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吸收汇。最近，生物学家指出，陆地生物群不是一个汇，可能是一个与化石燃料源一样大的二氧化碳源。因此，人们认为，海洋吸收的大气二氧化碳可能比以前假设的要多，但这并没有得到直接测量的证明。本研究计画旨在利用气象技术来检视所谓的“缺失碳汇”，并借由实地实验来阐明以下问题。二氧化碳的功率谱密度在高频范围内遵循-5/3幂律。二氧化碳波动的这种频率依赖性基本上与温度和湿度的频率依赖性相似。二氧化碳和垂直风速的共谱在整个分析频率范围内都有负分量，代表了海洋湍流涡旋对二氧化碳的向下输送。平均流引起的CO2通量为正值，约为湍流涡动通量的2倍。这说明海洋上空CO2通量的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层结时，CO2的向上通量可能发生。结果表明，CO_2的总通量（湍流涡动通量项和平均气流通量项之和）随海洋感热、潜热和动量通量的增加而增加。

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.