4.12. MERSI-2 L1B Reader¶
The FY-3D MERSI2 Level 1B reader operates on Level 1B (L1B) HDF5 files.
The files come in four varieties; band data and geolocation data, both at 250m and 1000m resolution. Files usually have the following naming scheme:
tf{start_time:%Y%j%H%M%S}.FY3D-X_MERSI_1000M_L1B.{ext}
This reader’s default resampling algorithm is ewa for Elliptical Weighted
Averaging resampling. The --weight-delta-max parameter is set to 40 and the
--weight-distance-max parameter is set to 1.
The frontend can be specified with the polar2grid.sh command using
the mersi2_l1b frontend name. The MERSI2 frontend provides the following products:
Product Name |
Description |
Central Wavelength (um) |
|---|---|---|
1 |
Channel 1 Reflectance Band |
0.47 |
2 |
Channel 2 Reflectance Band |
0.55 |
3 |
Channel 3 Reflectance Band |
0.65 |
4 |
Channel 4 Reflectance Band |
0.865 |
5 |
Channel 5 Reflectance Band |
1.38 |
6 |
Channel 6 Reflectance Band |
1.64 |
7 |
Channel 7 Reflectance Band |
2.13 |
8 |
Channel 8 Reflectance Band |
0.412 |
9 |
Channel 9 Reflectance Band |
0.443 |
10 |
Channel 10 Reflectance Band |
0.490 |
11 |
Channel 11 Reflectance Band |
0.555 |
12 |
Channel 12 Reflectance Band |
0.670 |
13 |
Channel 13 Reflectance Band |
0.709 |
14 |
Channel 14 Reflectance Band |
0.746 |
15 |
Channel 15 Reflectance Band |
0.865 |
16 |
Channel 16 Reflectance Band |
0.905 |
17 |
Channel 17 Reflectance Band |
0.936 |
18 |
Channel 18 Reflectance Band |
0.940 |
19 |
Channel 19 Reflectance Band |
1.24 |
20 |
Channel 20 Brightness Temperature Band |
3.80 |
21 |
Channel 21 Brightness Temperature Band |
4.05 |
22 |
Channel 22 Brightness Temperature Band |
7.20 |
23 |
Channel 23 Brightness Temperature Band |
8.55 |
24 |
Channel 24 Brightness Temperature Band |
10.8 |
25 |
Channel 25 Brightness Temperature Band |
12.0 |
true_color |
Rayleigh corrected true color RGB |
N/A |
false_color |
False color RGB (bands 7, 4, 3) |
N/A |
natural_color |
Natural color RGB (bands 6, 4, 3) |
N/A |
4.12.1. Command Line Arguments¶
usage: polar2grid.sh -r mersi2_l1b -w <writer> [-h]
Examples:
$POLAR2GRID_HOME/bin/polar2grid.sh -r mersi2_l1b -w geotiff -h
polar2grid.sh -r mersi2_l1b -w geotiff --list-products -f tf2019259173245.FY3D-X_MERSI*.HDF
polar2grid.sh -r mersi2_l1b -w geotiff -p 1 2 3 4 6 7 20 25 -f tf2019233172521.FY3D-X_MERSI_0250M_L1B.HDF tf2019233172521.FY3D-X_MERSI_1000M_L1B.HDF tf2019233172521.FY3D-X_MERSI_GEOQK_L1B.HDF tf2019233172521.FY3D-X_MERSI_GEO1K_L1B.HDF
polar2grid.sh -r mersi2_l1b -w geotiff -p true_color false_color -g lcc_fit -f ../mersi/tf2019259173245.FY3D-X_MERSI*.HDF
polar2grid.sh -r mersi2_l1b -w hdf5 -p 20 21 22 23 24 25 --grid-configs ${HOME}/my_grid.yaml -g shanghai seoul -f ../data/*.HDF
polar2grid.sh -r mersi2_l1b -w binary --sza-threshold=90 -p 1 2 3 4 6 7 20 25 -f tf2019226095418.FY3D-X_MERSI_*.HDF
