Landsat Analysis Ready Data for LCMAP Gene Fosnight LSI-VC-3 Frascati, Italy March 20, 2017

ARD Science Data and QA Bands Collection Management ARD processing flow ARD Tiling Top of Atmosphere Reflectance, Brightness Temperature, Surface Reflectance Measurements – primarily L8 examples Per pixel metadata

Landsat Collection Management Landsat data archive will, going forward, be managed as a formal tiered data Collection. Managing the Landsat Archive as a Data Collection provides a consistent archive of known data quality to support time series analyses and data “stacking”, while controlling continuous improvement of the archive and providing access to all data as they are acquired. No change will be made to a Collection that would create a discontinuity in the environmental record. Any significant change would be deferred to the release of a new Collection.

Collection Categories: aka Tiers A Collection consists of three data categories: Tier 1, Tier 2, and Real-time. Data in Tier 1 meet formal geometric and radiometric quality criteria. Current criterion is a RMSE geometric threshold, but this not expected to always be the case Data in Tier 2 do not meet the Tier 1 criteria. The Real-time category contains data immediately after acquisition processed using estimated parameters. Real-time data are reprocessed and assessed for inclusion into Tier 1 or Tier 2 as soon as final parameters are available.

Tiers Tier 1 provides a starting point for data considered to be “optimal” for time series analysis However it is understood that this is only a guideline and that application requirements and reality may intervene For data rich areas and sensitive analysis, data with higher RMSE estimates can be rejected For data poor and robust methodologies, data with lower RMSE estimates can be incorporated from Tier 2, which may require further georegistration The goal of ARD is to provide sufficient metadata to permit adaptive selection of data from a ”data cube” structure.

Archive Characterization Sensor OLI/TIRS ETM+ TM Product % %L1T L1TP=<12m (T1) 62.60 90.66 74.98 96.51 64.78 96.23 L1TP>12m (T2) 6.45   2.71 2.68 L1GT/L1GS FB (T2) 14.78 17.70 28.39 L1GT/L1GS (T2) 16.17 4.61 4.15

OLI L1 Tier 1 L1TP Spatial Distribution Green indicates greatest temporal density

ETM+ L1 Tier 1 L1TP Spatial Distribution Green indicates greatest temporal density

TM L1 Tier 1 L1TP Spatial Distribution Green indicates greatest temporal density

ARD Processing Flow

ARD Tiling Concept  

Map Projection Parameters and Grid Extents

CONUS ARD Grid – after WELD

Alaska ARD Grid – after WELD

Landsat 8 TOA Reflectance Bands Ta (top of atmosphere reflectance) INT16 (16-bit signed integer) Refl (reflectance)

Solar and Sensor View Angles Sensor viewing angles Sun angles Azimuth Zenith

Landsat 8 Brightness Temperature bt (brightness temperature) INT16 (16-bit signed integer) K (Kelvin) temp (temperature)

Landsat 4-7 Surface Reflectance LEDAPS Version 3.0.0 Per pixel solar zenith angles corrections computed and applied Quality Assurance bands remain as is; SR internal quality accompanies the product, CFmask-derived quality band is requested separately Planned release into ESPA January 11, 2017 (this week) LEDAPS Version 3.1.0 Revisions to QA band pixel quality attributes to support ARD generation (see next slide) To be released no earlier than February 2017

Landsat 8 Surface Reflectance (LaSRC) Updates LaSRC Version 1.0 Modifications to how aerosol retrieval is handled over water Angstrom coefficient used to modify the AOT value Per pixel solar azimuth and zenith angles computed and applied Aerosol inversion algorithm applied to all pixels including clouds Aerosol retrieval algorithm spatially interpolates ancillary data for each pixel Cloud and ipflag Quality Attributes bands are now combined into one aerosol Quality Attributes band Addition of new Pixel Quality Attributes (pixel_qa) and Radiometric Saturation Quality Attributes (radsat_qa) bands

Landsat 8 Surface Reflectance sr (surface reflectance) INT16 (16-bit signed integer) Refl (reflectance)

Spectral Band Differences

ARD Quality Band Specifications QA quality assurance, UINT16 16-bit unsigned integer, INT16 16-bit signed integer, NA not applicable, UINT8 8-bit unsigned integer, SR surface reflectance, toa top of atmosphere reflectance, NA not applicable

Quality Band Bit Value Cumulative Sum Description - OLI 1 1 Designated Fill 2 3 Terrain Occlusion 4 7 Radiometric Saturation 8 15 16 31 Cloud 5 x32 63 Cloud Confidence 6 64 127 128 255 Cloud Shadow 256 511 9 512 1023 Snow/Ice 10 1024 2047 11 2048 4095 Cirrus 12 4096 8191 13 8192 16383   14 16384 32767 32786 65553 Bit Value Cumulative Sum Description – TM/ETM+ 1 Designated Fill 2 3 Dropped Pixel 4 7 Radiometric Saturation 8 15 16 31 Cloud 5 32 63 Cloud Confidence 6 64 127 128 255 Cloud Shadow 256 511 9 512 1023 Snow/Ice 10 1024 2047 11 2048 4095   12 4096 8191 13 8192 16383 14 16384 32767 32786 65553

Landsat 4-7 Radiometric Saturation Quality Bit Index LSB least significant bit, MSB most significant bit, PQA pixel quality attributes

Landsat 8 ARD Lineage Quality Attribute Band

Tile Lineage QA Band

Landsat 8 ARD Internal Surface Reflectance Aerosol Quality Bits

Landsat 8 ARD Internal Surface Reflectance Aerosol Quality Bit Values

Landsat ARD Tile-based XML Metadata Global Metadata Level-2 Pixel QA Metadata Level-2 Radiometric Saturation QA Metadata Level-2 Lineage QA Metadata Level-2 Angle Band Metadata Level-2 TOA Reflectance Metadata Level-2 Brightness Temperature Metadata Level-2 Surface Reflectance Metadata Level-1 Scene Metadata

Analysis Ready Data (ARD) for the U.S. Finalizing Data Format Control Book (DFCB) that lays out product specifications, format, and packing details Generation of and public access to sample ARD products conforming to DFCB no earlier than March 2017 Begin CONUS ARD in late February and public access no earlier than May 2017 Currently working on integrating and refining LaSRC for ESPA Begin processing OLI/TIRS CONUS ARD is still TBD Tiling is a separate processing step that follows Level-2 processing Initial investigations into Global ARD tiling based on the OGC Discrete Global Grid System have begun.