Difference between revisions of "IC SG4"

From Icctwiki
Jump to: navigation, search
Line 1: Line 1:
−
<big>'''JSG 0.13: Integral equations of potential theory for continuation and transformation of classical and new gravitational observables'''</big>
+
<big>'''JSG 0.4: Coordinate systems in numerical weather models'''</big>
  
−
Chair:''Michal Šprlák (Czech Republic)''<br>
+
Chair:''T. Hobiger (Japan)''<br>
−
Affiliation:''Commission 2 and GGOS''
+
Affiliation:''all Commissions''
  
 
__TOC__
 
__TOC__
−
 
 
===Introduction===
 
===Introduction===
  
−
The description of the Earth's gravitational field and its temporal variations belongs to fundamental pillars of modern geodesy. The accurate knowledge of the global gravitational field is important in many applications including precise positioning, metrology, geophysics, geodynamics, oceanography, hydrology, cryospheric and other geosciences. Various observation techniques for collecting gravitational data have been invented based on terrestrial, marine, airborne and more recently, satellite sensors. On the other hand, different parametrization methods of the gravitational field were established in geodesy, however, with many unobservable parameters. For this reason, the geodetic science has traditionally been formulating various gravitational parameter transformations, including those based on solving boundary/initial value problems of potential theory, through Fredholm's integral equations.
+
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.
−
 
 
−
Traditionally, Stokes’s, Vening-Meinesz’s and Hotine’s integrals have been of interest in geodesy as they accommodated geodetic applications. In recent history, new geodetic integral transformations were formulated. This effort was mainly initiated by new gravitational observables that became gradually available to geodesists with the advent of precise GNSS (Global Navigation Satellite Systems) positioning, satellite altimetry and aerial gravimetry/gradiometry.  The family of integral transformations has enormously been extended with satellite-to-satellite tracking and satellite gradiometric data available from recent gravity-dedicated satellite missions.
 
  
−
Besides numerous efforts in developing integral equations to cover new observables in geodesy, many aspects of integral equations remain challenging. This study group aims for systematic treatment of integral transformation in geodesy, as many formulations have been performed by making use of various approaches. Many solutions are based on spherical approximation that cannot be justified for globally distributed satellite data and with respect to requirements of various data users requiring gravitational data to be distributed the reference ellipsoid or at constant geodetic altitude. On the other hand, the integral equations in spherical approximation possess symmetric properties that allow for studying their spatial and spectral properties; they also motivate for adopting a generalized notation. New numerically efficient, stable and accurate methods for upward/downward continuation, comparison, validation, transformation, combination and/or for interpretation of gravitational data are also of high interest with increasing availability of large amounts of new data.
+
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.
  
 
===Objectives===
 
===Objectives===
  
−
* To consider different types of gravitational data, i.e., terrestrial, aerial and satellite, available today and to formulate their mathematical relation to the gravitational potential.
+
* Understand the horizontal coordinate systems of the different NWMs, ranging from global to small-scale regional models
−
* To study mathematical properties of differential operators in spherical and Jacobi ellipsoidal coordinates, which relate various functionals of the gravitational potential.
+
* Understand the vertical coordinate systems of the different NWMs, ranging from global to small-scale regional models
−
* To complete the family of integral equations relating various types of current and foreseen gravitational data and to derive corresponding spherical and ellipsoidal Green’s functions.
+
* Formulate a clear mathematical description on how to transform between NWMs and a geodetic frame (in both directions)
−
* To study accurate and numerically stable methods for upward/downward continuation of gravitational field parameters.
+
* Summarize these findings in a peer-reviewed paper that will act as a standard for future use of NWM-produced fields.
−
* To investigate optimal combination techniques of heterogeneous gravitational field observables for gravitational field modelling at all scales.
 
−
* To investigate conditionality as well as spatial and spectral properties of linear operators based on discretized integral equations.
 
−
* To classify integral transformations and to propose suitable generalized notation for a variety of classical and new integral equations in geodesy.
 
  
 
===Program of Activities===
 
===Program of Activities===
  
−
* Presenting research results at major international geodetic and geophysical conferences, meetings and workshops.
+
* Launch a webpage for dissemination of information, presentation, communication, outreach purposes.  
−
* Organizing a session at the forthcoming Hotine-Marussi Symposium 2017.
+
* Provide a bibliography.
−
* Cooperating with related IAG Commissions and GGOS.
+
* Conduct working meetings in association with international conferences.
−
* Monitoring activities of JGS members as well as other scientists related to the scope of JGS activities.
+
* Present research results in appropriate sessions.
−
* Providing bibliographic list of relevant publications from different disciplines in the area of JSG interest.
+
* 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.
  
 
===Members===
 
===Members===
  
−
'' '''Michal Šprlák (Czech Republic), chair''' <br /> Alireza Ardalan (Iran) <br /> Mehdi Eshagh (Sweden) <br /> Will Featherstone (Australia) <br /> Ismael Foroughi (Canada) <br /> Petr Holota (Czech Republic) <br /> Juraj Janák (Slovakia) <br /> Otakar Nesvadba (Czech Republic) <br /> Pavel Novák (Czech Republic) <br /> Martin Pitoňák (Czech Republic) <br /> Robert Tenzer (China) <br /> Guyla Tóth (Hungary) <br />''
+
'' '''Thomas Hobiger (Japan), chair'''<br /> Johannes Boehm (Austria)<br /> Tonie van Dam (Luxembourg) <br />Pascal Gegout (France) <br /> Rüdiger Haas (Sweden) <br /> Ryuichi Ichikawa (Japan) <br /> Arthur Niell (USA) <br /> Felipe Nievinski (USA) <br /> David Salstein (USA) <br /> Marcelo Santos (Canada) <br />Michael Schindelegger (Austria) <br /> Henrik Vedel (Denmark) <br /> Jens Wickert (Germany) <br /> Florian Zus (Germany) <br />''

Revision as of 12:27, 2 July 2012

JSG 0.4: Coordinate systems in numerical weather models

Chair:T. Hobiger (Japan)
Affiliation:all Commissions

Introduction

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.

Objectives

  • 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 webpage 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.

Members

Thomas Hobiger (Japan), chair
Johannes Boehm (Austria)
Tonie van Dam (Luxembourg)
Pascal Gegout (France)
Rüdiger Haas (Sweden)
Ryuichi Ichikawa (Japan)
Arthur Niell (USA)
Felipe Nievinski (USA)
David Salstein (USA)
Marcelo Santos (Canada)
Michael Schindelegger (Austria)
Henrik Vedel (Denmark)
Jens Wickert (Germany)
Florian Zus (Germany)

Retrieved from "http://icct.kma.zcu.cz/index.php?title=IC_SG4&oldid=208"