# Presentation: 258714

## Henri LAUR

***MERIS US Workshop, 14 July 2008, Washington (USA)***

**Henri LAUR**
***Envisat Mission Manager***

## Sentinel-3 is one element of the GMES system.
Sentinel-3 is an operational mission for oceanography & global land applications.
Provides continuity of existing missions, delivering:
Sea/Land colour data (at least MERIS quality)
Sea/Land surface temperature (at least AATSR quality) 
Sea surface topography data (at least Envisat RA quality)
Applicable Sentinel-3 user requirements identified through surveys conducted within the relevant user groups:
Operational and Institutional Oceanography Groups
Oceanographic Research Users
Land Users
A series of satellites, each designed for a lifetime of 7 years, shall provide an operational service over 15 to 20 years
Only 1 satellite is in development at this moment

**Sentinel-3 is an**** operational mission**** for oceanography & ****global land applications.**
**Provides ****continuity**** of existing missions, delivering:**
**Sea/Land colour**** data (at least MERIS quality)**
**Sea/Land surface temperature**** (at least AATSR quality) **
**Sea surface topography**** data (at least Envisat RA quality)**
**Applicable Sentinel-3 user requirements identified through surveys conducted within the relevant user groups:**
**Operational and Institutional Oceanography Groups**
**Oceanographic Research Users**
**Land Users**
**A series of satellites, each designed for a lifetime of 7 years, ****shall provide an operational service over 15 to 20 years**
**Only 1 satellite is in development at this moment**

**Sentinel-3 overview**

## Sentinel-3 instruments

**OLCI**

**SLST**

**SRAL  **

- .

- .

- .

- MWR

**Sentinel-3 instruments**

- Instruments:
- Ocean and Land Colour Instrument (OLCI) with 5 cameras, 8 bands (only VIS) for open ocean (low res), 15 bands (only VIS) for coastal zones (high res). Spatial sampling: 300m @ SSP 	*** MERIS follow-on*
- Sea and Land Surface Temperature (SLST) with 9 spectral bands, 0.5 (VIS, SWIR) to 1 km res (MWIR, TIR). Swath: 180rpm dual view scan, nadir & backwards 	*** ATSR follow-on*
**Radar Altimeter package**SRAL Ku-C altimeter (LRM and SAR measurement modes), MWR, POD (with Laser Retro Reflector and DORIS)

## Heritage from MERIS
5 cameras, 21 programmable spectral bands (incl. channels for MERIS & VGT legacy products)
Sun Glint free configuration by design
Across-track tilt = 12.20°
Low polarisation < 1%
Swath covered by SLST for 
    atmospheric correction

**Heritage from MERIS**
**5 cameras, 21 programmable spectral bands (incl. channels for MERIS & VGT legacy products)**
**Sun Glint free configuration by design**
**Across-track tilt = 12.20°**
**Low polarisation < 1%**
**Swath covered by SLST for **
**    ****atmospheric correction**

**OLCI instrument**

## OLCI spectral channels

| Channel | Central wavelength
(nm) | Width
(nm) |
| --- | --- | --- |
| 1 | 400 | 15 |
| 2 | 412.5 | 10 |
| 3 | 442.5 | 10 |
| 4 | 490 | 10 |
| 5 | 510 | 10 |
| 6 | 560 | 10 |
| 7 | 620 | 10 |
| 8 | 665 | 10 |
| 9 | 681.25 | 7.5 |
| 10 | 708.75 | 10 |
| 11 | 753.75 | 7.5 |
| 12 | 761.25 | 2.5 |
| 13 | 764.375 | 3.75 |
| 14 | 773.75 | 5 |
| 15 | 781.25 | 10 |
| 16 | 862.5 | 15 |
| 17 | 872.5 | 5 |
| 18 | 885 | 10 |
| 19 | 900 | 10 |
| 20 | 940 | 20 |
| 21 | 1020 | 40 |

**OLCI spectral channels**

## Heritage from AATSR, dual-view (nadir & backward) required for aerosol corrections:
Nadir swath >74°	(up to 1800 km)
Dual view swath 49°  ~ 750 km 
Nadir swath covering OLCI 
9 spectral bands:
3 Visible : 555 – 659 – 865 nm
3 SWIR : 1.38 – 1.61 – 2.25 μm
3 TIR  :  3.74 – 10.85 – 12 μm

One Vis/IR channel used for          co-registration with OLCI

**Heritage from AATSR, dual-view (nadir & ****backward****) required for aerosol corrections:**
**Nadir swath >74°****	****(up to 1800 km)**
**Dual view swath 49°  ~ 750 km **
**Nadir swath covering OLCI **
**9 spectral bands:**
**3 Visible : 555 – 659 – 865 nm**
**3 SWIR : 1.38 – 1.61 – 2.25 μm**
**3 TIR  :  3.74 – 10.85 – 12 μm**
**One Vis/IR channel used for          co-registration with OLCI**

**OLCI FOV**

**Nadir view**

**S****ea & ****L****and ****S****urface ****T****emperature Radiometer**

**SLST instrument**

## OLCI and SLST spatial resolution

| OLCI – Open ocean | 1.2 km |
| --- | --- |
| OLCI – Coastal ocean | 300 m |
| OLCI - Land | 300 m |
| SLST – Solar channels | 500 m |
| SLST – Thermal channels | 1 km |

**Pushbroom type imager spectrometer**
**21 Spectral Channels**
**Full Resolution: Coastal/Land**
**Reduced Resolution: Open Ocean**

**Conical scanning imaging radiometer with dual view capability:**
**• ****Near-nadir view**
**• ****Inclined view with an OZA of 55o ± 0.1o**
**9 Spectral Channels + 2 (option) for Active FIRE**

**OLCI and SLST spatial resolution**

## Sentinel-3 mission orbit

**Slow Time Critical (1 to 2 days) delivery of higher quality products for assimilation in models (e.g. SSH, SST)**

| Type: | Sun-synchronous low earth orbit |
| --- | --- |
| Repeat cycle: | 27 days (14 + 7/27 orbits per day) |
| Average altitude: | 814.5 km over geoid |
| Mean solar time: | 10:00 at descending node |
| Inclination: | 98.65O |

|  |  | Revisit at Equator | Revisit for latitude >30° | Specification |
| --- | --- | --- | --- | --- |
| Ocean Colour (Sun-glint free) | 1 Satellite | < 3.8 days | < 2.8 days | < 2 days |
|  | 2 Satellite | < 1.9 days | < 1.4 days |  |
| Land Colour | 1 Satellite | < 2.2 days | < 1.8 days | < 2 days |
|  | 2 Satellite | <  1.1 day | < 0.9 day |  |
| SLST dual view | 1 Satellite | < 1.8 days | < 1.5 days | < 4 days |
|  | 2 Satellite | <  0.9 day | <  0.8 day |  |

**Sentinel-3 mission orbit**