AVHRR-and-VIIRS CoastWatch SST Readme

Contents

• Introduction
• Directory Naming Conventions
• Data File Naming Conventions
• Variable Naming Conventions
• Feedback

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:

Extension	Description
.hdf	CoastWatch product data in Hierarchical Data Format (HDF). Large files (approx. 40–60 MB) are full pass swath projection data, mainly for NOAA research personnel. Smaller files (approx. 1–10 MB) are mapped projection data and are 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 more.
.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:

Code	Description
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:

Code	Description
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 with Gulf of America	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:

Parameter	Description
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.