Recent Updates to the NUCAPS CH4 and CO2 Products and Inter-comparison to Other Satellite Products

The NOAA Unique Combined Atmospheric Processing System (NUCAPS) was upgraded for the Cross-track Infrared Sounder (CrIS) thermal sensors on SNPP and NOAA-20 satellites using in situ data collected in the 2014-2018 timeframe. The upgrades focused on trace gas products such as carbon monoxide (CO), methane (CH₄), and carbon dioxide (CO₂). However, recent observations revealed that NUCAPS CH₄ and CO₂ products did not reflect the accelerated increase in concentrations over the past two years. Consequently, the NUCAPS algorithm was adjusted to reflect these changes.

Moreover, NUCAPS can process retrievals from other sensors like AIRS and IASI, enhancing its robustness. We will present updates and evaluations, including comparisons with AIRS, IASI, TROPOMI (for CO and CH₄), and OCO-2 (for CO₂). The results demonstrate that NUCAPS products align well with other satellite data in terms of global distribution, seasonality, and trends. Additionally, we will highlight differences due to the vertical information content from thermal sensing versus sensors using shortwave solar energy.