Aircraft Observation of CO₂, CO, O₃ and H₂ over the North Pacific during the PACE-7 Campaign     

Y. SAWA  H. MATSUEDA  Y. MAKINO  H. Y. INOUE  S. MURAYAMA  M. HIROTA  Y. TSUTSUMI  Y. ZAIZEN  M. IKEGAMI  K. OKADA 《Tellus. Series B, Chemical and physical meteorology》2004,56(1):2-20

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Long-range transport of carbon monoxide from tropical ground to upper troposphere: a case study for South East Asia in October 1997     

SHOICHI TAGUCHI  HIDEKAZU MATSUEDA  HISAYUKI Y. INOUE  YOUSUKE SAWA 《Tellus. Series B, Chemical and physical meteorology》2002,54(1):22-40

High concentrations of carbon monoxide (CO) were observed in October 1997 at the upper troposphere of the western tropical Pacific. Transport from the potential sources of CO due to biomass burnings in the tropics was investigated by using a global chemical transport model (CTM) driven by assimilated meteorological data provided from European Centre for Medium-Range Weather Forecasts (ECMWF). A CTM evaluation simulation using water vapor showed that the amount of vertical transport of moisture by large-scale flow was consistent with the precipitation predicted at the convective zone. A series of CTM simulations using 10-day emission periods of an artificial material with lifetime of 60 days indicated that vertical lifting of surface air at the Indonesian archipelago occurred in the concentrated convections west of Sumatra Island. No evidence was found that CO from the Amazon region or Africa significantly contributed to high concentrations in the western tropical Pacific. Transport formed a large-scale anvil below the tropopause by rapid vertical transport and by divergence flow. The average time required for the transport from Kalimantan and Sumatra Island to the point of high CO concentration was about 15 days. High concentrations at an altitude of 10 km in the Southern Hemisphere were transported by large-scale subsidence from the upper tropospheric maximum, which was presumably produced from the sources at Kalimantan and Sumatra Island. Estimated emissions of CO in September and October from Kalimantan and Sumatra were substantially larger than the previous estimates. Omission of chemical reaction was a possible problem for the overestimate, but not significant. The possible problems in the transport were incorrect CTM transport due to insufficient horizontal (2.5×2.5°) and vertical resolution of the CTM, and to inaccuracy in the wind fields at the upper part of the troposphere and a divergent flow pattern in the upper part of the troposphere.  相似文献   

Simulation of CO<Subscript> <Emphasis Type="Bold">2</Emphasis> </Subscript> concentrations at Tsukuba tall tower using WRF-CO<Subscript> <Emphasis Type="Bold">2</Emphasis> </Subscript> tracer transport model     

SRABANTI BALLAV  PRABIR K PATRA  YOUSUKE SAWA  HIDEKAZU MATSUEDA  AHORO ADACHI  SHIGERU ONOGI  MASAYUKI TAKIGAWA  UTPAL K DE 《Journal of Earth System Science》2016,125(1):47-64

Simulation of carbon dioxide (CO₂) at hourly/weekly intervals and fine vertical resolution at the continental or coastal sites is challenging because of coarse horizontal resolution of global transport models. Here the regional Weather Research and Forecasting (WRF) model coupled with atmospheric chemistry is adopted for simulating atmospheric CO₂ (hereinafter WRF-CO₂) in nonreactive chemical tracer mode. Model results at horizontal resolution of 27 × 27 km and 31 vertical levels are compared with hourly CO₂ measurements from Tsukuba, Japan (36.05°N, 140.13 ^oE) at tower heights of 25 and 200 m for the entire year 2002. Using the wind rose analysis, we find that the fossil fuel emission signal from the megacity Tokyo dominates the diurnal, synoptic and seasonal variations observed at Tsukuba. Contribution of terrestrial biosphere fluxes is of secondary importance for CO₂ concentration variability. The phase of synoptic scale variability in CO₂ at both heights are remarkably well simulated the observed data (correlation coefficient >0.70) for the entire year. The simulations of monthly mean diurnal cycles are in better agreement with the measurements at lower height compared to that at the upper height. The modelled vertical CO₂ gradients are generally greater than the observed vertical gradient. Sensitivity studies show that the simulation of observed vertical gradient can be improved by increasing the number of vertical levels from 31 in the model WRF to 37 (4 below 200 m) and using the Mellor–Yamada–Janjic planetary boundary scheme. These results have large implications for improving transport model simulation of CO₂ over the continental sites.  相似文献