Models of the global cloud structure on Venus derived from Venus Express observations
Models of the global cloud structure on Venus derived from Venus Express observations
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DOI：
10.1016/j.icarus.2011.05.018
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发表时间：
2012-02-01
期刊：
影响因子：
3.2
通讯作者：
Tellmann, S.
中科院分区：
文献类型：
--
作者：
Barstow, J. K.;Tsang, C. C. C.;Tellmann, S.
利用金星快车上的可见光和红外热成像光谱仪（VIRTIS）的空间分辨近红外光谱，推导出金星南半球云层性质垂直结构和全球分布的改进模型。VIRTIS首次实现了金星在1.6-2.6 μ m透明窗口波长范围内的系统全球制图，该波段在夜侧对低层大气热发射辐射被低层和中层云层吸收非常敏感（Taylor, f.w., Crisp， D., Bezard， B.[1997]）。金星11号：地质、地球物理、大气和太阳风环境，第325-351页)。用于解释光谱的云模型是基于Pollack等人以前的工作（Pollack， J., Dalton， J., Grinspoon， D., Wattson， R., Freedman， R., Crisp， D., Allen， D., Bezard， B., de Bergh， C., Giver, L .[1993]）。（gringspoon， D.H, Pollack， J.B, Sitton， BR）。卡尔森，r.w.，坎普，LW。陈国强，陈国强，陈国强[1993]。星球。空间科学41,515-542)和Crisp （Crisp， D. [1986].）伊卡洛斯67,484-514)，并假设硫酸和水的云粒子组成，酸浓度作为一个自由参数有待确定。其他检索参数是粒子的平均大小和模型中云底的高度。利用金星射电科学实验（VeRa）的数据，结合了大气温度结构的纬度变化。最初使用对每个参数的独特灵敏度选择的波长对来估计值，然后通过比较整个波长范围内的测量光谱和计算光谱来验证，后者使用NEMESIS辐射传输和检索代码（Irwin， P.G.J, Teanby， NA）生成。， de Kok， R., Fletcher, l.n., Howett， C.J.A, Tsang， C.C.C, Wilson， C.F, Calcutt, s.b., Nixon， C.A, Parrish， P.D.[2008]。J.量子光谱。Radiat。译。109,1136-1150)。在光学厚度较厚的云中，云颗粒中的硫酸浓度较高。云底高度与纬度有关，在-50度附近达到最大高度。Wilson等人发现（Wilson, c.f., Guerlet， S., Irwin, p.g.j., Tsang, c.c.c., Taylor, f.w., Carlson, r.w., Drossart， P., Piccioni， G.[2008]）。j .地球物理学。Res. (Planets) 113, E12)和Tsang等人首次报道的35-40 km海拔高度水汽丰富度空间变化的发现(Tsang， C.C.C, Wilson, c.f., Barstow, j.k., Irwin, p.g.j., Taylor, f.w., McGouldrick， K, Piccioni， G., Drossart， P., Svedhem， H.[2010]。地球物理学。Res. Lett. 37, L02202)都得到了确认。简要讨论了这些改进的云结构和变率描述对金星化学、气象和辐射能量平衡的影响。(C) 2011爱思唯尔公司版权所有。
Spatially-resolved near-infrared spectra from the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) on Venus Express have been used to derive improved models of the vertical structure and global distribution of cloud properties in the southern hemisphere of Venus. VIRTIS achieved the first systematic, global mapping of Venus at wavelengths within transparency windows in the 1.6-2.6 mu m range, which are sensitive on the nightside to absorption by the lower and middle cloud layers of thermally-emitted radiation from the hot lower atmosphere (Taylor, F.W., Crisp, D., Bezard, B. [1997]. Venus 11: Geology, Geophysics, Atmosphere, and Solar Wind Environment, pp. 325-351). The cloud model used to interpret the spectra is based on previous work by Pollack et al. (Pollack, J., Dalton, J., Grinspoon, D., Wattson, R., Freedman, R., Crisp, D., Allen, D., Bezard, B., de Bergh, C., Giver, L [1993]. Icarus 103, 1-42), Grinspoon et al. (Grinspoon, D.H., Pollack, J.B., Sitton, BR., Carlson, R.W., Kamp, LW., Baines, K.H., Encrenaz, T., Taylor, F.W. [1993]. Planet. Space Sci. 41, 515-542) and Crisp (Crisp, D. [1986]. Icarus 67,484-514), and assumes a composition for the cloud particles of sulfuric acid and water, with acid concentration as a free parameter to be determined. Other retrieved parameters are the average size of the particles and the altitude of the cloud base in the model. Latitudinal variation in the atmospheric temperature structure was incorporated using data from the Venus Radio Science experiment (VeRa). Values are estimated initially using wavelength pairs selected for their unique sensitivity to each parameter, and then validated by comparing measured to calculated spectra over the entire wavelength range, the latter generated using the NEMESIS radiative transfer and retrieval code (Irwin, P.G.J., Teanby, NA., de Kok, R., Fletcher, L.N., Howett, C.J.A., Tsang, C.C.C., Wilson, C.F., Calcutt, S.B., Nixon, C.A., Parrish, P.D. [2008]. J. Quant. Spectrosc. Radiat. Trans. 109, 1136-1150). The sulfuric acid concentration in the cloud particles is found to be higher in regions of optically thick cloud. The cloud base altitude shows a dependence on latitude, reaching a maximum height near -50 degrees. The increased average particle size near the pole found by Wilson et al. (Wilson, C.F., Guerlet, S., Irwin, P.G.J., Tsang, C.C.C., Taylor, F.W., Carlson, R.W., Drossart, P., Piccioni, G. [2008]. J. Geophys. Res. (Planets) 113, E12) and the finding of spatially variable water vapor abundance at 35-40 km altitude first reported by Tsang et al. (Tsang, C.C.C., Wilson, C.F., Barstow, J.K., Irwin, P.G.J., Taylor, F.W., McGouldrick, K., Piccioni, G., Drossart, P., Svedhem, H. [2010]. Geophys. Res. Lett. 37, L02202) are both confirmed. The implications of these improved descriptions of cloud structure and variability for the chemistry, meteorology, and radiative energy balance on Venus are briefly discussed. (C) 2011 Elsevier Inc. All rights reserved.