南极长城站近二十九年气候特征

Climatic characteristics in the past 29 years at the Great Wall Station,Antarctic

使用南极长城站常规地面气象观测资料、澳大利亚南极局海冰外缘线资料和NOAA南极涛动指数资料,对长城站自1986—2014年的气候特征进行了多时间尺度的统计分析。结果表明:长城站冬季气温有升高的趋势,升温速率约为0.19℃/10 a;冬季气温与59°W经线上海冰外缘线位置的年际变化特征呈显著正相关,但对于气候平均的海冰外缘线位置月变化比气温滞后约一个月;夏季气温有降低的趋势,其他季节总体增暖。长城站的风向主要集中在西北和东南方向;1986—2014年间长城站年平均风速变化较小,大风的每年累积日数分布情况与年平均风速变化曲线相似;春季平均风速较大,并且约有半数大风风向为西北,夏季的大风天数少于其他季节。长城站年平均气压呈降低趋势,其变化与南极涛动指数呈负相关。年平均云量持续增加,且当风向为东北或西北时总云量较多;夏季平均总云量最多,冬季最少。长城站的年平均降水量变化明显,先减少后增多;降水量季节变化为秋季降水量最多,夏季次之,春季和冬季的降水量较少;日平均降水量西南风时较少,东北风时较多。雾的变化特点为春季和夏季雾天较多,其中1—3月的浓雾日数多于轻雾日数;大约三分之二有雾天的风向为西北向,约二分之一的雾出现在风力为3—4级时。

A statistical analysis of multiple-time-scale climatic characteristics at the Great Wall Station from 1986 to 2014 were explored based on the Meteorological observation data at the Antarctic Great Wall Station, outer line of sea ice data from the Australian Antarctic Division and the Antarctic Oscillation index data from NOAA. The results showed that： the winter time temperatures at the Great Wall Station tended to increase at a rate of about 0.19℃/10 a, and had a significant positive correlation with the sea ice outer line annual trends at the northern boundary of the 59℃ W , while the monthly changes of the sea ice had a one-month delay comparing to the temperature. The temperature was decreasing in summers and increasing in other seasons. The prevailing winds at the Great Wall Station mainly came from northwest and southeast. From 1986 to 2014, the annual average wind speed at the Great Wall Station remained relatively stable, and had a similar tendency comparing to the number of windy days. The average wind speed in spring was large and about half gale winds came from northwest, and windy days in summer were less than that in other seasons. The annual mean surface air pressure at the Great Wall Station was decreasing;and was negatively correlated with the Antarctic Oscillation Index. The annual mean cloud amount continued to increase, and was largest when the wind came from northeast or northwest; Seasonally speaking, it was relative larger in summer and smaller in winter. The annual mean precipitation at the Great Wall station changed significantly： firstly decrease and then increase. The seasonal precipitation was the highest in autumn, followed by summer, and lowest in spring and winter; daily average precipitation was lowest with southwest wind and highest with northeast wind. Spring and summer experienced more fog days than other seasons. Days of thick fog were more than that of light fog from January to March;about two-thirds of the days of fog experienced winds from northwest and roughly half of fog appeared with the wind of Beaufort scale 3 to 4.