19/04/23 NOV-30XX-SL-XXX 1

Component decomposition of IASI measurements

Cloud decontamination scheme

Variational cloud-decontamination

prototype

Decontaminated spectrum Atmospheric parameters

Cloudy component

Clear component

Measurement

Partially cloudy adjacent IASI fields of

view(FOV)

Each measured spectrum (black) is the linear combination of clear (blue) and cloudy (red) components. Measured spectra for the 4 IASI fields of view are given as input of the cloud-

decontamination process, which provides the clear component spectrum, and the corresponding retrieved atmospheric parameters.

19/04/23 NOV-30XX-SL-XXX 2

Component decomposition of IASI measurements

Spectral correctionalgorithm

Variational cloud-clearing algorithm

RTM

Scguessj

(j=1,J)j

kjkk

(j=1,J: k=1,K)

AVHRR analysis

Sok

(k=1,K)

Seik

(k=1,K)

jk

(j=1,J: k=1,K)

Scij

(j=1,J)

ik

(k=1,K)

+

j=1,J

j=1,J

k=1,K

i=1,It

Spectral correction algorithm