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JWG C.1: Climate Variability and Climate Change in Earth Orientation Parameters

Chair: Henryk Dobslaw (Germany)
Vice chair: Jolanta Nastula (Poland)
Affiliations: Commission 3, IERS, GGOS

Introduction

Earth orientation parameters comprising variations of both the position of the rotational pole and the spin rate are precisely observed by modern space geodetic techniques for several decades. In addition, optical astrometric observations extending back in time over more than 100 years carry information about the mass transport and mass distribution processes acting on Earth at historical times that might be explored to quantify slow and subtle variations in the Earth’s climate due to both natural variability and anthropogenic impacts.This working group will study the various contributors of the global and interactively coupled climate system to the observed changes of the Earth’s orientation on time-scales from days to centennials. It will explore possibilities to validate numerical climate models and its individual components by means of assessing the angular momentum budget and the associated torques. The working group will further investigate present-day uncertainties of various Earth system state and flux variables in order to attribute residual (i.e., yet unexplained) signals in polar motion and changes in the length-of-day, and assess time-scales for potentially skillfull forecasts of Earth orientation parameters with numerical models.

Objectives

  • Exploring temporal limits of predictability of individual Earth orientation parameters with (partially) coupled climate models
  • Quantification of contributions from various components of the (anthropogenically altered) Earth’s system to rotational variations on time-scales from days to centennials
  • Assessment of angular momentum budgets of global numerical climate and Earth system models

Activities

  • Regular online working group seminars as well as in-person meetings aligned to major conferences
  • Establishment of “best practices” for deriving angular momentum and torque estimates from numerical climate model data
  • Contributions to the future development of the Global Geophysical Fluid Centre (GGFC) of the International Earth Rotation and Reference Systems Service (IERS)

Members

  • Christian Bizouard (France)
  • Sigrid Boehm (Austria)
  • Lara Boerger (Germany)
  • Benjamin Fong Chao (Taiwan)
  • Masato Furuya (Japan)
  • Yavor Chapanov (Bulgaria)
  • Jianli Chen (China)
  • Alberto Escapa (Spain)
  • José Manuel Ferrandiz (Spain)
  • Laura Fernandez (Argentina)
  • Richard Gross (USA)
  • Sébastien Lambert (France)
  • Arya Paul (India)
  • David Salstein (USA)
  • Michael Schindelegger (Germany)
  • Adam Scaife (Great Britain)
  • Florian Seitz (Germany)
  • Justyna Sliwinska (Poland)