August 1, 2014


The Parasol Payload is composed of a set of elements and sub-systems based on the Polder instrument developed for a launch on board the Japanese platform ADEOS and ADEOS-2. The main evolutions involve the spectral bands.

The Parasol payload will have the following characteristics :

total massabout 30 kg
volumeabout 0.5 x 0.5 x 0.3 m3
Power consumption (imaging mode)77 W
Mean power29 W
data rate880 bits/s

PARASOL payload

It consist basically of a digital camera composed of a 284x364 pixels CCD detection matrix, a wide field of view telecentric optics (± 51° along the great axis) and of a rotating wheel carrying spectral and polarized filters.
There are 15 filters (plus an obscurity current measure), and could cover a spectral domain ranging from 443 to 1020 nm. For some wave length, 3 filters measure the linear polarization of the incoming light in three directions separated by 120°, thus allowing to supply the Stokes parameters and the total radiance. Moreover, the acquisition of an image sequence every 20 secondes enable the observation of one natural target from different directions.

Compared to Polder, the telecentric optics array has been turned 90 degrees to favour multidirectional viewing over daily global coverage. Likewise, a 1020-nm waveband has been added to conduct observations for comparison with data acquired by the lidar on Calipso, one of its companion satellites.
The Polder 443 P band was replaced by the 490 P band and the Polder 490 band was replaced by the 1020 band.

The radiometric performances of the Parasol payload are similar to the Polder ones. The vicarious calibration methods, based on the observation of natural targets (no calibration system on board), are also the same than the Polder ones.

The Parasol spectral bands

In order to correct from absorption effects, spectral sensitivities
of all Parasol bands are given in the spectrum file.

Polder channelsBandwidthParasol channelsRationale
443P20 nmcancelledPolarization moved to 490 nm
44320 nm443
no change but high dynamic
Cloud detection, Drop of ocean color applications
49020 nm490P
addition of polarization
Aerosol retrieval, Cloud pressure
56520 nm565
high dynamic
Lidar at 532 nm
670P20 nm670P
no change
Aerosol retrieval, Cloud properties
865P40 nm865P
no change
Aerosol retrieval, Cloud properties
76310 nm763
no change
Cloud oxygen pressure by Differential absorption technique in Oxygen A band
76540 nm765
no change
91020 nm910
no change
Water vapor retrieval
/20 nm1020
new channel
Lidar at 1064nm, Aerosol retrieval