中文摘要：

低层大气垂直物理剖面是研究大气边界层过程、模拟大气环流过程和进行天气预报的关键参数,海洋特别是北冰洋地区是气象实测资料的稀疏区甚至是空白区。因此,中国第6次北极科学考察期间（2014年7月21日至9月11日）,我们使用GPS低空探空系统,对北极地区的大气垂直结构和边界层特征进行了观测实验。实地观测结果表明：（1）递减率对流层顶（LRT）和冷点对流层顶（CPT）均能准确的判断该地区对流层顶的高度和温度,NCEP再分析资料在较低纬度能够很好的反应对流层顶变化特征,但是在海冰密集的北极地区（海冰密集度达9成以上）则相对较差,所以很有必要在该区域开展探空观测研究。（2）在高空存在一个明显的低温区和高空急流,低温区和高空急流中心区的海拔高度与对流层顶高度一致;在晴天和少云天气,对流层顶高度变化不大;在多云和阴雨天气,随着纬度的升高对流层顶高度逐渐降低。在晴天和少云天气相比多云和阴雨天气,高空急流区的强度较弱,垂直和水平均范围较小。（3）CPT和高空急流的高度随着纬度有降低的趋势,75°N以北的区域降低显著;对流层垂直温度递减率随着纬度呈现出逐渐增大的趋势。（4）观测期间,在海拔3km以下均存在多个逆温层。其中风速切变在逆温层的消失或者减弱过程中起着重要作用,而在80°N以北区域,对流层顶逆温（TIL）明显小于其他区域。表明极点附近对流层与平流层之间的物质和能量交换相比其他区域更加强盛。

英文摘要：

Atmospheric vertical structure is a significant element to study planetary boundary layer and simulate atmospheric circulation. Therefore, based on the GPS radiosonde data obtained from the 6th Chinese Arctic expedi- tion during summer of 2014, the vertical structure of the troposphere and the boundary layer characteristics over high latitude region of the northern hemisphere and the Arctic region were analyzed. The results show that. （1） LRT and CPT can both estimate the tropopause. The NCEP reanalysis data can represent the characteristics of tropopause over lower latitude area properly, however, it is not as well in the Arctic region where ice concentration is more than 90%. It is of importance to carry out GPS radiosonde. （2） These GPS soundings reveal a vertical do- main of low temperature and high wind speed, which correspond to the tropopause. When it is sunny or cloudless, the tropopause tends to stable along the variation of the latitude. On the contrary, when it is cloudy or rainy, the tropopause tends to decrease at latitudes form 60°N to 82°N. （3） The height of the CPT and high wind speed both remarkably decrease in the region with latitude higher than 75°N. （4） All 6 regions have inversions in the bounda- ry layer. The peaks of wind speed in the boundary layer result to weaken the reversion or make the reversion dis- appear.