Sentinel 2 Science for Rangeland Applications: A Case

Study from Alberta Canada

Michael J. Hill1 and Anne M. Smith2

2Earth System Science and Policy, University of North Dakota, Grand Forks, ND, USA

2Agriculture and Agri-Food Canada, Lethbridge, Alberta, Canada

Sentinel 2 for Science Workshop

ESA/ESRIN, Frascati. Italy, May 19-21 2014

This research is supported by a grant

from the Canadian Space Agency

Rangelands

Southern

Alberta

http://www.webpages.uidaho.edu/what-is-range/rangelands_map.htm

“Rangelands produce a wide variety of goods and services desired by society, including livestock forage,

wildlife habitat, water, mineral resources, wood products, wildland recreation, open space and natural beauty.”

Grazed Lands

http://www.uni-klu.ac.at/socec/inhalt/1189.htm Erb, K.-H., Gaube, V., Krausmann, F., Plutzar, C., Bondeau, A., H. Haberl. 2007. A comprehensive

global 5min resolution land-use dataset for the year 2000 consistent with national census data. Journal

of Land Use Science 2(3), 191-224.

Rangeland Concepts – State and Transition

Sentinel2

Spectral

Spatial

Temporal

Vegetation

Indices

Rangeland Concepts – Landscape Health

Landscape

Health

Better and stable

Stress

Poorer and irreversible

Vigor

Organization

Resilience

Ecosystem

service delivery

Sources: http://nmnh.typepad.com/rogers_archaeology_lab/weblogs/

http://oregonstate.edu/instruct/anth481/ectop/ecservices.html; http://www.ranchadvisory.com/about_us/news/

http://www.intechopen.com/books/advances-in-landscape-architecture/understanding-landscape-structure-using-landscape-metrics

How well does

the landscape

function?

State

change

Landscape Health from Remote Sensing

Vigor

Organization

Resilience

Measures Criteria

Biomass, fractional cover, GPP

Composition, 3-dimensional structure

Time series, temporal comparisons

Indicators

Pigment indices, VNIR/SWIR

index relationships

LiDAR, patch delineation,

plant functional type

classification, fractional

cover unmixing, clumping

Temporal stability of signal,

pixel distribution shapes and

metrics, time series trends and

decompositions

Description of Landscape States

Indi

cato

rs o

f lan

dsca

pe h

ealth

State Change in Managed Rangelands

- changes in metrics of suites of VIs linked to biophysical properties

Baseline

Time-of-season specific

Climatic oscillation

Management issue – fire/grazing

State change

Minimum detection threshold

Based on multiple metrics

Includes persistence of trend

Hill (2013). Remote Sensing of Environment, 137, 94 –111

Sentinel 2

Specifically, Sentinel 2 provides:

– a temporal frequency that captures serially dependent

processes of degradation and regeneration;

– high spatial resolution to resolve finer patch structures

vital to the process of water harvest;

– high spatial resolution to improve retrieval of bare soil as

an indicator of degradation;

– spectral resolution in pigment wavelengths to improve

discrimination of community structure and detection of

invasive species

– Landsat-match bands for synergies from enhanced

temporal coverage at fine spatial resolution.

350 M ha North America

25 M ha Western Canada

Canadian Grasslands – Southern Alberta

Canadian Grasslands – Southern Alberta

Grassland Cultivated crop

C emission 26 Mg ha-1

C sequestration

0.5 Mg ha-1 year-1

Photographs courtesy of

G. Bourgeois, M. Didkowsky,

R. Bourchier, J. Nicholsen, G. Larson, C. Kloppenburg.

Image courtesy of Barry Adams, Alberta Environment and Sustainable Resource Development

Native Prairie Vegetation Inventory

1990-1993

1:30,000 aerial photography

¼ section based

% ground cover of tree, shrub,

graminoid, riparian, lake or wetland

Grassland Vegetation Inventory

colour infrared digital airborne imagery 0.5 m

Comprehensive biophysical, anthropogenic and

land use inventory

polygon-based, 5.0 ha for upland site types and

1.0 ha for wetland site types.

Accuracy estimated at >90%

Grassland

Vegetation

Inventory

Site Types – Complex units for assessment

Predominantly loamy

Cropland

No site type > 65%

of polygon

Dryland pasture

or hayfields

Updated GVI

2007 SPOT Image 2006 GVI

GVI updates through satellite imagery?

Database

Record

Add/edit/delete

Slides courtesy of Barry

Adams AESRD

Native Grassland, Hyperion Sites, Vegetation Indices

Sensitivity Hyperspectral Broad and Narrow-Band

Vegetation Indices Photosynthetic

activity (PS)

NDVI (Normalized Difference Vegetation Index)

PS EVI (Enhanced Vegetation Index)

PS RENDVI (Red Edge Normalized Difference Vegetation Index)

PS CRI1 (Carotenoid Reflectance Index I)

PS/stress ARI1 (Anthocyanin Reflectance Index I)

PS/stress RGR (Red-Green Ratio)

Water NDII (Normalized Difference Infrared Index)

Senescence/Soil PSRI (Plant Senescence Reflectance Index)

Senescence/Soil SWIR32 (Short Wave Infrared Reflectance Ratio

Biomass SATVI (Soil Adjusted Total Vegetation Index)

Late season Hyperion used to simulate Sentinel 2

Site Hyperion

Cressday, Alberta September 5, 2009

Aden, Alberta September 8, 2009

Twin River, Alberta August 8, 2009

Taber, Alberta August 21, 2009

Some indices are

approximate due to

mix of broad and

narrow bands

Characterizing Site Type – Photosynthetic Activity

ADEN TABER NDVI

EVI

RENDVI

RGR

Dry site – Aden (Sentinel 2-specific VIs)

NDVI

ARI1

CRI1

RENDVI

Mesic Site – Taber (VIs sensitive to water, soil,

senescence, biomass)

Converted polygon

Partially converted

NDII

PSRI

SWIR32

SATVI

Indicator Maps PSRI

RGR SWIR32 CRI1

RENDVI NDII SATVI

Relative importance of

indicators will vary between

- dry and wet sites,

- over seasons, and

- with different land cover

types and phenologies.

19

Conclusions

Follow-up work is expanding analysis for CSA project

– using Landsat archive and Landsat 8 data, as well as additional Hyperion for

Sentinel 2 simulation

– developing routine methods for GVI change detection and range monitoring

The Group on Earth Observations (GEO) and its GLobal

Agricultural Monitoring (GEOGLAM) initiative

– collaborative effort across international and institutional communities to

develop global systems for monitoring condition and measuring productivity

in pastures and rangelands (RAPP: Rangelands and Pasture Productivity).

Sentinel 2 provides:

– important enhancements in frequency of coverage, spectral bands and

synergies with Landsat

– enable more detailed and intensive monitoring and implementation of recent

conceptual and methodological developments across the global rangelands