Workshop Program & Presentations Schedule (in PDF)

Sunday 22 April 2018

Welcome Reception 19:00

Monday 23 April, 2018

9:00- 9:40  Opening Session.

09:40-10:20 Session 1: Fiducial Reference Measurements for Altimetry and Metrology.
Chairs: Craig Donlon, Stelios Mertikas

The concept of Fiducial Reference Measurements for Altimetry. Why it is important? Altimeter measurement equation and uncertainties. The uncertainty budget of all FRM instruments and derived results over the entire end-to-end duration of a satellite mission. Procedures in satellite altimetry so that results are traceable to SI-units, reliable in the long term, comparable worldwide to support an objective and unquestionable monitoring of the Sea Level and Climate Change.

10:20-10:40 Coffee Break

10:40-12:00 Session 1: Fiducial Reference Measurements for Altimetry and Metrology.
Chairs: Craig Donlon, Stelios Mertikas

The concept of Fiducial Reference Measurements for Altimetry. Why it is important? Altimeter measurement equation and uncertainties. The uncertainty budget of all FRM instruments and derived results over the entire end-to-end duration of a satellite mission. Procedures in satellite altimetry so that results are traceable to SI-units, reliable in the long term, comparable worldwide to support an objective and unquestionable monitoring of the Sea Level and Climate Change.

12:00-12:30 Panel Discussion.
Chairs: Craig Donlon, Stelios Mertikas

What, Why and How FRM for Altimetry? How metrology and fundamental standards are to help establish guidelines for Cal/Val uncertainty? How to monitor Oceans, Inland Waters, and Polar Regions in an Objective, Homogeneous and Continuous manner?

12:30-14:00 Lunch

14:00-15:40 Session 2: Past and Current International Cal/Val Activities.
Chairs: Bruce Haines, Pascal Bonnefond

Determining uncertainties in the fundamental instrument observations and in the Level-2 geophysical data products is a continuing process that involves participation of both the project teams and the scientists. The principal objectives of joint verification are to: 1) assess the performance of the measurement system, including the altimeter and orbit-determination subsystems; 2) improve ground and on-board processing; 3) enable a seamless and accurate connection between the past, current and future missions. To succeed in these objectives, the general approach is to pool the talents and resources of the project and science teams. Engaging the science teams in the continuous Cal/Val effort has been one of the hallmarks of success for the TOPEX/Poseidon and Jason altimeter programs.

Cal/Val activities are conducted based on dedicated in-situ observations, statistics, cross comparisons between models, different algorithms and external satellite data. The studies go well beyond validation of the overarching error budget underlying the mission requirements. They focus in particular on the temporal and geographically correlated characteristics of the errors. Reduction of this class of errors is critical, since they are conspicuously damaging to estimates of ocean circulation and sea level. Cal/Val activities also encompass issues related to data return, such as data editing and flagging. Participants from all Cal/Val infrastructure of the world (European Space Agency, EUMETSAT, NASA, CNES, Indian Space Research Organization, China, France, Greece, Australia, India, Japan, Brazil, Spain, United Kingdom, Germany, etc.) are to get involved in this Session.

15:40-16:10 Coffee Break

16:10-17:15 Session 2: Past and Current International Cal/Val Activities.
Chairs: Mingsen Lin, Christopher Watson

17:15-18:00 Panel Discussion.
Chairs: Bruce Haines, Pascal Bonnefond

Various constituents contributing to Val/Val uncertainties? How each individual Cal/Val team addresses them? How to set the foundations for International Cal/Val Altimetry standardization?

Tuesday 24 April, 2018

9:00-10:40 Session 2: Past and Current International Cal/Val Activities.
Chairs: Christopher Watson, Denise Dettmering

10:40-11:10 Coffee Break

11:10-12:10 Session 3: Evaluating Uncertainties for Earth Observation with Metrology Standards.
Chairs: Aloke K. Mathur, Ambrus Kenyeres

Define requirements and establish standards and provide recommendations and best practices for altimerty calibration such that all measurements and results made for monitoring the Earth, the environment, the sea level, etc., are well-characterized and linked to other areas of science and technology through a world’s measurement system established and maintained under the International System of Units and Metrology Standards.

12:10-12:30 Panel Discussion.
Chairs: Christopher Watson, Elizabeth Laier English

Variations between transponder, sea-surface, absolute, relative, inland waters and polar calibrations. Guidelines for expressing uncertainty in Cal/Val. Best practices and transparent protocols.

12:30-14:00 Lunch

14:00-15:40 Session 4: Calibration of Future Satellite Altimetry.
Chairs: Lee-Lueng Fu, Pierre Féménias

Satellite altimetry was developed in the 1970s-80s to advance the science of geodesy and oceanography on global scales. Its calibration and validation (CalVal) had been focused on the absolute height of sea surface at a few selected sites. Because of the stringent measurement accuracy requirement for oceanography, altimetry CalVal has been extended to the measurement accuracy at various scales. The ultimate goals of altimetry in oceanography is to demonstrate that the sea surface height (SSH) measurement can be related to the ocean surface topography, defined as the difference between the SSH and the geoid, after the corrections for the measurement errors as well as the effects of high-frequency motions (period shorter than ~ 1 day) on SSH. The goals of CalVal for oceanography are then focused on the accuracy of the ocean surface topography.

The oceanographic goals of future missions like SWOT are to extend the observations of ocean surface topography to 2 dimensions over wavelengths shorter than 150 km, posing significant challenges to CalVal. Over these wavelengths, the effects of high-frequency motions become difficult to remove by models. In-situ observations are required to assess their impacts on the validity of the ocean surface topography.Over the past decade, the utility of satellite altimetry for land hydrology has been recognized. The storage of lakes and discharge of rivers are part of the science goals of future missions like SWOT. CalVal of altimetry over land waters on scales of 1 km and less requires new ideas and commitments. Moreover, the spatial resolution of the future missions will make altimetry measurement ever closer to the boundary of land and sea, making CalVal right at the coast, including estuaries, an important task.

A key legacy of the past altimetry record is the establishment of a benchmark to detect the effects of climate change in the future. Therefore a challenge in the CalVal is to define and document procedures, protocols and best practices to maintain satellite altimetry observations to support the Earth Observation for the future, such as those of Sentinel-3, Sentinel-6/Jason-CS, SWOT, CFOSAT, ICESat-2, Sentinel-9, etc.

15:40-16:10 Coffee Break

16:10-17:40 Session 5: Maintaining the EO Climate Record from altimetry & ESA Climate Change Initiative.
Chairs: Robert Cullen, Lee-Lueng Fu

What do we need for calibration future altimeter missions? How can we work together to achieved this? Are we agreed about the FRM methods? How do we compare methods at different Cal/Val sites? What do we need to maintain the Earth Observation climate data record from altimetry? Do we have the right setup for the job? What are the threats, opportunities and challenges to address in the next 20 years of altimetry?

17:40-18:10 Panel Discussion.
Chairs: Robert Cullen, Lee-Lueng Fu

Framework for future altimetry missions in terms of their calibration (Ku-band, Ka-band, X-band, wide swath, SAR, LRM, radiometer, etc.). Needs for new measurements and instrumentation. Synergy with other non-altimetry missions. Practical guidelines for future Cal/Val sites. 

Wednesday 25 April, 2018

9:00-10:30 Session 6: The Changing Environment.
Chairs: Roland Pail, Xiaoli Deng, Michael Sideris

With the ever increasing spatio-temporal resolution and improved accuracy of geodetic sensors, new target areas can be approached and new contributions to neighboring disciplines can be achieved with geodetic monitoring. This session invites contributions from studies which employ modern geodetic sensors to monitor and observe natural hazards and the Earth' changing environment on multiple-scales. The geodetic sensors used may include GNSS, satellites (altimetry, SAR, gravimetric), spaceborne and airborne Lidar, gravimetry, tide gauges and buoys, and surveying based on and/air/ship-borne platforms. Primary target areas include natural hazards due to earthquake cycles, volcanoes, subsidence and deformation of the Earth' surface, sea level change, Arctic/Antarctic change, sea ice dynamics, melting of glaciers and ice sheets, permafrost change and flooding. Secondary targets involve changes in the Earth' environmental systems; vegetation, geomorphology, urban environments, surface water, avalanches and snow cover, rivers and lakes. It should be emphasized that this session will focus on integrated studies covering both geodetic sensors and target systems rather than focusing on improvements of sensors or numerical modelling of systems alone.

10:30-11:00 Coffee Break

11:00-12:00 Session 7: Polar Regions Applications.
Chairs: Lars Stenseng, Petr Knudsen

This Session is to focus on topics like: Altimetric challenges caused by sea ice and ice debris; Modelling mean sea surface, mean dynamic topography, and gravity field from altimetry in a noisy environment; Limited observations for validation; Closing the polar gap, etc.

12:00-12:30 Panel Discussion.
Chairs: Lars Stenseng, Petr Knudsen, Ole Andersen

Coastal Altimetry and Polar regions requirements for altimetry calibration. Wind, Wave and Extreme value calibration. Model and Reference Surface calibration and validation.

12:30-14:00 Lunch

14:00- Free Afternoon.
Archeological Excursion in the Chania Old Town: Guided Walking Tour: Walk through centuries and explore the culture and religious influence of several civilizations (Ancient Greek but also Venetian, Jewish, and Turkish) in city’s architecture.

19:00-21:00 Gala Dinner

Thursday 26 April, 2018

9:00-10:00 Session 8 & 9: Modelling with Altimetry: Bathymetry, Geoid, Sea Level, Gravity, Heights & GGOS.
Chairs: Ole B. Andersen, Denise Dettmering

Space-based Earth observations by satellite altimetry have evolved to operational remote sensing techniques with important interdisciplinary applications to many Geosciences. This session focuses on potential and already realized applications of this technique, latest results and new developments with specific impact to geodetic science. Topics to be covered in this session include, but are not limited to (1) precise mapping and monitoring the oceans on different scales (sea level rise, surface currents, tides, storm surges, etc.) (2) improvement in marine gravity modelling by refined analysis of altimetry data or by combination with other data sets, (3) using satellite altimetry for bathymetry mapping, and (4) inland water applications of satellite altimetry.

10:00-10:30 Coffee Break

10:30-11:20 Session 8 & 9: Modelling with Altimetry: Bathymetry, Geoid, Sea Level, Gravity, Heights & GGOS.
Chairs: Ole B. Andersen, Denise Dettmering

Space-based Earth observations by satellite altimetry have evolved to operational remote sensing techniques with important interdisciplinary applications to many Geosciences. This session focuses on potential and already realized applications of this technique, latest results and new developments with specific impact to geodetic science. Topics to be covered in this session include, but are not limited to (1) precise mapping and monitoring the oceans on different scales (sea level rise, surface currents, tides, storm surges,etc.) (2) improvement in marine gravity modelling by refined analysis of altimetry data or by combination with other data sets, (3) using satellite altimetry for bathymetry mapping, and (4) inland water applications of satellite altimetry.

 11:20-12:30 Session 10: International Cal/Val Review Summary and Conclusions.
Chairs: Rob Cullen, Stelios Mertikas

Round Table: Scientific and Operational Roadmap for Satellite Altimetry Cal/Val

• Critically review the current methodology applied at the Permanent Facilities for satellite altimetry calibration and validation using ground-based measurements;
• Define requirements, establish standards and provide recommendations and best practices for altimerty calibration such that all measurements and results made for monitoring the Earth, the environment, the sea level, etc., are well-characterized and linked to other areas of science and technology through a world’s measurement system established and maintained under the International System of Units and Metrology Standards;
• Document procedures for Fiducial Reference Measurements in satellite altimetry so that results are traceable to SI-units, reliable in the long term, comparable worldwide, to support an objective and unquestionable monitoring of the Sea Level and Climate Change;
• Establish procedures and protocols for characterizing the uncertainty budget of all FRM instruments and derived results over the entire end-to-end duration of a satellite mission;
• Define and document procedures, protocols and best practices to evaluate differences in instrument performances under a range of conditions to maintain satellite altimetry observations, to support the Earth Observation for the future;
• Summarize all scientific achievements for satellite altimetry Cal/Val and its applications in the context of Fiducial Reference Measurements.