Microwave Observations of Venus with CLASS

TL;DR

This paper presents microwave brightness temperature measurements of Venus across four frequency bands using CLASS, revealing atmospheric temperature insights and lower absorber abundances than previous studies.

Contribution

First microwave brightness temperature measurements of Venus with CLASS across multiple frequencies, providing new atmospheric temperature and composition insights.

Findings

Measured brightness temperatures at four microwave frequencies.

No dependence of temperatures on solar illumination observed.

Indicates warmer atmospheric temperatures and lower absorber abundances than prior data.

Abstract

We report on the disk-averaged absolute brightness temperatures of Venus measured at four microwave frequency bands with the Cosmology Large Angular Scale Surveyor (CLASS). We measure temperatures of 432.3 $\pm$ 2.8 K, 355.6 $\pm$ 1.3 K, 317.9 $\pm$ 1.7 K, and 294.7 $\pm$ 1.9 K for frequency bands centered at 38.8, 93.7, 147.9, and 217.5 GHz, respectively. We do not observe any dependence of the measured brightness temperatures on solar illumination for all four frequency bands. A joint analysis of our measurements with lower frequency Very Large Array (VLA) observations suggests relatively warmer ($\sim$ 7 K higher) mean atmospheric temperatures and lower abundances of microwave continuum absorbers than those inferred from prior radio occultation measurements.