This data set contains carbon flux measurements recorded by an aircraft at the Duke, Harvard, and Howland Forest sites during the summers of 2012-2014 as part of the Airborne Microwave Observatory of Subcanopy and Subsurface (AirMOSS) project. Frequent measurements of CO2 and H2O were obtained using a cavity ring down spectrometer on board the Airborne Laboratory for Atmospheric Research, operated by Purdue University. Estimates of surface CO2 flux, sensible and latent heat fluxes, their corresponding uncertainties, and average wind speed and direction are provided for each of the 26 flights.
There are 27 files in comma-separated (*.csv) format included with this data set.
Figure 1: Fluxes of carbon dioxide observed during airborne sampling over the Harvard Forest site on June 1, 2014.
Spatial Resolution: Each value represents the average of all measurements obtained throughout one AirMOSS flight.
Temporal Resolution: Each value represents the average of all measurements obtained throughout one AirMOSS flight.
This data set includes 26 comma-separated values (*.csv) files. Scientific data is in AirMOSS_aircraft_Cflux_v2.csv. The remaining files provide coordinates for the flight paths.
Table 1. AirMOSS sites where airborne carbon flux was measured.
These data are provided with no QA information other than the standard deviation of observations during each flight.
Measurements were made with a Picarro Wavelength-Scanned Cavity Ring Down Spectrometer, a greenhouse gas analyzer that measures spatial variations in atmospheric CO2, CH4, and H2O over the duration of flight. Rapid (12 Hz) measurements of CO2 and H2O were used to estimate CO2 and latent heat flux, respectively.
Where ρ is the average dry-air density along the transect, L is the latent heat of vaporization of water, Cp is the specific heat of dry air at constant pressure, S¯ is the average groundspeed of the aircraft over the length of the transect (20 km), and T is the time to complete a transect. The variation in scalar concentration about the transect mean is given by q', the perturbations in specific humidity for Equation 1, and θ', the perturbations in potential temperature for Equation 2. CO2 are perturbations in CO2 concentration. The aircraft’s instantaneous groundspeed is denoted by Si, and the discrete sampling interval by Δt. Fluxes are calculated using 20 km-long averaging lengths to ensure adequate sampling of the spectrum of eddy sizes for the cruising speed of ~55 m s-1. Units have been converted to report latent and sensible heat fluxes in W m-2 and CO2 flux in μmol m-2 s-1. Negative flux values indicate the surface is a sink.