity of 0.7g/(kg·10m))of the specific humidity profile and the shear structure of the wind direction and wind speed (with the wind direction shear of 1.1°/m and the wind speed shear of 0.11m·s -1/m),especially the inversion layer with the thickness of several hundred meters and the mean intensity sometimes up to 1.4℃/10m,which often lasts a few days during the polar day period. On the basis of these observation,we proposed a screen process of atmospheric inversion,which has an important influence on the vertical exchange of the turbulent fluxes between air-ice-sea momentum,sensible heat and latent heat etc. and heat balance. This proposal presents a new approach for studying the influences of the Arctic region on the global climate and the model,which needs to learn the air-ice-sea exchange for simulating the present and future Arctic area climate. In addition,We have given the depth of the stable ABL on different underlying surfaces over this ocean area.