This data file represents a time series of canopy biomass of the giant
kelp, Macrocystis pyrifera, derived from Landsat
5 Thematic Mapper (TM), Landsat 7 Enhanced Thematic Mapper Plus
(ETM+), and Landsat 8 Operational Land Imager (OLI) satellite imagery,
along with relevant metadata. The kelp canopy is composed of the
portions of fronds floating on the surface of the water. Biomass data
(wet weight, kg) are given for individual 30 x 30 meter pixels in the
coastal areas extending from near Año Nuevo to San Diego, CA,
including the Northern and Southern Channel Islands.
Data were derived from the three Landsat sensors listed above.
Observations are made on a 16 day repeat cycle, for each instrument,
but the temporal coverage is irregular because of cloud cover,
instrument failure, and the mission length of each sensor (TM: 1984 –
2011, ETM+: 1999 – present, OLI: 2013 – present). Estimates of kelp
canopy biomass are derived from the relationship between satellite
surface reflectance and empirical measurements of kelp canopy biomass
in long-term SBC LTER study plots obtained using SCUBA. The different
Landsat sensors were calibrated to each other using simulated Landsat
data derived from hyperspectral imagery. Missing data due to the ETM+
scan line corrector error were filled using a synchrony-based gap
filling method.
Data are organized into a single NetCDF file and contain the quarterly
means for each Landsat pixel across the three sensors. Relevant
metadata such as number of Landsat estimates from which the mean was
derived, the number of estimates from each sensor, standard error for
each quarterly estimate, spatial coordinates, and date are all
included in the file. For assistance with the data, please contact
sbclter@msi.ucsb.edu.