readme.txt v1.0, supporting data for 'Nitrogen Availability and Summer Drought, but not N:P Imbalance, Drive Carbon Use Efficiency of a Mediterranean Tree-Grass Ecosystem', Nair et al Global Change Biology and supplementary material.

This dataset contains phenocam transition dates (PTDs), flux and meteo, and the NDVI data used in the paper. 

In this repository we provide partially processed data to reproduce the analysis.
Raw is already available on Zenodo or other open access repositories and are indicated with each dataset. 

# PTDs.csv
A dataframe of phenocam-derived phenology transition dates during the experiment used to calculate seasons. 
Full methods for extraction of phenological transition dates with code continually updated are described in the following two publications
- Luo Y et al.  Remote Sens. 2018, 10(8), 1293; https://doi.org/10.3390/rs10081293 
- Luo Y et al. Glob. Change. Biol. 2020, 26(8), 4379-440;  https://doi.org/10.1111/gcb.15138
Raw Phenocam Imagery is available from the Phenocam network (https://phenocam.nau.edu/webcam/, sites - CT: eslma, NT: eslma1, NPT: eslma2). 

variable names:
	
hyear		hydrological year of observation
metric		PTD as described in SI part 2.
treatment	treatment (tower footprint)
date 		date of PTD

#fluxes.csv
A dataframe of daily averages of fluxes and meteo data used for the finest level analysis. 
A description of calculating indexes is given in the paper. 
Fluxes are presented as mean micromol co2 m-2 s-1 across 24hour period.
Flux data until 2020 is available at https://zenodo.org/records/4453567 as supporting data for previously published material https://doi.org/10.1029/2020JG006005. 
These data are also available from the European Flux Database (https://www.europe-fluxdata.eu/, sites - CT: ES-LMa, NT: ES-LM1, NPT: ES-LM2. 

variable names:

date		date
NEE		Net Ecosystem Exchange (micromol co2 m-2 s-1)
NEE_sd		standard deviation of net ecosystem exchange 
GPP		mean Gross Primary Productivity (micromol co2 m-2 s-1)
GPP_U95		95% confidence interval of Gross Primary Productivity
Reco		mean Ecosystem Respiration (micromol co2 m-2 s-1)
Reco_U95	95% confidence interval of Ecosystem respiration 
Ta02		Air Temperature (degC) at 2m
PARDR		mean daytime Direct Photosynthetially Active Radiation µmol photons m −2 s −1
Rain		preciptiation (mm)
VPD		Vapour pressure deficit (kPa)
CSWI		Conservative Soil Wetness Index
WAI		Water Availabilioty Index
SWCn		Normalized Soil Moisture Content
nRecNight	number of records at night
qc_daily	quality control flag	
treatment	treatment (tower footprint)
season		season assigned from PTDs
hyear		hydrological year

#sentinel.csv
Satellite NDVI was calculated from Sentinel-2 data available at https://dataspace.copernicus.eu/. The dataset in this repository is a combined dataset of Sentinel 2A and Sentinel2B.
A combined dataset of NDVI in a 100m radius around each tower from Sentinel 2A and Sentinel 2B, interpolated between days using a Kalman smoothing filter.
A full description is given in the methods section of the paper.

variable names:
date		date
treatment	treatment (tower footprint)
mean_NDVI	mean observed NDVI in cloud free overpasses
S2_NDVI_Imp	imputed daily main NDVI
