Spatiotemporal Assessment of the TEMPO Formaldehyde Column Retrieval Using the Pandonia Global Network

Area of Science:

• Atmospheric Science
• Environmental Monitoring
• Remote Sensing

Background:

• The Tropospheric Emissions: Monitoring of Pollution (TEMPO) instrument, launched in April 2023, offers unprecedented hourly, high-resolution atmospheric pollutant measurements over North America.
• Formaldehyde (HCHO) is a key air pollutant with significant implications for air quality and human health.

Purpose of the Study:

• To evaluate the performance and accuracy of the TEMPO total formaldehyde column (ΩHCHO) retrievals (version 3) during its first year of operation.
• To assess the instrument's capability across diverse geographical locations, seasons, and meteorological conditions.

Main Methods:

• Validation of TEMPO ΩHCHO data against 36 ground-based Pandora direct-sun measurements from the Pandonia Global Network (PGN).
• Comparison of TEMPO data with Pandora reference data, considering different measurement modes, times of day, and meteorological conditions.

Main Results:

• TEMPO ΩHCHO (version 3) demonstrated moderate to strong agreement with Pandora ground-based measurements (R² = 0.63 to 0.85).
• Negligible bias observed at lower ΩHCHO levels (-2 ± 20%), with a larger underestimation at higher concentrations (-22 ± 5%).
• TEMPO accurately captured seasonal variability, showing highest values in summer and significantly lower values in other seasons.

Conclusions:

• The TEMPO instrument provides high-quality ΩHCHO measurements suitable for scientific applications.
• TEMPO's hourly measurements offer a significant advantage in observational frequency compared to traditional polar-orbiting satellites.