Towards understanding the variability in biospheric CO 2 fluxes: using FTIR spectrometry and a chemical transport model to investigate the sources and sinks of carbonyl sulfide and its link to CO 2
Towards understanding the variability in biospheric CO 2 fluxes: using FTIR spectrometry and a chemical transport model to investigate the sources and sinks of carbonyl sulfide and its link to CO 2
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DOI：
10.5194/acp-16-2123-2016
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发表时间：
2015-09
影响因子：
6.3
通讯作者：
Yuting Wang;N. Deutscher;M. Palm;T. Warneke;J. Notholt;I. Baker;J. Berry;P. Suntharalingam;N. Jones;E. Mahieu;B. Lejeune;J. Hannigan;S. Conway;J. Mendonca;K. Strong;Jesse W. Campbell;A. Wolf;S. Kremser
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文献类型：
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作者：
Yuting Wang;N. Deutscher;M. Palm;T. Warneke;J. Notholt;I. Baker;J. Berry;P. Suntharalingam;N. Jones;E. Mahieu;B. Lejeune;J. Hannigan;S. Conway;J. Mendonca;K. Strong;Jesse W. Campbell;A. Wolf;S. Kremser
抽象的。了解二氧化碳（CO2）的生物圈过程是非常重要的，因为陆地交换驱动的季节和年际变化的CO2在大气中。仅基于CO2浓度测量的大气逆温只能确定生物圈净通量，而不能区分光合作用（吸收）和呼吸作用（产生）。羰基硫（OCS）可以提供一个重要的额外限制：它也被植物在光合作用过程中吸收，但在呼吸过程中不排放，因此是区分这些过程的潜在手段。太阳吸收傅里叶变换红外光谱法（FTIR）可以从测量的太阳吸收光谱中反演大气中CO2和OCS的浓度。在这里，我们调查位于北方半球的五个选定的站点进行OCS和CO2的同位和准同时FTIR测量。这些测量结果进行了比较，使用化学传输模型（GEOS-Chem）的OCS和CO2的模拟。本文采用简单生物圈模式（SiB）的OCS和CO2耦合通量。SiB通量的CO2模拟与测量结果一致，而OCS模拟再现了较弱的下降比FTIR测量在选定的网站，和一个较小的纬度梯度在北方半球在生长季节时，与HIPPO（HIAPER极点到极点观测）数据跨越两个半球。SiB模拟和测量之间的季节性周期最小值的时间偏移也被看到。利用外大陆架作为光合作用的代用指标，可以帮助理解生物圈过程是如何在模型中再现的，并进一步理解真实的世界中的碳循环。
Abstract. Understanding carbon dioxide (CO2) biospheric processes is of great importance because the terrestrial exchange drives the seasonal and interannual variability of CO2 in the atmosphere. Atmospheric inversions based on CO2 concentration measurements alone can only determine net biosphere fluxes, but not differentiate between photosynthesis (uptake) and respiration (production). Carbonyl sulfide (OCS) could provide an important additional constraint: it is also taken up by plants during photosynthesis but not emitted during respiration, and therefore is a potential means to differentiate between these processes. Solar absorption Fourier Transform InfraRed (FTIR) spectrometry allows for the retrievals of the atmospheric concentrations of both CO2 and OCS from measured solar absorption spectra. Here, we investigate co-located and quasi-simultaneous FTIR measurements of OCS and CO2 performed at five selected sites located in the Northern Hemisphere. These measurements are compared to simulations of OCS and CO2 using a chemical transport model (GEOS-Chem). The coupled biospheric fluxes of OCS and CO2 from the simple biosphere model (SiB) are used in the study. The CO2 simulation with SiB fluxes agrees with the measurements well, while the OCS simulation reproduced a weaker drawdown than FTIR measurements at selected sites, and a smaller latitudinal gradient in the Northern Hemisphere during growing season when comparing with HIPPO (HIAPER Pole-to-Pole Observations) data spanning both hemispheres. An offset in the timing of the seasonal cycle minimum between SiB simulation and measurements is also seen. Using OCS as a photosynthesis proxy can help to understand how the biospheric processes are reproduced in models and to further understand the carbon cycle in the real world.