European Space Agency, GFZ Helmholtz Centre for Geosciences, 2021, "SW_PPIxFAC_2F", European Space Agency, https://doi.org/10.57780/esa-ad69715
| Variable | Units | Description | Dim | Type |
|---|---|---|---|---|
| Timestamp | ms | Time of observation, UTC | 1 | CDF_EPOCH |
| Counter | Swarm orbit counter and quarter orbit (four per Swarm orbit) counter that are based on magnetic coordinates as defined in Swarm PRISM processing algorithm description (Sect. 4.1.2.2) | 2 | CDF_UINT4 | |
| Latitude | deg | Position of the SSFAC boundary in ITRF - Geocentric latitude | 1 | CDF_DOUBLE |
| Longitude | deg | Position of the SSFAC boundary in ITRF - Geocentric longitude | 1 | CDF_DOUBLE |
| Radius | m | Position of the SSFAC boundary in ITRF - Geocentric radius (from the Earth center) | 1 | CDF_DOUBLE |
| Latitude_QD | deg | QD latitude of the SSFAC boundary | 1 | CDF_DOUBLE |
| Longitude_QD | deg | QD longitude of the SSFAC boundary | 1 | CDF_DOUBLE |
| MLT | h | Magnetic Local Time of SSFAC boundary | 1 | CDF_DOUBLE |
| L_value | R_E | L-value of the SSFAC boundary | 1 | CDF_DOUBLE |
| SZA | deg | Solar zenith angle of the SSFAC boundary | 1 | CDF_DOUBLE |
| dL | Boundary width in Earth radii | 1 | CDF_DOUBLE | |
| Sigma | Standard deviation of the linear fit of S at the boundary (Heilig, B. and Lühr, H., doi: 10.5194/angeo-31-529-2013) | 1 | CDF_DOUBLE | |
| PPI | R_E | Midnight Plasmapause index | 1 | CDF_DOUBLE |
| Quality | Quality indicators of SSFAC boundary detection | 7 | CDF_INT1 | |
| Timestamp_ID | Time vector of observations | 2 | CDF_EPOCH | |
| Latitude_ID | deg | Position in ITRF - Geocentric latitude | 2 | CDF_DOUBLE |
| Longitude_ID | deg | Position in ITRF - Geocentric longitude | 2 | CDF_DOUBLE |
| Radius_ID | m | Position in ITRF - Geocentric radius (from the Earth centre) | 2 | CDF_DOUBLE |
| Latitude_QD_ID | deg | QD latitude | 2 | CDF_DOUBLE |
| Longitude_QD_ID | deg | QD longitude | 2 | CDF_DOUBLE |
| MLT_ID | h | Magnetic Local Time | 2 | CDF_DOUBLE |
| L_value_ID | L-value in Earth radii | 2 | CDF_DOUBLE | |
| SZA_ID | deg | L-value in Earth radii | 2 | CDF_DOUBLE |
| Position_Quality_ID | Vector of quality indicators characterising the detection quality of each single positions | 2 | CDF_INT1 |
| Product identifier | PPIxFAC_2F |
| Definition | Equatorward boundary of SSFACs and the associated midnight PP index |
| Input data | FACxTMS_2F1, EFIx_LP_1B1, TECxTMS_2F1, AOBxFAC_2F1, AUXxORBCNT |
| Input time span | Up to one year2 |
| Spatial representation | One geographic and QD-latitude/longitude pair, the McIlwain L-value as well as radius for each output position at the nearest FAC measurement for each trough crossing, i.e., up to four per orbit |
| Time representation | Up to four records per orbit (up to one record per orbit quarter) |
| Units | see at Output Data below |
| Resolution | 0.1 degree for coordinates, 0.01 for L-value |
| Uncertainty | ~1 degree for coordinates, ~0.1 for L-value |
| Quality indicator | Quality vector flag values are integers ranging from 3 to -1. Positive values indicate good or acceptable observation, while -1 means a likely false observation. For all flags, a 0 value means that the information needed to derive the flag is not available. In general, greater numbers indicate higher quality. A detailed description of the derivation of these flags is given in Swarm PRISM processing algorithm description (see also related resources) Position_Quality_ID describes the overall quality of the corresponding boundary/position identified by ID. These flags are defined based on the parameter’s sigma and SZA. 3: sig-ma<0.25, 2: 0.25≤sigma<0.5, 1: 0.5≤sigma AND SZA>90°, -1: 0.5≤sigma AND SZA≤90°. |
| Data volume | Up to 1.9 MB |
| Output data | See file contents |
| Output time span | Up to one year2 |
| Latency | < 5 minutes |
| Update rate | Daily |
| Notes | 1 Version information of Input Data are available in the CDF global attributes.2 Product always contains data from the start of the first boundary crossing of the first day until the end of the last boundary-crossing starting the latest day available for that year, i.e., may contain data from the next day if boundary crossing occurs around midnight.3 The meaning of ID: 1 – Equatorward edge of SSFAC boundary; 2 – Poleward edge of SSFAC boundary.4 NaN values: if an ID is not identified Timestamp_ID is set to {the value of} Timestamp and corresponding variable values will be set to NaNs. |