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AVHRR-and-VIIRS CoastWatch SST Readme

AVHRR-and-VIIRS CoastWatch SST Readme

Contents

Introduction

The AVHRR-and-VIIRS CoastWatch SST products supply users with operational satellite data, processed using TeraScan software and CoastWatch utilities. All data are contained in subdirectories named according to the date, time (UTC), satellite, and ground station for the satellite pass. Each directory contains a number of files:

.hdf
CoastWatch product data in Hierarchical Data Format (HDF). Large files approximately 40-60 Mb are full pass swath projection data, and are mainly for use by research personnel at NOAA. Smaller files approximately 1-10 Mb in size are mapped projection data. These are the standard CoastWatch product files viewable in CDAT.
.jpg
JPEG browse image for the full pass swath projection.
.log
Data processing log file showing details on ingest, automatic navigation, SST equations and coefficients, and so on.
.inf
Information file containing pass parameters such as dimensions, date, time, spacecraft attitude, and GCP mesh coordinates.
The mapped HDF data is divided into files for a number of CoastWatch regions of interest, where each file contains multiple data variables. Mapped HDF files may be downloaded and viewed using the CoastWatch Utilities software, which includes the graphical CoastWatch Data Analysis Tool (CDAT), available from:
https://coastwatch.noaa.gov/cw/user-resources/coastwatch-utilities.html

Directory Naming Conventions

Directories are named according to the date, UTC time, satellite, and ground station for the satellite pass as in the following template:

YYYY_DDD_HHMM_SSS_GG
where:
YYYY
Full year with century
DDD
Julian day [001-366]
HHMM
Hour and minute in Greenwich (UTC) time
SSS
Satellite code:
m01 = Metop-1
m02 = Metop-2
n15 = NOAA-15
npp = SNPP
n20 = NOAA-20
GG
Ground station where the data was captured:
mo = Monterey, CA
gc = Gilmore Creek, AK
wi = Wallops Island, VA
eb = Ewa Beach, HI
mi = Miami, FL

Data File Naming Conventions

Both mapped and swath HDF product files are named using the same convention with the following template:

YYYY_DDD_HHMM_SSS_RR.FMT
where:
YYYY
Full year with century
DDD
Julian day [001-366]
HHMM
Hour and minute in Greenwich (UTC) time
SSS
Satellite code (see above for examples)
RR
CoastWatch region code
FMT
File format
The current CoastWatch region codes are as follows:

Region code Region description Projection type Map projection
gc Gilmore Creek, AK swath n/a
aa Alaska Sitka mapped Polar stereographic
ax Alaska south mapped Polar stereographic
ay Alaska west mapped Polar stereographic
az Alaska north mapped Polar stereographic
 
mi Miami, FL swath n/a
ce Caribbean east mapped Mercator
cw Caribbean west mapped Mercator
mr Gulf of Mexico mapped Mercator
wa West Coast Acapulco mapped Mercator
 
wi Wallops Island, VA swath n/a
er East Coast north mapped Mercator
sr East Coast south mapped Mercator
sb East Coast Bermuda mapped Mercator
gr Great Lakes regional mapped Mercator
 
eb Ewa Beach, HI swath n/a
hr Hawaii regional mapped Mercator
 
mo Monterey, CA swath n/a
wj West Coast Baja mapped Mercator
wn West Coast north mapped Mercator
ws West Coast south mapped Mercator
sl Great Salt Lake mapped Mercator

Variable Naming Conventions

Each HDF data file contains multiple data variables stored using the HDF Scientific Data Sets (SDS) model. Each variable is named according to the data that it represents as follows:

avhrr_ch1
AVHRR channel 1 albedo (%)
avhrr_ch2
AVHRR channel 2 albedo (%)
avhrr_ch3a
AVHRR channel 3a albedo (%)
avhrr_ch3
AVHRR channel 3 brightness temperature (deg C)
avhrr_ch4
AVHRR channel 4 brightness temperature (deg C)
avhrr_ch5
AVHRR channel 5 brightness temperature (deg C)
sst
Moisture corrected sea-surface-temperature (deg C)
cloud
8-bit CLAVR ocean cloud mask:
Daytime
Bit 1: Reflective Gross Cloud Test
Bit 2: Reflectance Uniformity Test
Bit 3: Reflectance Ratio Cloud Test
Bit 4: Channel 3 Albedo Test
Bit 5: Thermal Uniformity Test
Bit 6: Four Minus Five Test
Bit 7: Thermal Gross Cloud Test
Nighttime
Bit 1: Thermal Gross Cloud Test
Bit 2: Thermal Uniformity Test
Bit 3: Uniform Low Stratus Test
Bit 4: Four Minus Five Test
Bit 5: Cirrus Test
Bit 6: Channel 3B Albedo Test
Bit 7: Channel 3B Albedo Uniformity Test
sat_zenith
Satellite zenith angle (degrees)
sun_zenith
Solar zenith angle (degrees)
rel_azimuth
Relative azimuth angle (degrees)
graphics
8-bit graphics layers:
Bit 1: Fill flag
Bit 2: Latitude/longitude grid
Bit 3: Coastline and political geography lines
Bit 4: Land/water flag
Bits 5-8: Unused

Feedback

For questions or comments regarding these products, please contact Sheekela.Baker-Yeboah@noaa.gov.

SST Swaths Overview