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