N: 59 S: -59 E: -160 W: 80
Description
The ACSPO H08/AHI L3C (Level 3 Collated) product is a gridded version of the ACSPO H08/AHI L2P product available at https://podaac.jpl.nasa.gov/dataset/AHI_H08-STAR-L2P-v2.70. The L3C output files are 1hr granules in NetCDF4 format, compliant with the GHRSST Data Specification version 2 (GDS2). There are 24 granules available per 24hr interval, with a total data volume of 0.2GB/day. Valid SSTs are found over clear-sky oceans, sea, lakes or rivers, with fill values reported elsewhere. The following layers are reported: SST, ACSPO clear-sky mask (ACSM; provided in each grid as part of l2p_flags, which also includes day/night, land, ice, twilight, and glint flags), NCEP wind speed and ACSPO SST minus reference (Canadian Met Centre 0.1deg L4 SST; available at https://podaac.jpl.nasa.gov/dataset/CMC0.1deg-CMC-L4-GLOB-v3.0 ). All valid SSTs in L3C are recommended for users, although data over internal waters may not have enough in situ data to be adequately validated. Per GDS2 specifications, two additional Sensor-Specific Error Statistics layers (bias and standard deviation) are reported in each pixel with valid SST (Petrenko et al., 2016). The ACSPO VIIRS L3U product is monitored and validated against iQuam in situ data (Xu and Ignatov, 2014) in SQUAM (Dash et al, 2010).
Product Summary
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Variables
Variables are a set of physical properties whose values determine the characteristics or behavior of something. For example, temperature and pressure are variables of the atmosphere. Parameters and variables can be used interchangeably. Variable level attributes provide individual information for each variable.
The Name in this table is the variable name. Fill value indicates missing or undefined data points in a variable. Valid range is the range of values the variable can store. Scale factor is used to increase or decrease the size of an object and can be used to correct for distortion. For questions on a specific variable, please use the Earthdata Forum.
| Name Sort descending | Description | Units | Data Type | Fill Value | Valid Range | Scale Factor |
|---|---|---|---|---|---|---|
| crs | crs | N/A | int | N/A | N/A | 1 |
| dt_analysis | Deviation from reference SST, i.e., dt_analysis = SST - reference SST | kelvin | byte | -128 | -127 to 127 | 0.1 |
| l2p_flags | L2P common flags in bits 1-6 and data provider flags (from ACSPO mask) in bits 9-16: bit01 (0=IR: 1=microwave); bit02 (0=ocean; 1=land); bit03 (0=no ice; 1=ice); bits04-07 (reserved,set to 0); bit08 (0=anti-solar; 1=solar); bit09 (0=radiance valid; 1=invalid); bit10 (0=night; 1=day); bit11 (0=ocean; 1=land); bit12 (0=good quality data; 1=degraded quality data due to "twilight" region); bit13 (0=no glint; 1=glint); bit14 (0=no snow/ice; 1=snow/ice); bits15-16 (00=clear; 01=probably clear; 10=cloudy; 11=clear-sky mask undefined) | N/A | short | N/A | -32768 to 32767 | 1 |
| lat | Latitudes for locating data | degrees_north | float | N/A | -90 to 90 | 1 |
| lon | Longitude for locating data | degrees_east | float | N/A | -180 to 180 | 1 |
| or_number_of_pixels | Original number of pixels from the L2Ps contributing to the SST value, not weighted | 1 | short | 0 | 1 to 32767 | 1 |
| quality_level | SST quality levels: 5 corresponds to “clear-sky” pixels and is recommended for operational applications and validation. | N/A | byte | -128 | 0 to 5 | 1 |
| satellite_zenith_angle | satellite zenith angle | degrees | byte | -128 | -90 to 90 | 1 |
| sea_surface_temperature | SST obtained by regression with buoy measurements, sensitive to skin SST. Further information at (Petrenko et al., JGR, 2014; doi:10.1002/2013JD020637) | kelvin | short | -32768 | -32767 to 32767 | 0.01 |
| sses_bias | Bias is derived against Piecewise Regression SST produced by local regressions with buoys. Subtracting sses_bias from sea_surface_temperature produces more accurate estimate of SST at the depth of buoys. Further information at (Petrenko et al., JTECH, 2016; doi:10.1175/JTECH-D-15-0166.1) | kelvin | byte | -128 | -127 to 127 | 0.016 |
| sses_standard_deviation | Standard deviation of sea_surface_temperature from SST measured by drifting buoys. Further information at (Petrenko et al., JTECH, 2016; doi:10.1175/JTECH-D-15-0166.1) | kelvin | byte | -128 | -127 to 127 | 0.01 |
| sst_dtime | time plus sst_dtime gives seconds since 1981-01-01 00:00:00 UTC | seconds | int | -2147483648 | -2147483647 to 2147483647 | 0.25 |
| time | Seconds since 1981-01-01 00:00:00 | seconds since 1981-01-01 00:00:00 | int | N/A | N/A | 1 |
| wind_speed | Typically represents surface winds (10 meters above the sea surface) | m s-1 | byte | -128 | -127 to 127 | 0.15 |