IAC-SG 12: Coordinate systems in numerical weather models
Chair: T. Hobiger (Japan)
Affiliation: Comm. 3,1,2,4
Numerical weather models (NWMs) contain valuable information that is relevant for a variety of geodetic models. Currently no clear description exists regarding how to deal with the NWM coordinate systems when carrying out the calculations in a geodetic reference frame. The problem can be split into two questions: First, how to relate the horizontal NWM coordinates, which are in most cases geocentric coordinates, derived initially from either Cartesian or spectral representations, properly into an ellipsoidal/geodetic frame? Second, how to transform the NWM height system into elliptical heights as used within geodesy? Although some work has been already done to answer these questions, still no procedures, guidelines or standards have been defined in order to consistently transform the meteorological information into a geodetic reference frame.
The study group will categorize the NWM coordinate systems, create mathematical models for transformation and summarize these findings in a peer-reviewed paper that will act as guidelines for those who intend to utilize NWM information. In addition, it will be necessary to define such transformations in both ways, in order to enable the assimilation of geodetic measurements into meteorological models as well. Moreover, the study group will deal with the issue of surface data contained in NWM and how this information can be consistently used.
- Understand the horizontal coordinate systems of the different NWMs, ranging from global to small-scale regional models
- Understand the vertical coordinate systems of the different NWMs, ranging from global to small-scale regional models
- Formulate a clear mathematical description on how to transform between NWMs and a geodetic frame (in both directions)
- Summarize these findings in a peer-reviewed paper that will act as a standard for future use of NWM-produced fields.
Program of activities
- Launch a web-page for dissemination of information, presentation, communication, outreach purposes; provide a bibliography
- Conduct working meetings in association with international conferences; present research results in appropriate sessions
- Organize workshops dedicated mainly to problem identification and to motivation of relevant scientific research
- Produce at least one peer-reviewed paper that presents a clear and consistent description of how to transform information from and to NWMs, and the relevance of different NWM structures, and, if possible, a second paper that deals with the uncertainty of the NWM related coordinate information will be considered.
- Thomas Hobiger (Japan, Chair)
- Johannes Boehm (Austria)
- Tonie van Dam (Luxembourg)
- Pascal Gegout (France)
- James Foster (USA)
- Ruediger Haas (Sweden)
- Ryuichi Ichikawa (Japan)
- Dan MacMillan (USA)
- Arthur Niell (USA)
- Felipe Nievinski (USA)
- David Salstein (USA)
- Marcelo Santos (Canada)
- Michael Schindelegger (Austria)
- Henrik Vedel (Denmark)
- Jens Wickert (Germany)
- Florian Zus (Germany)