Automated Pipeline for Venusian Cloud Tracking
Abstract
At 2.3 microns, a gap in the absorption spectrum of Venus' CO2-atmosphere allows observations of the nightside, where the lower clouds show up as silhouettes, backlit by thermal emission from below. Observations in this region are of particular interest for determining wind velocities via cloud tracking. Wind velocity measurements allow us to compare observed winds with those predicted by Global Circulation Models (GCMs). Of particular interest are latitudinal wind-velocity profiles, time-varying cycles in the Venusian atmosphere, and correlation of wind speeds with surface features. We are currently investigating all of the above. We present an automated pipeline for data reduction, from raw images of Venus' nightside to useful wind velocity maps using cloud-tracking methods. By stacking subsets of the sharpest Venus images, we are able to achieve angular resolutions of 0.5" or better, corresponding to an approximately 150 km resolution near the center of Venus' disk. From these image stacks we are able to extract wind velocity fields over the night side with at least 20 latitudinal divisions, RMS errors of approximately 5 m/s, and temporal changes in wind speeds at the 10% level or less. We use this pipeline to reduce data from the IRTF's SpeX instrument, spanning over 15 years of observation. In particular, we compare methodology and results between two image sets: an IRTF campaign from April-May 2017 and Akatsuki IR2 images taken in 2016.
- Publication:
-
AAS/Division for Planetary Sciences Meeting Abstracts #50
- Pub Date:
- October 2018
- Bibcode:
- 2018DPS....5011908A