Trace Gas Cross-Site Comparison: A TRAGNET Project

小行星9416813 该项目将建立一个数据库和模型分析，用于确定气候、大气氮沉降和土壤中广泛的环境梯度中痕量气体交换的一般关系，以更好地量化这些生物源辐射活性痕量气体在整个北美的通量。 将使用痕量气体网络（TRAGNET）站点，这是一个国际地圈生物圈计划/国际全球大气化学（IGBP/IGAC）中纬度活动，由美国各地的网络组成，作为研究中心的核心。 该网络包括许多LTER站点和其他长期研究站点，其中正在测量CO、EMB 1 2、CH 4和N2 O以及可能的其他痕量气体的通量，并正在进行痕量气体模型开发。 在北美的一个网络中测量生物痕量气体，并对这些数据进行综合分析，对于了解控制生物痕量气体生产和消费的因素至关重要。 该区域的生态系统是这些重要的放射性活性生物源痕量气体的主要贡献者。 人类活动直接和间接地改变气体通量。 农业和森林管理做法直接影响到土壤的物理和生物特性，包括控制气体流通的特性。 间接地，空气污染和酸沉降影响通量和修改相关的地球化学循环，特别是N动态，与微量气体通量。 自然系统既是痕量气体的源又是痕量气体的汇，但这些通量的大小尚不清楚。 虽然温带生态系统中的痕量气体通量测量已经进行了几十年，但测量通常很少（很少超过生长季节），通常是小规模的，例如，地块大小的处理，并不总是可比的其他通量数据收集在其他网站。 协调分析的生物痕量气体通量测量是必不可少的，以了解这些sources和汇在区域和全球范围内。 三个关键的研究需要是：（1）改进对甲烷、一氧化二氮和二氧化碳净通量以及控制这些通量的环境因素的估计;（2）查明和量化其他可能重要的通量大的区域，特别是过去研究中忽略的地理区域;（3）发展模型以量化痕量气体通量对气候、氮沉降和土地管理变化的响应。 这项工作将汇集正在进行的示踪气体通量项目的数据，并为参与研究的研究人员提供综合数据库。 {PAGE\#“'页面：'#' '”|页码：1 } EMB 1

9416813 Ojima This project will establish a database and model analyses to be used in determining general relationships of trace gas exchange across a broad environmental gradients in climate, atmospheric deposition of N, and soils to better quantify fluxes of these biogenic radiatively active trace gases across North America. Trace Gas Network (TRAGNET) sites will be used, an International Geosphere-Biosphere Programme/International Global Atmospheric Chemistry (IGBP/IGAC) Midlatitude Activity of a network of locations around the U.S., as the core set of study sites. This network includes many LTER sites and other long-term research sites, where fluxes of CO EMB1 2, CH4, and N2O and possibly other trace gases are being measured and locations where trace gas model development is being conducted. Measurement of biogenic trace gas across a network of sites in North America and comprehensive analysis of these data are critical to understanding the factors controlling biogenic trace gas production and consumption. Ecosystems in this region are major contributors of these important radiatively active biogenic trace gases. Human activities modify gas fluxes both directly and indirectly. Directly, agricultural and forest management practices affect soil physical and biological properties, including those that control gas fluxes. Indirectly, air pollution and acid deposition affect fluxes and modifying biogeochemical cycles associated, especially N dynamics, with trace gas fluxes. Natural systems are both sources and sinks of trace gases, but the magnitudes of these fluxes are not known. Although trace gas flux measurements in temperate ecosystems have been made for decades, measurements have generally been infrequent (rarely extending beyond a growing season), usually small-scale, e.g., plot size treatments and may not always be comparable to other flux data collected at other sites. A coordinated analysis of biogenic trace gas flux measurements is essential to understanding these sour ces and sinks in a regional and global context. Three critical research needs are : (1) improved estimates of net fluxes of methane, nitrous oxide and carbon dioxide and of environmental factors which control these fluxes; (2) identification and quantification of other potentially important regions of significant fluxes, particularly those from geographic areas that have been neglected in past research; and (3) development of models to quantify how trace gas fluxes will respond to climatic, N deposition, and land management changes. The effort will bring together data from on going trace gas flux projects and provide the integrated database to researchers involved in the study. {PAGE \# "'Page: '#' '"|Page: 1 } EMB1