Isoprene concentration and flux were measured at the University of Michigan Biological Station (UMBS) PROPHET and AmeriFlux towers in a mixed northern hardwood forest in 2000-2003. The isoprene concentration profiles sampling heights in 2000 were: 3.5, 7, 11, 14, 22, 31, and 46 meters above ground level. The isoprene concentration profiles sampling heights in 2001 were: 3.5, 7, 14, 17, and 31. The isoprere flux sampling height was 31 meters above ground level in 2000 and 2001.
Isoprene samples were collected over a 30-minute period into the stainless steel canisters and analyzed using GC/FID. Midpoints of the 30-minute periods were 15 minutes and 45 minutes after each hour. All temperature and photosynthetic photon flux density (PPFD)data were collected on the AmeriFlux tower (2000 only).
The AmeriFlux Data were time averaged using the following techniques:
Temperature: For the 4 and 15 m samples, temperature is the average of 30 samples for the half hour period. Each sample is a 1 minute average of 0.5 Hz sampling. For the 21, 34, and 46 m heights, temperature is the average of 3 samples collected every 10 minutes within the half hour period. Each of the 3 samples is an average over 10 minutes at 0.5 Hz frequency.
PPFD: The PPFD samples are averages of 3 samples collected every 10 minutes within the half hour period. Each of the 3 samples is an average over 10 minutes at 0.5 Hz frequency.
NOTE: In the data file "WSU_Isoprene_Profiles_v1.csv", PPFD is denoted as PAR (Photosynthetically Active Radiation).
Missing data are indicated by –999 and values below the detection limit are indicated by –777
Detection limits: isoprene 0.3 ppbv
Instrument precision 5%
Total uncertainty: 10%
All flux data reported are from the AmeriFlux Tower at 31 m above ground level. Data was collected at 10 Hz and averaged over 30 minute periods. Midpoints of the 30-minute periods are 15 minutes and 45 minutes after each hour. Periods missing more than 15 minutes of data were eliminated. Rainy periods were deleted due to problems with both the sonic anemometer and the IRGA.
Missing data are indicated by –999 and values below the detection limit indicated by –888.
NOTE: Isoprene Flux data and Isoprene mixing ratio data are subject to filtering for various applications. The data posted here have not been filtered, so please contact WSU for guidance if you plan on using either data set.
Hills Scientific Fast Isoprene Sensor, model FIS-97, with associated ClearWater Tech., L.L.C. Ozone Generator
Open Path Infrared Gas Analyzer (IRGA) developed at the Atmospheric Turbulence and Diffusion Division, NOAA
Applied Technologies, Inc. 3-D sonic anemometer/thermometer model #SATI/3K
KNF sampling pumps
6-liter stainless steel canisters
Gas Chromatography with Flame Ionization Detection
Rotronic RH/temperature sensor
PPFD Quantum sensor
KBK and Pressley QC
These files came off of the PROPHET archive, here is the mapping of file names:
Research Gateway -> PROPHET Archive
Isoprene_flux_2000_v[x].csv -> Prophet_archive_6_03.txt
Isoprene_flux_2001_v[x].csv -> blis2a07.p01.txt