Laboratory and Field Measurements of Methanol Fluxes

挥发性有机化合物(VOCs)在对流层化学中起着积极的作用，但我们对它们的源和汇的分布以及驱动它们的环境因素的了解往往很少。甲醇是对流层中普遍存在的一种重要的含氧VOC，是全球奇数氢(HOx=OH+HO2)的来源。它被认为主要作为果胶在植物生长过程中去甲基化的副产物排放到大气中，并主要通过与羟基自由基反应从大气中去除。这些和其他来源和汇的相对贡献仍然不确定，需要广泛的实验室和实地测量才能提高我们的理解。我们建议首先对甲醇的土壤交换进行深入的实验室研究，利用由不来梅大学实验室开发和测试的极其灵敏的甲醇测量技术监测动态通量舱，对甲醇的土壤交换进行深入的实验室研究，甲醇是甲醇收支中潜在的重要因素，但很少被研究。我们还建议使用松弛涡旋积累(REA)方法、冠层内梯度和动态室，在由W.Kutsch博士从耶拿MPI操作的Kannenbruch野外站点观察到北欧森林生态系统的树冠上方、树冠内和树冠下的甲醇。这一测量组合是朝着进一步阐明不来梅大学实验室已经开始的甲醇预算迈出的积极一步，并将加强我们实验室与流量测量社区的联系。

Volatile organic compounds (VOCs) play an active role in tropospheric chemistry, however our knowledge concerning their distribution of sources and sinks and the environmental factors driving them is often sparse. Methanol is an important oxygenated VOC found ubiquitously in the troposphere, serving as a source of global odd hydrogen (HOx=OH+HO2). It is thought to be emitted to the atmosphere mainly as a by-product of pectin demethylation during plant growth and removed from the atmosphere primarily through reaction with the hydroxyl radical. Relative contributions from these and other sources and sinks remain uncertain and will require extensive laboratory and field measurements to improve our understanding. We propose to contribute to these endeavors first by performing an in-depth laboratory study of soil exchanges of methanol, a potentially important but seldom studied player in the methanol budget, using a dynamic flux chamber monitored using an extremely sensitive methanol measurement technique developed and tested by our laboratory at the University of Bremen. We also propose to observe methanol both above, within, and below the canopy of a northern European forest ecosystem at the Kannenbruch field site operated by Dr. W. Kutsch from the MPI for Biogeochemistry in Jena, using a relaxed eddy accumulation (REA) method, an in-canopy gradient, and dynamic chambers. This combination of measurements is a positive step towards further elucidation of the methanol budget already begun in our laboratory at the University of Bremen and will strengthen the ties of our laboratory to the flux measurement community.