Distribution of CO₂ in Western Pacific, Studied Using Isotope Data Made in Taiwan, OCO‐2 Satellite Retrievals, and CarbonTracker Products

Abstract

To assess sources and processes that affect the variability of CO2 at local to regional scales, we have analyzed the mixing ratio [CO2] and stable isotopic compositions (δ13C and δ18O) of atmospheric CO2 for three years (2014–2016) in urban and sub‐urban areas in Taipei, Taiwan. The data are compared with those from some background sites, viz., Lulin, Mauna Loa, and Minamitorishima, to evaluate how local emissions affect CO2 level regionally. [CO2] over the urban and sub‐urban stations are significantly higher than that observed at the three aforementioned remote sites mainly due to local emissions, which partly mask the seasonal cycle caused by photosynthesis and respiration. Likewise, significantly low δ13C and δ18O values observed at two Taipei stations also point to anthropogenic emissions. The seasonal cycles in [CO2] and in the isotopic compositions are retrieved using the ensemble empirical mode decomposition method. Regional impact is assessed using CO2 products from the Orbiting Carbon Observatory‐2 satellite, the NOAA/EARL CarbonTracker project, and meteorological data from European Centre for Medium range Weather Forecast‐Interim. We found that besides local emissions, Taiwan is largely affected by external CO2 in winter and spring originated from north, west and southwest landmasses. In winter air masses with elevated CO2 concentrations, originated in eastern China influence Taipei. In spring season, about 2 ppmv enhancement in CO2 observed at the top of Lulin, a high mountain station (2.8 km), could be linked to CO2 produced by biomass burning in the southeast Asian countries and transported to the region by easterly winds.

Variable thermoregulation of Late Cretaceous dinosaurs inferred by clumped isotope analysis of fossilized eggshell carbonates

“…All δ 13 C and δ 18 O values are expressed relative to VPDB in per mil (‰). Measurements were carried out against the Academia Sinica working reference (called AS-2; Laskar et al., 2018 ), a high purity commercial CO 2 with δ 13 C = -32.54 ‰ and δ 18 O = -4.67 ‰, respectively (procured from Air Products and Chemicals, Inc., Taiwan). Δ 47 values were calculated using the following relation where R 13 and R 18 (ratios 13 C/ 12 C and 18 O/ 16 O) were obtained by measuring the masses 44, 45 and 46 of the CO 2 sample and R 17 was calculated by assuming a mass dependent relation with R 18 with a slope of 0.5164.…”

“…All δ 13 C and δ 18 O values are expressed relative to VPDB in per mil (‰). Measurements were carried out against the Academia Sinica working reference (called AS-2; Laskar et al, 2018), a high purity commercial CO 2 with δ 13 C ¼ -32.54 ‰ and δ 18 O ¼ -4.67 ‰, respectively (procured from Air Products and Chemicals, Inc., Taiwan). Δ 47 values were calculated using the following relation…”

Sulfur isotope analysis for representative regional background atmospheric aerosols collected at Mt. Lulin, Taiwan

“…Time series analysis for the concentrations of lead and vanadium, however, does show significant enhancement in spring (March-June) and winter (September-December) time. The former is due clearly to biomass burning is southeast countries (e.g., see 37,51,52 ). The latter is affected by winter monsoons that carry pollutants from China.…”

Role of Vehicular Catalytic Converter Temperature in Emission of Pollutants: An Assessment Based on Isotopic Analysis of CO2 and N2O

“…There is no significant difference in δ 13 C values between the types of vehicles and the average value is similar to that estimated for fossil fuels in Taiwan. 27,41 However, δ 18 O values are significantly different between different types of vehicles. While δ 18 O values of the gasoline-operated cars and diesel-operated trucks and buses are the same as those expected, they are significantly lower for motorcycles.…”