ecosystem spaceborne thermal radiometer experiment on ... · blackbody temperature images. •...

ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station

L1 Radiance at Sensor & Instrument DesignScience and Applications Team Meeting

11FEB2020 William R. Johnson, JPLThomas L. Logan, JPLMichael M. Smyth, JPL

Eugene Y. Chu, JPLDana J. Freeborn, JPL

Jet Propulsion Laboratory, California Institute of Technology

© 2020 California Institute of Technology. Government sponsorship acknowledged

ECOSTRESS ScienceFebruary 11-13, 2020

Historical Context

• Level-1 (L1) is part of the Science Data System (SDS), where the SDS:• Creates L0, L1, L2, L3, and L4 products, and• Delivers products to the Land Process DAAC (Sioux Falls, SD)

• Level-1 Inputs include:• L0 Data

• Raw Image Data Packets• Ground Imagery and BlackBody packets

• Spacecraft Orbital Metadata• Ancillary Data

• Landsat Ortho-Rectified Image Base (geolocation)

• Digital Terrain Models (pass-through)

• Elevation• Land/Water Mask

• Level-1 Outputs include:• Calibrated Radiance images with• Geolocation (position) and• Associated metadata

Level-1 Introduction

Science Data Products

L0 Raw data

L1 Radiometrically corrected Brightness Temperature

L2 Surface Temperature and Emissivity

L3 Evapotranspiration

L4 Water Use Efficiency, Evaporative Stress Index

Radiances


L1 Overview

SDS

SRTM

DEMValidated Products

L0A PACKETS

Production Facility

SCF/testbed

Co-Investigators

L1A PGE L1B PGE L2 PGEPT-JPLL3/L4PGEs

DAAC I/F(format)

NWP

Met

DAAC

Time referenced annotated data,

radiometric calibration coeff

NDVI

Data Portal

ISS Landsat

Static Ortho Base

AtmosProfile

Calibrated Sensor

Radiances & geolocation parameters

Land Surface Temperature & Emissivity,

Cloud

Evapotranspiration, Evaporative Stress Index, Water Use

Efficiency (PT-JPL)

MODISProducts Landsat

USDAALEXIL3/L4PGEs

ET, ESI(ALEXI

)

Geo, LSTE, Cloud

L0B PGE

L0 packets: time codes, ephemeris,

attitude, black body temperatures

Level-1 (L1) ProcessingSDS Processing Flow

Optional Outputs


L1 Overview

• L1 Processing consists of four PGEs (Product Generation Executives)• L1A

• Raw Data Processing (Chu)• Reformat Incoming ISS data packets, metadata, and ancillary data

• Formulate Focal Plane (FPA) Earth images by spectral band DNs• Formulate on-board FPA Blackbody Calibration image DNs

• Radiometric Calibration (Logan and Johnson)• Convert Image Pixel DNs to Radiance Coefficients

• FPA Blackbody temperatures are converted to radiances using the Planck function.

• FPA DNs are converted to radiance values using a two-point affine transformation. Conversions are stored as coefficients.

• L1B• Resampling and Radiance Delivery (Smyth)

• Merge Focal Plane overlap and average pixels (lines) to improve signal.• Fill Missing Data (Nguyen and Hulley)

• Geolocation (Smyth)• Geolocation Matching (using Landsat orthobase) to correct for Positional Errors• Geolocated L1B Products


L0 Inputs to L1A Raw Data PGE

L0 to L1 Travel Path of the ECOSTRESS Pixel

L0A/L0B PGEOrbital/SceneFLEX Packet Maintenance

ISS VelocityDirection

±25.5°, 57m nadir resolution, 6186 Pixels, 384 km, 183 msec

Scan MirrorFocal Plane5 Bands

x 256 Pixels

8.28

μm

8.63

μm

9.07

μm

11.3

5 μm

12.0

5 μm

Unus

ed

Unus

ed

Unus

ed

Analog MUXAnalog MUXAnalog MUXAnalog MUXAnalog MUXAnalog MUXAnalog MUXAnalog MUXAnalog MUXAnalog MUXAnalog MUXAnalog MUXAnalog MUXAnalog MUXAnalog MUXAnalog MUX

Analog MUXAnalog MUXAnalog MUXAnalog MUXAnalog MUXAnalog MUXAnalog MUXAnalog MUXAnalog MUXAnalog MUXAnalog MUXAnalog MUXAnalog MUXAnalog MUXAnalog MUXAnalog MUX

16 x 256 pixels in each spectral band.

Alon

g Tr

ack

(X)

Across Track (Y)

4 (x2) of 16 pixel columns imaged

4 Pixels

256Pixels

1 Pixel

256Pixels

5400 Pixels

11264Pixels(44scans x256)

16x16=256Pixels

Ground Processing On-Board SC Processing

Ground Processing

On-Board SC Processing

Across Track (Y)

Alon

g Tr

ack

(X)TDI

Across Track

Ground Processing

L1A CALPGE

Radiometric Calibration of three to five

thermal bands.

SWIR band is not calibrated.

L1A RawData PGE

DataReformatting

Image Formation


L1B Resampling PGE

L1B Resampling

1) Average FPA 2-to-1to improve signal

L1B Resampled Product(Six Bands)

5400 Pixels

5632Pixels

Alon

g Tr

ack

(X)

Processing Output

• L1B Corrections Include:• FPA Overlap• Resampling• Optical Distortion Removal• Data Fill for Dropped Lines

using Machine Learning

2) Composite multiple FPAs into one image3) Fill Dropped Lines


L1A Radiometric Calibration PGE

L1A Radiometric Calibration Steps*• Purpose: Convert Image TIR DNs to Radiance

• Procedure for each image:• Read temperatures from Sensor’s Cold (~295K) and Hot (~325K) Blackbodies.• Create synthetic FPA temperature images of Cold and Hot Blackbodies and

convert them to Radiance (Watt/m2/sr/um) using the center wavelength of each TIR band and the Planck function.

• Collect push-whisk FPA Digital Number (DN) scans of the Cold and Hot Blackbodies And Ground for all wavelengths.

• Using the FPA Radiance values and corresponding FPA DNs, use a two-point affine transformation (creating gain/offset coefficients) to convert each Ground pixel’s DN to Radiance.

• Accuracy is expected to be ~1.0 Kelvin. The Science Team can also choose between two Planck algorithms and linearly fine tune each TIR band radiance.

• TOA Radiance and Temperature images can be generated for Validation and Verification purposes as necessary.

• SWIR band is not radiometrically calibrated. It was intended for Geolocation “matching,” but provided unsuitable. It maybe provided as a non-science “visual” product.

*Documented in: “Level-1 Focal Plane Array and Radiometric Calibration Algorithm Theoretical Basis Document (ATBD),” JPL D-94803.


L1A Radiometric Calibration PGE

L1A Radiometric Two-Point Calibration*

GroundFPA DNs

Scan Mirror

Hot

Cold64x256 pixels

Blackbody FPA DNs

5400x256 pixels

Approach• Read BB Temperatures.• Create synthetic FPA 256x1

Blackbody Temperature Images.• Convert FPA BB Images to

Radiances using Planck Function.• Collect FPA Blackbody and Ground

DNs.• Apply 2pt Algorithm à

*Documented in: “Level-1 Focal Plane Array and Radiometric Calibration Algorithm Theoretical Basis Document (ATBD),” JPL D-94803.


Pre-Launch Performance (20180202)


L1B Geolocation*

*Documented in: “Level-1B Resampling and Geolocation Algorithm Theoretical Basis Document (ATBD),” JPL D-94641

• Purpose: Calculate the Latitude and Longitude of each image pixel.• Corrections for Small Errors (less than 2 pixels):

• Focal Plane Scan-Line Offsets.• ISS altitude, pitch, yaw, and roll.• Orbital position uncertainties and camera jitter.

• Corrections for Large Errors (2.5km to 7.5km):• Attitude drift can be large (position must be extrapolated from the ISS. No Star

Tracker).• Attitude correction is performed by co-registration/matching an

ECOSTRESS TIR image with a similar ortho-rectified Landsat wavelength.

• Testbed results suggest ECOSTRESS images with positional offset errors up to 12.5km can be geolocated to about 0.1pixel RMS.

• Geolocation accuracy meets the 50m positional requirement.• Latitude and Longitude coordinates are extracted and supplied for each input

75x68m ECOSTRESS pixel. Note that pixel size will vary with ISS Altitude.

L1B Geolocation PGE


L1B Geolocation PGE

Position CorrectionECOSTRESS TIR Band Registered to Landsat TIR Ortho-Base

Orbital

Path

ECOSTRESS TIR BandSimulated from ASTER Band14 (11u)

With Rotation for Geolocation Matching

Landsat 7 Global Ortho-BaseBand6 (TIR) Band (10.4-12.5u)

Co-Registration provides precise Geolocation


L1B Geolocation PGE

TOA Radiance Swath Mapped TOA Radiance*

*With rotation to North/South


L1 Product

Has anything changed recently? What are the current topics?

• Modifying the firmware to optionally choose between the current 3 bands with more collects versus 5 bands with fewer collects

• GeoTIFF generation in addition to the hdf5 products: For L1B, only the map-rad will have an added GeoTIFF. Most of the new GeoTIFFs will be for L2, L3-4


Has the ECOSTRESS calibration system changed since launch?

Calibration System


Calibration System


ECOSTRESS Acquired Scenes

Safehold 2/3/2019

Safehold 3/21/2019

Safehold 11/23/2019

Safehold 2/02/2020

First Cooldown

7/2018

Block 1 Block 2 Block 3 Gerardo Rivera


Calibration System

8.78µm 10.49µm 12.09mmBlock 1 0.44 0.46 0.52Block 2 0.4 0.88 0.49Block 3 0.9 0.75 0.67

Noise Levels (DN)


Temperature has had no noticeable increased since deployment

Calibration System

Warm ColdBlock 1 0.018 0.292Block 2 0.054 0.524Block 3 0.031 0.734

Noise Levels (C)


Temperature has increased upward by >2C since deployment.

Calibration System

Warm ColdBlock 1 0.018 0.292Block 2 0.054 0.524Block 3 0.031 0.734

Noise Levels (C)


Along Track Stability


Day vs. Night BB Observations


On-Orbit Vicarious Performance

Kerry Cawse-Nicholson & Robert Radocinski

Tahoe and Salton Sea Cal/Val Sites


L1 Process Summary & Products

Raw FLEX packets in orbit

files, House Keeping Data Calibration Inputs:

Image PixelsBlackbody TempBlackbody BandsTime referenced

Sensor Pixels Separated by

Scenes

Calibration Black Body Pixels (scene)

Orbital Engineering data

Radiance Data

Time Aligned Calibrated and

Resampled Sensor Radiances In Square Pixels

SRTM DEM

Landsat Static Ortho Base

Corrected Att / Eph

L1A RawData PGE

L1A CalPGE

L1B RADPGE

L1BGeolocation

PGE

SPICE kernels

L1A Products

L1B Products

Intermediate data

Other data

PGEs

Raw Attitude / Ephemeris

Radiometrically calibrated pixels(Gain/Offsets)

Geolocation Data*

L1A_BB

L1A_RAW_PIX

L1A_RAD_GAIN(optional V&VRadiances & Temperatures K)

Camera Model

L1A_PIX

L1B_CAL

L1B_RAD

L1B_GEO

L1B_MAP_RADL1A_RAW_ATT

L0B L1A Output Product

L1B Output Products

Geolocation Data*

L1B_ATT

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