Microwave remote sensing of the temperature and distribution of sulfur compounds in the lower atmosphere of Venus
Microwave remote sensing of the temperature and distribution of sulfur compounds in the lower atmosphere of Venus
复制标题
金星低层大气温度和硫化合物分布的微波遥感
DOI：
10.1006/icar.2002.6894
复制
发表时间：
2001
期刊：
影响因子：
3.2
通讯作者：
P. Steffes
中科院分区：
文献类型：
--
作者：
J. Jenkins;M. Kolodner;B. Butler;S. Suleiman;P. Steffes
摘要：1996年4月5日，利用甚大阵列（甚大阵列）对金星进行了多波长射频观测，研究金星大气中温度和硫化物二氧化硫（SO2）、硫酸蒸气（H2SO4(g)）的垂直和水平分布变化。在两种观测频率下，亮度温度图的特征是极地地区与较亮的低纬度地区相比明显变暗。这是第一次在对金星的无线电波长观测中明确地看到这样的极地特征。图中显示的边缘变暗有助于限制H2SO4(g)、温度和一定程度上SO2的垂直分布。在假定SO2的云下丰度的情况下，应用检索算法对这些图进行解释，生成温度和H2SO4(g)丰度的垂直剖面。结果表明，高纬度地区（45°以上）的H2SO4(g)丰度明显高于低纬度地区。在低于40公里的高度（取决于位置和假设的SO2丰度），检索到的温度曲线比先锋金星探测器获得的温度曲线高25 K。对于150ppm的SO2，它更符合水手5号通过干绝热器外推到地表的温度剖面。在高纬度地区获得的H2SO4(g)剖面与麦哲伦无线电掩星实验的结果一致，在海拔46公里处达到8 ppm左右的峰值，并在该高度处迅速衰减。在低纬度地区，无论假设的SO2含量如何，都没有观察到显著的H2SO4(g)。这远低于水手10号（Lipa and Tyler 1979, icarus39,192 - 208）的测量值，水手10号在47公里附近的峰值为~ 14 ppm。我们的研究结果表明，低纬度地区SO2浓度≤100ppm，极地地区≤50ppm。低纬度值在统计上与Bezard et al. （1983, Geophs.）的结果一致。Res. letter . 20,1587 - 1590)，他们发现云下SO2丰度为130±40 ppm与他们在近红外波段的观测结果最吻合。反演的温度剖面和极地地区较高的H2SO4(g)丰度与金星大气中Hadley细胞造成的强烈的赤道到极地云层流动相一致。
Abstract A multi-wavelength radio frequency observation of Venus was performed on April 5, 1996, with the Very Large Array to investigate potential variations in the vertical and horizontal distribution of temperature and the sulfur compounds sulfur dioxide (SO2) and sulfuric acid vapor (H2SO4(g)) in the atmosphere of the planet. Brightness temperature maps were produced which feature significantly darkened polar regions compared to the brighter low-latitude regions at both observed frequencies. This is the first time such polar features have been seen unambiguously in radio wavelength observations of Venus. The limb-darkening displayed in the maps helps to constrain the vertical profile of H2SO4(g), temperature, and to some degree SO2. The maps were interpreted by applying a retrieval algorithm to produce vertical profiles of temperature and abundance of H2SO4(g) given an assumed sub-cloud abundance of SO2. The results indicate a substantially higher abundance of H2SO4(g) at high latitudes (above 45°) than in the low-latitude regions. The retrieved temperature profiles are up to 25 K warmer than the profile obtained by the Pioneer Venus sounder probe at altitudes below 40 km (depending on location and assumed SO2 abundance). For 150 ppm of SO2, it is more consistent with the temperature profile obtained by Mariner 5, extrapolated to the surface via a dry adiabat. The profiles obtained for H2SO4(g) at high latitudes are consistent with those derived from the Magellan radio occultation experiments, peaking at around 8 ppm at an altitude of 46 km and decaying rapidly away from that altitude. At low latitudes, no significant H2SO4(g) is observed, regardless of the assumed SO2 content. This is well below that measured by Mariner 10 (Lipa and Tyler 1979, Icarus39, 192–208), which peaked at ∼14 ppm near 47 km. Our results favor ≤100 ppm of SO2 at low latitudes and ≤50 ppm in polar regions. The low-latitude value is statistically consistent with the results of Bezard et al. (1983, Geophs. Res. Lett.20, 1587–1590), who found that a sub-cloud SO2 abundance of 130±40 ppm best matched their observations in the near-IR. The retrieved temperature profile and higher abundance of H2SO4(g) in polar regions are consistent with a strong equatorial-to-polar, cloud-level flow due to a Hadley cell in the atmosphere of Venus.