Grating-based GHG system for satellite validation

The Grating GHG Measurement System developed by LuftBlick is an automated, cost-effective solution for ground-based observations of greenhouse gases, primarily carbon dioxide (CO₂), methane (CH₄), water vapor (H₂O), and reactive trace gases such as nitrogen dioxide (NO₂). Designed for integration into the existing Pandonia Global Network (PGN), the system aims to enhance satellite validation through increased spatial coverage and observational capabilities.

• Develop an affordable (<€100,000), automated, grating-based measurement system.
• Improve global coverage of ground-based greenhouse gas observations.
• Enable direct sun and sky observations to support satellite validation.
• Retrieve data on the spatial distribution and vertical profiles of greenhouse and reactive trace gases.
• Facilitate rapid access to real-time, quality-controlled data.
• Ensure compatibility with existing Pandora Spectrometer Systems and integration into the Pandonia Global Network (PGN).
• Enable high-temporal-resolution retrievals of greenhouse gas column amounts.
• Perform systematic calibration and quality assurance with minimal human intervention.
• Provide freely available operational and processing software for scientific use.

Overview

The Grating GHG Measurement System project aims to develop a grating-based instrument capable of obtaining measurements of CO₂, CH₄, H₂O, and NO₂. Designed to complement existing ground-based Fourier Transform Infrared (FTIR) spectrometers, the instrument offers cost-effective installation and operation, greater potential for global deployment, and expanded observational capabilities through Multi-AXes Differential Optical Absorption Spectroscopy (MAXDOAS) for profiling and spatial analysis.

The first phase, completed in October 2024, demonstrated the technical feasibility and identified key areas for improvement – most notably, the need to replace the detector and readout electronics to enhance measurement precision and stability. Additional developments include improvements to spectral fitting algorithms, extended non-linearity correction capabilities, incorporation of pressure considerations, and refinement of data correction algorithms to address issues observed during calibration and field operations.

The second phase will implement these improvements, including hardware upgrades, refined spectral fitting algorithms, and a comprehensive uncertainty analysis. Additional field operations and intercomparisons with existing networks, such as TCCON, will be conducted to validate the system’s enhanced capabilities.