Global climate change has become a significant challenge facing human society, with greenhouse gas (GHG) emissions being one of its primary driving factors. To effectively assess global progress in greenhouse gas reduction, the Paris Agreement established the Global Stocktake (GST) mechanism, which requires independent verification of national GHG emission inventories. However, existing “bottom-up” emission inventories face significant uncertainties in compilation methods, data completeness, and verifiability, making it difficult to meet the need for high-precision, standardized carbon emission data for the GST. Therefore, it is urgent need to develop “top-down” satellite monitoring methods to enhance the transparency and scientific rigor of carbon emission inventory verification.This study focused on the requirement analysis and design for China’‍s next-generation carbon monitoring satellite (TanSat-2). Based on Observing System Simulation Experiments (OSSE), an evaluation framework for satellite program assessment was constructed, and a carbon satellite design proposal aimed at GST needs is presented. First, a satellite verification technology system for GHG emission inventories at multiple scales (“global-regional-hotspot”) was established, defining key technological requirements for inventory verification at different scales and proposing uncertainty constraints for the next-generation carbon satellite inventory verification. Second, a multi-component synergistic observation and anthropogenic emission source separation technology system was developed by integrating “greenhouse gases-pollutant gases-vegetation fluorescence”. The system was applied to evaluate the ability of satellite carbon monitoring to distinguish between ecosystem carbon cycles and anthropogenic carbon emissions, leading to the development of a scientific product indicator system. Additionally, we assessed the impact of various payload technical parameters (spectral resolution, signal-to-noise ratio, wavelength range, etc.) on the retrieval errors of each observation element. The technical indicators for GHG, pollutant gas, aerosol, and Solar-Induced Chlorophyll Fluorescence (SIF) detection payloads was qualified, aligned with the engineering capabilities and constraints of satellite platforms and payloads.Based on this, a design for the TanSat-2 platform was completed, incorporating multi-component, high-temporal, multi-scale, and high-precision capabilities. A mid-orbit elliptical frozen sun-synchronous orbit satellite scheme was proposed. The TanSat-2 was designed to equipped with three advanced effective payloads: (1) the Ultra-wide-field Carbon Pollution collaborative monitoring Instrument (UCPI), (2) the Hotspot Greenhouse gas Emission Tracker (HGET), (3) the Cloud Aerosol Polarization Imager (CAPI). With a coverage capacity of up to a thousand kilometers, UCPI was designed for monitoring carbon emissions at the national and regional scales. HGET was specially designed for detailed monitoring of major emission sources, capable of high spatial resolution for hotspot area investigation. And CAPI was designed to optimize GHG inversion accuracy and reduce the uncertainty of aerosol scattering in the remote sensing inversion of CO_2, CH₄, and other gases.

TanSat-2; Inventario de carbono; Emisiones de carbono; Teledetección por satélite; Asimilación