Airborne flux measurements of biogenic isoprene over California
MetadataShow full item record
Biogenic isoprene fluxes were measured onboard the CIRPAS Twin Otter aircraft as part of the California Airborne Biogenic volatile organic compound (BVOC) Emission Research in Natural Ecosystem Transects (CABERNET) campaign during June 2011. The airborne virtual disjunct eddy covariance (AvDEC) approach used measurements from a proton transfer reaction mass spectrometer (PTR–MS) and a wind radome probe to directly determine fluxes of isoprene over 7400 km of flight paths focusing on areas of California predicted to have the largest emissions. The fast Fourier transform (FFT) approach was used to calculate fluxes of isoprene over long transects of more than 15 km, most commonly between 50 and 150 km. The continuous wavelet transformation (CWT) approach was used over the same transects to also calculate instantaneous isoprene fluxes with localization of both frequency and time independent of non-stationarities. Fluxes were generally measured by flying consistently at 400m±50m (a.g.l.) altitude, and extrapolated to the surface according to the determined flux divergence determined in the racetrack-stacked profiles. The wavelet-derived surface fluxes of isoprene averaged to 2 km spatial resolution showed good correspondence to basal emission factor (BEF) land-cover data sets used to drive BVOC emission models. The surface flux of isoprene was close to zero over Central Valley crops and desert shrublands, but was very high (up to 15 mgm−2 h−1) above oak woodlands, with clear dependence of emissions on temperature and oak density. Isoprene concentrations of up to 8 ppb were observed at aircraft height on the hottest days and over the dominant source regions.
The article of record as published may be located at http://dx.doi.org/10.5194/acp-14-10631-2014The Supplement related to this article is available online at doi:10.5194/acp-14-10631-2014-supplement.
Showing items related by title, author, creator and subject.
Nuss, Wendell A.; Miller, Douglas K. (2003);The role of surface sensible and latent heat fluxes in rapid oceanic cyclone development was a common topic in the late 1980s and early 1990s. The debate centered on the importance of these fluxes in overall storm ...
Airborne Flux Measurements of BVOCs above Californian Oak Forests: Experimental Investigation of Surface and Entrainment Fluxes, OH Densities, and Damköhler Numbers Karl, T.; Misztal, P.K.; Jonnson, H.H.; Shertz, S.; Goldstein, A.H.; Guenther, A.B. (2013-10);Airborne flux measurements of isoprene were performed over the Californian oak belts surrounding the Central Valley. The authors demonstrate for the first time 1) the feasibility of airborne eddy covariance measurements ...
Impact of sea spray on the Yellow and East China Seas thermal structure during the passage of Typhoon Rammasun (2002) Zhang, L.X; Zhang, X.F.; Chu, P.C.; Guan, C.L.; Fu, H.L.; Chao, G.F.; Han, G.J.; Li, W. (AGU Publications, 2017);Strong winds lead to large amounts of sea spray in the lowest part of the atmospheric boundary layer. The spray droplets affect the air-sea heat fluxes due to their evaporation and the momentum due to the change of sea ...