土卫六大气数值模拟研究

Numericla simulation of Titan's atmosphere is one of the most important area in planetary atmosphere research. The PGCM simulated the basic atmosphere circulation of Titan well, including the superrotation on the stratosphere over the equator, zonal wind circulation, vertical wind profile, east wind near the surface. The results are as follows: zonal wind is very strong especially at the upper stratosphere, whose largest velocity reaches 108 m s-1 so called supperrotation; Meridional and vertical velocities are very small at the whole levels, which means that the meiridional mean wind and circulation are very weak; Meridional circulation has the characteristic of two cells and distributes disorderly near surface; At the height between 30 and 100 hPa, there is a sink on the vertical wind profile named 'zonal wind sink', which is more obvious at low latitude between 30S and 30N than high latitude. The special phenomenan is related to the specail atmosphere on Titan. The physical parameterization will be improved for a better simulation result. More researchs about Titan's atmosphere will be done by simulations and theories. At the same time, it will improve people's acknowledge on the Earth's atmosphere.

土卫六大气的数值模拟研究是行星大气研究的重要领域。本项目使用行星大气模式PGCM充分地模拟土卫六大气环流的基本结构，例如赤道上空平流层超级旋转、经圈环流、垂直廓线以及近地面东风等等。模拟结果初步显示：在土卫六上，纬向风速很大，尤其是在赤道上空的平流层，最大风速达到108m/s，即超旋转现象；整层大气的经向风速和垂直风速都非常小，环流较弱；经圈环流以两圈环流为主要分布特征；风场的垂直廓线在30~100 hPa高度之间呈凹陷状，即所谓的"西风塌陷"现象，这一变化特征主要发生在30 S和30 N之间，这一现象可能与土卫六独特的大气成分和结构相关。本项目将进一步完善PGCM物理参数化方案,并通过一系列的模拟试验和理论推导来完善土卫六大气状况的初步研究。同时，通过对比来加强对地球大气规律的认识。