The 3rd joint jcsda-ecmwf workshop on assimilating satellite observations of clouds and precipitation into nwp models
December 1-3, 2015 - College park, md

Group Photo: 3rd Joint JCSDA-ECMWF Workshop on Assimilating Satellite Observations of Clouds and Precipitation into NWP Models

Group Photo: 3rd Joint JCSDA-ECMWF Workshop on Assimilating Satellite Observations of Clouds and Precipitation into NWP Models

Satellite observations in the visible, infrared, and microwave (active and passive) provide a great deal of information on clouds and precipitation and therefore are strongly linked to hydrometeors (ice, non-precipitating cloud, liquid and frozen precipitation, mixed phase) geophysical characteristics (particle size, distribution, density, shape, amount, etc). Both satellite observations and ground (or field) experiment measurements have been and are continuing to be studied in order to (1) understand the interaction and correlations between the hydrometeors parameters, (2) simulate their optical and radiative properties, (3) invert the satellite observations to provide cloud and precipitation parameters, (4) assimilate the same observations into NWP models and to, (5)improve cloud modeling parameterizations. The workshop intends to bring together the scientific communities involved in these applications in order to make progress and learn from each others' results. The outcome is hoped to lead to improved data assimilation and therefore initialization of clouds and precipitation in models, to improved accuracy in the simulation of cloud and precip-impacted measurements, to higher-quality inverted cloud and precipitation products and to a full utilization of the field campaign results. Since clouds and precipitation often occur in sensitive regions for forecast impacts, such improvements are necessary for continuing significant gains in weather forecasting.


In 2005, the JCSDA sponsored an international workshop that covered the three main topics related to assimilating observations in cloudy/precipitating regions: satellite observing capabilities, modeling radiative transfer and cloud/precipitation formation, and data assimilation. The papers presented at the 2005 workshop were published as a Special Section of the Nov. 2007 issue of JAS. In spring 2010, the European Centre for Medium-Range Weather Forecasts (ECMWF) hosted a joint ECMWF-JCSDA workshop to document the developments since the 2005 workshop and to produce recommendations to ECMWF, JCSDA, and other NWP centers and scientific communities for future research developments and collaboration. About 65 participants attended the workshop, representing most major NWP centers around the world as well as research institutes and universities. See more details in this summary article.

Since then, and because of their importance and expected significant value to extreme weather prediction and NWP forecast skill, major efforts are being undertaken in operational and research centers to tackle the problem of assimilating data impacted by cloud and precipitation. In parallel, the remote sensing community involved in cloud and precipitation retrievals have invested significantly in the improvement of the physical methods employed to invert the same data used in the NWP assimilation, for the determination of cloud and precipitation and other atmospheric and surface products obtained in these areas. In addition, major efforts have taken place, in particular in preparation of the Global precipitation Mission (GPM), to understand hydrometeors parameters interaction, correlation, through multiple field campaigns. Some of this progress was recently highlighted at the International Precipitation Working Group (IPWG) meeting held in Tsukuba, Japan.

The purpose of this workshop follows the tradition of 5-year cycle joint ECMWF-JCSDA workshops dedicated on tackling this problem, this time extending the invitation to scientific communities involved in tackling the interpretation and utilization of satellite observations impacted by hydrometeors for the purpose of the simulation, inversion, NWP assimilation and modeling and actual measurement of microphysical and optical properties.


Accelerate the cross-fertilization of knowledge in the different communities to benefit all activities. Document recent developments and make recommendations to ECMWF, JCSDA, and other NWP centers and scientific communities for future research developments and collaboration.

Workshop Setup

  • The introduction will include a brief summary of the 2005 workshop as well as a summary of the relevant recommendations presented in the recent IPWG.

  • Workshop sessions will cover current status of cloud/precipitation assimilation in NWP, their observations, radiative transfer and optical properties modeling, cloud and precipitation modeling and special issues related to inversion and data assimilation of cloud/precipitation-affected observations.

  • Presenters will be tasked to present status and issues/solutions that can be addressed in working groups and not to present well-known results.

  • Working groups run in parallel and each group comprises experts in different fields. Each group, led by co-chairs, should devise an implementation plan across disciplines. Final report will merge individual reports into one consistent document.

  • Selected papers will be submitted for a special issue of a peer review journal [TBD]. A short workshop summary will also be submitted to ECMWF and JCSDA newsletters [TBD].

Date and Location

The 3rd Joint JCSDA-ECMWF Workshop on Assimilating Satellite Observations of Clouds and Precipitation into NWP Models will be held at the NOAA Center for Weather and Climate Prediction (NCWCP) in College Park, Maryland, on December 1-3, 2015.

Workshop Objectives

  • Critically review the current state of the art in:

    • Modeling of clouds and precipitation in NWP (specific attention to what current and near future generation models can realistically represent, and therefore what observations could be ingested).

    • Science validation: Reviewing the findings from the field campaigns, targeting the hydrometeors and their microphysical and macrophysical properties: focusing on uncertainties.

    • Satellite observations of clouds and precipitation: focusing on what exists and information content.

    • Simulating the optical properties and radiative transfer in cloudy and rainy conditions: Focusing on how accurately can we model observations.

    • Physically-based Inversion methodologies using satellites data impacted by cloud and precipitation.

    • Assimilating satellite observations of clouds and precipitation.

  • Identify the key issues for successful assimilation of cloud and precipitation information.

  • Develop a prioritized list of additional examinations of issues, further evaluations of techniques, and needed new developments.

  • Plan coordination mechanisms to facilitate progress on needed developments.


By bringing together experts in: cloud/precipitation remote sensing, radiative transfer in cloudy or precipitating atmospheres, modeling clouds and precipitation, and assimilating cloud and precipitation-impacted observations as well as the actual measurements of the hydrometeors microphysical and macrophysical characteristics.

Expected Outcome

A workshop report that will summarize workshop deliberations and include a prioritized list of needed research and development, plans of the various groups, and how these groups could better coordinate their activities.

Fee, Registration, and Deadlines

The workshop is by invitation. To be invited, please contact one of the co-chairs of the workshop or one of the members of the Scientific and Organization Committee.

Once invited, participation in the meeting requires a nominal charge of $30 (to be paid at sign in, cash). Note that no-host Group dinners will be arranged during the workshop. Prepayment for dinner(s) will be expected at registration.

Deadlines and Milestones

This first circular is expected to be issued on or around August 10, 2015.
The second circular is expected to be issued on or around October 21, 2015.
All invitation requests must be received by November 1, 2015.

Registration closes November 15, 2015.
The third and final circular (with technical program), to be issued on or around November 15, 2015.

Presentation Uploading

Presenters are encouraged to submit their presentations ahead of time, by sending an email to Erin.Jones with CC to René Brown and Junye Chen. The preferred format is pdf or ppt.