The colocation activity is an important part of the work for the Sentinel-1 Mission Performance Center.
This page deals with the massive colocations realized between Sentinel-1 products (L1 or L2) and different reference datasets.
FTP link to netCDF colocalisation files
Here is the list of reference dataset used:
| average delay between SAR availability on MPC ftp and coloc file availability | spatial window (km) | temporal window (min) | |
| model | |||
| WW3 (IOWAGA) 0.5° 3h global | SAR data driven | 65 | 90 |
| Arpege High Resolution 0.1° 1h Europe (MeteoFrance) | SAR data driven | 35 | 30 |
| ECMWF forecast Global 0.125° 3h | SAR data driven | 20 | 90 |
| in situ | |||
| Coriolis network(IFREMER) | 12h | 5 | 60 |
| NDBC network (NOAA) | 12h | 5 | 60 |
| CDIP network (Scripps) | 1 month | 5 | 60 |
| MEDS network (Canada) | not available yet | 5 | 60 |
| ECMWF collection (ECMWF) | 6 months | 5 | 60 |
| scatterometer | |||
| metop-A ascat (KNMI netCDF) 25km | 48h | 25 | 360 |
| metop-B ascat(KNMI netCDF) 25km | 48h | 25 | 360 |
| oceansat-2 oscat(KNMI netCDF) 25km | satellite down | 25 | 360 |
| coriolis windsat | not available yet | 25 | 360 |
| ISS rapidscat (JPL/PODAAC) 12.5km | not available yet | 25 | 360 |
| altimeter | |||
| Cryosat-2 L2p GDR (Globwave) | 48h | 25 | 360 |
Colocation parameters
- The default method of colocation is closest neighbour.
- For Level1 SAR data, the resolution is lowered to 1km in order to enhance processing performances.
Colocation netCDF files content
| collocation with | Satellites and models | moored buoys | ||
| level | Level1 | Level2 | Level1 and Level2 | |
| SAR data | all variables at 1km resolution (ex: sigma0, incidence_angle,...) | all variables L2 resolution (ex: oswHs,oswWindSpeed, oswNrcs,...) | all SAR variables at original resolution on a 5x5 pixels box centered on the buoy position. | |
| ancillary data | defined variables depending of the data resampled on SAR positions (ex: wind_speed_selection for scatterometer matchup, Hs for WW3 model,...) | measured buoy parameters at the nearest time step. | ||
| miscellanous |
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Colocation files naming
| Satellites and models | Buoys | |
| example | 20150219T030000_WW3_s1a-wv1-ocn-vv-20150219t030204-20150219t032548-004686-005CAB-093.nc | s1a-s1-slc-hh-20141016t143858-20141016t143923-002856-0033a4-001.tiff_sentinel1A_ndbcnrt_matchups.nc |
| rule |
yyyymmddTHHMMSS_A_sat-inc-type-pol-yyyymmddtHHMMSS-yyyymmddtHHMMSS-cycle-datatakeid-imagetteNbre.ext
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