CM-SAF Board Meeting , Helsinki, September 2006

CM-SAF TOA radiation status report

D. Caprion

Royal Meteorological Institute of Belgium

CM-SAF Board Meeting , Helsinki, September 2006

Overview

CERES status GERB status and reprocessing TOA flux products status

– Missing data (sunglint...)– New chains

CM-SAF Board Meeting , Helsinki, September 2006

CERES status Use of CERES ES9 products

– Available until June 2006

No plan to switch to CERES SRBAVG products– No suitable for “real time” usage– Maybe to be include in a future reprocessing

CM-SAF Board Meeting , Helsinki, September 2006

GERB status 2 instruments on fly (GERB 2 /SEVIRI 1 and GERB

1 / SEVIRI 2):– Data from both satellites are consistent

Currently GERB 2 operational – But stopped at night (between 20:00 and 02:00) till mid-

October: eclipse season

When SEVIRI 2 operational then switch to GERB 1

CM-SAF Board Meeting , Helsinki, September 2006

GERB reprocessing Two steps (at the RMIB)

– First compute clearsky

– Then compute fluxes for any month

Technical restrictions– Take a few weeks (2 or 3) for the clearsky (from 02/2004 to 03/2006)

– 1 month of data in 2 weeks (worse case) for the fluxes (same period)

– But… depends on pre-processing at the RAL (quite fast)

Schedule– Should start this week

– First some « independent » dates to cover validation and intercalibration studies

– Later all since February 2004

CM-SAF Board Meeting , Helsinki, September 2006

TOA products status Most of the production chains stopped 04/2006 STA products (fluxes at SEVIRI resolution

needed for surface fluxes) are still produced

So what did we do ?– GERB/GERB_like intercalibration – Change of the production chains– Introduction of GERB aerosol products

CM-SAF Board Meeting , Helsinki, September 2006

GERB/GERB_like intercalibration • Why ?

– need to solve the “sunglint” and “edge” problems

CM-SAF Board Meeting , Helsinki, September 2006

GERB/GERB_like intercalibration

• Impact on treatment: e.g. sunglint effect !

Monthly Mean April 2006Reflected Solar Flux

CM-SAF Board Meeting , Helsinki, September 2006

GERB/GERB_like intercalibration

• Impact on treatment:– Missing data strategy has to be changed:

i.e. replacement of GERB-like by GERB

• Until now: image per image.

• From now on: pixel per pixel !

Get intro trouble: inter-calibration !

CM-SAF Board Meeting , Helsinki, September 2006

GERB/GERB_like inter-calibration

• Idea: GERB and GERB-like (mean) fluxes are proportional

<Fgerb_like>= k * <Fgerb>

– Strong assumption :• k is constant over a month

• then it can be determined from monthly mean flux

CM-SAF Board Meeting , Helsinki, September 2006

GERB/GERB_like intercalibration

CM-SAF Board Meeting , Helsinki, September 2006

GERB/GERB_like inter-calibration

• Second idea: (only for shortwave)– First correct the diurnal cycle effect

(i.e. flatten the curve)

– Rescale FGerb_like to FGerb

FGerb_like=k*((s,v,...)*FGerb)

Correction to take into account:• solar angle s

• viewing angle v

• and more if needed… like surface type for instance

CM-SAF Board Meeting , Helsinki, September 2006

GERB/GERB_like intercalibration Introduction of 9 matrices of correction:

– 3 surfaces types (ocean – vegetation – desert)– 3 types of sky (clear – partially cloudy – cloudy)

The coefficients of theses matrices depend on solar zenithal angle (sza) and viewing zenithal angle (vza)– Sza and Vza are binned every 10° between 0° and 90°

The matrices were computed with a set of random data picked up in March and April 2006

CM-SAF Board Meeting , Helsinki, September 2006

GERB/GERB-like intercalibration So what we get is something like (9 times):

# CLEAR OCEAN 1.115 1.111 1.092 1.077 1.068 1.074 1.089 1.0891.091 1.080 1.068 1.073 1.072 1.070 1.085 1.0931.057 1.050 1.056 1.071 1.079 1.073 1.083 1.0901.031 1.045 1.051 1.067 1.080 1.076 1.087 1.0901.017 1.039 1.052 1.062 1.078 1.077 1.086 1.0951.008 1.031 1.047 1.064 1.078 1.083 1.090 1.0971.002 1.025 1.045 1.069 1.086 1.086 1.103 1.1081.005 1.032 1.054 1.074 1.088 1.084 1.089 1.083

NOT REALLY UNDERSTANDABLE

CM-SAF Board Meeting , Helsinki, September 2006

GERB/GERB_like intercalibration

= factor to scale the GERB_like to GERB

CM-SAF Board Meeting , Helsinki, September 2006

GERB/GERB_like intercalibration

= factor to scale the GERB_like to GERB

CM-SAF Board Meeting , Helsinki, September 2006

GERB/GERB_like intercalibration

= factor to scale the GERB_like to GERB

CM-SAF Board Meeting , Helsinki, September 2006

GERB/GERB_like intercalibration

CM-SAF Board Meeting , Helsinki, September 2006

GERB/GERB_like intercalibration

Monthly Mean April 2006 Reflected Solar Flux(GERB + GERB_like)

Percentage of GERB_like

CM-SAF Board Meeting , Helsinki, September 2006

New production chains Before:

First mapping onto sinusoidal grid then averaging

Now:First averaging and then mapping to LonLat grid and sinusoidal grid

So :We had to (re)write and/or update part of the softwares

CM-SAF Board Meeting , Helsinki, September 2006

Gerb aerosol products New products: aerosol optical depth compute

with VIS-0.6, VIS-0.8 and IR-1.6 + dust detection

Daily mean of aod 0.8

SEVIRI grid

27th April 2006

CM-SAF Board Meeting , Helsinki, September 2006

Gerb aerosol products

• With both projection:LatLon grid Sinusoidal grid

CM-SAF Board Meeting , Helsinki, September 2006

In the next weeks/months Restart of the production chains Check of the corrections on « winter » months Update of the cmsaf.oma.be web site

– New status page corresponding to the new chains– Pages software sources (with username and

password)

CM-SAF Board Meeting , Helsinki, September 2006

Last but not least User feedback: (need surface albedo)

– Why 15km2 resolution when SAF Land has a SEVIRI resolution ?

– Why such a limited area ?– Why surface albedo only over land ?– The command and the retrieval of the data are not

clear» Interface not intuitive» Problem with the ftp through a browser» But quite fast !!!!