Assimilating Morning, Evening, and Nighttime Greenhouse Gas Observations in Atmospheric Inversions
Year: 2024
Type: article
Abstract: Improved urban greenhouse gas (GHG) flux estimates are crucial for informing policy and mitigation efforts. Atmospheric inversion modeling (AIM) is a widely used technique combining atmospheric measurements of trace gas, meteorological modeling, and a prior emission map to infer fluxes. Traditionally, AIM relies on mid‐afternoon observations due to the well‐represented atmospheric boundary layer in meteorological models. However, confining flux assessment to daytime observations is problematic for the urban scale, where air masses typically move over a city in a few hours and AIM therefore cannot provide improved constraints on emissions over the full diurnal cycle. We hypothesized that there are atmospheric conditions beyond the mid‐afternoon under which meteorological models also perform well. We tested this hypothesis using tower‐based measurements of CO 2 and CH 4 , wind speed observations, weather model outputs from INFLUX (Indianapolis Flux Experiment), and a prior emissions map. By categorizing trace gas vertical gradients according to wind speed classes and identifying when the meteorological model satisfactorily simulates boundary layer depth (BLD), we found that non‐afternoon observations can be assimilated when wind speed is >5 m/s. This condition resulted in small modeled BLD biases (<40%) when compared to calmer conditions (>100%). For Indianapolis, 37% of the GHG measurements meet this wind speed criterion, almost tripling the observations retained for AIM. Similar results are expected for windy cities like Auckland, Melbourne, and Boston, potentially allowing AIM to assimilate up to 60% of the total (24‐hr) observations. Incorporating these observations in AIMs should yield a more diurnally comprehensive evaluation of urban GHG emissions.
DOI: 10.1029/2024jd040998
Language: English
Subfield: Global and Planetary Change
Field: Environmental Science
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,880
Awards: Advancing New Zealand’s carbon inventory: forest, grassland, and urban environments, PURPOSE: THIS AWARD WILL INVESTIGATE AND DEVELOP CAPABILITIES TO ESTIMATE EMISSIONS IN THE INDIANAPOLIS REGION ON A MONTHLY TO QUARTERLY CADENCE. RESEARCH WILL FOCUS ON DEVELOPMENT OF ECONOMIC SECTOR-SPECIFIC EMISSIONS METHODOLOGIES, IMPACT OF BIOGENIC CO2 FLOWS TO AND FROM THE ATMOSPHERE AND THEIR IMPACT ON EMISSIONS ESTIMATES.ACTIVITIES TO BE PERFORMED: RESEARCH EFFORTS ARE AIMED AT THE FOLLOWING:* CONTINUED OPERATION OF THE INDIANAPOLIS TESTBED,* ADVANCING ATMOSPHERIC INVERSION MODELING BOTH NEAR REAL-TIME AND LONG-TERM,* HIGH RESOLUTION, SECTOR-SPECIFIC EMISSION FLUX MEASUREMENT OF BIOGENIC/ANTHROPOGENIC SOURCES,* INTEGRATION OF LOW-COST SENSORS INTO INVERSIONS,* CREATION OF AN URBAN GHG DISPERSION OBSERVATORY.EXPECTED OUTCOMES: SEVERAL OUTCOMES ARE EXPECTED. DEMONSTRATIONS WILL INCLUDE:* CONTINUOUS, MULTI-YEAR MONITORING OF ATMOSPHERIC INVERSE FLUX ESTIMATES THAT IS OF SUFFICIENT ACCURACY AND PRECISION FOR OPERATIONAL NEEDS;* A FRAMEWORK FOR NEAR-REAL TIME URBAN GHG EMISSIONS ESTIMATES THAT COULD BE MAINTAINED PRIMARILY WITH OPERATIONAL METEOROLOGICAL DATA AND MODELS;* SIGNIFICANTLY REDUCE THE POTENTIAL FOR SYSTEMATIC BIAS IN URBAN GHG INVERSE FLUX ESTIMATES;* DEMONSTRATE NEW APPROACHES FOR CONTINUOUS MONITORING OF SPATIALLY RESOLVED, SECTOR-SPECIFIC URBAN GHG EMISSIONS AND USE OF THESE METHODS TO TEST PROCESS BASED MODELS OF URBAN GHG EMISSIONS, AND* IMPROVE THE SIMULATION OF LAND-ATMOSPHERE FLUXES WITHIN CITIES, IN SUPPORT OF IMPROVED URBAN GHG FLUX INVERSIONS.INTENDED BENEFICIARIES: ACADEMIA, LOCAL AND STATE GOVERNMENTS AND THE PRIVATE SECTOR.SUBRECIPIENT ACTIVITIES: THE RECIPIENT DOES NOT INTEND TO SUBAWARD FUNDS., ESTIMATION OF URBAN GREENHOUSE GAS EMISSIONS USING REGIONAL ATMOSPHERIC INVERSIONS
OpenAlex ID: W4402008003