4.1. VIIRS SDR Reader¶
The VIIRS SDR Reader operates on Science Data Record (SDR) HDF5 files from the Suomi National Polar-orbiting Partnership’s (NPP) and/or the NOAA20 Visible/Infrared Imager Radiometer Suite (VIIRS) instrument. The VIIRS SDR reader ignores filenames and uses internal file content to determine the type of file being provided, but SDR are typically named as below and have corresponding geolocation files:
SVI01_npp_d20120225_t1801245_e1802487_b01708_c20120226002130255476_noaa_ops.h5
The VIIRS SDR reader supports all instrument spectral bands, identified as
the products shown below. It supports terrain corrected or non-terrain corrected
navigation files. Geolocation files must be included when specifying filepaths to
readers and polar2grid.sh
. The VIIRS reader can be specified to the polar2grid.sh
script
with the frontend name viirs_sdr
.
Note
This reader used to be named “viirs”. Both “viirs_sdr” and “viirs” will
work when passed to polar2grid.sh
, but in future versions only
viirs_sdr
will be supported. The name viirs_l1b
is the only way
to access the VIIRS L1B Reader.
This reader’s default remapping algorithm is ewa
for Elliptical Weighted
Averaging resampling. The --fornav-D
parameter set to 40 and the
--fornav-d
parameter set to 2.
Product Name
Description
i01
I01 Reflectance Band
i02
I02 Reflectance Band
i03
I03 Reflectance Band
i04
I04 Brightness Temperature Band
i05
I05 Brightness Temperature Band
i01_rad
I01 Radiance Band
i02_rad
I02 Radiance Band
i03_rad
I03 Radiance Band
i04_rad
I04 Radiance Band
i05_rad
I05 Radiance Band
m01
M01 Reflectance Band
m02
M02 Reflectance Band
m03
M03 Reflectance Band
m04
M04 Reflectance Band
m05
M05 Reflectance Band
m06
M06 Reflectance Band
m07
M07 Reflectance Band
m08
M08 Reflectance Band
m09
M09 Reflectance Band
m10
M10 Reflectance Band
m11
M11 Reflectance Band
m12
M12 Brightness Temperature Band
m13
M13 Brightness Temperature Band
m14
M14 Brightness Temperature Band
m15
M15 Brightness Temperature Band
m16
M16 Brightness Temperature Band
m01_rad
M01 Radiance Band
m02_rad
M02 Radiance Band
m03_rad
M03 Radiance Band
m04_rad
M04 Radiance Band
m05_rad
M05 Radiance Band
m06_rad
M06 Radiance Band
m07_rad
M07 Radiance Band
m08_rad
M08 Radiance Band
m09_rad
M09 Radiance Band
m10_rad
M10 Radiance Band
m11_rad
M11 Radiance Band
m12_rad
M12 Radiance Band
m13_rad
M13 Radiance Band
m14_rad
M14 Radiance Band
m15_rad
M15 Radiance Band
m16_rad
M16 Radiance Band
dnb
Raw DNB Band (not useful for images)
histogram_dnb
Histogram Equalized DNB Band
adaptive_dnb
Adaptive Histogram Equalized DNB Band
dynamic_dnb
Dynamic DNB Band from Steve Miller and Curtis Seaman. Uses erf to scale the data.
hncc_dnb
Simplified High and Near-Constant Contrast Approach from Stephan Zinke
ifog
Temperature difference between I05 and I04
i_solar_zenith_angle
I Band Solar Zenith Angle
i_solar_azimuth_angle
I Band Solar Azimuth Angle
i_sat_zenith_angle
I Band Satellite Zenith Angle
i_sat_azimuth_angle
I Band Satellite Azimuth Angle
m_solar_zenith_angle
M Band Solar Zenith Angle
m_solar_azimuth_angle
M Band Solar Azimuth Angle
m_sat_zenith_angle
M Band Satellite Zenith Angle
m_sat_azimuth_angle
M Band Satellite Azimuth Angle
dnb_solar_zenith_angle
DNB Band Solar Zenith Angle
dnb_solar_azimuth_angle
DNB Band Solar Azimuth Angle
dnb_sat_zenith_angle
DNB Band Satellite Zenith Angle
dnb_sat_azimuth_angle
DNB Band Satellite Azimuth Angle
dnb_lunar_zenith_angle
DNB Band Lunar Zenith Angle
dnb_lunar_azimuth_angle
DNB Band Lunar Azimuth Angle
For reflectance/visible products a check is done to make sure that at least 10% of the swath is day time. Data is considered day time where the solar zenith angle is less than 100 degrees.
Note
Terrain corrected geolocation for the DNB band has recently been added and is included in the non-TC file (GDNBO).
This may cause some confusion to users as the VIIRS SDR reader currently only checks for terrain corrected data. To
use non-TC data use the --no-tc
flag (described below).
4.1.1. Command Line Arguments¶
usage: polar2grid.sh viirs_sdr <writer> [-h] [--list-products] [--no-tc]
[--day-fraction DAY_FRACTION]
[--night-fraction NIGHT_FRACTION]
[--sza-threshold SZA_THRESHOLD]
[--dnb-saturation-correction]
[-p PRODUCTS [PRODUCTS ...]]
[--adaptive-bt] [--i-bands]
[--m-bands] [--dnb-angle-products]
[--i-angle-products]
[--m-angle-products]
[--m-rad-products] [--i-rad-products]
4.1.1.1. Frontend Initialization¶
swath extraction initialization options
- --list-products
List available frontend products and exit
Default: False
- --no-tc
Don’t use terrain-corrected navigation
Default: True
- --day-fraction
Fraction of day required to produce reflectance products
Default: 0.1
- --night-fraction
Fraction of night required to produce products like fog
Default: 0.1
- --sza-threshold
Angle threshold of solar zenith angle used when deciding day or night
Default: 100.0
- --dnb-saturation-correction
Enable dynamic DNB saturation correction (normally used for aurora scenes)
Default: False
4.1.1.2. Frontend Swath Extraction¶
swath extraction options
- -p, --products
Specify frontend products to process
- --adaptive-bt
Create adaptively scaled brightness temperature bands
- --i-bands
Add all I-band raw products to list of products
- --m-bands
Add all M-band raw products to list of products
- --dnb-angle-products
Add DNB-band geolocation ‘angle’ products to list of products
- --i-angle-products
Add I-band geolocation ‘angle’ products to list of products
- --m-angle-products
Add M-band geolocation ‘angle’ products to list of products
- --m-rad-products
Add M-band geolocation radiance products to list of products
- --i-rad-products
Add I-band geolocation radiance products to list of products
Changed in version 2.1: The reader name has been changed to viirs_sdr
although viirs
is still
supported for the time being.
Examples:
polar2grid.sh viirs_sdr gtiff -f <path to files>/<list of files>
viirs2awips.sh -g 211e 211w -f ../sdr/*.h5
polar2grid.sh viirs_sdr gtiff -h
polar2grid.sh viirs_sdr gtiff --list-products -f ../sdr/*.h5
polar2grid.sh viirs_sdr scmi -p i04 adaptive_dnb dynamic_dnb --sza-threshold=90.0 --letters --compress --sector-id Polar -g polar_alaska_1km -f <path to files>
polar2grid.sh viirs_sdr hdf5 --compress gzip --m-bands -f ../sdr/*.h5
polar2grid.sh viirs_sdr binary -g lcc_fit -p m15 -f ../sdr/SVM15*.h5 ../sdr/GMTCO*.h5