FACE Ecosystems and Variables

Ecosystems and Variables

Ecosystems

The following list is preliminary and by no means complete. But it does demonstrate the wide variety of measurements being taken or planned at FACE sites.

aspen (Populus tremuloides)
birch (Betula papyrifera)
bog
castor bean (Ricinus communis)
chaparral
clover (Trifolium repens)
cotton (Gossypium hirsutum)
desert
grape (Vitis vinifera)
grassland
maple (Acer saccharum)
millet (Setaria italica)
mungbean (Vigna)
pine (Pinus taeda)
poplar (Populus)
potato (Solanum tuberosum)
rapeseed mustard (Brassica)
rice (Oryza)
ryegrass (Lolium perenne)
sorghum (Sorghum)
soybean (Glycine max)
sweetgum (Liquidambar styraciflua)
temperate forest
treeline ecotone
tropical rain forest
wheat (Triticum aestivum)

Variables

One of the goals of an overall data management system for FACE is to achieve greater consistency in methodology and nomenclature (variable names, units of measurement), to facilitate syntheses and analyses across data sets and across sites. The following list documents the variable name, units, and definitions used in the files archived and distributed by CDIAC; this list will be expanded over time.

Variable Units Definition

ATMAXxm °C Maximum air temperature, at x meters height

ATMEANxm °C Mean air temperature, at x meters height

ATMINxm °C Minimum air temperature, at x meters height

BLK - Block, for statistical replication (e.g., 1 through 3)

CO2 ppm Concentration of CO₂

CUMDAY d Cumulative day from start of experiment

DATE - Date, formatted as 4-digit year, followed by 2-digit month, followed by 2-digit day (e.g., 1997-10-30)

DAY d Day (1-31)

DM g/m² Dry matter

DOY d Day of the year (1 = 1 January, ..., 365 or 366 = 31 December)

LAI m²/m² Leaf area index

MGMT - Management scheme (e.g., grazed)

MONTH mo Month (1-12)

N - Number of observations used to derive mean

PARxm µmol/m²/s Incident photosynthetically active radiation, at x meters height

PYRANxm W/m² Integrated incident total radiation, at x meters height

RAIN mm Total rain

RHxm % Relative humidity, at x meters height

RING - Experimental ring (e.g., 1 through 6, plus 0 = ambient, i.e., not measured in a ring)

SOLAR_ANG ° Solar angle above (positive values) or below (negative values) the horizon

STMAXxcm °C Maximum soil temperature, at x cm depth

STMEANxcm °C Mean soil temperature, at x cm depth

STMINxcm °C Minimum soil temperature, at x cm depth

WIND m/s Wind speed

WIND_DIR ° Wind direction, where 0 = N, 90 = E, 180 = S, and 270 = W

YEAR y Year, in 4-digit format (e.g., 1998)

Variable	Units	Definition
ATMAXxm	°C	Maximum air temperature, at x meters height
ATMEANxm	°C	Mean air temperature, at x meters height
ATMINxm	°C	Minimum air temperature, at x meters height
BLK	-	Block, for statistical replication (e.g., 1 through 3)
CO2	ppm	Concentration of CO₂
CUMDAY	d	Cumulative day from start of experiment
DATE	-	Date, formatted as 4-digit year, followed by 2-digit month, followed by 2-digit day (e.g., 1997-10-30)
DAY	d	Day (1-31)
DM	g/m²	Dry matter
DOY	d	Day of the year (1 = 1 January, ..., 365 or 366 = 31 December)
LAI	m²/m²	Leaf area index
MGMT	-	Management scheme (e.g., grazed)
MONTH	mo	Month (1-12)
N	-	Number of observations used to derive mean
PARxm	µmol/m²/s	Incident photosynthetically active radiation, at x meters height
PYRANxm	W/m²	Integrated incident total radiation, at x meters height
RAIN	mm	Total rain
RHxm	%	Relative humidity, at x meters height
RING	-	Experimental ring (e.g., 1 through 6, plus 0 = ambient, i.e., not measured in a ring)
SOLAR_ANG	°	Solar angle above (positive values) or below (negative values) the horizon
STMAXxcm	°C	Maximum soil temperature, at x cm depth
STMEANxcm	°C	Mean soil temperature, at x cm depth
STMINxcm	°C	Minimum soil temperature, at x cm depth
WIND	m/s	Wind speed
WIND_DIR	°	Wind direction, where 0 = N, 90 = E, 180 = S, and 270 = W
YEAR	y	Year, in 4-digit format (e.g., 1998)

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