Summaries of the working groups

Second MEGHA-TROPIQUES Scientific Workshop
Paris July 2-6, 2001

Working groups conclusions

Following the presentation sessions, two working groups met on the subjects concerning science issues and data processing.

Their conclusions are given below :

Working Group I

Preliminary scientific studies using existing data. Requirements for different thematic applications

1) Necessity of building a data base including satellite data of the same kind that those that will be provided by Megha-Tropiques + complementary data

CERES (co-localisation ?)
METEOSAT and other geostationaries
Data on particular events with satellite data coincident in space and time
Meteorological analyses
Data from in situ experiments
Climatic satellite data sets (ISCCP, GPCP, Claus,…)

User friendly data base for scientists which are not familiar with satellite processing.

Actions :

– get the whole archive of METEOSAT over the Indian Ocean
– get other satellite data for corresponding periods, icluding monsoons of 1998 and 1999
– begin actions in the frame of CLIMSERV/IPSL data base. Visit of expert from India to develop the system and develop a corresponding one in India

2) Study of Physical processes relevant to the instrumental combination of Megha-Tropiques, its sampling, and corresponding geostationaries data.


Hadley Walker circulations, Water vapour transport, Feedbacks on radiation

Relevant in particular to the ScaRaB-SAPHIR combination, but also to Madras and geostationaries.

Already planned actions :
– AMIP-2 model evaluations
– Interactions African area, Indian Ocean
– Global scale interactions (warm pool, el Niño)
– Validation of GCM’s over India


– Modulation of convective activity
– Madden-Julian oscillations
– Onset,, break and variations of monsoons
– Ocean-Atmosphere interactions
– Continent-Atmosphere interactions

Relevant to geostationaries + M.T. Observations


Require special combinations of existing instruments for specific systems where co-locations and time coincidence exist : SSM/I, TMI, AMSU, Geostationaries.

– Dry air intrusions (SAPHIR, METEOSAT, MADRAS)
– WV in middle atmospher and convective systems (SAPHIR, METEOSAT, MADRAS)
– Convective clouds properties and radiation (MADRAS, Geostationaries, ScaRaB)
– WV above clouds (SAPHIR)
– (Climatology of WW) (SSMT/2 ?)
– Convection and surface fluxes (MADRAS, Geostationaries)
– Initiation of convection (MADRAS, Geostationaries)
– Life cycle of systems (MADRAS, Geostationaries)
– Help to convection parameterization (all instruments)

Specific tools to be considerd

– cloud resolving and mesoscale models
– new satellites (MSG, INSAT, EOS, METOP,…)
– Assimilation in different models (radiances and/or products)


Call for proposals on scientific themes emphasizing the specificities of Megha-Tropiques :

– instrument combinations
– repetititvity
– combination with geostationaries

Megha-tropiques fellowships for young scientist exchanges

Working Group II

Definition and Planning of Studies on Algorithm definition, constitution of data bases and Validation Experiments

Participants: L Eymard, N Viltard, …………………….

B S Gohil, R M Gairola, U C Mohanty, G Raju, M S Narayanan,
R Narasimha

The following points were discussed by the Working Group:

– Standard products from the 3 MT instruments
– Levels of data products
– Development and selection of operational Algorithms
– Calibration, Quality control and Validation

A) Standard Products

The following parameters were identified to be made available as standard products operationally from the three Megha Tropiques instruments (based on today’s state-of-art knowledge):

a) MADRAS: over oceans – under non-rainy conditions / below a specified
liquid water content (to be defined)

Parameter Horizontal Auxillary Data

Total Water Vapour Content 40 km None
Liquid Water Content 40 km None
Sea Surface Wind speed 40 km None
Surface Rain Rate (SRR) 40 km None

Over Land

Surface Rain Rate 40 km None


Water vapour content – in 6 layers 10 km . Temperature profile
(over oceans) from ECMWF
. Geostationary images

Water vapour content – 5-6 layers 10 km . Temperature profile
(over land) from ECMWF
c) ScaRaB

Top of Atmosphere Fluxes

. Short Wave 40 km None
. Long Wave 40 km
. Scene identification (useful for 40 km
MADRAS, SAPHIR processing)

B) Levels of Data Products

Level 1a calibrated / corrected for instumental errors

1b geolocated and collocated TB from 89, (37,23,18) together
157 GHz at original location

1c ? gridded (preferably in GrADS type format) TB from
the 3 instruments

Level 2a Standard Geophysical Products from the 3 instruments

2b Gridded product (in GrADS – type format) – with no time-averaging

Research Products (to be defined)

Combination of TBs and / or Geophysical Products from
2 or more of MT instruments

Value Added Products
(using data from other satellites also)

Ice – related products (from 157 GHz)

C) Development of Algorithms:

Approaches . Inhouse development (in France and in India)
. Through Global AO (in the context of GPM rainfall)
(this proposal has to be discussed by JSC)

RT code selection (in house) . compare the performance of the available codes
on the data base to be prepared for an year
going in complexity from clear sky to cloudy to raining
. Selection of an appropriate code

Data Base for Atmospheres . NCMRWF and ECMWF Analysis + Forecasts
(1-year’s data of 1999) . SSMI/SSMT-2 + TMI + AMSU-B data
. Geostationary data sets
. Radiosonde, ship, buoy, raingauge etc

D) Calibration:

Inflight Free space and BB target

Quality Control

Data Quality Evaluation (TBD)
Data impact studies


. Insitu data
. Special cruises
. IMD Radar (Karaikal), NMRF Radar – Gadanki

E) Tentative Time Schedule:

Preparation of Data base To – 5 yr to To – 4 yr

Preparation of Guidelines for To – 4 yr
Selecting the RT code

Announcement of Opportunity To – 4 yr to To – 3 yr

Selection of RT code for To – 2 yr
the 3 instruments

Conversion to operational To – 1 yr

(Note –whether 2 years are sufficient to convert from selected RT code to operational algorithms )