Top-Of-Atmosphere simulations for Copernicus CO2M
Photo Credit: NASA/ISS
This study will provide EUMETSAT with Top-Of-Atmosphere simulations for the evaluation of data processing for the forthcoming Copernicus CO2M mission.
16 June 2021
15 June 2020
The study will produce a set of simulated measurements for the planned Copernicus CO2 monitoring mission (CO2M). The test data is intended to be used to test the operational processors which will be developed (via parallel activities) to analyse flight data.
Data from this study will be delivered in the planned (Level 1) format for top-of-atmosphere radiance data from the CO2M spectrometers. Accurate simulation of the CO2M spectrometer radiances is highly computationally intensive. It involves modelling polarised multiple scattering in the atmosphere and at the surface, including detailed representation of the many molecular absorption lines.
Much of the work of this study involves developing tools capable of simulating orbits of data within reasonable computational resources. The tools are to be developed in a flexible way such that it will become relatively straightforward to perform further work to simulate radiances for new test conditions and for the imaging sensors also planned for CO2M.
The main instrument on the proposed CO2 monitoring platform CO2M is the imaging grating spectrometer (Figure 1), measuring in the visible region between 405 and 490 nm, in the near infra-red between 747–773 nm and in two bands in the short-wave infra-red between 1590–1675 and 1990–2095 nm, with a spectral resolution between 0.12 and 0.6 nm. This study will simulate Top-of-Atmosphere radiances from these instruments for multiple day-side orbits and for a swath-width wider than 250 km.
- Implement a documented and configurable system for realistically simulating radiance measurements by the visible/near-ir/short-wave-ir spectrometers (NO2IS and CO2IS) on the CO2M.
- Use the system to generate (at least) three orbits of realistic level 1 data. Orbit geometry, sensor spatial sampling and L1 format are being provided by EUMETSAT. Correctly formatted L1 files will be provided, containing all necessary information to enable the L2 processors to be realistically tested.
The work is divided into four tasks:
- Setup of the radiative transfer model and input data. This work builds on existing tools developed and applied in an earlier EUMETSAT study to generate test data for Copernicus Sentinel-4 and 5 [Test Data for the EPS-SG instrument UVNS, NOV-7427-NT-4988, issue 4.]. A fast but accurate approach to simulate molecular absorption with polarised multiple scattering from cloud, aerosol and surface is developed.
- Collection of input data, including information on orbit sampling (from EUMETSAT), and the atmospheric state from a combination of model data from the CO2 Human Emissions (CHE) project and CAMS reanalysis.
- Production of the CO2IS datasets. Work will be carried out using the UK Jasmin high performance computing facility. The quality of the resulting data will be extensively tested and results formatted as required.
- Project Outreach. Results will be presented in suitable academic conferences. A peer reviewed publication is also planned.
The methods used and products produced by the study will be documented in a suite of technical reports.
Other CO2M studies
Ground-based network capacity analysis for CO2M
Assessing the current state of the ground-based networks crucial for CO2M mission.
Scientific support for CO2M Level-1 processing requirements
Support to EUMETSAT for the definition of Level-0 to 1 processing requirements for Copernicus CO2M mission.
Scientific service support for GHG: Level 2 algorithm prototyping for Copernicus CO2M
Providing EUMETSAT with scientific support in preparation for the forthcoming Copernicus CO2M mission.
CO2M CLIM Level-2 product requirements
Providing scientific support to EUMETSAT in establishing the requirements for the cloud products derived from the Cloud Imager (CLIM) on board the Copernicus CO2M mission.