=============================================================================== PRISM/ORCAS L1 and L2 Distribution Document v01 =============================================================================== Michelle Gierach, Michelle.Gierach@jpl.nasa.gov Sarah R. Lundeen, Sarah.R.Lundeen@jpl.nasa.gov Robert O. Green, Robert.O.Green@jpl.nasa.gov David R. Thompson, David.R.Thompson@jpl.nasa.gov This document describes the PRISM and ORCAS L1B and L2 data products. PRISM is an imaging spectrometer that measures reflected radiance at 3nm intervals in the Visible/Near-Infrared (VNIR) spectral range from 380-1050nm. Additional information may be found on http://prism.jpl.nasa.gov ------------------------------------------------------------------------------- OVERVIEW ------------------------------------------------------------------------------- Each flightline uses a specific base filename prefix: prmYYYYMMDDtHHNNSS YYYY: The year of the airborne flight run. MM: The month of the airborne flight run (i.e. 05 represents May). DD: The day of the airborne flight run (22 is the 22nd day of the month) HH: UTC hour at the start of acquisition NN: UTC minute at the start of acquisition SS: UTC second at the start of acquisition The CORAL/PRISM data products for a particular airborne flight run are organized in the following directory structure, labeled with a processing version marker VVV: /prmYYYYMMDDtHHNNSS_rdn_VVV | prmYYYYMMDDtHHNNSS_rdn_VVV_img | prmYYYYMMDDtHHNNSS_rdn_VVV_img.hdr | prmYYYYMMDDtHHNNSS_rdn_VVV_obs | prmYYYYMMDDtHHNNSS_rdn_VVV_obs.hdr | prmYYYYMMDDtHHNNSS_rdn_VVV_obs_ort | prmYYYYMMDDtHHNNSS_rdn_VVV_obs_ort.hdr | prmYYYYMMDDtHHNNSS_rdn_VVV_loc | prmYYYYMMDDtHHNNSS_rdn_VVV_loc.hdr | prmYYYYMMDDtHHNNSS_rdn_VVV_loc_ort | prmYYYYMMDDtHHNNSS_rdn_VVV_loc_ort.hdr | prmYYYYMMDDtHHNNSS_rdn_VVV_glt | prmYYYYMMDDtHHNNSS_rdn_VVV_glt.hdr | prmYYYYMMDDtHHNNSS_rdn_VVV_igm | prmYYYYMMDDtHHNNSS_rdn_VVV_igm.hdr The file product codes signify: *rdn_VVV_obs parameters relating to the geometry of observation and illumination in the raw spatial format *rdn_VVV_obs.hdr obs image header file *rdn_VVV_obs_ort parameters relating to the geometry of observation and illumination rendered using the *glt lookup table *rdn_VVV_obs_ort.hdr obs_ort image header file *rdn_VVV_glt geometric look-up table *rdn_VVV_glt.hdr GLT image header file *rdn_VVV_loc pixel locations (WGS-84 lat/lon) for each science pixel in the corresponding unorthocorrected radiance image *rdn_VVV_loc.hdr LOC image header file *rdn_VVV_loc_ort pixel locations (WGS-84 lat/lon) for each science pixel in the corresponding orthocorrected radiance image *rdn_VVV_loc_ort.hdr loc_ort image header file *rdn_VVV_igm input geometry file *rdn_VVV_igm.hdr IGM image header file *rdn_VVV_img orthocorrected, scaled radiance image file *rdn_VVV_img.hdr RDN image header file ------------------------------------------------------------------------------ FILE DESCRIPTIONS ------------------------------------------------------------------------------ *rdn_VVV_glt GEOMETRIC LOOKUP TABLE (GLT) Contents: Orthocorrected product with a fixed pixel size projected into a rotated UTM system that contains the information about which original pixel occupies which output pixel in the final product. Additionally, each pixel is sign-coded to indicate if it is real (indicated by a positive value) or a nearest-neighbor infill (indicated by negative values). The GLT file contains two parameters: 1) sample number 2) original line number File type: BINARY 32-bit signed long integer. Format: Band interleaved by pixel ------------------------------------------------------------------------------ *rdn_VVV_glt.hdr HEADER FILE FOR GEOMETRIC LOOKUP TABLE (GLT.HDR) DATA Contents: Format of each *rdn_VVV_glt file. This file contains the number of lines, samples, channel, integer format, pixel size, scene elevation, UTM zone number and rotation angle information, etc. File type: ASCII ------------------------------------------------------------------------------- *rdn_VVV_igm INPUT GEOMETRY FILE (IGM) Contents: UTM ground locations (x,y,elevation) in meters for each pixel in the corresponding unorothcorrected radiance image. The IGM file data contain three parameters: 1) Easting (meters) 2) Northing (meters) 3) Estimated ground elevation at each pixel center (reported in meters) No map correction or resampling is applied to the radiance image cube; the IGM file only reports the surface location of the unadjusted pixel centers. File type: BINARY 32-bit signed long integer. Units: Band 1 - meters Band 2 - meters Band 3 - meters Format: Band interleaved by pixel ---------------------------------------------------------------------------- *rdn_VVV_igm.hdr HEADER FILE FOR INPUT GEOMETRY FILE (IGM) DATA Contents: Format of each *rdn_VVV_igm file. This file contains the number of lines, samples, channel, integer format, etc. File type: ASCII ---------------------------------------------------------------------------- *rdn_VVV_img CALIBRATED PRISM RADIANCE (IMAGE) DATA Contents: PRISM calibrated radiance File type: BINARY 32-bit big-endian floating point Intel. Units: microwatts per centimeter_squared per nanometer per steradian Format: Band interleaved by line -------------------------------------------------------------------------------- *rdn_VVV_img.hdr HEADER FILE FOR CALIBRATED PRISM RADIANCE (IMAGE) DATA Contents: Format of each PRISM calibrated radiance scene. This file contains the number of lines, samples, channel, etc. It also records the spectral calibration (wavelength and full-width at half-maximum value) for every channel in the radiance data. File type: ASCII ---------------------------------------------------------------------------- *rdn_VVV_loc UNORTHOCORRECTED PIXEL LOCATION DATA (LOC) Contents: Pixel locations (WGS-84 lat/lon) for each science pixel in the corresponding unorthocorrected radiance image. The LOC file data contain three parameters: 1) WGS-84 longitude (decimal degrees) 2) WGS-84 latitude (decimal degrees) 3) Estimated ground elevation at each pixel center (reported in meters) File type: BINARY 64-bit double-precision, floating point. Units: Band 1: decimal degrees Band 2: decimal degrees Band 3: meters Format: Band interleaved by line -------------------------------------------------------------------------------- *rdn_VVV_loc.hdr HEADER FILE FOR UNORTHOCORRECTED PIXEL LOCATION DATA (LOC) Contents: Format of each PRISM *loc file. This file contains the number of lines, samples, channel, etc. File type: ASCII ---------------------------------------------------------------------------- *rdn_VVV_loc_ort ORTHOCORRECTED PIXEL LOCATION DATA (LOC_ORT) Contents: Pixel locations (WGS-84 lat/lon) for each science pixel in the corresponding orthocorrected radiance image. The LOC file data contain three parameters: 1) WGS-84 longitude (decimal degrees) 2) WGS-84 latitude (decimal degrees) 3) Estimated ground elevation at each pixel center (reported in meters) File type: BINARY 64-bit double-precision, floating point. Units: Band 1: decimal degrees Band 2: decimal degrees Band 3: meters Format: Band interleaved by pixel -------------------------------------------------------------------------------- *rdn_VVV_loc_ort.hdr HEADER FILE FOR ORTHOCORRECTED PIXEL LOCATION DATA (LOC_ORT) Contents: Format of each PRISM *loc file. This file contains the number of lines, samples, channel, etc. File type: ASCII ---------------------------------------------------------------------------- *rdn_VVV_obs OBSERVATION PARAMETER FILE (OBS) Contents: Observation parameter files in the raw spatial format; matches the corresponding unorthocorrected radiance image. The OBS file data contain eleven parameters: 1) path length (sensor-to-ground in meters) 2) to-sensor-azimuth (0 to 360 degrees clockwise from N) 3) to-sensor-zenith (0 to 90 degrees from zenith) 4) to-sun-azimuth (0 to 360 degrees clockwise from N) 5) to-sun-zenith (0 to 90 degrees from zenith) 6) solar phase (degrees between to-sensor and to-sun vectors in principal plane) 7) slope (local surface slope as derived from DEM in degrees) 8) aspect (local surface aspect 0 to 360 degrees clockwise from N) 9) cosine i (apparent local illumination factor based on DEM slope and aspect and to sun vector, -1 to 1) 10) UTC time (decimal hours for mid-line pixels) 11) Earth-sun distance (AU) File type: BINARY 64-bit double-precision, floating point. Format: Band interleaved by pixel -------------------------------------------------------------------------------- *rdn_VVV_obs.hdr HEADER FILE for OBSERVATION PARAMETER FILE (OBS) Contents: Format of each PRISM *obs file. This file contains the number of lines, samples, channel, etc. File type: ASCII -------------------------------------------------------------------------------- *rdn_VVV_obs_ort ORTHOCORRECTED OBSERVATION PARAMETER FILE (OBS_ORT) Contents: Observation parameter files in the raw spatial format; matches the corresponding orthocorrected radiance image. The OBS file data contain eleven parameters: 1) path length (sensor-to-ground in meters) 2) to-sensor-azimuth (0 to 360 degrees clockwise from N) 3) to-sensor-zenith (0 to 90 degrees from zenith) 4) to-sun-azimuth (0 to 360 degrees clockwise from N) 5) to-sun-zenith (0 to 90 degrees from zenith) 6) solar phase (degrees between to-sensor and to-sun vectors in principal plane) 7) slope (local surface slope as derived from DEM in degrees) 8) aspect (local surface aspect 0 to 360 degrees clockwise from N) 9) cosine i (apparent local illumination factor based on DEM slope and aspect and to sun vector, -1 to 1) 10) UTC time (decimal hours for mid-line pixels) 11) Earth-sun distance (AU) File type: BINARY 64-bit double-precision, floating point. Format: Band interleaved by pixel -------------------------------------------------------------------------------- *rdn_VVV_obs_ort.hdr HEADER FILE for ORTHOCORRECTED OBSERVATION PARAMETER FILE (OBS_ORT) Contents: Format of each PRISM *obs_ort file. This file contains the number of lines, samples, channel, etc. File type: ASCII -------------------------------------------------------------------------------- REFERENCES -------------------------------------------------------------------------------- P. Mouroulis, R. O. Green, and D. W. Wilson: Optical design of a coastal ocean imaging spectrometer, Opt. Express 16, 9087-9095 (2008) -------------------------------------------------------------------------------- ACKNOWLEDGEMENTS -------------------------------------------------------------------------------- This research was performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration (NASA). We are grateful for the help and assistance of colleagues including Bo-Cai Gao (NRL), Ian McCubbin (JPL), Dar Roberts (UCSB), Mark Helmlinger (JPL), Scott Nolte (JPL), Ernie Diaz (JPL), Daniel Nunes (JPL), and the rest of the PRISM team. Copyright 2016 California Institute of Technology. All Rights Reserved. U.S. Government Support Acknowledged. -------------------------------------------------------------------------------- MODIFICATIONS -------------------------------------------------------------------------------- 30 June 2016 (S. R. Lundeen) - Initial document 20 July 2016 (S. R. Lundeen) Revision - added OBS product 22 August 2016 (S. R. Lundeen) Revision - added OBS_ORT and LOC_ORT products =============================================================================== PRISM/ORCAS L2 Distribution Document v01 =============================================================================== Michelle Gierach, Michelle.Gierach@jpl.nasa.gov Sarah R. Lundeen, Sarah.R.Lundeen@jpl.nasa.gov Robert O. Green, Robert.O.Green@jpl.nasa.gov David R. Thompson, David.R.Thompson@jpl.nasa.gov This document describes the PRISM and ORCAS L2 data products. PRISM is an imaging spectrometer that measures reflected radiance at 3nm intervals in the Visible/Near-Infrared (VNIR) spectral range from 380-1050nm. Additional information may be found on http://prism.jpl.nasa.gov ------------------------------------------------------------------------------- OVERVIEW ------------------------------------------------------------------------------- Each flightline uses a specific base filename prefix: prmYYYYMMDDtHHNNSS YYYY: The year of the airborne flight run. MM: The month of the airborne flight run (i.e. 05 represents May). DD: The day of the airborne flight run (22 is the 22nd day of the month) HH: UTC hour at the start of acquisition NN: UTC minute at the start of acquisition SS: UTC second at the start of acquisition The CORAL/PRISM data products for a particular airborne flight run are organized in the following directory structure, labeled with a processing version marker VVV: /prmYYYYMMDDtHHNNSS_rb_VVV | prmYYYYMMDDtHHNNSS_corr_VVV_img | prmYYYYMMDDtHHNNSS_corr_VVV_img.hdr The file product codes signify: *corr_VVV_img Orthocorrected and atmospherically corrected water-leaving reflectance data. *corr_VVV_img.hdr rfl image header file ------------------------------------------------------------------------------ FILE DESCRIPTIONS ------------------------------------------------------------------------------ *corr_VVV_img WATER-LEAVING REFLECTANCE (IMAGE) DATA Contents: This file contains estimates of the water-leaving reflectance directly above the water surface for each measured wavelength. This is comparable to the Hemispherical Directed Reflectance Function (Shaepman-Strub et al., 2006). It is calculated using a variant of the ATREM atmospheric correction method (Gao et al., 1993; Gao et al., 2009). The modifications are described in texts by Thompson et al. (2015a and 2015b). For Lambertian surfaces, this value is related by a scale factor to the commonly-used remote sensing reflectance (Rrs). File type: BINARY 32-bit big-endian floating point Intel. Units: Unitless. In order to convert to remote sensing reflectance (Rrs), divide by pi. Format: Band interleaved by line ------------------------------------------------------------------------------ *corr_VVV_img.hdr HEADER FILE FOR WATER-LEAVING REFLECTANCE (corr_VVV_IMG.HDR)DATA Contents: Format of each *corr_VVV_img file. This file contains the number of lines, samples, channel, integer format, pixel size, scene elevation, UTM zone number and rotation angle information, etc. File type: ASCII -------------------------------------------------------------------------------- REFERENCES -------------------------------------------------------------------------------- Gao, B. C., Heidebrecht, K. B., & Goetz, A. F. (1993). Derivation of scaled surface reflectances from AVIRIS data. Remote sensing of Environment, 44(2-3), 165-178. Gao, B. C., Montes, M. J., Davis, C. O., & Goetz, A. F. (2009). Atmospheric correction algorithms for hyperspectral remote sensing data of land and ocean. Remote Sensing of Environment, 113, S17-S24. Maritorena, S., Morel, A., & Gentili, B. (1994). Diffuse reflectance of oceanic shallow waters: Influence of water depth and bottom albedo. Limnology and oceanography, 39(7), 1689-1703. Schaepman-Strub, G., Schaepman, M. E., Painter, T. H., Dangel, S., & Martonchik, J. V. (2006). Reflectance quantities in optical remote sensing — Definitions and case studies. Remote sensing of environment, 103(1), 27-42. Thompson, D. R., Gao, B. C., Green, R. O., Roberts, D. A., Dennison, P. E., & Lundeen, S. R. (2015a). Atmospheric correction for global mapping spectroscopy: ATREM advances for the HyspIRI preparatory campaign. Remote Sensing of Environment, 167, 64-77. Thompson, D. R., Seidel, F. C., Gao, B. C., Gierach, M. M., Green, R. O., Kudela, R. M., & Mouroulis, P. (2015b). Optimizing irradiance estimates for coastal and inland water imaging spectroscopy. Geophysical Research Letters, 42(10), 4116-4123. -------------------------------------------------------------------------------- ACKNOWLEDGEMENTS -------------------------------------------------------------------------------- This research was performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration (NASA). We are grateful for the help and assistance of colleagues including Bo-Cai Gao (NRL), Ian McCubbin (JPL), Dar Roberts (UCSB), Mark Helmlinger (JPL), Scott Nolte (JPL), Ernie Diaz (JPL), Daniel Nunes (JPL), and the rest of the PRISM team. Copyright 2016 California Institute of Technology. All Rights Reserved. U.S. Government Support Acknowledged. -------------------------------------------------------------------------------- MODIFICATIONS -------------------------------------------------------------------------------- 30 June 2016 (S. R. Lundeen) - Initial document 1 July 2016 (D. R. Thompson/S. R. Lundeen) - Revisions to content descriptions and references.