IMAGe Theme Of the Year

IMAGe’s Theme Of the Year (TOY) is a series of activities that explore the opportunity to enrich both applied mathematics and the geosciences through a common scientific topic. TOY is designed to advance research and education between the mathematical and geosciences communities; it uses targeted projects for building interdisciplinary communities. The topics are selected by the IMAGe external advisory panel and coordinated by one or more visiting co-directors. The yearly TOY programs support CISL’s education imperative to integrate research and education, sparking collaborations between the mathematics community and Earth System scientists.

Glen Romine teaching
Dr. Glen Romine, a project scientist with a joint appointment between NCAR’s MMM and CISL laboratories makes a point about numerical weather forecasting during the tutorial part of the Frontiers in Ensemble Data Assimilation workshop. Glen is also a member of the NCAR team testing a real-time ensemble forecasting system for forecasting storms. These ensemble forecasts are an operational and practical use of the DART assimilation software presented in this tutorial.

For 2015 the TOY focused on data assimilation through two events: STATMOS Summer School in Data Assimilation (18-21 May 2015) and Frontiers in Ensemble Data Assimilation for Geoscience Applications (3-7 August 2015). Data assimilation (DA) refers to a class of methods that link physical and probability models with the goal of inference or prediction for often complex, nonlinear dynamical systems. In applied mathematics this area is referred to as inverse problems or Bayesian hierarchical models. Applications are many and include geophysical sciences, engineering, and computational sciences.

Perhaps the most visible application at NCAR is weather forecasting where a physical model for the atmosphere is updated by observations to give a better estimate of the atmospheric state. Typically, neither the model or the observations on their own are adequate for forecasting. However, their combination through DA often gives an improved estimate of the atmosphere.

One hurdle for entry into DA applications and research is the difficulty of creating software to work with large and realistic geophysical models. The Data Assimilation Research Testbed (DART) is a software environment developed and supported in CISL to provide a tool for DA research. It has been very successful in allowing graduate students, university faculty, and other scientific groups to apply DA in novel ways without the substantial investment of engineering a new software system. One of the TOY goals was to offer tutorials for students to learn how to use DART.

Both the school and workshop provided a mathematical/statistical introduction to a variety of data assimilation techniques, talks on current research, and also a DART tutorial. Presenting DART in a lab setting allowed students to get hands-on experience using this software with Matlab-based analysis tools to study results. The school in May was partly sponsored by the NSF-DMS Research Network for Statistical Methods for Atmospheric and Oceanic Sciences (STATMOS). This research group is comprised mainly of statistical and data scientists and the activity reached a group that is not well engaged in DA. Thus, the goal of this school was to stimulate more interest in DA research within a mathematical community.

The workshop in August also included more technical material on new directions for DA and featured 13 presentations by scientists from national research labs, NCAR, and U.S. and international universities.

For the coming year, a TOY is planned on the analysis of climate extremes including the probability models that can represent rare events. Philippe Naveau, LSCE-CNRS, France, will co-direct this theme and will be visiting NCAR for a year on a sabbatical leave. The elements of this TOY will focus on bringing some key visitors that represent the areas of climate, statistics, probability, and machine learning. Besides organizing an independent workshop at NCAR to synthesize ideas, this program will also partner in the organization of three other international conferences. Of particular interest is involving statisticians more closely in the attribution of extreme weather events through participation in the International Detection and Attribution Group, held annually at NCAR.

Outreach activities of the Theme of the Year are supported by NSF Core funding, and the STATMOS summer school was partly sponsored by the NSF-DMS Research Network for Statistical Methods for Atmospheric and Oceanic Sciences.