融池辐射特性及其对北极夏季海冰快速融化影响机制的研究

The impact of melt pond on Arctic sea ice surface on the melting of sea ice in summer has attracted many attentions of people, but a deep understanding on the physical mechanism inside this influence process and the quantitative degree of the impact is still absent. In this proposal, aiming at the radiative characteristics of melt pond, simultaneous observations on the basic physical properties and radiative characteristics of melt pond and underlying ice are planned to carried out during field investigations, combining with tests of radiative transfer and physical modeling of the full-process of sea ice melting conducted in laboratory experiments, observational evidences for the key process during melting seasons, namely variations in microstructure of ice—changes in inner optical properties of ice—alterations in melt-pond albedo, will be obtained. These data will serve to improve the radiative transfer model of sea ice with considerations of difference conditions of surface melting, and to develop a parameterization relationship between melt pond albedo and pond water properties and microstructure of underlying ice. Through applications of the parameterization in a one-dimensional sea ice thermodynamic model, the situation in present numerical modeling where pond albedo is a constant or only associated with pond depth will be changed. Numerical modeling on the melting process of summer sea ice with melt pond on surface, snow on surface and bare ice case will be conducted, to evaluate the difference in physical properties, radiative transfer, melt rate of inner ice under different surface conditions, and the important role of melt ponds in the mass and energy balance of summer Arctic sea ice can be explored. This study will provide solid theoretical supports to the improvement of the capability of numerical modeling on the rapid decline of Arctic sea ice.

北极冰面融池对夏季海冰融化的影响虽然已经为人们所关注，但对其内在影响机制以及定量的影响程度仍缺乏深刻理解。以融池的辐射特性为切入点，通过在现场调查中实施融池水体和池底冰层基本物理性质和辐射特性的同步观测，结合实验室开展对冰表面融化全过程的物理模拟和辐射传输实验，获得海冰融化过程中冰内微观结构变化引起内在光学性质变化、进而影响融池反照率这一关键物理过程的观测依据。在此基础上发展考虑不同表面融化情况的海冰辐射传输模型，建立融池反照率与水体、冰层性质以及冰内微观结构的参数化关系。通过在一维海冰热力学模式中的应用，改变模式中融池反照率为常数或仅与融池水深相关的现状，并对融池覆盖、裸冰、积雪覆盖等不同表面形态的夏季海冰融化过程进行模拟研究，评估不同表面形态下冰内部物理性质、辐射传输、融化速率的差异，揭示融池对海冰质量和能量平衡的影响，为提高数值模拟对北极海冰快速变化的模拟能力提供重要理论支持。

针对北极冰面融池对海冰快速变化的重要影响，以融池辐射特性为切入点开展了现场观测、实验室试验和数值模拟研究。认识了北极海冰分布与融池覆盖率的时空变化规律，发现了快速变化大背景下北极夏季海冰基本物理性质的重大变化，获得了不同表面形态条件海冰辐射特性的变化规律。通过发展融池辐射传输模式，并通过湖冰野外试验和实验室物理模拟试验的补充，发展了适应于快速变化北极海冰的融池反照率参数化方案，获得太阳辐射在融池水体、底部海冰和冰下海洋中吸收和分配的影响规律，揭示了融池对冰内能量收支和质量平衡的重大影响。发展了融池颜色的数学分析方法，获得了融池颜色变化规律及其与不同影响因素的定量联系，发现了利用融池颜色反演夏季海冰厚度的可能性。在《Journal of Geophysical Research-Oceans》、《The Cryosphere》等国内重要学术期刊和会议上共发表与项目研究相关论文12篇，其中SCI检索5篇。培养优秀青年科学基金获得者1名、全国博士后博新计划资助获得者1名；1人获得博士学位，4人获得硕士学位。