Using satellite-based Other Long-Lived GHGs datasets for climate models applications and climate studies : The ESA LOLIPOP CCI project

To gain a comprehensive understanding of the Earth’s climate system, it is essential to consider all the atmospheric gases with high global warming potential or substantial effects on the ozone layer. Besides CO₂ and CH₄, nitrous oxide (N₂O) and halogenated carbon compounds—such as CFCs, HFCs, HCFCs, and PFCs—collectively classified as Other Long-Lived Greenhouse Gases (OLLGHGs), are particularly important due to their long atmospheric lifetimes and strong warming influence. In addition, nitrous oxide and chlorine-containing compounds are major contributors to anthropogenic ozone depletion.

The Long-Lived Greenhouse Gas Products Performance (LOLIPOP) Climate Change Initiative (CCI+) project, initiated by ESA in 2023, focuses on the OLLGHGs through the exploitation of multi-mission, satellite-based datasets. The main objective of the project is to assess whether the current suite of satellite observations is sufficiently robust for its use in climate science and climate services. If that is the case, the development of a harmonized and consistent dataset will be pursued in the future. Conversely, if limitations are identified, recommendations will be provided to improve the quality of satellite measurements of the OLLGHGs or to develop dedicated satellite missions for their monitoring.

Within the project, an inventory of available limb and nadir satellite datasets has been compiled for 11 OLLGHGs. Based on the outcomes of a literature review, the user needs (identified through a survey), and the dataset inventory, a subset of data has been selected for homogenization and intercomparison/validation exercises. The potentiality of satellite datasets for climate research and modeling is further demonstrated in the project through five test cases addressing the sensitivity of climate model simulations to OLLGHGs, including their radiative forcing, atmospheric lifetimes, and impacts on the stratosphere, such as effects on ozone recovery and atmospheric circulation. A growing community of scientific users is engaging with the project and has been involved in discussions on data quality and needs at a recent user workshop. Results from these studies, together with findings from the user needs survey and the dataset quality assessment, will be presented.