Near-Surface Processes Affecting Gas Exchange at Summit, Greenland

9321420 Albert提议的项目是对影响格陵兰冰盖表面大气成分被纳入极地雪和雪的方式的物理过程进行实地研究。这些过程是利用深冰芯包裹体观测重建古大气特征的重要组成部分，包括雪内气流的直接输送（平流）、分子尺度的扩散（扩散）和太阳辐射穿透雪的作用。大气成分的空气到雪的转移被这种过程过滤并可能被改变。目标是定义这些转移过程在空间和时间上的大小和范围，并发展过程级的理解和对这些过程建模的能力。1994年夏季将在格陵兰中部进行实地研究，以确定关键参数的空间和时间变化，并观察约束模式所需的边界条件。将扩展并验证现有的多维数值模型，以模拟平流、扩散和辐射传输/吸收过程。＊＊＊

9321420 Albert The proposed project is a field study of the physical processes that affect the manner in which atmospheric constituents are incorporated into polar snow and firn at the surface of the Greenland ice sheet. These processes are an important component in reconstructing the characteristics of paleoatmospheres from the observation of inclusions in deep ice cores, and consist of the direct transport by the flow of air within the snow (advection), the molecular scale dispersion (diffusion), and the effects of solar radiation penetrating into the snow. The air-to-snow transfer of atmospheric constituents is filtered and potentially altered by such processes. The objectives are to define the magnitude and extent in space and time of these transfer processes, and to develop a process-level understanding and a capability to model these processes. Field studies will be conducted in central Greenland in the summer of 1994 to determine the spatial and temporal variability of key parameters, and to observe boundary conditions needed to constrain the model. An existing multidimensional numerical model will be extended and verified to simulate the advection, diffusion, and radiation transmission/absorption processes. ***