中国：助焊剂合作Integrating CPEC310 and AP200 systems to explore the theories and techniques of measuring fluxes

This case study discusses the integration of CPEC310 and AP200 systems to explore the theories and techniques of measuring CO₂/H₂O/trace-gas fluxes over heterogeneous landscapes in the Chinese Academy of Sciences Qingyuan Forest CERN laboratory.

CPEC310（闭合路径涡流系统）和AP200（大气轮廓系统）以及微观测压传感器，硝酸盐相关的痕量气体分析仪和土壤表面CO₂flux systems, have been integrated into three 50-meter-tall towers facilitating studies on forest ecology and management in the Chinese Academy of Sciences Qingyuan Forest CERN Field Laboratory (Fig. 1). (CERN is the China Ecology Research Network.) Taking advantage of new developments in the CPEC and AP systems from Campbell Scientific, the integrated network of systems is a state-of-the-art design to explore the theories and techniques of measuring CO₂/H₂O/trace-gas fluxes over mountain forests (i.e., heterogeneous landscapes). It does this while collecting long-term data of the fluxes over Qingyuan Forest CERN watershed covered with the three types of forests (natural mixed broadleaf deciduous forest, natural Mongolian oak forest, and larch plantation forest) that are most common in northeast China.

Qingyuan Forest CERN CAS

Qingyuan Forest CERN is a field laboratory directly supported by the Chinese Academy of Sciences (CAS) and is administrated principally by the Institute of Applied Ecology (IAE), CAS. It is open internationally for collaborations among ecologists, meteorologists, and hydrologists on forestry. Dr. Jiaojun Zhu is the director of Qingyuan Forest CERN, while also being the director general of IAE, CAS. Having his philosophy of research in field forests representative to most cases (e.g., mountain forests over heterogeneous landscapes, Fig. 1), he chose a mountain watershed covered with natural mixed broadleaf, natural oak, and planted larch forests as a practical field of Qingyuan Forest CERN. In 2003, he designed and established this field laboratory to be comprehensive enough for major projects in forest ecology and management, as well as the resulting environmental influences. These projects are funded by China National Science Foundation, CAS, and the China Council of Sciences and Technology. Now, dozens of projects with annual support of millions in US dollars are running here. Long-term, quality data to quantify the exchange of CO₂/H₂O and nitrogen-related trace gases between forest ecosystems and the atmosphere (i.e., fluxes over forests) as influenced by forest growth and development under human disturbance are indispensable in this laboratory (Zhu et al. 2018).

Integration of CPEC310 and AP200 systems with other sensors

清远森林山林森林领域在异质景观中，理论上挑战了通常适用于均匀景观的量化势态的技术。要求数据尽可能连续，以时间序列质量，清远森林CERN的主要目标有人挑战磁通测量设备系统的质量和功能。对于三座塔，这两个挑战都导致了CPEC310和AP200集成的选择，作为最先进的主要组件。还选择了研究级微型气象传感器，硝态相关的痕量气体分析仪在各种天气条件下耐用，土壤有限公司₂flux systems compatible with CPEC310 and AP200 in system control and data sharing.

CPEC310

CPEC310是来自Campbell Scientific的新发布的CPEC系统（图2A和2C）。它的co.₂/H₂O flux measurements are the benchmark used to assess the same measurements by an open-path eddy-covariance (OPEC) system (Helbig et al. 2016). Compared with other CPEC systems, it has the fast response of 4.2 Hz cutoff frequency (Ma et al. 2017), less consumption of power, and consistent performance in various weather conditions (Novick et al. 2013). Compared to its OPEC counterpart, it measures the temperature and pressure of measured air flows more accurately in better synchronization by thermo-equilibrium design. This avoids the measurement errors incurred in an OPEC system in which pressure is assumed to be static for WPL correction (Webb et al. 1980, Zhang et al. 2011), and the temperature for the correction of the spectroscopic effect on CO₂/H₂O signals at high frequency (e.g., 10 Hz) is measured using a conventional, slower sensor (e.g., a model 107 probe. Wang et al. 2016b).

更重要的是，CPEC310具有两个可区别的优势：

1. 自动零/跨度的功能set at a user-defined time interval. This functionality regularly (via user settings) adjusts the zero and span parameters in the working equation of a CO₂/H₂O analyzer (LI-COR Biosciences 2016) to fit the temperature near which the system is running, which technically improves the accuracies of measurements for CO₂/H₂O fluxes.
2. EasyFlux-DL-CR6CP software. This software controls and operates the measurements and auto-zero/span while processing the data as to the specifications the flux community has adopted.

AP200.

由Campbell Scientific制造的AP200（图2B和2D）是测量CO的大气配置文件系统₂/H₂啊,空气温度和相对湿度eight height levels, with their vertical distribution arranged by users. It is commonly used in connection with an eddy-covariance system. In this case, it was integrated with the CPEC310. Over an averaging interval used in CPEC310 for flux computation, its data from different levels are used to calculate the individual changes in CO₂/H₂o和在配置文件上的生物圈和大气之间的热存储器，到CPEC310级（即控制量）。更改是控制卷内存储的增加/减少，如此，被称为存储术语。这些术语的数量取决于边界层分层与物种组成，营养表面和体积密度的相互作用，以及树冠内的空间分布。因此，在磁通计计算中，基于CPEC310测量的快速响应配置系统的这些存储项的集成可以大大提高通量估计的可靠性（NEE，Wang等，2016A）。这已经通过国际碳天文台系统倡导，以标准化对系统基础设施的存储术语测量的方法（Montagnani等，2018）。

Similar to the CPEC310, the AP200 also has two distinguishing advantages:

1. 自动零/跨度的功能
2. EasyFlux-DL-CR1KXAP software (under development)

The software is adaptable and, for this case study, it was modified to accommodate a vertical profile of cup anemometers (model: 010C, Met One Instrument, OR) and soil moisture and temperature measurements (models: CS655, TCAV, Campbell Scientific, UT). These additions enable the AP200 to measure more variables of interest for comprehensive analyses.

Micrometeorology sensors

Each tower was equipped with the following sensors: a CNR4 four-component radiometer (Kipp & Zonen, Amsterdam) measures incoming and outgoing radiation (longwave and shortwave) over the forest canopy (Fig. 3a); three replications of HFP01SC self-calibrated soil heat-flux plates (Hukseflux Thermal Sensors, Delft), TCAV, and CS655 measure soil heat flux, along with soil moisture and temperature profiles (Fig. 3b for one replication); SI-111 infrared radiometers measure surface temperature inside (Fig. 3d2) and outside canopy (Fig. 3d1); and a 52202 rain gauge (R. M. Young Company, MI) measures precipitation (Fig. 3c).

土壤有限公司₂flux system and trace-gas flux system

Each tower was equipped with the following sensors: a soil surface CO₂flux system compatible with CPEC310 and AP200 in system control and data sharing has been designed for CO₂从森林地板和痕量气体分析（TGA）（Campbell Scientific，UT）的流出已经安排了氮气相关的痕量气体的势态。痕量气体通量将用于解决三种森林类型的营养循环和农业和森林生态系统之间的环境相互作用。

Full options, research grade, and integration

完整的选项,可用,选择时systems installed in the three towers. CPEC310 has its options of valve and scrub modules for its best performance in auto-zero/span; AP200 has its option of a zero gas bottle along with the maximum number of sampling intakes for its most reliable measurements; CNR4 has its option of CNF4 to acquire better data in evening, low wind, and moist conditions; and 52202 rain gauge has its option of a heating accessory for data availability in the winter season.

All sensors installed in the three towers are research grade for ecology. The CNR4 is a high-end, four-component radiometer; HFP01SC is the only soil heat flux plate with self-calibration capability for forests; and 52202 rain gauge is a top-quality choice for attaching to the towers.

All the measurement systems and sensors are integrated into a whole system. The data from the CPEC310 are designed to be shared online by the AP200, the soil-surface CO₂flux system, and the trace-gas system, and eventually to compute the values of variables at an ecosystem level (e.g., NEE). This computation can be summarized by the CR1000X Datalogger in the AP200. The summary can be a core data file robust enough for the use of most research topics on forest ecology and management.

Challenge, advantage, and perspective

For flux measurements and related studies, mountain forests in Qingyuan Forest CERN over a heterogeneous landscape is challenging, and the state-of-the-art design in an integration of CPEC310 and AP200 along with other quality sensors is an advantage. Facing the challenge and taking this advantage, the CAS-CSI Joint Laboratory of Research and Development for Monitoring Forest Fluxes of Trace Gases and Isotope Elements (Ker Joint Laboratory) (Fig. 4) has been established. This laboratory organizes scientists from the Institute of Applied Ecology, other institutes under CAS, Campbell Scientific, Campbell Scientific (Beijing) Company Limited, Shenyang Agricultural University, Northeast Forestry University, Beijing Techno Solutions Limited, and foreign visiting scientists as a team (Fig. 4b).

在收集长期数据的同时，这支球队主要关注三个任务：（1）制定测量CO的势量的理论和技术₂/H₂O and nitrogen-related gases over mountain forests of the three types; (2) research education for masters and Ph.D. candidates and postdoctoral fellows, as well; and (3) applications of new developments in CO₂/H₂O和来自Campbell Scientific的轨迹通量系统。

该团队将投影三个观点：（1）提供有关助焊剂和环境的长期数据，因为生态系统规模的三种森林分开影响，支持在清远森林核心核心中进行的所有研究项目;（2）改善在异构景观中测量大气成分的势态的理论和技术;（3）展示CPEC310和AP200的集成到中国助推器社区作为FOUX测量系统的未来核实信息更新的最佳选择。

Contributor Information

• Ning Zheng: Campbell Scientific (Beijing) Company Limited, CAS-CSI Joint Laboratory of Research and Development for Monitoring Forest Fluxes of Trace Gases and Isotope Elements (Ker Joint Laboratory)
• Emily Fu: Campbell Scientific (Beijing) Company Limited
• Tian Gao: Qingyuan Forest CERN, Institute of Applied Ecology, Chinese Academy of Sciences; CAS-CSI Joint Laboratory of Research and Development for Monitoring Forest Fluxes of Trace Gases and Isotope Elements (Ker Joint Laboratory)
• Fengyuan Yu: Qingyuan Forest CERN, Institute of Applied Ecology, Chinese Academy of Sciences; CAS-CSI Joint Laboratory of Research and Development for Monitoring Forest Fluxes of Trace Gases and Isotope Elements (Ker Joint Laboratory)

References

Helbig, M, K Wischnewski, GH Gosselin, SC Biraud, I Bogoev, WS Chan, ES Euskirchen, AJ Glenn, PM Marsh, WL Quinton, O Sonnentag. 2016. Addressing a systematic bias in carbon dioxide flux measurements with the EC150 and the IRGASON open-path gas analyzers. Agr For Meteorol 228-229: 349-359.

Li-Cor Biosciences。2016. Li-7500RS开放式道路公司₂/H₂O Gas Analyzer: Instruction Manual. Lincoln NE. p. 4-1 to 4-11 and 8-1 to 8-9.

Ma, JY, TS Zha, X Jia, S Sargent, R Burgon, CA Bourque, XH Zhou, WJ Chen, YJ Bai, P Liu, YJ Wu. 2017. An innovative eddy-covariance system with vortex intake for measuring carbon dioxide and water fluxes of ecosystems. Atmos Meas Tech 10: 1259-1267.

Montagnani, L, T Crűnwald, A Kowalski, I Mammarella, L Merbold, S Metzger, P Sedlák, L Siebicke. 2018. Estimating the storage term in eddy covariance measurements: the ICOS methodology. International Agrophysics 32: 551-567.

Novick, KA, J Walker, WS Chan, A Schmidt, C Sobek, JM Vose. 2013. Eddy covariance measurements with a new fast-response, enclosed-path analyzer: Spectral characteristics and cross-system comparison. Agr For Meteorol 181: 17-32.

Wang, X, C Wang, Q Guo, J Wang. 2016a. Improving the CO₂storage measurements with a single profile system in a tall-dense-canopy temperate forest. Agr For Meteorol 228: 327-338.

Wang, W, JP Xu, YQ Gao, I Bogoev, J Cui, LC Deng, C Hu, C Liu, SD Liu, J Shen, XM Sun, W Xiao, GF Yuan, XH Lee. 2016b. Performance evaluation of an integrated open-path eddy covariance system in a cold desert environment. J Atmos Oceanic Techn 33: 2385-2399.

韦伯，ek，gi pearman，r runing。1980.由于热量和水蒸气转移，对密度效应的磁通测量校正。Q J Royal Mete SoC 106：85-100。

Zhang, JH, XH Lee, GZ Song, SJ Han. 2011. Pressure correction to the long-term measurement of carbon dioxide flux. Agr For Meteorol 151: 70-77.

朱吉杰，QL yan，lz yu，jx zhang，k杨，t gao。2018年，基于森林生态与示威研究，支持东北地区森林的生态恢复与可持续管理。中国科学院公报，33：107-118。