THIS PROJECT HAS TWO MAIN COMPONENTS: IT WILL CONTINUE INFRARED OBSERVATIONS OF VENUS DURING UPCOMING INFERIOR CONJUNCTIONS TO COMPLEMENT AKATSUKI'S CURRENT INSTRUMENT SUITE AND IT WILL ANALYZE PAST AND UPCOMING OBSERVATIONS TO DETERMINE CLOUD VELOCITIES CLOUD PROPERTIES (PARTICLE SIZES AND ACIDITIES) AND TRACE GAS ABUNDANCES. THE GOALS OF THIS PROJECT ARE TO HELP AKATSUKI DATA SETS ADDRESS A HOST OF KEY QUESTIONS (LISTED BELOW) BY SUPPLEMENTING THEM WITH GROUND-BASED SPECTRAL IMAGE CUBES THAT IMPART CLOUD PROPERTIES O2 (1 D) AIRGLOW MAPS AND TRACE GAS DISTRIBUTIONS PLUS NIGHTSIDE CLOUD MOTIONS. WE WILL APPLY FOR OBSERVING TIME TO CARRY OUT THE OBSERVATIONAL COMPONENT OF THIS PROJECT. WE HAVE ALREADY APPLIED FOR TIME AT THE IRTF AND NOT (NORDIC OPTICAL TELESCOPE) FOR THE JUNE/JULY 2020 INFERIOR CONJUNCTION. IMAGING FROM THE IRTF BY ITSELF CAN RESOLVE CLOUD MOTIONS AT THE 3-5 M/S LEVEL BETTER THAN RESOLUTIONS REPORTED IN VENUS EXPRESS CLOUD TRACKING INVESTIGATIONS. LONGITUDINALLY SEPARATED SITES (LIKE THE IRTF AND NOT) CAN PROVIDE 10-H BASELINES BETWEEN CLOUD IMAGING SEQUENCES AND REDUCE CLOUD MOTION UNCERTAINTIES TO THE 1 M/S LEVEL. WE WILL ALSO APPLY FOR TIME AT THE IRTF AND OTHER TELESCOPES DURING THE JANUARY/FEBRUARY 2022 INFERIOR CONJUNCTION. THE IRTF WITH SPEX IS WELL-SUITED TO OBSERVING VENUS AT INFERIOR CONJUNCTION: WE REGULARLY OBTAIN 4-H SPANS OF NIGHTSIDE CLOUD IMAGE SEQUENCES WITH SPATIAL RESOLUTIONS OF 0.5" FROM SELECTED SHARP IMAGES. DURING IMAGING SEQUENCES WE DRIFT THE SPEX SPECTROMETER SLIT ACROSS VENUS'S DISK TO GET CONCURRENT SPECTRA FROM 0.8 TO 2.45 M COVERING CO2 WINDOWS AT 1.74 AND 2.2-2.45 M THAT ARE DIAGNOSTIC OF CO OCS H2O CLOUD PARTICLE SIZES AND CLOUD ACIDITIES. WE WILL ANALYZE THESE SPECTRA WITH SMART A RADIATIVE TRANSFER CODE THAT HAS BEEN USED WITH APO/TRIPLESPEC OBSERVATIONS OF VENUS. TO HELP US AND OTHERS BETTER EXTRACT CLOUD MOTIONS FROM IMAGING SEQUENCES WE ARE PUBLISHING VENIM (VENUS IMAGING PACKAGE) A PYTHON PACKAGE BASED ON ALGORITHMS WE DEVELOPED IN THE SUMMER OF 2018 WITH CALTECH SURF STUDENTS. THIS PROPOSAL IS COMPLIANT WITH THE C.25 ROSES CALL IN THAT IT PROVIDES GROUND-BASED OBSERVATIONS THAT COMPLEMENT AND ADD CAPABILITIES TO THE AKATSUKI DATA SETS. A SPECIFIC GOAL OF THIS PROPOSAL IS TO SUPPORT INTERNATIONAL COLLABORATIONS BETWEEN AKATSUKI INVESTIGATORS AND OURSELVES.