A Numerical Microphysical Model of the Condensational Venus Cloud
A Numerical Microphysical Model of the Condensational Venus Cloud
复制标题
凝结金星云的数值微物理模型
DOI：
--
复制
发表时间：
1995
期刊：
影响因子：
--
通讯作者：
G. Schubert
中科院分区：
文献类型：
--
作者：
E. P. James;O. B. Toon;G. Schubert
一个数值微物理模型，处理一维垂直输送的硫酸/水溶液气溶胶，其成核，生长/蒸发，凝结和沉淀，适用于冷凝的中，低金星云。该模式预测的垂直廓线的硫酸气体和水蒸气，云微物理特性，和酸浓度的气溶胶粒子。模型模拟的结果同意有利的先锋金星粒径谱仪数据，消光系数和后向散射系数测量先锋金星和金星探测器，在situand远程观测云光学厚度，和硫酸蒸气丰度从麦哲伦无线电掩星数据检索。据发现，较低的金星云形成的结果，从云底以下的蒸发区的硫酸蒸汽的大向上通量。低云的形成机制可能是硫酸和水蒸气在可溶核上的异质成核。模式高度分布的水蒸气和气态硫酸的丰度证明了这些蒸汽的冷凝云的控制。云的过程解释了观测到的水蒸气浓度随海拔高度的下降，从云层以下的30 ppm下降到60公里高度的10 ppm。低云和中云的结构强烈地依赖于涡动扩散系数。因此，传输速率的变化可以解释先驱金星和金星探测器原位测量以及地球和伽利略近红外观测金星云下部所揭示的云特性的变化。
A numerical microphysical model that treats one-dimensional vertical transport of sulfuric acid/water solution aerosols, their nucleation, growth/evaporation, coagulation, and sedimentation, is applied to the condensational middle and lower Venus clouds. The model predicts the vertical profiles of sulfuric acid gas and water vapor, cloud microphysical properties, and the acid concentration of the aerosol particles. Results of model simulations agree favorably with Pioneer Venus particle size spectrometer data, extinction and backscattering coefficients measured by Pioneer Venus and Venera probes,in situand remote observations of cloud optical depth, and sulfuric acid vapor abundances retrieved from Magellan radio occultation data. It is found that the lower Venus cloud is formed as a consequence of a large upward flux of sulfuric acid vapor from the evaporation region below the cloud base. The mechanism of lower cloud formation is probably heterogeneous nucleation of sulfuric acid and water vapors on soluble nuclei. Model altitude profiles of the abundances of water vapor and gaseous sulfuric acid demonstrate the control of these vapors by the condensational cloud. Cloud processes account for the observed decline in concentration of water vapor with altitude, from ≈30 ppm below the clouds to ≈10 ppm at 60-km altitude. The structure of the lower and middle clouds is strongly dependent on the eddy diffusion coefficient. Hence, changes in transport rates may explain the variations in cloud properties revealed by the Pioneer Venus and Venera probein situmeasurements as well as by Earth-based and Galileo near-infrared observations of the lower part of the Venus cloud.