Validation and interoperability of continental-scale ... · Validation and interoperability of continental-scale surface reflectance from multiple sensors Medhavy Thankappan, Guy

Validation and interoperability of continental-scale

surface reflectance from multiple sensors

Medhavy Thankappan, Guy Byrne, Andrew Walsh, Lan-Wei Wang, Fuqin Li, Tim Malthus , Cindy Ong

Team Guy Byrne

Mike Caccetta

Alicia Caruso

Laurie Chisholm

Ken Clarke

Peter Fearns

Claire Fisk

Erin Kenna

Neil Sims

Kylie Smith

Liam Stephen

Lola Suarez

Medhavy Thankappan

Dan Tindall

Andrew Walsh

Lan-Wei Wang

Ian Lau

Fuqin Li

Stefan Maier

Tim Malthus

Glenn Newnham

Cindy Ong

Stuart Phinn

Peter Scarth

Reviewers:

Dennis Helder

Chris Maclellan

Kurt Thome

Joint Agency Commercial Imagery Evaluation Workshop Sep 17-19 2018 College Park Maryland USA

Analysis Ready Data

Analysis Ready Data (ARD) are data that have been processed to a minimum set

of requirements for it be interoperable through time and with other data without

much additional user effort

ARD opens opportunities for massive and sustainable exploitation of EO data

streams and new ways to produce, analyse and validate EO products

For non-experts to use ARD products, they need to be based on repeatable

measurements that can be compared through space and time.

Analysis

Ready

Data


ARD products need validation

The focus of validation is not how the corrections are made, but how

effective the corrections are



Continental scale validation of surface reflectance

Project funded through Digital

Earth Australia (DEA) – data

analysis infrastructure based

on Open Data Cube

technology

Two phases of field data

acquisition – Phase 1

collection commenced in Mar

2018, continues to Dec 2018

Nationally coordinated multi-

temporal field data acquisition

strategy

Protocols


• Draws on existing good practice protocols (QA4EO

Principles, CEOS-LPV, AusCover field validation)

• Near-coincident field measurements with satellite

overpass for Landsat 8, Sentinels 2a,b

• Coordinated multi-temporal data acquisition by

multiple teams

• Common approach to calibration of field

instruments (ASDs, reference panels)

• Field reference data to be managed as a national

collection for free and open access by EO

community

• Protocols developed for validation of SR to support

the development of a global validation protocol for

SR

Field measurements


ASD transects over a 100 m x 100 m area with regular

reference panel measurements; direct / diffuse and

microtops measurements Actual measurement transects at site

Data workflow / QA QC


Panel Transect

Transect data

Transect data

Averaged for site

Transect data

Averaged for line

Convolve to sensor

specific SRFs

Polygon defining

site

USGS SRGA SR

Compare spectra

Whole site / central

Extract pixels

from data

Reporting

Compare spectra


Compare spectra


Validation sites

Surface type


Lake George Temporal stability

Surf

ace R

eflecta

nce

Sentinel-2 Bands


Pinnacles

Surf

ace R

eflecta

nce

Sentinel-2 Bands

Temporal stability


Phase 1 field data collection status

Site Name Field Data

Collects

Satellite Comments

Blanchetown 1 S2a

Dookie 3 L8, S2a, S2b 2 Tandem

Fowler’s Gap 1 S2a

Heron Island 1 S2b Marine

Lake Lefroy 1 L8, S2a 1 Tandem

Lake George 8 L8, S2b, S2a

Litchfield 1 S2a Drone

Longreach 3 L8, S2a, S2b 2 Tandem

Narrabundah 4 L8, S2a, S2b

Pinnacles 7 L8, S2a, S2b 1 Tandem

Winton 4 L8, S2a, S2b 1 Tandem


Landsat 8 Field Satellite

Bands

Bands

Bands

Reflecta

nce

DOO LGR LGR LKG LKG

LKG LLF NRB PIN PIN

Landsat 8Bands

Reflecta

nce

Bands

PIN WIN WIN

Field Satellite

Sentinel 2 Field Satellite

Bands

Bands

Reflecta

nce

Bands

BLA FOW LGR LGR LGR

LKG LKG LKG LLF NRB

Sentinel 2 Field Satellite

Bands

Bands

Reflecta

nce

Bands

NRB NRB PIN PIN PIN

PIN PIN PIN PIN WIN

Sentinel 2R

eflecta

nce

Bands

Field Satellite

No text

WIN

Coincident measurements with two ASDs (L8) Pinnacles

GA ASD CSIRO ASD

Bands

Re

fle

cta

nce


Field Satellite

Coincident measurements with two ASDs (S2) Pinnacles

GA ASD CSIRO ASD

Bands

Re

fle

cta

nce


Field Satellite

Tandem overpasses (L8 + S2) Lake Lefroy

Bands

Re

fle

cta

nce

Re

fle

cta

nce

Landsat 8 Sentinel-2


Field Satellite

Lake Lefroy 25 June 2018


Drone based validation (Litchfield, NT)

Site overview (Litchfield, NT)

Measuring direct irradiancePre-flight reference panel measurement

Miniature Spectrometer

• Trial flight over Litchfield

site synchronous with a

Sentinel-2a overpass

• Sub-2kg drone with

Ocean Optics miniature

spectrometer (350-800

nm)

• Flown at 50m altitude,

~10m footprint (S2)

Litchfield results

Site photo from drone


Litchfield site: comparison with Sentinel-2A SR

Pixel by Pixel Average + SD Comparison

Re

fle

cta

nc

e

Bands

Field Satellite

Sa

tell

ite

Field


Landsat 8 comparison across all sites

Sa

tell

ite

SR

Field SR


Sentinel-2A comparison across all sites

Sa

tell

ite

SR

Field SR


Sentinel-2B comparison across all sites

Sa

tell

ite

SR

Field SR


DEA Validation WorkshopBrisbane 16-17 August 2018

Left to right : Dale Hughes (ANU), Arko Lucieer (Uni Tas), Ian Lau (CSIRO), Lola Suarez (Uni Melb), Stuart Phinn (Uni Qld), Guy Byrne (GA), Ken Clarke (Uni Adl), Kurt

Thome (NASA), Stefan Maier (Maitec), Tim Malthus (CSIRO), Andrew Walsh (GA), Cindy Ong (CSIRO), Lan-Wei Wang (GA), Fuqin Li (GA), Laurie Chisholm (Uni Wol),

Peter Fearns ( CSIRO), and Medhavy Thankappan (GA)


Quantifying uncertainty : field measurements

Wavelength

Refl

ecta

nce

CSIRO ASD GA ASD


Multi-sensor interoperability


• Understand sensor interoperability based on sensitivity of correction

parameters (e.g. aerosol, BRDF) and impact on SR

• Understand temporal stability of SR from different sources (e.g. GA,

USGS) through time series intercomparison

SR sensitivity analysis


• Three AOD values tested - 0.05, 0.25 and 0.5

• Two sites - one with seasonal burning (smoke), NT

• Tests for BRDF sensitivity in progress

NT NSW

SR

x 1

00

00

Multi-sensor ARD inter-comparison tool

LAMB

NBART

SZA

NBAR

USGS GA


• Time-series inter-comparison of GA / USGS SR

products – NIR band (2013 to 2017)

• Animation cycles through multiple sites represented

by cover type on the left

Cover types

ESA Living Planet Symposium May 2019 Milan

LPS 2019: Session on Analysis Ready Data

The ARD session will consolidate the current state of

knowledge, uptake and benefits of global efforts

towards producing Analysis Ready Data (ARD) for

Earth observations across the optical, thermal and

microwave domains.

Potential topics for this session would include:

maturity of ARD products and frameworks; ARD

methods, and the availability of ARD products from

government and commercial sources; comparison of

multi-sensor ARD products; validation of ARD

products; and user-uptake of ARD.

You are invited to submit abstracts on these ARD

related topics through the LPS 2019 website by

11 November 2018:

https://lps19.esa.int/QuickEventWebsitePortal/living-planet-symposium-2019/website


https://lps19.esa.int/QuickEventWebsitePortal/living-planet-symposium-2019/website

Documents

Validation and interoperability of continental-scale ... · Validation and interoperability of continental-scale surface reflectance from multiple sensors Medhavy Thankappan, Guy