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Harvard Forest Data Archive

HF197

CO2 Profile at Harvard Forest HEM and LPH Towers since 2009

Related Publications

Data

Overview

  • Lead: William Munger, Julian Hadley
  • Investigators: Mark VanScoy, Liza Nicoll
  • Contact: Information Manager
  • Start date: 2009
  • End date: 2020
  • Status: ongoing
  • Location: Prospect Hill Tract (Harvard Forest)
  • Latitude: +42.539 to +42.542
  • Longitude: -72.185 to -72.180
  • Elevation: 355 to 380 meter
  • Taxa:
  • Release date: 2021
  • Revisions:
  • EML file: knb-lter-hfr.197.16
  • DOI: digital object identifier
  • EDI: data package
  • DataONE: data package
  • Related links:
  • Study type: long-term measurement
  • Research topic: forest-atmosphere exchange
  • LTER core area: primary production, inorganic nutrients
  • Keywords: carbon dioxide, eddy covariance, photosynthesis, respiration
  • Abstract:

    Carbon dioxide profile measurements are designed to supplement eddy flux measurements in calculating the carbon exchange of a forest. In the case of the Harvard Forest flux towers, the change in CO2 storage between the ground and the height of the eddy flux system during each half hour must be added to the eddy flux measured above the forest to determine the total carbon exchange. The profile measurements are also necessary in order to calculate CO2 movement by advection, or horizontal air transport. The amount of CO2 removed from a particular site by advection is the product of the total CO2 within the air a given range of height above the ground, and the average velocity of airflow parallel to the ground surface within that height range.

  • Methods:

    LPH Profile. CO2 profile inlets are at 0.1, 0.3, 1, and 2 m above ground on a short tower about 20 m from the flux tower, and 5, 10, 16 and 21 m above ground on the flux tower.

    Hemlock Profile. CO2 profile inlets are at 0.3, 1, and 2 m above ground on a short tower about 20 m from the flux tower, and 5, 10, 16, 22 and 29 m above ground on the flux tower.

    For both LPH and Hemlock profiles, during each 30-minute interval, measurements at each of the 8 levels are made every 10 seconds for a period of 3 or 4 minutes, and concentrations during the last two minutes are used to characterize the CO2 concentration at that level. Data from the first 1 or 2 minutes at each level are discarded, to allow the last air sampled at the previous level, which is still in the tubing at the end of an interval, to pass through the analyzer, insuring that measurements collected are really from the current sampling level.

  • Use:

    This dataset is released to the public under Creative Commons license CC BY (Attribution). Please keep the designated contact person informed of any plans to use the dataset. Consultation or collaboration with the original investigators is strongly encouraged. Publications and data products that make use of the dataset must include proper acknowledgement.

  • Citation:

    Munger W, Hadley J. 2021. CO2 Profile at Harvard Forest HEM and LPH Towers since 2009. Harvard Forest Data Archive: HF197.

Detailed Metadata

hf197-01: Hemlock CO2 profile

  1. datetime: date and time (EST) of measurement
  2. year: year of measurement
  3. dec.date: day of the year with hours and minutes converted to a decimal fraction of a day (unit: nominalDay )
  4. l1.co2: CO2 concentration at level 1 (unit: dimensionless / missing value: NA)
  5. l2.co2: CO2 concentration at level 2 (unit: dimensionless / missing value: NA)
  6. l3.co2: CO2 concentration at level 3 (unit: dimensionless / missing value: NA)
  7. l4.co2: CO2 concentration at level 4 (unit: dimensionless / missing value: NA)
  8. l5.co2: CO2 concentration at level 5 (unit: dimensionless / missing value: NA)
  9. l6.co2: CO2 concentration at level 6 (unit: dimensionless / missing value: NA)
  10. l7.co2: CO2 concentration at level 7 (unit: dimensionless / missing value: NA)
  11. l8.co2: CO2 concentration at level 8 (unit: dimensionless / missing value: NA)

hf197-02: Little Prospect Hill CO2 profile

  1. datetime: date and time (EST) of measurement
  2. year: year of measurement
  3. dec.date: day of the year with hours and minutes converted to a decimal fraction of a day (unit: nominalDay )
  4. l1.co2: CO2 concentration at level 1 (unit: dimensionless / missing value: NA)
  5. l2.co2: CO2 concentration at level 2 (unit: dimensionless / missing value: NA)
  6. l3.co2: CO2 concentration at level 3 (unit: dimensionless / missing value: NA)
  7. l4.co2: CO2 concentration at level 4 (unit: dimensionless / missing value: NA)
  8. l5.co2: CO2 concentration at level 5 (unit: dimensionless / missing value: NA)
  9. l6.co2: CO2 concentration at level 6 (unit: dimensionless / missing value: NA)
  10. l7.co2: CO2 concentration at level 7 (unit: dimensionless / missing value: NA)
  11. l8.co2: CO2 concentration at level 8 (unit: dimensionless / missing value: NA)