부산대학교 도서관

Satellite measurements of urban CO2plumes offer a global approach to track CO2emissions for large cities. To examine and to quantify the feasibility of space‐based monitoring, an intensive measurement campaign (MERCI‐CO2) using seven solar‐tracking Fourier transform infrared (FTIR) spectrometers has been conducted over the Mexico City Metropolitan Area (MCMA) to monitor urban emissions and to evaluate Snapshot Area Map (SAM) observations from the NASA's Orbiting Carbon Observatory‐3 (OCO‐3) mission. Once adjusted for their respective averaging kernels, we diagnosed a positive difference between OCO‐3 and FTIR column measurements (1.06 ppm). Thanks to this unprecedented amount of column observations over a large city, we demonstrate that XCO2gradients within OCO‐3 SAMs align with the inter‐calibrated FTIR measurements (mean bias of 0.3 ppm), confirming the potential to track CO2emissions from space over large metropolitan areas. XCO2urban‐rural differences across the FTIR network, show a strong correlation with observed gradients, with Pearson's correlation coefficients (R) around 0.92. The correlation is significantly lower when considering intra‐urban gradients, where R drop to around 0.24. Simulated XCO2enhancements (ΔXCO2) based on X‐STILT for both FTIR and OCO‐3 show relatively high correlations (R is around 0.6) using high‐resolution footprints and two gridded inventories. Spatial correlations with OCO‐3 improve when aggregating satellite retrievals at coarser resolutions (10 km). Our study demonstrates the capabilities of detecting urban gradients by FTIR network and OCO‐3 SAM observations over MCMA, a promising result to evaluate the evolution of MCMA's emissions over the coming decade. Despite the fact that large metropolitan areas across the world account for a significant fraction of the global CO2emissions from fossil fuels, city‐scale CO2emissions estimates from inventories remain highly uncertain and usually lag real time by several years. Observations obtained from satellites and ground‐based sensors are expected to improve the quantification of CO2emissions in urban regions. Observed CO2gradients (site‐to‐site differences) over urban areas is essential for quantifying CO2emissions. In this study, we assess intra‐urban CO2gradients over the Mexico City Metropolitan Area utilizing dense observations from both space and ground. Our analysis reveals that space and ground observations exhibit greater consistency when comparing urban‐to‐rural gradients, as opposed to gradients observed exclusively within urban areas. Furthermore, simulated urban gradients based on inventories show good coherence with our observed gradients, underscoring the potential for utilizing both space and ground spatial gradients in city‐scale CO2emissions estimation. Validating fine‐scale XCO2 gradients observed by NASA's OCO‐3 Snapshot Area Map through an unprecedented deployment of dense ground‐based sensorsIntroducing a correction method in a coarser global model to establish reliable background valuesDemonstrating consistency between inventory‐simulated urban gradients and observed data from FTIR and OCO‐3 Validating fine‐scale XCO2 gradients observed by NASA's OCO‐3 Snapshot Area Map through an unprecedented deployment of dense ground‐based sensors Introducing a correction method in a coarser global model to establish reliable background values Demonstrating consistency between inventory‐simulated urban gradients and observed data from FTIR and OCO‐3