Loss of Water from Venus. I. Hydrodynamic Escape of Hydrogen
Loss of Water from Venus. I. Hydrodynamic Escape of Hydrogen
复制标题
金星的水流失。
DOI：
10.1016/0019-1035(83)90212-9
复制
发表时间：
1983
期刊：
影响因子：
3.2
通讯作者：
J. Pollack
中科院分区：
文献类型：
--
作者：
J. Kasting;J. Pollack
利用一维光化学动力学模型研究了金星原始富水大气中氢的流体动力学损失。逃逸通量的计算作为在大气冷阱的H2O混合比的函数。冷阱混合比，然后在一个近似的方式在低层大气中的H2O浓度。当低层大气中的H2O质量混合比超过0.1时，流体动力逃逸应该是氢的主要损失过程。逃逸率将取决于太阳紫外线通量的大小和大气极紫外线加热效率，并在较小程度上，对O2含量的大气。金星失去大部分陆地海洋所需的时间大约是10亿年。如果逃逸速率足够高，氘会沿着氢一起被冲走，但当逃逸速率减慢时，应该会发生一些D/H富集。
A one-dimensional photochemical-dynamic model is used to study hydrodynamic loss of hydrogen from a primitive, water-rich atmosphere on Venus. The escape flux is calculated as a function of the H2O mixing ratio at the atmospheric cold trap. The cold-trap mixing ratio is then related in an approximate fashion to the H2O concentration in the lower atmosphere. Hydrodynamic escape should have been the dominant loss process for hydrogen when the H2O mass mixing ratio in the lower atmosphere exceeded ∼0.1. The escape rate would have depended upon the magnitude of the solar ultraviolet flux and the atmospheric euv heating efficiency and, to a lesser extent, on the O2content of the atmosphere. The time required for Venus to have lost the bulk of a terrestrial ocean of water is on the order of a billion years. Deutrium would have been swept away along with hydrogen if the escape rate was high enough, but some D/H enrichment should have occurred as the escape rate slowed down.