JWG C.6: GNSS mass-market devices in climate and environmentalsensing: approaches, opportunities, challenges, and socialimpact

Chair: Tobias Kersten (Germany)
Vice chair: Balaji Devaraju (India)
Affiliations: Commission 4, GGOS

Introduction

At a time of urgent need to combat climate change and promote global cooperation, geo-monitoring with global navigation satellite systems (GNSS) is at the centre of attention. In particular, extreme hydrological and weather situations such as heavy precipitation and floods as well as other hazards such as landslides or rock falls often happen abruptly and are now more frequently observed under climate change conditions. In order to understand the causes and processes of such changes, long-term monitoring is of high importance. This is also the case for other short to long term changes, e.g., of the snow storage, glaciers, soil moisture, water levels, vegetation, atmosphere, and urban environments. In general, we still know too little about inter-relationships of geophysical effects that act in a complex interaction, which is also due to a lack of observations, being often limited by costs, manpower or accessibility. Regarding climate and environmental research, all challenges have one thing in common: they are geo-referenced and closely linked to the need to ensure high precision, reliability and repeatability. GNSS is an efficient instrument in the space segment for already 50 years. With the access to mass market products especially in the last two to three decades, geophysical processes of our planet can be monitored more (cost-)effectively also in the user domain, on different scales, from both local to global andin dimension of different time periods.

In this Joint Working Group, we intend to review and redefine methods using mass-market equipment by which dynamic geophysical processes can be monitored by geodetic means and be made available as products or reliable metrics to other disciplines working primarily in the climate and environmental sector. Central to our work is the essential question that goes beyond mere GNSS position determination: how can we exploit the power of mass-market GNSS equipment and data to meet the complex requirements of climate and environmental processes happening on the Earth surface and the atmosphere, not only achieving centimetre or even millimetre-scale accuracies, which is the main focus of positioning, but also exploring the question of what other quantities and variables in each specific domain can be effectively determined. Examples in this context would be the determination of, e.g., snow water equivalent (using GNSS carrier phases and signal strength measurements), the water vapour content in atmospheric layers as well as atmospheric and ionospheric delay (using carrier phasemeasurements), the wave motion and the sea level height or also the soil moisture, snow height and growth changes of plants and their foliage-effect of trees on GNSS observables (applying e.g., reflected signals). These are all essential variables, whichare largely relevant in climate and environmental research.

As climate change is global phenomena, a key objective of this group is not only to bridge the boundaries of technological innovation, but also to enable collaborations and support knowledge transfer among different countries. We see GNSS technology, especially the mass market equipment, as a catalyst for international collaboration including global technology transfer and capacity building. In this way, we are not only advancing geomonitoring, but also contributing to global efforts to combat climate change and its far-reaching consequences.

Objectives

Our JWG goals involve the use of GNSS technology and geomonitoring in various surroundings ranging from fully natural to urban environments to better understand, prepare for, and adapt to the impacts of climate change, such as extreme hydrological and weather events, rising sea levels, changing precipitation patterns as well as changes in short- and long-term hydrological and cryospheric variables. We focus on monitoring and assessing environmental changes, developing techniques and strategies to make communities and ecosystems more resilient to these challenges.

To achieve our goals, we carefully classify and categorize GNSS units according to their application areas, laying the foundation for seamless integration into globalgeomonitoring networks. We explore the possibilities of interchangeability between high-performance and low-cost GNSS units, emphasizing their potential to make geomonitoring more efficient and cost-effective, in regions with limited resources and others. We go on to analyse the practicality and limitations of using mass-market GNSS units in geophysical and geodetic applications, particularly in the context of climate studies. Spatial and temporal scales, result accuracy, and efficiency will be explored to, highlight the way forward.

• Investigate the limitations and capabilities of mass-market GNSS units, w.r.t.standard or high-end devices, with particular emphasis on their applicability to environmental and climate change studies (different scales and resolution i.e., time and space).
• Extend investigation to positioning quality in static and kinematic contexts as applicability to environmental and climate change studies.
• Assessing and finding ways to potentially improve the precision and reliability of mass-market GNSS instruments to meet the critical requirements of geophysical applications.
• Provide a comprehensive overview and classification of GNSS units based on their application areas. Distinguish the unique characteristics of mass-market GNSS units and highlight their potential to make geomonitoring more efficient and cost-effective,especially in resource-limited regions
• Evaluate interchangeability and interoperability among high-performance, mass-market GNSS units to ensure seamless integration into global geomonitoringnetworks.
• Promote the use of GNSS technology as a tool to democratize science for international cooperation, technology transfer for effective geomonitoring, and augment climate change adaptation strategies..

Program of Activities

The following activities shall be performed:

• Ice breaking and closing workshops
• Organising sessions at conferences (such as EGU, AGU, etc.) and (hybrid) splinter meetings
• Commission work (regular meetings)
• Annual webinars on that topic
• Paper / technical report (white paper and/or journal paper) on topics like e.g. reviewand categorization of devices as well as fields of application / table of scalability vs.precision, field work hints
• Enable the possibility for writing joint research proposals
  

Members

• Franziska Koch (Austria)
• Robert Odolinski (New Zealand)
• Jens-André Paffenholz (Germany)
• Kristine M. Larson (USA)
• Inese Varna (Latvia)
• Shivam Tripathi (India)
• Jacek Paziewski (Poland)
• Yong Chien Zheng (New Zealand)
• Felipe Geremia-Nievinsk (Brazil)
• Makan Karegar (Germany)
• Yuanxin Pan (Switzerland)
• Günter Retscher (Austria)