Tomasko M G, Doose L R, Smith P H
Science. 1979 Jul 6;205(4401):80-2. doi: 10.1126/science.205.4401.80.
In this report the fluxes measured by the solar flux radiometer (LSFR) of the Pioneer Venus large probe are compared with calculations for model atmospheres. If the large particles of the middle and lower clouds are assumed to be sulfur, strong, short-wavelength absorption results in a net flux profile significantly different from the LSFR net flux measurements. Models in which the smallest particles are assumed to be sulfur gave flux profiles consistent with the measurements if an additional source of absorption is included in the upper cloud. The narrowband data from 0.590 to 0.665 micrometer indicate an absorption optical depth of about 0.05 below the cloud bottom. The broadband data imply that either this absorption extends over a considerable wavelength interval (as might be the case for dust) or that a very strong absorption band lies on one side of the narrowband filter (as suggested by early Venera 11 and Venera 12 reports). Thermal balance calculations based on the measured visible fluxes indicate high surface temperature for reasonable assumptions of cloud opacity and water vapor abundance. The lapse rate becomes convective within the middle cloud. For water mixing ratios of 2.0 x 10(-4) below the clouds we find a subadiabatic region extending from the cloud bottom to altitudes near 35 kilometers.
在本报告中，将先锋金星大探测器的太阳通量辐射计（LSFR）测量的通量与模型大气的计算结果进行了比较。如果假设中下层云的大颗粒为硫，强烈的短波吸收会导致净通量剖面与LSFR净通量测量结果显著不同。如果在上层云中包含额外的吸收源，假设最小颗粒为硫的模型给出的通量剖面与测量结果一致。0.590至0.665微米的窄带数据表明云底以下的吸收光学深度约为0.05。宽带数据表明，要么这种吸收在相当大的波长区间内延伸（如尘埃的情况），要么在窄带滤光片的一侧存在一个非常强的吸收带（如早期金星11号和金星12号报告所暗示的）。基于测量的可见通量进行的热平衡计算表明，在合理假设云的不透明度和水汽丰度的情况下，表面温度较高。在中层云内，递减率变为对流状态。对于云下2.0×10⁻⁴的水混合比，我们发现一个从云底延伸到海拔约35公里高度的次绝热区域。
