Soil Moisture Active Passive (SMAP) Calibration and Validation

Plan and Current Activities T. J. Jackson, M. Cosh, R. Bindlish, W. Crow, USDA ARS HRSL

A. Colliander, E. Njoku, K. McDonald; NASA JPL J. S. Kimball; University of Montana

S. Belair; Environment Canada J. Walker, R. Panciera; University of Melbourne

P. O'Neill; NASA GSFC

July 29, 2010

• General aspects of the SMAP Cal/Val Plan– Objectives– Timeline– Pre-launch vs. post-launch validation activities

• Ground-based (In Situ) validation – Core Validation Sites

• Field experiments– CanEx SM 2010

Outline

ApproachSMAP Cal/Val Objective

• A Cal/Val Plan is a SMAP mission requirement.– Objective: calibrate and validate Level 1 through

Level 4 algorithms and products relative to the mission requirements.

– Mission requirements include quantitative specifications of accuracy associated with each mission product

• Example: Provide estimates of the 0-5 cm soil moisture with an accuracy of 0.04 m3/m3 at a resolution of 10 km.

L1C_TBSMAP Cal/Val Timeline• Current plans are for SMAP to complete an In-Orbit Checkout

(IOC) period within 60 days after launch• Following the IOC period, the SMAP Project will complete an

initial Cal/Val of the data products (6 months for Level 1 products and 12 months for Levels 2, 3, and 4).

• Cal/Val will continue throughout the mission to monitor performance and assist in the improvement of algorithms.

Level 2/3/4

2/3/42/3/4

Level 2/3/4

2/3/42/3/4

Must reach a conclusion by this point.

Demands being ready and timely delivery of validation data.

ApproachSMAP Cal/Val: Pre-launch vs. Post-launch

Instrument

counts

Instrument calibration

Geophys. param. retrieval

On-ground calibration data,

in-orbit calibration data, etc,

Ancillary data, masks, external model outputs,

etc.

SDS

TB, σ0

L1

SM (sf+rz), F/T, NEE

L3,L4

Feed

back

Feed

back

Post-launch Cal/Val Activities

Instrument calibration

Geophys. param. retrieval

On-ground calibration data,

in-orbit calibration data, etc,

Ancillary data, masks, external model outputs,

etc.

SDS

TB, σ0

L1

Pre-launch Cal/Val Activities

SM (sf+rz), F/T, NEE

L3,L4Instrument

counts

(schematic diagram of data processing flow; SDS = Science Data System)

• Pre-launch Cal/Val is focused on validating that there are means in place to fulfill the mission objectives. In particular

– ATBD identified activities that will improve algorithms and products.

– Establish infrastructure necessary for post-launch Cal/Val.

• Post-launch Cal/Val is focused on validating that the science products meet their quantified requirements, and on improving the algorithms and quality of products over the mission life.

ApproachSMAP Cal/Val: Post-launch Resources

• Ground-based (in situ, tower, and aircraft)• Products from other satellites• Model products

ApproachSMAP Cal/Val: Pre-launch• Algorithm testbed• Satellite products

– AMSR-E, SMOS, Aquarius• Field campaigns

– Past• SGP, SMEX….• SMAPVEX08

– Ongoing • Canadian campaign (CanEx)• Australia campaign (SMAPEx)• San Joaquin Valley experiment

– Future

• ATBD identified activities that will improve algorithms and products

• In situ sensor testbed• Scaling methodologies• Tower and aircraft SMAP simulators• Core validation sites/collaboration

• Establish infrastructure necessary for post-launch Cal/Val

Bindlish, Misra

Walker

Cosh

SMAP Ground-Based Validation

• SMAP will rely on in situ observations as one of the tools used to validate the L2, L3, and L4 products.– The logistics and costs require that we exploit

partnerships to the maximum extent.– These must be ready to go before launch.– What infrastructure do we need to establish now?

SMAP Ground-Based Validation

• Existing networks are a key resource/partner in SMAP validation (No cost, mostly real time, and public domain). – These are typically sparse…scaling is the key issue.– Standards and compatibility are also concerns.

• Dense networks with nested scales are needed: Core Validation Sites (CVS).– Some exist but more are needed.– These should meet some criteria that will facilitate SMAP

product validation.– Some form of agreement establishing collaboration with the

SMAP project.

SMAP Cal/Val SM Core Validation Sites• Basic science requirements (suggestions!)

– Represent the 10 km product area• Also consider providing 40 km and 3 km scales

– Provide the equivalent of volumetric soil moisture obtained using the gravimetric method (Calibrated)

• Establish that it provides a measure of the 0-5 cm layer• Also consider providing the 0-100 cm layer

– Multiple sampling locations within the site that can be used to accurately estimate the product grid average

• Statistical confidence must be established

– Supporting meteorological instrumentation– Supporting ancillary data sets such as soils, land use, and

vegetation biomass

SMAP Radar pixels ~ 3x3km

SMAP joint radiometer/radar soil moisture – 9x9km

SMAP Radiometer Pixel – 34x38km

Example of a SMAP Soil Moisture Core Validation Site (J. Walker Univ. Monash)

Existing stationsNew stations

Augmenting an existing radiometer scale network to support SMAP

SMAP Cal/Val SM Core Validation Sites

• Logistical requirements – Near real time availability of data – Site is accessible to researchers – Existing site facilities– Heritage of scientific studies to build from– Long term commitment by the sponsor/host– Agreement with SMAP project

• Setting up a process now.

SMAP Cal/Val SM Core Validation Sites

• SMAP project priorities– An area that is homogeneous or has a uniform

mixture of land covers at the product scale– Represents an extensive or important biome– Complement the overall set of sites– Operational by 2012

SMAP Cal/Val SM Core Validation Sites

• Next Steps – Survey candidate sites. – Evaluate the effectiveness of the ongoing SMOS

validation program. – Decide on appropriate mechanism for

collaboration.– Workshop

ApproachSMAP Cal/Val: Pre-launch• Satellite Products

– AMSR-E, SMOS, Aquarius• Field Campaigns

– Past• SGP, SMEX….• SMAPVEX08

– Ongoing • Canadian campaign (CanEx)• Australia campaign (SMAPEx)• San Joaquin Valley experiment

– Future• SMAPVEX ??

• ATBD identified activities that will improve algorithms and products

• In situ sensor testbed• Tower and aircraft SMAP simulators• Core validation sites • Collaboration

• Establish infrastructure necessary for post-launch Cal/Val

Just completed

CanEx SM 2010: CSA and NASA

• Primary mission objectives: (1) validation of SMOS brightness temperature and soil moisture products and (2) concurrent time series of active and passive microwave observations for SMAP passive, active, and combined soil moisture algorithms.

• Flight dates: – June 2-15 Kenaston (KEN) (7 dates) (agricultural)– June 16 BERMS (1 date) (forest)

• Other mission considerations– Both domains include two independent SMOS grid

footprints.– Coordination with SMOS over passes.– Calibration and scaling of permanent in situ networks

CanEx Permanent In Situ Networks

Environment Canada

Kenaston

University of Guelph

Environment CanadaBERMS

• Close to desired SMAP Core Validation site requirements

CanEx SMOS Pixel Centers and Aircraft Coverage

SMOS products are at ~40 km resolution and gridded at ~16 km.

Each area includes ~ 2 independent pixels (~33 by 70 km).

Aircraft logistics limit the size of the coverage domain.

CanEx Campaign Soil Moisture Sites

Ground sampling sites included most permanent sites, the BERMS temporary network, and additional sites selected to be representative of domain, provide spatial coverage, and support multiple scaling objectives.

59

50

BERMS Temporary Network• Will provide a longer record for SMOS/BERMS and to establish scaling of the limited permanent network.

NASA G-III

Environment Canada Twin Otter

CanEx Campaign AircraftUAVSAR: L-band fully polarimetric radar (Swath 20 km, resolution 6 m).Multiple lines were required to provide coverage between 35 and 45o.

L-band dual polarization radiometer, 40o (single beam, resolution 3 km). Multiple lines were required to provide coverage .

6.9, 19, 37 and 89 GHz radiometers, 53o (single beam, res. are 1.3 km for 6.9 GHz and 0.8 km for the others)

CanEx SummaryDate Saskatoon

Daily Rainfall (mm)

Prince Albert Daily Rainfall

(mm)

Aircraft Flights Site

Satellite Coverage Note

May 22-30 67.3 68.4

June 1

2 0.7 KEN SMOS

3 9.8 14.8 SMOS

4 2.2

5 6.8 KEN SMOS

6 0.2 KEN

7 5.5 2.8

8 16.9 7.2 SMOS Partial Twin Otter

9 KEN

10 5.5 4.0 SMOS

11 13.2

12

13 0.4 KEN SMOS

14 0.1 KEN

15 0.3 KEN SMOS Only UAVSAR

16 0.2 BERMS SMOS

Significant Rain

Re-wetting

CanEx Campaign Ground Conditions

Wettest Spring…ever

Waterlogged soils resulted in limited planting and tillage

25o

65o

CanEx Kenaston Area

Composite radar image (HH-red, VV-blue, HV- green)

June 5, 2010

SMAP Major Field Campaigns ver. 07/10

Year/Quarter

1 2 3 4

2008SMAPVEX08

2009 SMOS

2010SMAPEx

CanEx-SMSMAPEx

2011SMAPEx

Aquarius GCOM-WCanEx-FT

2012 SAOCOMSMAPVEX12

2013

2014 SMAP

2015 SMAPVEX15 SMAPVEX15 SMAPVEX15

• SMAPVEX08– High priority design/algorithm issues

• SMAPEx (Australia)– 4 one-week campaigns to span four

seasons– Aircraft Radar/Radiometer

• CanEx-SM (Canada)– Two-week soil moisture campaign– Aircraft Radar/Radiometer

• CanEx-FT (Canada)– Two-week freeze/thaw campaign– Aircraft Radar/Radiometer

• SMAPVEX12– Major hydrology campaign – Long duration– Aircraft Radar/Radiometer

• SMAPVEX15– Extended campaign for both SM and

FT – Long duration– Aircraft Radar/RadiometerSatellite Launch in Red

SMAP Cal/Val Key Points

• Pre-launch Cal/Val is driven by the Algorithm teams and the post-launch mission requirements.

• Timeline has a major impact!• Core Validation Sites must be established.• Field campaigns

– Recent field campaigns have exploited partnerships.– CanEx, SJV, and SMAPEx have all been successful.– Planning for a 2011 freeze-thaw activity is beginning.– Broad input is needed for the next campaign.

• Cal/Val Workshop Week of May 3-5, 2011 (S. Calif.).