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NCAR's Data Assimilation Research Section

The NCAR Data Assimilation Initiative was founded to create and to then lead a research community for data assimilation where individuals benefit from sharing ideas, methodologies, and software tools as well as access to a data assimilation testbed. NCAR has a large number of researchers for whom data assimilation is an essential part of their ongoing or planned research. New developments in theoretical data assimilation and in software engineering are making collaborations between data assimilation experts, modelers, observational specialists and statisticians easier and more productive than was possible in the past. The maturation of the Initiative resulted in the Data Assimilation Research Section (DAReS). The primary goal of DAReS is to continue to advance the theory and practice of ensemble data assimilation. Also, DAReS accelerates the progress of many other NCAR projects by providing a centralized data assimilation expertise which can be coordinated with existing observational and modeling expertise.

The Data Assimilation Research Section (DAReS)

The people of the Data Assimilation Research Section
from left to right: Kevin Raeder, Glen Romine, Jeff Anderson, Nancy Collins, Tim Hoar, Jonathan Hendricks, and Moha El Gharamti.

Our small group is comprised of experts in software design, algorithm development, large-model implementation and execution, observations and observation operators, and hardware/software portability. We have given many presentations on DART - our software facility for ensemble data assimilation, and have held several workshops for young researchers interested in DA.

DAReS Staff (alphabetically) DAReS Support (alphabetically)
Jeff Anderson, Scientist
Nancy Collins, Software Engineer
Moha El Gharamti, Scientist
Jonathan Hendricks, Software Engineer
Tim Hoar, Associate Scientist
Kevin Raeder, Associate Scientist
Glen Romine, Project Scientist
Elizabeth Chapin, Business Analyst
Elizabeth Faircloth, Administrative Assistant
Kathryn Peczkowicz, Administrative Assistant
Mary Pronk, Administrator

The Data Assimilation Research Testbed Facility : DART

The Data Assimilation Research Testbed (DART), is a software environment for making it easy to match a variety of data assimiliation methods to different numerical models and different kinds of observations. DART has been through the crucible of many compilers and platforms. It is ready for friendly use and has been used in several field programs requiring real-time forecasting. The DART source code is distributed through our anonymous subversion server (meaning you don't need an account on our machines) after you fill out a trivial form asking for your name, email address, and institution. We need to gather summary statistics to maintain an email list should there be an important update and to help us quantify our impact on the community. This is an ultra-low-traffic email list. We have never sent an email to the entire list! Please be assured we will keep your email address confidential.

The "Manhattan" version of DART was released on 15 March 2017. The DART source code and documentation can be downloaded at The most current version of the documentation is (always) distributed with the code, but if you want to take a look before downloading, visit the Manhattan release document.

The most current version of the documentation is distributed with the code, but if you want an idea of what it takes to build DART and run experiments before downloading, look at the Getting Started page.

Ensemble Filters for Geophysical Data Assimilation

animation demonstrating the assimilation schematic
dart download icon

We regularly give tutorials on Ensemble Data Assimilation

IMAGe Theme of the Year (2015):

The Workshop and Tutorial page is available [here].


WRF/DART Tutorial at NCAR: 22 Jan 2014

A WRF/DART Ensemble Data Assimilation Tutorial was taught on 22 January 2014 at NCAR in Boulder, Colorado. The tutorial materials are available [here]. It covered:

  1. Introduction to ensemble DA
  2. Using DART with simple models
  3. Running the WRF/DART assimilation system
  4. Using WRF/DART analysis tools
  5. Examples of WRF/DART ensemble analyses and forecasts

Contact information:

Our central email address is, which will hit 'everyone' and find its way to the best person.
The categories that follow are not set in stone, everyone has some expertise in all areas.

algorithms diagnostics platforms/mpi CAM WRF
Jeff Anderson Tim Hoar Nancy Collins Kevin Raeder Glen Romine
jla @ ucar . edu  thoar @ ucar . edu  nancy @ ucar . edu  raeder @ ucar . edu  romine @ ucar . edu 

Shipping information:

postal address "overnight" deliveries electronic methods
Kathy Peczkowicz Kathy Peczkowicz kathyp @ ucar . edu
NCAR NCAR 303 497 2431
P.O. Box 3000 1850 Table Mesa Dr. 303 497 2483 (FAX)
Boulder, CO 80307-3000 Boulder, CO 80305