SENTINEL-4 mission is part of ESA’s Copernicus program. SENTINEL-4 was launched in 2019 and is the heaviest of the Copernicus missions at 3,600 kg. Unlike SENTINEL-1 and SENTINEL-2 which orbit at around 700km, this orbits at nearly 36,000 KM in a geostationary orbit.
S4, like SENTINEL-5, is focused on monitoring of pollutants and traces gases in the atmosphere, including:
- Air Quality measurements
- Stratospheric Ozone monitoring
- Solar Radiation measurements
- Climate monitoring
This data will monitoring of air-quality in near-real-time applications, with its high revisit time. SENTINEL-4 will be sampling 8 km over Europe, a fast repeat cycle over Europe and North Africa (Sahara), of just 60 minutes.
The Sentinel-4 instruments include a high-resolution spectrometer with three bands ultraviolet (305-400 nm), visible (400-500 nm) and near-infrared (750-775 nm). SENTINEL-5 has seven bands.
SENTINEL-4 Technical Details
|
Band |
Spectral range (nm) |
Spectral |
SSD |
SNR @ 50ºN, 15:00 UTC, Equinox, albedo 0.05 (UV-VIS) & 0.15 (NIR) (per spectral sample) |
Spectral sampling ratio |
Species |
|
UV |
305-400 |
0.5 |
8 km |
200 – 1000 |
3 |
O3, SO2, BrO, HCHO, AAI, AOD, Ring |
|
VIS |
400-500 |
0.5 |
8 km |
1400 |
3 |
NO2, O4, IO CHOCHO, AOD |
|
NIR |
750-775 |
0.12 |
8 km |
600 |
3 |
Cloud, Aerosol |
| Spectral | |||
| Parameter | UV-VIS values | NIR values | Comments |
| Wavelength range | 305-500 nm | 750-775 nm | |
| Spectral Resolution/Spectral Oversampling | 0.5 nm/3 | 0.12 nm/3 | Oversampling is Resolution divided by spectral pixel sampling |
| Spectral Calibration Accuracy | 0.0017 nm | 0.0020 nm | |
| Geometric and Temporal Coverage | |||
| Parameter | Value(s) | Comments | |
| Spatial Sampling Distance (SSD) | 8 km (E/W) × 8 km (N/S) | On-ground-projected SSD at reference point in Europe (45°N latitude; sub-satellite-point longitude) | |
| Integrated Energy | 70% over 1.47SSDEW*1.13SSDNS90% over 1.72SSDEW*1.72SSDNS | Integrated energy is a measure for the spatial resolution of the instrument | |
| N/S slit field-of-view (swath) | 4.0° | ||
| E/W coverage & Repeat cycle | See Fig. 2 | See Fig. 2 | |
| Daily Earth observation time | Summer max: 01:40 – 21:40Winter min: 03:40 – 19:40 | Adjusted to seasonally varying solar Earth illumination on monthly basis | |
| Spatial co-registration | Intra-detector: 10% of SSDInter-detector: 20% of SSD | 2-dimensional (E/W & N/S) absolute co-registration | |
| Radiometric | |||
| Parameter | UV-VIS values | NIR values | Comments |
| Optical Throughput | ~50% (in UV) | ~60% | End-to-end scanner-to-detector |
| Radiometric Aperture | 70 mm | 44 mm | Circular diameter |
| Earth Signal-to-Noise-Ratio (SNR) | UV: >160VIS: >1600 | 759-770nm: >90Rest NIR: >600 | For specified Earth radiance Reference scene |
| Earth Absolute RA | < 3% | < 3% | For Earth radiance & reflectance |
| Sun Absolute RA | < 3% | < 3% | For sun irradiance |
| Polarization Sensitivity | < 1% | < 1% | |
| Relative Spectral RA | < 0.05% | < 0.5% | For a spectral window of 3nm (UVVIS) and 7.5nm (NIR) and for reflectance only |
| Relative Spatial RA | < 0.25% | < 0.25% | For Earth radiance & reflectance |
| Power | 212 W (average in operating mode) | ||
| Mass | 200 kg | ||
| Data | 25.1 Mbps (instantaneous, during acquisition) | ||
| Number of units | Three (3): •Optical Instrument Module (OIM), which contains the optical and detection part•Instrument Control Unit (ICU)•Scanner Drive Electronic (SDE) | ||
| Dimensions | OIM : 1080 x 1403 x 1785 mmICU: 460 x 300 x 300 mmSDE: 300 x 200 x 100 mm |