Leaf Area Index

The Leaf Area Index (LAI) of a plant canopy or ecosystem, defined as one half of the total green leaf area per unit horizontal ground surface area, measures the area of leaf material present in the specified environment. On sloping surfaces, the leaf area should be projected to the underlying ground along the normal to the slope. This dimensionless variable varies between 0 and values of about 10 or so, depending on local conditions. It partly controls important mass and energy exchange processes, such as radiation and rain interception, as well as photosynthesis and respiration, which couple vegetation to the climate system. Hence, LAI appears as a key variable in many models describing vegetation–atmosphere interactions, particularly with respect to the carbon and water cycles.

Leaf Area Index after Fire

Figure: Time series of LAI (from Copernicus Global Land Service), spatially averaged over 6 x 6 km2, around the Pearsoll Peak, Oregon, United States (42°18’N; 123°51’W). In June 2002, a big fire event occurred. The error bars correspond to the spatial standard deviation around the central pixel. Landsat 7 images from https://earthexplorer.usgs.gov/

ECV Products and Requirements

These products and requirements reflect the Implementation Plan 2022 (GCOS-244).

The requirements are found in the complete 2022 ECVs Requirements document as well: ECV Leaf Area Index.

Products			Leaf Area Index (LAI)
	*()**	Unit	Values
Horizontal Resolution	G	m	10
	B		100
	T		250
Vertical Resolution	G		-
	B		-
	T		-
Temporal Resolution	G	d	1
	B
	T		10
Timeliness	G	d	1
	B		5
	T		10
Required Measurement Uncertainty (2-sigma)	G	% or m2 m-2	10% for values ≥0.5; 0.05 (absolute value) for smaller values
	B
	T		20% for values ≥0.5; 0.1 (absolute value) for smaller values
Stability	G	m2 m-2 / decade	<3%
	B
	T		<6%

(*) Goal (G): an ideal requirement above which further improvements are not necessary. Breakthrough (B): an intermediate level between threshold and goal which, if achieved, would result in a significant improvement for the targeted application. The breakthrough value may also indicate the level at which specified uses within climate monitoring become possible. It may be appropriate to have different breakthrough values for different uses. Threshold (T): the minimum requirement to be met to ensure that data are useful.

Data sources

This list provides sources for openly accessible data sets with worldwide coverage for which metadata is available. It is curated by the respective GCOS ECV Steward(s). The list does not claim to be complete. Anyone with a suitable dataset who wishes it to be added to this list should contact the abombelliwmo [dot] int (GCOS Secretariat).

Copernicus Global Land Service providing bio-geophysical products of global land surface
CEOS Working Group on Calibration and Validation, Land Product Validation Subgroup
Satellite ECV Inventory by the CEOS/CGMS Working Group on Climate (WGClimate)

Domain:

Land

Subdomain:

Biology

Scientific Area:

Biosphere

ECV Steward:

Nadine Gobron

Products:

Leaf Area Index