The netCDF file for SML data is split over the following dimensions: time period (time), ground receiver identifier (receiver_id), satellite identifier (satellite_id), transponder identifier (transponder_id), and sublink identifier (sublink_id).
| Type | Attributes | Requisite | Comments | |
|---|---|---|---|---|
Dimensions |
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time |
Unlimited size, enforce UTC seconds since 1970-01-01 |
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sml_id |
Minimum length is 1 |
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sublink_id |
Minimum length is 1 |
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Coordinate variables (dimension) |
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time (time) |
int/float/double |
units = seconds since 1970-01-01 00:00:00 UTC, long_name = “time_utc”, _FillValue |
Required |
|
sml_id (sml_id) |
string |
long_name = “satellite_microwave_link_identifier” |
Required |
sml_id has to be unique across the link. It includes: receiver_id, satellite_id, trasponder_id |
sublink_id (sublink_id) |
string |
long_name = “sublink_identifier”, |
Required |
sublink_id does not have to be unique across the network (but unique within each SML) |
Auxiliary coordinate variables (dimension) |
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site_0_lat (sml_id) |
float/double |
units = degrees_in_WGS84_projection, long_name = “site_0_latitude” |
Required |
|
site_0_lon (sml_id) |
float/double |
units = degrees_in_WGS84_projection, long_name = “site_0_longitude” |
Required |
|
site_0_alt (sml_id) |
float/double |
units = degrees_in_WGS84_projection, long_name = ”antenna_altitude_above_sea_level_at_site_0” |
Required |
|
site_1_lat (sml_id) |
float/double |
units = degrees_in_WGS84_projection, long_name = “site_0_latitude” |
Optional |
0 degrees |
site_1_lon (sml_id) |
float/double |
units = degrees_in_WGS84_projection, long_name = “site_1_longitude” |
Required |
|
site_1_alt (sml_id) |
float/double |
units = metres_above_sea, long_name = “ground_elevation_above_sea_level_at_site_1” |
Optional |
36,000 km |
frequency (sml_id, sublink_id) |
float/double |
units = MHz, long_name = “sublink_frequency” |
Required |
|
polarisation (sml_id, sublink_id) |
string |
units = no units, long_name = “sublink_polarization” |
Required |
When string then ‘vertical’ or ‘horizontal’ |
Data variables (dimension) |
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snr (sml_id, time) |
float/double |
units = dB, coordinates = string_with_auxiliary_coordinate_variable_names, long_name = "signal_to_noise_ratio", _FillValue |
Required* |
|
rsl (sml_id, time) |
float/double |
units = dBm, coordinates = string_with_auxiliary_coordinate_variable_names, long_name = "received_signal_level", _FillValue |
Required* |
|
modcod (sml_id, time) |
string |
long_name = “modcod_format” |
Optional |
|
External data variables (dimension) |
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rain_height (time, sml_id) |
float/double |
units = m, long_name = “length_of_the_slant_path_through_the_rain” |
Required |
*It is required to store either SNR or rsl.