Name: measurements of co2 fluxes at non-ideal eddy covariance sites
Uploaded: 2019-06-24T14:00:00
Description: Watch this Scientific Journal Video about Measurements of CO2 Fluxes at Non-Ideal Eddy Covariance Sites at JoVE.com

这项研究得到了波兰华沙国家森林总局(LAS项目,OR-2717/27/11号)的资助。我们要感谢波兰波兹南生命科学大学气象系的整个研究小组参与执行该协议,并感谢他们在创建协议视觉版本时的帮助。

1. 场地位置和仪表设置
<ol><li>选择相对均匀和平坦的地形中的测量场地位置,以满足 EC 方法的基本要求。避免使用地形复杂(凹陷、斜坡)或靠近空气动力学障碍物的地方(例如,幸存的树架),以免扭曲气流。<ol>
<li>检查物种组成和植物覆盖。选择特征最相似的地方:主要植被类型的年龄和高度。</li>
		<li>如果可能的话,进行一些额外的土壤调查,这有助于选择均匀区域。比较几个地点的土壤类型(土壤剖?...

<ol>
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A Field Book on Measuring Ecosystem Gas Exchange and Areal Emission Rates. , (2013).</li><li>Pan, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Large+and+Persistent+Carbon+Sink+in+the+World&#8217;s+Forests.">A Large and Persistent Carbon Sink in the World&#8217;s Forests.</a> Science. 333, 988-993 (2011).</li><li>Wofsy, S. 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G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Interannual+variability+in+the+leaf+area+index+of+a+boreal+aspen-hazelnut+forest+in+relation+to+net+ecosystem+production.">Interannual variability in the leaf area index of a boreal aspen-hazelnut forest in relation to net ecosystem production.</a> Agricultural and Forest Meteorology. 126, 237-255 (2004).</li><li>Krishnan, P., Black, T. A., Jassal, R. 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该协议提出了在非理想地点(这里为重新造林的风投场)使用的涡流协方差 (EC) 方法:场地位置和测量基础设施设置、净 CO2通量计算和后处理,以及有关填补和通量分区程序。
尽管 EC 技术在世界各地的许多测量站点中普遍使用,但大多数都是不受干扰的生态系统,其中设计和以下数据处理可以根据标准解决方案(例如 FLUXNET 或 ICOS 网络协议)进行).虽然在诸如风投地点等要求高...

目前,在大气-陆地生态系统二氧化碳(CO2)交换研究中最常用的技术是涡测协方差(EC)技术1。EC方法已经使用了几十年,关于所有方法、技术和实际问题的全面说明已经出版2,3,4。与用于类似目的的其他技术相比,EC 方法允许从自动点测量中获得空间和时间平均净 CO2通量,该测量考虑复杂中所有元素的贡献生态系统,而不是费力的手动测量(例如,腔室技术)或采集许多样本的要求1。
在陆地生态系统中,森林在C循环中起着最重要的作用,许多科学活动的重点是研究其CO2周期、木质生物量中的碳储存及其与不断变化的气候条件之间的相互关系。直接测量或建模5。许多EC地点,包括最长的通量记录之一6,被设置在不同类型的森林7。通常,在测量开始之前,会仔细选择场地位置,目标是尽可能实现最均匀和最大的区域。虽然,在受干扰的林场,如风向,EC测量站的数量仍然不足8,9,10。原因之一是测量场地设置的后勤困难,最重要的是,少数突然出现的位置。为了在风投区获得信息最丰富的结果,在发生此类偶发事件后尽快开始,这可能会导致其他问题。与未受污染的林场相比,EC在风投地点的测量更具挑战性,并可能偏离已经确立的程序3。由于一些极端风现象造成了空间有限的区域,因此需要周到的测量站位置和仔细的数据处理,以便得出尽可能多的可靠通量值。在EC方法应用中也出现了类似的困难(例如,在一个长而狭窄的湖上完成的完成研究),其中测量的CO2通量需要严格的数据过滤11,12,以确保其空间代表性。
因此,所提出的协议是一个在非典型地点使用EC方法的例子,不仅针对风投区,而且针对所有具有有限面积的其他类型的短植被(例如,位于较高植被类型之间的农田)。拟议方法的最大优点是一般描述复杂的程序,需要高级知识,从站点位置选择和仪器设置到最终结果:高质量 CO2的完整数据集通 量。测量协议的技术新颖性是使用独特的基础结构用于 EC 系统放置(例如,具有定义高度的三脚架,即带有可调节的电动桅杆的"迷你塔",允许更改传感器)。

<table>
	<tbody>
		<tr>
			<td>Adjustable mast with metal rails and electric engine (24 V)</td>
			<td>maszty.net</td>
			<td>-</td>
			<td>Alternative basic construction. To be designed and made by professionals</td>
		</tr>
		<tr>
			<td>EddyPro</td>
			<td>LI-COR, Inc.</td>
			<td>ver. 6.2.0.</td>
			<td>Free commercial software for fluxes calculation. Available on a website: https://www.licor.com/env/products/eddy_covariance/software.html, on request</td>
		</tr>
		<tr>
			<td>Enclosed-path infrared gas analyzer</td>
			<td>LI-COR, Inc.</td>
			<td>LI-7200</td>
			<td>One of two instruments of the eddy covariance system (EC) used for CO2 fluxes measurements. Other types of fast analyzers (&#62;10Hz sampling frequency) can be used</td>
		</tr>
		<tr>
			<td>REddyProc</td>
			<td>-</td>
			<td>-</td>
			<td>Free software for EC fluxes gap filling and partitioning. Available on Max Planck Institute for Biogeochmistry: https://www.bgc-jena.mpg.de/bgi/index.php/Services/REddyProcWeb. Both online tool and R package are provided.</td>
		</tr>
		<tr>
			<td>Short aluminum tower base with concrete foundation</td>
			<td>maszty.net</td>
			<td>-</td>
			<td>Alternative basic construction (pioneering solution). To be designed and made by professionals</td>
		</tr>
		<tr>
			<td>Sonic anemometer</td>
			<td>Gill Instruments</td>
			<td>Gill Windmaster</td>
			<td>One of two instruments of the eddy covariance system (EC) used for wind speed measurements. Other types of three-dimensional sonic anemometers can be used</td>
		</tr>
		<tr>
			<td>Stainless-steel tripod</td>
			<td>Campbel Scientific, Inc.</td>
			<td>CM110 10 ft</td>
			<td>The basic construction for eddy covariance (EC) system. Can be constructed by yourself- materials to be found in a hardware store</td>
		</tr>
		<tr>
			<td>Sunshine sensor</td>
			<td>Delta-T Devices Ltd.</td>
			<td>BF5</td>
			<td>One of the exemplary instruments for photosynthetic photon flux density measurements (PPFD). To be bought from several commercial companies. Remember to place it above the canopy, far from reflective surfaces.</td>
		</tr>
		<tr>
			<td>Thermistors</td>
			<td>Campbel Scientific, Inc.</td>
			<td>T107</td>
			<td>One of the exemplary instruments for soil temperature measurements. To be bought from several commercial companies. It is advisable to have a profile of soil temperature</td>
		</tr>
		<tr>
			<td>Thermohygrometer</td>
			<td>Vaisala Oyj</td>
			<td>HMP155</td>
			<td>One of the exemplary instruments for air temperature and humidity measurements. To be bought from several commercial companies. Remember to place it inside radiation shield at similar height as the EC system.</td>
		</tr>
	</tbody>
</table>

measurements of co2 fluxes at non-ideal eddy covariance sites

该协议是利用涡流协方差(EC)技术在波兰目前重新造林的风投区,在非典型生态系统中研究空间和时间平均净CO2通量(净生态系统生产,NEP)的一个例子。龙卷风事件发生后,在幸存的林场内形成了一条相对狭窄的"走廊",使这类实验复杂化。在这种情况下,其他测量技术(如室法)的应用更加困难,因为特别是在开始时,倒下的树木和一般地的异质性为执行提供了一个具有挑战性的平台磁通量测量,然后适当高档获得的结果。与在未受破坏的森林中进行的标准EC测量相比,在选址和数据分析方面,风投地区需要特别考虑,以确保其代表性。因此,在这里,我们提出了一个实时的连续CO2磁通量测量协议,在一个动态变化的非理想EC站点,其中包括(1)站点位置和仪器设置,(2)磁通量计算,(3)严格的数据过滤和质量控制,以及(4)间隙填充和净通量划分成CO2呼吸和吸收。所述方法的主要优点是,它提供了实验设置和从头开始测量性能的详细描述,可应用于其他空间有限的生态系统。也可以将其视为如何处理非常规站点操作的建议列表,为非专家提供说明。获得质量检查,填补缺口,半小时净CO2值,以及吸收和呼吸通量,可以最终汇总到每日,每月,季节性或每年的总数。

在非理想EC场址的磁通过滤和质量控制中,关键步骤之一是评估测得的磁通量的空间代表性。鉴于计算是使用商业的、广泛应用的软件进行的,进行这种分析的最简单方法是仅根据风向和足迹估计包括所需区域的测量(见第3.7节)。因此,在Tlen I站点的卫星图片背景上,风玫瑰图,具有选择的风向和最大可接受的通量足迹延伸,标记为蒙带多边形,在这里显示为分析结果的可视化表示(<...

Watch this Scientific Journal Video about Measurements of CO2 Fluxes at Non-Ideal Eddy Covariance Sites at JoVE.com

Measurements of CO2 Fluxes at Non-Ideal Eddy Covariance Sites

所提出的协议在波兰目前重新造林的风投地点,在非典型地点使用涡差差法,适用于总面积有限的所有类型的短冠生态系统。详细介绍了测量现场设置规则、通量计算和质量控制以及最终结果分析。

非理想涡流位点的 CO2通量测量

This protocol is an example of utilizing the eddy covariance (EC) technique to investigate spatially and temporally averaged net CO2 fluxes (net ecosystem ...

该协议是涡流协方差站点设置和从零开始测量性能的分步描述，可以成功地应用于空间有限的生态系统。我们认为，该协议更容易认识到，然而，严格的要求需要得到满足。协方差技术也可以令人满意地应用于非理想位置。一旦以可视形式呈现，该协议就可以作为非专家被迫或愿意使用涡流协方差技术的第一个和相对容易的选择。首先，在高度图上，选择相对均匀平坦地形的测量地点位置，以满足 EC 方法的基本要求。选择无障碍物的位置，并确保要调查的区域在每个方向上至少延伸 100 倍于要放置的传感器的高度。在现场，使用风速计调查一年的风向，或分析来自最近的气象站的数据。决定使用哪个 EC 系统。如果电源没有限制或恶劣环境中，打开功耗较低的路径红外气体分析仪，或者使用短进气管打开闭路分析仪。在现场，放置一个带垂直杆的三脚架，将 EC 系统安装在顶部。将红外气体分析仪和 3D 声波测角仪彼此靠近。将声波测雨仪放置到完全垂直的位置。稍微倾斜气体分析仪，使雨水轻松耗尽。将仪器提升到从土壤表面的两倍于树冠高度的高度，以及至少比顶篷顶部高出一米半到两米的高度。避免在EC系统附近安装任何不必要的元件，因为这可能会扭曲气流。对于进一步的计算和通量分析，同时测量一些辅助变量，包括至少空气和土壤温度、空气的相对湿度、光合作用光子通量密度、传入太阳辐射和降水。要计算二氧化碳通量，请使用市售的免费软件 EddyPro，该软件包括 EC 通量计算的校正应用。首先，创建一个新项目，然后在项目信息选项卡中指定原始数据文件格式并选择元数据文件。转到通量信息选项卡，选择数据集和输出目录，指定原始文件名格式，并检查通量计算的项列表。然后，转到处理选项选项卡并选择原始数据处理设置。选择旋转方法以校正风速计的测量值，从而考虑声风速计与局部风速流线线的任何不对齐。勾选非交易异构位置的第一个平面拟合方法。选择 012 类型的标记策略。选择对测量通量的影响区域的首选足迹方法。保持所有其他设置不变。单击在高级模式下运行，在末尾开始通量计算。创建包含通量计算软件和辅助测量结果的电子表格。使用电子表格中的过滤工具过滤在恶劣天气条件和仪器故障期间测量的二氧化碳通量。对于封闭式路径分析仪，请检查平均信号强度值。然后，标记并丢弃使用 ASS 测量的所有通量，其测量值低于仪器手册中建议的 60% 阈值。丢弃在 P 大于或等于 0.1 毫米的任何降雨事件期间测量的通量。为了考虑涡流协方差方法应用的不适当条件，请丢弃质量差的通量数据，在常见结果文件中二氧化碳标记值大于一个。使用输出文件中给出的夜间周期指示器（日间等于零）来过滤夜间测量的二氧化碳通量值。根据相应的摩擦速度值绘制夜间二氧化碳通量，并找到这些通量停止增加的 U 星值。将获得的值标记为摩擦速度阈值，以用作测量湍流条件不足的情况。从数据集中丢弃所有 U 星值小于阈值的二氧化碳通量，表示湍流不足。现在，绘制风上升的地图调查区域为通量空间代表性约束。根据对跨风综合足迹的估计，选择 70% 作为空间受限站点用于进一步分析的概率。接下来，以相同的方式定位地图和风，并使用北向作为指示器，检查感兴趣区域的任何方向是否有障碍，例如其他类型的生态系统，并标记它们为不具有代表性的。选择最代表测量地点的风向扇区和足迹值，检查尺寸，并指定最大长度。筛选出不符合这两个要求的通量值。要对二氧化碳数据进行间隙填充，从三个基本组（基于过程的方法、统计方法和神经网络的使用）中选择质量检查二氧化碳通量间隙填充和分段吸收和呼吸的方法。协议最薄弱的一点是间隙填充和通量分区描述，因为建议的方法是由其他专家单独开发的，并且只作为建议的技术在这里实现。基于流程的方法的一个例子来自FLUXNET加拿大研究网络。为了填补空白，不仅在二氧化碳，而且在其他易Flux值，如合理和潜在的热量，以及在重要的气象元素，使用REddyProc在线工具，这也是作为R软件包。接下来，例如，在 R 软件中，计算所有填补了缺口的二氧化碳通量（包括净生态系统生产、生态系统总产量和生态系统呼吸）的每日、每月和年度总计。TLEN 1 站点区域背景上的风玫瑰图显示所选风向的蓝阴影多边形，其中的红色阴影多边形显示为半径为 200 米的圆的扇区，表示磁通足迹的最大可接受程度。此图显示了 TLEN 1 风投场一年净生态系统生产通量测量的过滤过程结果。由于不利的天气条件和仪器故障，丢弃的数据点数量最小。虽然质量保证协议的最后一部分考虑到磁通量空间代表性限制，最终数据覆盖率只有欧共体测量的所有原始净生态系统生产通量的1/3。基于过程的方法的净生态系统生产通量、填充缺口和统计方法之间的关系显示了一种简单的线性回归，表明一般来说，这两种技术是可比的，因此可用于净生态系统生产通量填补了缺口。通过这两种方法，还从分治过程中获得了每日生态系统呼吸通量总量。必须记住，在非理想站点进行数据过滤和质量控制的关键步骤之一是评估测量的通量的空间代表性。

Research

JoVE Journal

Environment

Measurements of CO2 Fluxes at Non-Ideal Eddy Covariance Sites

Multimodal Optical Microscopy Methods Reveal Polyp Tissue Morphology and Structure in Caribbean Reef Building Corals

多模态光学显微镜方法在加勒比海礁珊瑚显示息肉组织形态和结构

An integrated suite of imaging techniques has been applied to determine the three-dimensional (3D) morphology and cellular structure of polyp tissues ...

科研

环境科学

Measuring Fluxes of Mineral Nutrients and Toxicants in Plants with Radioactive Tracers

植物与放射性示踪剂测量矿质营养和毒物的通量

Unidirectional influx and efflux of nutrients and toxicants, and their resultant net fluxes, are central to the nutrition and toxicology of plants. ...

Physical, Chemical and Biological Characterization of Six Biochars Produced for the Remediation of Contaminated Sites

物理，化学和六Biochars生产的生物表征污染场地修复的

The physical and chemical properties of biochar vary based on feedstock sources and production conditions, making it possible to engineer biochars with ...

A CO2 Concentration Gradient Facility for Testing CO2 Enrichment and Soil Effects on Grassland Ecosystem Function

A CO2 Concentration Gradient Facility for Testing CO2 Enrichment and Soil Effects on Grassland Ecosystem Function

一个外线<sub&gt; 2</sub&gt;浓度梯度用于测试CO<sub&gt; 2</sub&gt;浓度与土壤对草地生态系统功能的影响

Continuing increases in atmospheric carbon dioxide concentrations (CA) mandate techniques for examining impacts on terrestrial ecosystems. Most ...

Measuring Carbon-based Contaminant Mineralization Using Combined CO2 Flux and Radiocarbon Analyses

Measuring Carbon-based Contaminant Mineralization Using Combined CO2 Flux and Radiocarbon Analyses

测量碳为基础的污染物矿化结合使用CO<sub&gt; 2</sub&gt;助焊剂和放射性碳分析

A method is described which uses the absence of radiocarbon in industrial chemicals and fuels made from petroleum feedstocks which frequently contaminate ...

Calibrated Passive Sampling - Multi-plot Field Measurements of NH3 Emissions with a Combination of Dynamic Tube Method and Passive Samplers

Calibrated Passive Sampling - Multi-plot Field Measurements of NH3 Emissions with a Combination of Dynamic Tube Method and Passive Samplers

校准被动采样 - NH多情节场测量<sub&gt; 3</sub&gt;与动态管法和被动采样的组合排放

Agricultural ammonia (NH3) emissions (90% of total EU emissions) are responsible for about 45% airborne eutrophication, 31% soil acidification and 12% ...

Measurement of the Rheology of Crude Oil in Equilibrium with CO2 at Reservoir Conditions

Measurement of the Rheology of Crude Oil in Equilibrium with CO2 at Reservoir Conditions

与CO平衡的原油流变学测量<sub&gt; 2</sub&gt;在水库条件

A rheometer system to measure the rheology of crude oil in equilibrium with carbon dioxide (CO2) at high temperatures and pressures is described. The ...

Adherence of Bacteria to Plant Surfaces Measured in the Laboratory

细菌附着在实验室测量的植物表面

This manuscript describes a method to measure bacterial binding to axenic plant surfaces in the light microscope and through the use of viable cell ...

Assessment of Methane and Nitrous Oxide Fluxes from Paddy Field by Means of Static Closed Chambers Maintaining Plants Within Headspace

This protocol describes the measurement of greenhouse gas (GHG) emissions from paddy soils using the static closed chamber technique. This method is based ...

High-throughput, Microscale Protocol for the Analysis of Processing Parameters and Nutritional Qualities in Maize (Zea mays L.)

High-throughput, Microscale Protocol for the Analysis of Processing Parameters and Nutritional Qualities in Maize Zea mays L.

玉米加工参数和营养品质分析的高通量、微尺度协议 (玉蜀黍)

Maize is an important grain crop in the United States and worldwide. However, maize grain must be processed prior to human consumption. Furthermore, whole ...