BackForwardInstrument:  Sentinel-4 

Instrument details
Acronym Sentinel-4
Full name UVN: Ultra-violet, Visible and Near-infrared sounder
Purpose Frequent observation of BrO, HCHO, NO2, O3, SO2 and aerosol; also cloud top height
Short description

Grating spectrometers covering the UV, VIS and NIR spectral bands [see detailed characteristics below]

Monitoring and calibration information here
Background

Embarking Sentinel-4 on Meteosat Third Generation implements the Sentinel-4 component of Copernicus, the European Commission's Earth Observation Programme, previously known as GMES (Global Monitoring for Environment and Security)
Scanning Technique

Mechanical, 3-axis stabilised satellite, E-W continuous, S-N stepping
Resolution Defined at 45°N, 0°: < 8 km in both N/S and E/W directions
Coverage / Cycle European area (lat. 30-65°N, long. 30°W to 45°E at lat. 40°N); 60 min repeat cycle over Reference Area which moves from East to West to follow solar illumination during the day
Mass 150 kg Power 100 W Data Rate 25 Mbps

 

Providing Agency ESA
Instrument Maturity Demonstrated by simulations
Utilization Period: 2025 to 2045
Last update: 2024-09-23
Detailed characteristics
Spectral ranges Number of channels Spectral resolution SNR at specified input spectral radiance
305-400 nm 600 0.5 nm 200-1400 @ 40-120 W m-2 sr-1 μm-1
400-500 nm 600 0.5 nm 1400 @ 140 W m-2 sr-1 μm-1
755-775 nm 300 0.2 nm 1200 @ 60 W m-2 sr-1 μm-1
Satellites this instrument is flying on

Note: a red tag indicates satellites no longer operational, a green tag indicates operational satellites, a blue tag indicates future satellites

Instrument classification
  • Earth observation instrument
  • Passive optical radiometer or spectrometer
  • Cross-nadir shortwave (UV/VIS) sounder
WIGOS Subcomponents
  • Subcomponent 1
  • UV/VIS/NIR sounders [in GEO]
  • UV/VIS/NIR sounder [in GEO]
  • Subcomponent 3
  • NIR spectrometer
  • NIR spectrometer
Mission objectives
Primary mission objectives
  • BrO
  • ClO
  • H2O
  • HCHO
  • HCHO Total Column
  • NO
  • NO2
  • NO2 Total Column
  • O3
  • O3 Total Column
  • SO2
  • SO2 Total Column
Evaluation of Measurements

The following list indicates which measurements can typically be retrieved from this category of instrument. To see a full Gap Analysis by Variable, click on the respective variable.

Note: table can be sorted by clicking on the column headers
Note: * Primary mission objective.
VariableRelevance for measuring this variableOperational limitationsExplanation
Aerosol column burden2 - very highCloud sensitive.. Daylight only.UV (for absorbing aerosol), VIS and NIR spectrometry including the 760 nm band for high-level aerosol
Aerosol effective radius2 - very highCloud sensitive.. Daylight only.UV, VIS and NIR spectrometry including the 760 nm band for high-level aerosol
Aerosol mass mixing ratio2 - very highCloud sensitive.. Daylight only.UV (for absorbing aerosol),, VIS and NIR spectrometry including the 760 nm band for high-level aerosol
Aerosol Optical Depth2 - very highCloud sensitive.. Daylight only.UV, VIS and NIR spectrometry including the 760 nm band for high-level aerosol
Aerosol type2 - very highCloud sensitive.. Daylight only.UV (for absorbing aerosol), VIS and NIR spectrometry including the 760 nm band for high-level aerosol
BrO*1 - primaryCloud sensitive.. Daylight only.UV spectrometry. BrO lines around 300 nm. Frequent sampling (GEO) enables monitoring diurnal variations
HCHO*2 - very highCloud sensitive.. Coarse vertical resolution.. Daylight only.UV spectrometry. HCHO lines around 350 nm. Frequent sampling (GEO) enables monitoring diurnal variations
HCHO Total Column*2 - very highCloud sensitive.. Daylight only.UV spectrometry. HCHO lines around 350 nm. Frequent sampling (GEO) enables monitoring diurnal variations
ClO*1 - primaryCloud sensitive.. Daylight only.UV Spectrometry. ClO lines around 300 nm Frequent sampling (GEO) enables monitoring diurnal variations
Cloud cover4 - fairDaylight only.VIS and NIR spectroscopy
Cloud drop effective radius4 - fairAt cloud top.. Daylight only.VIS and NIR spectrometry
Cloud ice effective radius4 - fairAt cloud top.. Daylight only.VIS and NIR spectrometry
Cloud optical depth4 - fairLow-density cloud only.. Daylight only.VIS and NIR spectrometry
Cloud top height4 - fairDaylight only.NIR spectrometry to estimate the total-column O2 above the cloud top as measured around 760 nm
Downward short-wave irradiance at Earth surface4 - fairCloud sensitive.. Highly indirect.. Daylight only.VIS and NIR spectrometry
Earth surface short-wave bidirectional reflectance4 - fairCloud sensitive.VIS and NIR spectrometry. GEO sees changing solar incidence angles as daylight progresses
H2O*3 - highCloud sensitive.. Daylight only.Spectrometry in UV and VIS (several weak bands), and NIR (strong band around 940 nm). Frequent sampling (GEO) for diurnal variations
NO*2 - very highCloud sensitive.. Coarse vertical resolution.. Daylight only.UV spectrometry. NO lines around 250 nm. Frequent sampling (GEO) enables monitoring diurnal variations
NO2*2 - very highCloud sensitive.. Coarse vertical resolution.. Daylight only.UV and VIS spectrometry. Several lines in the ranges around 220 nm and 400 nm. Frequent sampling (GEO) enables monitoring diurnal variations
NO2 Total Column*2 - very highCloud sensitive.. Daylight only.UV and VIS spectrometry. Several NO2 lines. Frequent sampling (GEO) enables monitoring diurnal variations
O3*2 - very highCloud sensitive.. Daylight only.UV and VIS spectrometry. Ozone lines in the bands around 260 nm (Hartley) and/or 340 nm (Huggins) and 600 nm (Chappuis). GEO enabling frequent sampling (GEO) for diurnal variations
O3 Total Column*2 - very highCloud sensitive.. Daylight only.UV and VIS spectrometry. Ozone lines in the bands around 260 nm (Hartley) and/or 340 nm (Huggins) and 600 nm (Chappuis). GEO enabling frequent sampling (GEO) for diurnal variations
PSC occurrence2 - very highMarginal view from GEO.. Daylight only.UV and VIS spectrometry
Short-wave cloud reflectance5 - marginalNo specific limitation.VIS and NIR spectrometry. Unsuitable dynamic range (saturation)
SO2*2 - very highCloud sensitive.. Coarse vertical resolution.. Daylight only.UV spectrometry. SO2 lines around 350 nm. Frequent sampling (GEO) for sources monitoring
SO2 Total Column*3 - highCloud sensitive.. Daylight only.UV spectrometry. SO2 lines around 350 nm. Frequent sampling (GEO) for sources monitoring
Upward short-wave irradiance at TOA3 - highSpectral interpolation needed.UV, VIS and NIR spectrometry with changing solar incidence angles as daylight progresses
Upward spectral radiance at TOA5 - marginalMissing SWIR and all Long-waves.UV, VIS and NIR spectrometry
Aerosol volcanic ash2 - very highCloud sensitive.. Daylight only.UV (specifically sensitive to ash), VIS and NIR spectrometry including the 760 nm band for high-level ash
Aerosol volcanic ash Total Column2 - very highCloud sensitive.. Daylight only.UV (specifically sensitive to ash), VIS and NIR spectrometry including the 760 nm band for high-level ash. Frequent sampling (GEO) for early detection of ash plumes