TITLE: Phenocamera RGB daily average composite image collection from Skogaryd Central, western Sweden.
SITES STATION: Skogaryd Research Catchment
TIME PERIOD: 2018-04-27 2018-12-30
TIME RESOLUTION: DAILY
TIME ZONE: UTC +1 
LATITUDE: 58.363759
LONGITUDE: 12.149442
ALTITUDE: 82.8 m.a.s.l.
FILE RETRIVED FROM: https://data.fieldsites.se Link to metadata landing page is available in separate file in the downloaded zip.
DATA POLICY: SITES data is licensed under a Creative Commons Attribution 4.0 international license (http://creativecommons.org/licenses/by/4.0/).

PARAMETERS & UNITS: Digital Numbers (DN)

DESCRIPTION: 
Collection of phenocamera RGB composite images averaged daily from quality-filtered photos from 10 a.m. to 2 p.m., photos taken with an hour frequency. 
The phenocamera is pointing to the understory of a spruce forest (Picea abies) composed by a floor of the perennial glittering wood moss (Hylocomium splendens) with hints of common wood sorrel (Oxalis acetosella). 

SENSOR DESCRIPTION:
Data acquired with Mobotix M25 RGB phenology camera, with a wide field of view angle (FOV) of 60 degrees. Photos are stored in JPG format. 

DATA ACQUISITION
The original photos were acquired with phenology cameras on a observation tower, at a height of 3 m above ground, looking to west (270 degrees from north) and a zenith angle of 47 degrees. The phenocamera operates between April and October. It starts collecting photos at 4 a.m. and ends at 8 p.m. and takes one photo every hour. 
The area surveyed by the phenocamera projects a footprint on the ground defined by an ellipse with a central coordinate (GCS WGS84, degrees decimal): 58.363714N, 12.149319E. The ellipse has a major diameter of 13 m (in east-west direction) and a minor diameter of 7 m (in north-south direction).  

PROCESSING METHODS:
Low quality photos were filtered from the original phenology photo collection using thresholds to the spectral signal of the photos (DN), as defined by Richardson et al., 2018. Low quality refers to photos that present sun glare, rain droplets, fog or shadows, or represent low-light or blurry conditions.
For phenology purposes, all photos from 10 a.m. to 2 p.m. were averaged per band (RGB) and pixel, daily. 

REFERENCES
Richardson, Andrew D., Koen Hufkens, Tom Milliman, Donald M. Aubrecht, Min Chen, Josh M. Gray, Miriam R. Johnston et al. "Tracking vegetation phenology across diverse North American biomes using PhenoCam imagery." Scientific data 5 (2018): 180028.







