ICOS Atmosphere Station Specifications Edited by O. Laurent Version 2.0 September 2020 Please cite this document as: ICOS RI (2020): ICOS Atmosphere Station Specifications V2.0 (editor: O. Laurent). ICOS ERIC. https://doi.org/10.18160/GK28-2188 Last revision: 22 September 2020 Document History Version Date Actions 1.0 2014-10-18 Creation 1.1 2015-10-21 Add N2O section. Modify boundary layer section. Recommendation on sample drying. Met sensor list update. 1.2 2016-08-09 Modify Boundary layer section. Recommendation on the Short Term Working Standard for short term variability correction (especially for N2O). Add table of the recommended air mixture for the gas tank. Met sensor list update. 1.3 2017-11-15 Include Picarro G5310 for CO and N2O measurement. Recommend the use of dryer for N2O measurement. Recommendation on the instrument inlet pressure. Met sensor list update. 2.0 2020-06-06 Include ARMON radon monitor for radon measurement (section 2.2.6.). Update on the flask sampling specifications (section 2.2.4.) and flask sampling strategy (section 3.1). Include radiocarbon sampling strategy (section 3.2). Include Ecotech Spectronus (FTIR) as a recommended instrument for CO2/CH4/CO/N20 (sections 3.3 and 4.1). Modify recommendations for H2O management and buffer volumes (section 3.3). Update the recommended mole fraction for cylinders (Table 12). Recommendations for O2 measurement (section 5). 2 Contents INTRODUCTION ................................................................................................................................................... 5 1. RATIONALE AND OBJECTIVES ...................................................................................................................... 6 1.1. GENERAL OBJECTIVES ..................................................................................................................................... 6 1.2. DATA QUALITY OBJECTIVES .............................................................................................................................. 6 1.2.1. Data quality ..................................................................................................................................... 6 1.2.2. Data compatibility ........................................................................................................................... 6 1.3. NETWORK DESIGN ......................................................................................................................................... 7 1.4. ICOS STANDARDIZED NETWORK ....................................................................................................................... 8 2. MEASUREMENT SETUP ............................................................................................................................... 9 2.1. STATION REQUIREMENT .................................................................................................................................. 9 2.1.1. Station location ................................................................................................................................ 9 2.1.2. Station setup .................................................................................................................................. 10 2.2. EQUIPMENT REQUIREMENTS AND SELECTION ..................................................................................................... 11 2.2.1. Continuous gas analyzer ................................................................................................................ 11 2.2.1.1. ICOS requirement ...................................................................................................................................... 11 2.2.1.2. Analyzer selection meeting requirements ................................................................................................. 12 2.2.1.3. N2O analyzer .............................................................................................................................................. 13 2.2.2. Meteorological sensors .................................................................................................................. 14 2.2.2.1. Wind sensors ............................................................................................................................................. 17 2.2.2.2. Temperature sensors ................................................................................................................................. 18 2.2.2.3. Relative humidity sensors .......................................................................................................................... 19 2.2.2.4. Barometric pressure sensors ..................................................................................................................... 20 2.2.2.5. Integrated weather station........................................................................................................................ 21 2.2.3. Planetary boundary layer height retrieval instrument ................................................................... 22 2.2.4. Flask sampling ................................................................................................................................ 22 2.2.5. Radiocarbon (14C) sampler ............................................................................................................. 23 2.2.6. Radon monitor ............................................................................................................................... 23 2.2.7. Eddy flux measurement ................................................................................................................. 24 2.3. EQUIPMENT INTEGRATION ............................................................................................................................. 24 2.3.1. Continuous gas analyzer ................................................................................................................ 24 2.3.2. Meteorological sensors .................................................................................................................. 25 2.3.3. Planetary boundary layer height retrieval instrument ................................................................... 27 2.3.4. Flask sampling ................................................................................................................................ 27 2.3.5. Radiocarbon sampler ..................................................................................................................... 27 2.3.6. Radon monitor ............................................................................................................................... 27 2.3.7. Shelter and tower setup requirement/recommendation ............................................................... 27 2.4. AIR SAMPLING DESIGN .................................................................................................................................. 28 2.4.1. Continuous measurement .............................................................................................................. 28 2.4.1.1. Plumbing design ............................................................................................................................. 28 2.4.1.2. Ambient air sampling ..................................................................................................................... 28 2.4.1.3. Gas distribution equipment............................................................................................................ 29 2.4.1.4. Monitoring of station ancillary data .............................................................................................. 29 2.4.2. Periodical sampling ........................................................................................................................ 32 2.5. MAINTENANCE ............................................................................................................................................ 32 3. MEASUREMENT PROTOCOL ...................................................................................................................... 33 3.1. FLASK SAMPLING STRATEGY ........................................................................................................................... 33 3.2. RADIOCARBON SAMPLING STRATEGY ............................................................................................................... 34 3.3. CONTINUOUS MEASUREMENT SAMPLING STRATEGY ............................................................................................ 35 3 3.4. PLANETARY BOUNDARY LAYER HEIGHT PROFILE STRATEGY .................................................................................... 37 4. CALIBRATION, STANDARDS ....................................................................................................................... 38 4.1. CONTINUOUS GAS ANALYZER .......................................................................................................................... 38 4.1.1. Calibration protocol ....................................................................................................................... 38 4.1.2. Calibration equipment ................................................................................................................... 40 4.1.3. Standard production and calibration ............................................................................................