Update on the progress and operations of the Pandonia Global Network (PGN)

The Pandora Spectrometer System (Pandora) for the ground-based, sun/sky/lunar passive remote sensing of trace gases in the UV/Vis spectral wavelengths was first developed in 2005. Since that time Pandora has continued to evolve with its use in a series of field campaigns such as DISCOVER-AQ, CINDI 1&2, KORUS-AQ, LMOS, OWLETS 1&2 and LISTOS. NASA and ESA are collaborating on the creation and expansion of a coordinated, global network of standardized, calibrated Pandora's focused on air quality and atmospheric composition (AQ/AC). The Pandonia Global Network (PGN) aims to ensure systematic processing and dissemination of the quality assured and quality controlled (QA/QC) data to the greater global community. A major joint objective is the validation and verification of the future CEOS AC-VC for observing global air quality using multiple LEO and GEO satellites, e.g. Sentinel 5P, OMPS, EMI GaoFen-5, Sentinel 5, GEMS, TEMPO, and Sentinel 4. PGN participants are primarily comprised of governmental and academic researchers and technicians. The network represents a programmatic shift by NASA and ESA away from primarily research/field campaign mode to long-term fixed observations focused on providing total column and vertically resolved observations of a range of trace gases. In the U.S. this includes the integration of a subset of the PGN instruments into the existing U.S. AQ monitoring network as part of PAMS and CASTNet. Major trace gases observed by Pandora include: O3 , NO2 , HCHO, and SO2 . The presentation covers the roles and responsibilities of the NASA and ESA designated teams and network progress to date. Insights regarding standardized calibration, real-time data processing, and determination of Pandora accuracy and precision, are presented. Guiding principles, expectations, and protocols of PGN participation are also discussed. This network and its evolution have been modeled in spirit to other, similar, ground-based atmospheric composition networks, most notably AERONET, TOLNET, and MPLNET.