Development of High Resolution Instrument for Measurements of Partial Pressure of Carbon Dioxide in Discrete Sea Water Samples

众所周知，大气中的二氧化碳含量正在增加。二氧化碳增加的来源一直被认为是化石燃料的燃烧，海洋和陆地生物群被认为是二氧化碳的主要汇。最近，生物学家指出，陆地生物群不是汇，可能是与化石燃料源一样大的二氧化碳来源。因此，人们认为大气层中的二氧化碳可能会被海洋吸收的比例比之前假设的要大，但这一点并未被直接测量所证实。本研究项目旨在利用气象技术对一个所谓的碳汇缺失进行检测。二氧化碳的功率谱密度在高频范围内服从-5/3次幂规律。二氧化碳波动的这种频率依赖关系与温度和湿度的依赖关系基本相似。分析了二氧化碳和垂直风速的同谱在整个频率范围内的负分量，代表了海洋上方的湍流涡旋向下输送二氧化碳。平均流量产生的二氧化碳通量为正值，其值约为湍流涡流通量的两倍。这意味着二氧化碳在海洋上空的通量方向主要受感热和潜热通量的输送方向控制，当海洋上空的大气层处于不稳定的层结时，二氧化碳的向上通量可能发生。结果表明，二氧化碳总通量是湍流通量项和平均流量项的总和，随着海洋感热、潜热和动量通量的增加而增大。

It is well known that the carbon dioxide contents of the atmosphere is increasing. The source of this increasing carbon dioxide has been assumed to be the combustion of fossil fuels, and the ocean and land biota have been considered as the major sink for carbon dioxide. Recently, biologists pointed out that the land biota is not a sink and may be a source of carbon dioxide as large as the fossil fuel source. It is thus considered that a larger portion of atmospheric carbon dioxide may be absorbed by the ocean than previously assumed, but this is not proved by direct measurements. This research project is intending to examine a so called missing carbon sink by the meteorological techniques.The field experiments have elucidated problems as follows. The power spectral density of carbon dioxide followed a -5/3 power law in high frequency ranges. This frequency dependency of carbon dioxide fluctuations is basically similar to those of temperature and humidity. The cospectrum of carbon dioxide and vertical wind velocity had negative components for whole frequency ranges analyzed, representing downward transport of carbon dioxide by the turbulent eddies over the ocean. The carbon dioxide flux due to the mean flow showed positive, and its value was about twice of the turbulent eddy flux. This means that the flux direction of carbon dioxide over the ocean is mainly controlled by the transport direction of fluxes of sensible heat and latent heat, The upward flux of carbon dioxide may occur when the air layer over the ocean is in unstable stratification. It is noted that the total flux of carbon dioxede, which is the summation of turbulent eddy flux term and mean flow flux term, increased with increasing fluxes of sensible heat, latent heat and momentum over the ocean.