夏季南极普里兹湾海冰及其光学特征观测研究

发布时间：2018-02-24 22:31

本文关键词： 南极海冰外缘线普里兹湾反照率密集度表面温度　出处：《大连理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：基于美国冰雪数据中心的海冰外缘线和海冰面积逐月平均值数据分析了1979-2014年南极每月海冰外缘线变化和面积变化及趋势。发现南极海冰的外缘线有扩张的趋势,海冰面积也在增加,并且最近几年增速在加大。利用每月冰密集度趋势数据,分析了南极海冰在不同地区的变化趋势。根据AMSR2密集度数据(以2013年为例)分析了南极普里兹湾的海冰在一年内不同阶段的空间分布特征。湾内以季节性海冰为主,存在较大的季节变化。冬季,整个海区全部被海冰覆盖,海冰边缘线可达到57°S左右；春夏季,海冰自北向南逐渐破碎和消融；盛夏,南极沿岸的固定冰也破碎消融,海面以不连续出现的浮冰带为主。于2013-2014年南半球夏季对东南极普里兹湾海区的海冰光学特征进行了走航观测。利用安装于破冰船船头的高光谱辐照度计测量入射和反射的350-920nm的太阳短波辐射,基于观测数据计算得到了反照率。分析和比较了不同下垫面的反照率,通过比较不同航段的观测结果,得到了反照率的空间变化,以及从海冰融化期至冻结初期的变化。比较了不同波段的反照率,发现融化期由于积雪含水量较大,增加对近红外辐射的吸收,降低了该波段的反照率。结合卫星遥感(AMSR 2)和人工观测的海冰密集度,发现区域平均的反照率主要取决于海冰密集度,然而也受下垫面物理特征影响,例如2月底至3月初形成的新冰的反照率只有老冰的1/3-1/2。新冰形成,会直接增加海冰密集度,但由于其反照率较低,其对空间平均反照率的贡献较小。因此,若要建立合理的冰水混合区的反照率参数化方案,必须充分考虑海冰类型和冰面积雪的物理状态,并考虑反照率的波长依赖性。与此同时,安装在同样位置的红外辐射计观测海冰／水表面温度,计算得到表面温度在4个航段的时间和空间变化,并将表面温度与反照率和海冰密集度的关系进行了相关的分析与研究。
[Abstract]:Based on the monthly mean data of the outer edge of sea ice and the area of sea ice in the US Ice and Snow data Center, the variation and area variation and trend of the outer edge of Antarctic sea ice during 1979-2014 are analyzed. It is found that the outer edge of Antarctic sea ice has a tendency to expand. The area of sea ice is also increasing, and in recent years it has been increasing. Using monthly ice intensity trend data, The variation trend of Antarctic sea ice in different regions is analyzed. The spatial distribution characteristics of sea ice in Prydz Bay in Antarctica at different stages in one year are analyzed based on AMSR2 intensity data (2013 as an example). Seasonal sea ice dominates the sea ice in the bay. There are great seasonal variations. In winter, the whole sea area is covered by sea ice, and the marginal line of sea ice can reach 57 掳S. in spring and summer, the sea ice gradually breaks and melts from north to south, and in the middle of summer, the fixed ice along the Antarctic coast is also broken and melted. The sea surface is dominated by discontinuous ice floes. The optical characteristics of sea ice in the Prydz Bay area, East Antarctica, were observed in the summer of 2013-2014. The incidence was measured by using a hyperspectral radiometer mounted on the bow of an icebreaker. And the reflected 350-920nm solar shortwave radiation, The albedo is calculated on the basis of observation data. The albedo of different underlying surfaces is analyzed and compared. The spatial variation of albedo is obtained by comparing the observed results of different sections. And the changes from the melting period of sea ice to the initial period of freezing. By comparing the albedo of different bands, it is found that the absorption of near infrared radiation is increased during the melting period due to the high water content of snow. Combined with satellite remote sensing AMSR2) and artificial observation of sea ice intensity, it is found that the regional average albedo mainly depends on the sea ice intensity, but is also affected by the physical characteristics of the underlying surface. For example, the albedo of the new ice formed from the end of February to the beginning of March is only 1 / 3 / 1 / 2 of the old ice. The formation of new ice will directly increase the density of sea ice, but because of its low albedo, its contribution to the spatial mean albedo is relatively small. In order to establish a reasonable albedo parameterization scheme in ice water mixing area, the type of sea ice and the physical state of snow cover on the ice surface must be fully considered, and the wavelength dependence of albedo should also be taken into account. The infrared radiometer installed in the same position observed the sea ice / water surface temperature, calculated the time and space variation of the surface temperature in the four sea sections, and analyzed and studied the relationship between the surface temperature and the albedo and sea ice density.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P731.15;P714.1

【参考文献】