2:15 PM - 2:30 PM
[ACG38-15] Ship-borne XCO2, XCO, and XCH4 measurements in the Pacific Ocean on board the research vessel Mirai
Keywords:Greenhouse Gases, Validation
Greenhouse gases (GHGs) play a crucial role with respect to global warming. Therefore, precise and accurate observations of anthropogenic GHGs, especially carbon dioxide (CO2) and methane (CH4), are of utmost importance for estimating their emission strengths, flux changes, and long-term monitoring. Satellite observations and atmospheric models are well suited for this task as they provide global coverage of column-averaged dry-air mole fractions of GHGs, denoted Xgas. However, like all measurements, these need to be validated. The Total Carbon Column Observing Network (TCCON) and, more recently, the COllaborative Carbon Column Observing Network (COCCON) perform ground-based observations of GHGs with reference precision using Fourier Transform spectrometers (FTS). For several satellites measuring GHGs, e.g. the GOSAT (Greenhouse Gases Observing Satellite) series, the OCO (Orbiting Carbon Observatory) series and, TROPOMI (Tropospheric Monitoring Instrument), these networks are the main validation sources.
However, these networks are mainly land-based, and validation over the ocean remains sparse. This lack of validation is especially troublesome as it complicates the identification of land-ocean bias that satellites might suffer from. New, innovative validation sources are therefore highly desirable. A GHG validation product was recently established combining ship-borne and aircraft in situ observations. Using a different approach, starting from a COCCON type FTS, a customized EM27/SUN FTS including a fast solar tracker and a weatherproof shelter was developed for ship-borne observations and successfully operated on dedicated research voyages. The results were used for satellite and model validation.
Here we present results from two cruises in the Pacific Ocean beginning and end of 2021 onboard the research vessel Mirai utilizing the aforementioned custom-built EM27/SUN FTS. We report updates on the instrumental setup, discuss difficulties encountered during the cruises, and present XCO2, XCO, and XCH4 measurements obtained during the deployment on the Mirai. We then give an outlook regarding the goal of performing continuous, operational measurements on board a cargo ship.
However, these networks are mainly land-based, and validation over the ocean remains sparse. This lack of validation is especially troublesome as it complicates the identification of land-ocean bias that satellites might suffer from. New, innovative validation sources are therefore highly desirable. A GHG validation product was recently established combining ship-borne and aircraft in situ observations. Using a different approach, starting from a COCCON type FTS, a customized EM27/SUN FTS including a fast solar tracker and a weatherproof shelter was developed for ship-borne observations and successfully operated on dedicated research voyages. The results were used for satellite and model validation.
Here we present results from two cruises in the Pacific Ocean beginning and end of 2021 onboard the research vessel Mirai utilizing the aforementioned custom-built EM27/SUN FTS. We report updates on the instrumental setup, discuss difficulties encountered during the cruises, and present XCO2, XCO, and XCH4 measurements obtained during the deployment on the Mirai. We then give an outlook regarding the goal of performing continuous, operational measurements on board a cargo ship.