Laboratoire d'Optique Atmosphérique

ICWG 2016
17-20 May 2016 in Lille, France

  • February 15th, 2016 : Deadline for abstracts submission
  • March 25th, 2016 : Draft Program
  • April 15th, 2016 : Deadline for early-registration fee of € 200,-
  • April 22nd, 2016 : Final Program
  • May 7th, 2016 : Deadline for late-registration fee € 250,-

On-line registration will be available at the rate of € 200,- before 15th April 2016. Register On-line HERE.
The on-site registration fee will be € 300,- collected by credit card using the on-line payment form at an on-site computer. There will be no cash option.

Submit your abstract before February 15th 2016

To submit your abstract for the ICWG 1, please send a one page pdf including authors, affiliation and text to the following email address
Submitting an abstract does not automagically register you to the workshop, so do not forget to register to the workshop through the dedicated online site.

Program of the ICWG1 2016

  Final Programm (if all goes well) ...

  Tuesday 17 Wednesday 18 Thursday 19 Friday 20

8:45 - 9:15 Gathering registration

9:15 - 9:30 Intro/Logistic - J. Riedi

Topical groups discussions
Introduction to Day 2 : purpose and scope of topical groups.

Parallel breakout sessions for TGs :
TG #B : Cloud Mask
Lead : Karl-Goran Karlsson

Kahn, B. 81
Byung-il, L. 82
Karlsson, K. G. 83
Doutriaux-Boucher, M. 84
Adybbroe, A. 85
Strandgren, J. 86
Hanschmann, T. 87

TG #D : Severe Weather
Lead : Mike Pavolonis

Session 2 : More retrievals on clouds and aerosols
Ferlay, N. 77
Garnier, A. 79
Fauchez, T. 7
Kinne, S. 16
Smith, W. L. 59
Summary of topical group discussion
10H30 Coffee Break Coffee Break Coffee Break Coffee Break
Session 1 : Retrieval methods/new methods
Platnick, S. E. 53
Horn, S. 64
Yoshida, R. 20
Bennartz, R. 19
Topical groups discussions
Parallel breakout sessions for TGs :
TG #A : Assessment of retrieval uncertainties (Optimal Estimation, Cloud modelling, others ...)
Lead : Phil Watts / Caroline Poulsen

TG #C : Climate Products
Lead : Mike Foster

Climate applications and links to other CGMS working groups
Sherwood, S. 43
Frey, R. 8
Poulsen, C. 65
Winker, D. M. 46
Stapelberg, S. 21
Foster, M. 31
Summary of topical group discussion
12H30 Lunch (table) Lunch (buffet) / Posters Lunch (buffet) / Posters Adjourn
Session 1 : Retrieval methods/new methods
Labonnote, L. 73
Meyer, K. 41
Palikonda, R. 37
Liu, J. 6
Chang, F. L. 50
Poster Formal Session *
Poster on display for the entire duration
Weather application / process analysis (Part I)
Pavolonis, M. 54
Roebeling, R. 17
Cooke, M. 26
Hamann, U. 56
Meirink, J. F. 24
15H30 Coffee Coffee Coffee
Cloud parameter assessments : validation
Choi, Y. S. 15
Benas, N. 22
Minnis, P. 63
Le Gleau, H. 1
Devasthale, A. 5
Kahn, B. 81
Topical groups discussions
Parallel breakout sessions for TGs :
ICWG Cloud Retrieval Intercomparison
Lead : Andrew Heidinger

TGs Discussion from morning (continued)

Weather application / process analysis (Part II)
Bedka, K. 61
Walther, A. 69
Deneke, H. 70
Fu, Y. 32
Chellappan, S. 45
18H00 Modern Art Museum ------ --- ---
Cocktail "Ice Breaker"
Workshop Diner
Downtown Discovery

* Maximum size for posters 96 x 118 cm (portrait)

  Click on poster titles for more information.

Permanent Poster Session *

Cloud Detection and Uncertainties : Algorithms Assessed through Application to Aqua MODISAckerman, S. 42

A CERES-Consistent Long-Term Cloud and Clear Sky Radiation Property Dataset Using AVHRR ObservationsBedka, K. 58

Daytime cloud optical and microphysical property retrievals over snow and ice using multispectral satellite data from MODISBedka, S. 60

High temporal resolution cloud amount estimates at Baseline Surface Radiation NetworkBojanowski, J. 2

Validation and homogeneity assessment of the monthly mean ESA-Cloud-CCI cloud fraction datasetBojanowski, J. 3

Introduction to CALIPSO Level 3 Cloud ProductsCai, X. 78

Assessments of 3D cloud heterogeneity effects on cloud parameters retrieved by POLDER3/PARASOL from simulated total and polarized multi-angular reflectancesCornet, C. 74

Impact of the cloud mask for reprocessing of geostationary dataDoutriaux-Boucher, M. 30

Cloud/No cloud separability at high latitudes with VIIRS and AVHRR for the retrieval of Ice Surface Temperatures and Radiative Fluxes over sea iceDybbroe, A. 67

Preparations for the ISMAR and ICI missions Eriksson, P. 55

Accuracy Versus Stability : Incorporating HIRS into the PATMOS-x/AVHRR Cloud Record and Assessing its ImpactFoster, M. 31

Update and Assessment of PATMOS-x Level-3 DatasetGumber, A. 68

Filtering of noisy channel 3.7 data from the AVHRR2 instrumentHakansson, N. 47

Differences in detecting clouds and cloud top height between AVHRR and HIRS based retrievals and their combined potentialHanschmann, T. 23

Intercomparison of Heights for AMV GenerationHeidinger, A. K. 52

Development and evaluating an algorithm suite for MODIS and VIIRS cloud Climate Data Record ContinuityHolz, R. 66

Comparison of satellite based and airborne hyperspectral cloud retrievals during ACRIDICON-CHUVA 2014Kölling, T. 34

CALIPSO validation of AVHRR cloud masks: towards deriving globally gridded LEVEL 2 performance mapsKarlsson, K. G. 18

The retrieval of cloud properties using the Multi-viewing, Multi-channel, Multi-polarization Imaging polarimeter (3MI) on board of the future Eumetsat Polar System - Second GenerationKokhanovsky, A. 25

Development of Cloud Detection Algorithm for GK-2A/AMILee, B. 44

Research on Latent Heat Distributions in Tropical Cyclones from TMI Retrievals of HydrometeorLi, W. 40

Bias Assessment of MODIS/MISR Cloud Motion WindLu, F. 39

Cloud physical properties derivation from AVHRR imagery by means of the Vectorized Earth Observation Retrieval (VEOR) method trained against NWCSAF PPS and PATMOS-x dataMusial, J. 4

Temporal Analysis of cloud parameters fields before heavy rainfall eventsPatou, M. 27

Light tunneling inside cloud droplets : a new approach to light-droplet interactionPujol, O. 75

An updated MODIS climatology of marine boundary layer cloud droplet number concentration for adiabatically stratified cloudsRausch, J. 36

West African weather system in the development of tropical CyclonesSalami, T. 14

Frequency and Vertical distribution of Tropical high clouds: VIS and IR geostationary satellite observations coupled with lidar and IR sounders observations from polar orbiting satellitesSeze, G. 62

Assessment of the single-layer approximation in A-Train integrated cloud products through several years of multi-layer retrievalsSourdeval, O. 76

Neural Network Based Retrieval of Ice Cloud PropertiesStrandgren, J. 9

Relation between cloud texture and vertical extinction profileTestorp, S. 51

Improved cloud masking: The merits of thresholding and probabilistic approachesThoss, A. 48

A Comparison of Cloud Detection Results Using Geostationary Satellites with CALIPSO, CERES-MODIS, and NASA LaRC AVHRRTrepte, Q. Z. 57

Study of the diurnal cycle of marine stratocumulus field off the coast of Southwest Africa with SEVIRIVidot, J. 12

Retrieval of ice cloud properties using an optimal estimation algorithm and MODIS IR observationsWang, C. 38

Multi-Sensor Cloud and Aerosol Retrieval Simulator and Its ApplicationsWind, G. 28

SEV06_CLD : latest updates for the MODIS-style cloud optical and microphysical properties product from SEVIRIWind, G. 29

Cloud stereo and IR heights : A comparison between MISR and GEO observationsWu, D. 71

Retrieval uncertainty due to polarized cloud ice scatteringWu, D. 72

Overview of Daytime Cloud Optical thickness, Effective radius, Water path (DCOEW) algorithm for the GEO-KOMPSAT-2A (GK-2A)Yang, Y. 13

Cocktail "Ice Breaker"

Dining Cocktail
(Tues. 17/05 - 18h00)
Lille Modern Art Museum (LaM)
Private tour of the special Amadeo Modigliani exhibit and dining cocktail at the musuem

Workshop Diner

Le Couvent des Minimes
(Wednesday 18/05 - 19h00)

Cocktail "Ice Breaker"

Map of Université de Lille 1 (Cité Scientifique) Campus

The International Cloud Working Group (ICWG) will be held on the campus of University of Lille 1 at the MACC’s conference center (Lille, France).

Download map here

Coming to Lille

By plane

  • From Paris (Charles de Gaulle international airport) : 50 minutes from Charles de Gaulle to Lille by TGV (high speed train)
  • From Lille/Lesquin airport (10 km from Lille), regular shutlle from/to Lille Europe international train station

By train

The two train stations Lille-Flandres and Lille-Europe are located downtown. Stations are connected through highspeed train TGV Nord to Paris, Brussells and London.
  • Paris - Lille : 50 minutes
  • Bruxelles - Lille : 38 minutes

Tél : +33 892 35 35 35   Web :

Coming to University of Lille - Cité scientifique

From station LILLE-EUROPE

  • Take the étro direction Saint Philibert (line 2)
  • Stop and change at Gare Lille-Flandres
  • Take line 1 direction 4 Cantons
  • Stop at Cité Scientifique


  • Take the etro direction 4 Cantons (Line 1)
  • Stop at Cité Scientifique

Tél : +33 820 42 40 40   Web :

You will find below some lodging options that are located near University of Lille 1 campus where the ICWG 2016 is being held. You are also welcome to look for hotels located downtown which is only 15 min by metro from the campus. A list of recommended hotels and further information can be found on the Lille tourist office website.

The MACC’s conference center where the workshop is being held is located within the complex of the Inter-hotel Ascotel on campus which offers a most convenient place to stay for the workshop attendees. For the workshop participants staying at the Ascotel, free breakfast (13 euros) will be offered with any room. Simply specify that you are participating to the ICWG 2016 workshop when making your booking online. Rooms will be available on a first come first serve basis.

Hôtel Ascotel

Avenue Paul Langevin, Cité Scientifique
Villeneuve d'Ascq
Tél : +33 3 20 67 34 34
Web :

Hôtel B&B Lille Gd Stade

Boulevard de Tournai
Villeneuve d'Ascq
Tél : +33 892 702 548
Web :

REEFLEX International Hall

On site international residence for visiting researchers and professors
Avenue Paul Langevin, Cité Scientifique
Villeneuve d'Ascq
Email : Concierge Service
Web :

Hôtel Park Inn Gd Stade

211 Boulevard de Tournai
Villeneuve d'Ascq
Tél : +33 320 644 000
Web :

Contact the organisation committee
You can contact the organisation committee by sending an email at


From 17 to 20 May 2016 the 1st Workshop of the International Cloud Working Group (ICWG) will be held on the campus of University of Lille 1 at the MACC’s conference center (Lille, France). This workshop is being hosted at the Université de Lille. The goals of the workshop are to assess and enhance cloud retrieval schemes, extend their applicability in complex situations, and better characterize their validity. We invite experts working with cloud parameter retrieval schemes from passive imagers (e.g. METEOSAT, AVHRR and MODIS), passive microwave (e.g. AMSR), and active lidar/radar observations (e.g. CloudSat, CALIPSO) to participate in the workshop and to contribute to the cloud parameter inter-comparison and validation activities.

Background The 1st Workshop of the International Cloud Working Group (ICWG) within the Coordinated Group for Meteorological Satellites (CGMS) is a continuation of four earlier workshops that we organized under the name of Cloud Retrieval Evaluation Workshops (CREWs). The four earlier Workshops were held in Grainau, Germany (2014), Norrköping, Sweden (2006), Locarno, Swiss (2009), and Madison, Wisconsin USA (2011). At these workshops, algorithms for cloud parameter retrievals were discussed, and results from these algorithms were compared for a set of golden scenes. As with the previous workshops, a common database will be prepared with cloud parameter retrievals from different product providers. This database comprises cloud parameter retrievals from MSG, MODIS, AVHRR, POLDER and/or AIRS for a number of olden days. A very important and integral part of the CREW workshops is the discussion on inter-comparison and validation studies performed with the data from the common database. In this way knowledge is gained on the behavior of the different retrieval schemes over different cloud conditions.

    The main recommendations of the CREW in Grainau, Germany were to:
  • Improve cloud models used in retrievals to more accurately reflect reality, in particular ice crystal models, vertical in-homogeneity and multiple layers;
  • Explore the potential of combining different types of observations in level-2 cloud retrievals methods;
  • Explore the definition of a set of essential filtering rules in level-3 aggregation methods for different cloud parameters;
  • Work towards the characterisation of uncertainties in level-2 and level-3 products;
  • Explore production of multi-algorithm ensembles to assess uncertainty/sensitivity;
  • Explore the production of long-term datasets aimed at stability and accurate assessment of product strengths and weaknesses;
  • Use of common ancillary data and validation procedures for level-2 and level-3 data;
  • Establish topical groups to make progress on a variety of outstanding issues, for example multi-layered clouds, severe weather applications, and aggregation methods.
See the ICWG website and wiki for more information on the project :


In the framework of the ICWG, the Topical Groups provide the focus necessary for addressing the recommendations and key research topics identified at the biennial Workshops of the ICWG. These Topical Groups work in collaboration, under the coordination from a lead, on these recommendations and research topics. The Topical Group leads will present their results, discuss the focal points to be addressed at the next biennial meeting in breakout sessions, and report on these focal points at the plenary final discussion. At the last CREW Workshop (CREW-4) a preliminary list was drafted of Topical Groups and proposed leads. For the ICWG-1, the leads of the Topical Groups have confirmed their involvement to date with the following list (Topic and name of Lead):
  • Use of Combined Sensors for Cloud Retrievals (Bryan Baum)
  • Cloud Modeling (Phil Watts)
  • Cloud Height for Wind Applications (Andrew Heidinger)
  • Cloud Retrievals over Snow and Ice Surface (Andy Walther)
  • Severe Weather Applications (Mike Pavalonis)
  • Validation Sources (Patrick Minnis)
  • Assessment of level-2 Passive Imager Cloud Parameter Retrievals (Yong-Sang Choi)
  • Assessment of Retrieval Uncertainties (Caroline Poulsen)
  • Aggregation Methods for Climate Applications (Nadia Smith)
  • Assessment of Cloud Parameter Data Records for Climate Studies (Martin Stengel)
More details on the plans of the Topical groups can be found on the ICWG Wiki at Participants of the 1st Workshop of the ICWG are encouraged to contribute to at least one (and hopefully more) of the Topical Groups before the next Workshop.

2016 Workshop Topics

The workshop will cover a wide range of topics concerning cloud parameter retrievals, their current and potential applications and related issues. The primarily focus will be on the topics that are addressed by the Topical Groups as these cover some of the most active research questions in our community. We propose that key issues for this meeting include:
  • Cloud Modeling (radiative transfer, cloud microphysics, etc)
  • Retrievals Methods (new methods, combined sensors retrievals, uncertainty estimates, etc)
  • Cloud Parameter Assessments (inter-comparisons, validation, uncertainty assessments, etc)
  • Climate Applications (model evaluation, trend analysis, ensemble products, aggregation methods, etc)
  • Weather Applications (nowcasting, extreme weather, aviation, derived products (wind, precipitation) etc )
  • Links to other CGMS working groups (Int. Winds WG (IWWG), Int. Precipitation WG (IPWG), Int. TOVS WG (ITWG) etc)


  • Bryan Baum, Co-chair - SSEC UWM
  • Rob Roebeling, Co-chair - EUMETSAT
  • Dong Wu, Rapporteur - NASA GSFC
  • Jérôme Riedi, Local Organizer - University of Lille


Jérôme Riedi, Laurent Labonnote, Frédéric Parol, Marie-Lyse Liévin, Romain De Filippi