UNION LECTURERS

• DESCRIPTION

  Changes in the climate system have been significant over the last two decades, with most of these years establishing successive records for the warmest global average temperature. There have been significant observed changes in the planetary system, often serving as “the beacons” for the extent and magnitude of climate change stress on environmental and societal systems. This pace of change is anticipated to continue over the next century even with global mitigation efforts outlined in the Paris Agreement and the Montreal Protocol. Earth system sciences have been essential to framing the issues and providing the actionable knowledge to support the call to action, policies and pathways for solutions.  The escalating demands for adaptive actions to support the 2030 Sustainable Development Goals, as outlined by the UN in 2015, will be commensurate with increased efforts among the natural and social science community to inform these actions through furthering understanding, reducing the uncertainties in predicting  the magnitude, extent and consequences of large-scale changes, and informing innovative social, cultural and environmental strategies to harmoniously adapt. The challenges will be formidable.

  By incorporating societal outcomes into its mandate, the World Meteorological Organization (WMO) has been a leader in providing decision and policy makers with a scientific foundation of how the earth system is predicted to change over time. The WMO’s vision includes a world where all nations, especially the most vulnerable, are more resilient to the socioeconomic impact of extreme weather, climate, water and other environmental events. The WMO seeks to achieve its vision by supporting and enabling international collaboration on weather, water and climate activities, working towards a fully-coupled earth system model approach. For example, through meteorological, climatological, and hydrological research activities, the WMO is improving impact-based weather forecasting, water resources management and agricultural sustainability. These directions directly translate into benefits for society and increased resilience and enable the WMO and its Member States to contribute to solutions to the global challenges we are currently facing.

  International political and scientific organizations, including WMO, have to adapt to strengthen their partnerships and become strategically aligned to respond to future human and environmental needs. At the same time, innovation and advances in technology will enable the earth sciences to meet the increasing demand for intelligent, evidence-based decision making that is vital to the global response to rapidly evolving societal impacts posed by environmental change.

• BIOGRAPHY

  David Grimes has been Assistant Deputy Minister and head of Environment Canada's Meteorological Service of Canada since July 2006. He has been Canada's Permanent Representative with World Meteorological Organization since December 2006. David was re-elected President of the WMO by the Seventeenth World Meteorological Congress in 2015 for another four-year term. He has more than 25 years of experience working with WMO initiatives and programmes. He has over 40 years of scientific, operations, research and management experience at Environment Canada. His experience also includes a significant number of challenging positions and assignments over the years, ranging from weather forecast operations to science policy. He occupied the positions of Director General with the Meteorological Service of Canada for 15 years.

   

  David has extensive educational experience in the domains of science and management (MBA level). He holds a Bachelor of Science in physics, mathematics and meteorology.  He has also been trained and carried out the responsibilities as an operational meteorologist.

• DESCRIPTION

  Throughout history, humans have always valued the view from above, seeking high ground to survey the land, find food, assess threats, and understand their immediate environment.  The advent of aircraft early in the 20th century took this capability literally to new levels, as aerial photos of farm lands, hazards, military threats, etc. provided new opportunities for security and prosperity.  And in 1960, with the launch of the first weather satellite, TIROS, we came to know our world in ways that were not possible before, as we saw the Earth as a system of interacting components. In the decades since, our ability to understand the Earth System and its dynamic components has been transformed profoundly and repeatedly by satellite observations.  From examining rapid changes in polar regions, to deformation of the Earth surface, to ozone depletion, to the Earth’s energy balance, satellites have helped us understand our changing planet in ways that would not have otherwise been possible.  The challenge moving forward is to continue to evolve beyond watching Earth processes unfold and understanding the underlying mechanisms of change, to anticipating future conditions, more comprehensively than we do today, for the benefit of society. The capabilities to do so are well within our reach, and with appropriate investments in observing systems, research, and activities that support translating observations into societal value, we can realize the full potential of this tremendous space-based perspective. Doing so will not just change our views of the Earth but will improve our relationship with it.

• BIOGRAPHY

  Waleed Abdalati is Director of the Cooperative Institute for Research in Environmental Sciences (CIRES), a joint institute of the National Oceanic and Atmospheric Administration (NOAA) and the University of Colorado, Boulder (CU-Boulder).  He is also a Professor in CU-Boulder’s Geography Department. Dr. Abdalati's research focuses on the use of satellites and aircraft to understand how Earth's glaciers, ice sheets, and sea ice are changing and the implications of those changes for the Earth System. In 2008, he became Director of the Earth Science and Observation Center, which is a research center within CIRES that focuses on the application of remote sensing observations to understand Earth’s physical and ecological processes. From January 2011 to December 2012, while on leave from CU-Boulder, Abdalati served as NASA Chief Scientist, advising the NASA Administrator on matters related to NASA’s science programs and strategic planning. His career also includes working as an aerospace engineer in industry, a research scientist and branch head at NASA’s Goddard Space Flight Center, and manager of NASA’s Cryospheric Sciences Program at NASA Headquarters. Dr. Abdalati earned a B.S. from Syracuse University and an M.S. and Ph.D. from CU-Boulder. Dr. Abdalati has received various professional awards and distinctions from the White House, NASA, NSF, The American Institute for Aeronautics and Astronautics, etc.

• DESCRIPTION

  Geodesy is an old discipline studying the shape, gravity field, and rotation of the Earth, with conventional techniques such as ground surveying, gravimeters, optical telescopes, tide gauges, strain/tiltmeters. Advent of space geodesy in 1980s replaced these classical sensors with SLR (Satellite Laser Ranging), satellite gravimetry, VLBI (Very Long Baseline Interferometry), DORIS, satellite-borne ocean altimeters, SAR (Synthetic Aperture Radar), and GNSS (Global Navigation Satellite System). Their order-of-magnitude higher accuracy shifted the role of post-1990 geodesy to studies of their “temporal changes”, e.g. crustal deformation (change in shape), mass redistribution (change in gravity), and subtle variations in earth rotation parameters. Multidisciplinary applications of space geodesy revolutionized other fields of earth sciences. Millimeter accuracy of GNSS positioning enabled precise mapping of tectonic plate/block boundaries and rapid determination of fault parameters after earthquakes. It also brought discovery of silent fault slips undetectable with seismometers. Precise determination of the earth’s equipotential surface (geoid) with satellite gravimetry enabled oceanographer to isolate dynamic topography and map ocean currents. Satellite altimetry revealed global mean sea level rise and short-term disturbances caused by water exchange with land, which can also be investigated by satellite gravimetry. Atmospheric water vapor information from GNSS data analyses improved routine numerical weather forecasts. Dual-frequency GNSS receiver became an important tool to study space weather. Satellite gravimetry also let us constrain mass loss of inaccessible mountain glaciers. In this lecture, I pick up various fields of earth sciences and show how geodesy has sharpened them up.

• BIOGRAPHY

  Kosuke Heki is professor in the Department of Earth and Planetary Sciences, Hokkaido University, Sapporo, Japan. He obtained bachelor, master and doctor degrees in geophysics all from University of Tokyo in 1979, 1981, and 1984, respectively. After working in a Very Long Baseline Interferometry (VLBI) team 1984 – 1994 in Kashima Space Research Center (also working as a post-doc 1990-1992 in Durham, UK), he moved to the Earth Rotation Division, National Astronomical Observatory, Mizusawa, in 1994. Since 2004, he has been working as a professor in Hokkaido University. He applies space geodetic techniques for various disciplines in earth and planetary physics, including time-variable gravity for studies of earthquakes and cryosphere, GNSS positioning for slow deformation of the earth, and sensing of upper atmosphere with GNSS. He pioneered geodetic studies of slow fault slips, seasonal crustal deformation, co- and postseismic gravity changes, and ionospheric disturbances associated with earthquakes and volcanic eruptions. He has been serving as the president of the Geodetic Society of Japan since 2015, and as the chair of Science Panel of Global Geodetic Observing System (GGOS), International Association of Geodesy (IAG) since 2018. He was the Bowie Lecturer in the 2011 American Geophysical Union Fall Meeting. He has authored about 140 papers in peer reviewed journals, and his most cited publication is Silent fault slip following an interplate thrust earthquake at the Japan Trench. Nature, , 1997.

• DESCRIPTION

  The strength of the magnetic field is one of the fundamental properties of the Earth, and its behavior over time has implications in disparate fields as geodynamics of archaeology. Thermal remanent magnetization (TRM), has a quasi-linear relationship to the ambient magnetic field applied during cooling and can be reproduced in the laboratory, making absolute paleointensity estimates possible. TRM, of all the forms of remanent magnetization formed in nature, has the strongest theoretical basis thanks to the work of Neel (1949) and Thellier & Thellier (1959).

  Despite the simplicity of TRM theory for ideal, uniformly magnetized grains, there are many complications that make interpretation of paleointensity experimental data difficult. And there are clues in the present data base that things can go very wrong. For example, although we know that directions on the surface of the Earth are well explained by a simple geocentric axial dipole field model the intensity data for even the best studied lava flow (Hawaii, 1960) have estimates spanning the entire range on the surface of the Earth and even higher. We must do better!

  Recent results from micromagnetic modeling, laboratory analogue experiments and new approaches to data selection and field sampling lead to the optimistic view that accurate estimates are achievable. In this lecture I will review where we are, how we got there and where we can go with paleointensity estimates.

   

  Neel, L., Ann. Geophys., 5,99-136, 1949.

  Thellier, E. and Thellier, O., Ann. Geophys. 15, .

   

• BIOGRAPHY

  Lisa Tauxe is a Distinguished Professor of Geophysics at the Scripps Institution of Oceanography, UCSD.  Her research is on the magnetism of geological and archaeological materials, which she uses to solve a variety of geological and geophysical problems.  Her current focus is to understand the behavior of Earth’s magnetic field, in particular its strength, on time scales ranging from the archaeological to planetary time scales.  Tauxe has published over 200 scientific papers and books; her textbook is freely available online and is used by students the world over.  She is a fellow of the American Geophysical Union, the American Association of Arts and Sciences and the Geological Society of America. She won the Benjamin Franklin Medal for Earth and Environmental Sciences and the Arthur L. Day Medal from the Geological Society of America.  She is also a member of the American Academy of the Arts and Sciences and the National Academy of Sciences. She earned her PhD from Columbia University.

   

• DESCRIPTION

  Our understanding of past changes in weather and climate rely on the availability of observations made over many decades. However, billions of historical weather observations are effectively lost to science as they are still only available in their original paper form in various archives around the world. The large-scale digitisation of these observations would substantially improve atmospheric circulation reconstructions back to the 1850s. Recently, volunteer citizen scientists have been assisting with the rescue of millions of these lost observations taken across western Europe over a hundred years ago. The value of these data for understanding many notable and extreme weather events will be demonstrated.

• BIOGRAPHY

  Ed is a climate scientist in the National Centre for Atmospheric Science at the University of Reading, and a Lead Author for the upcoming Intergovernmental Panel on Climate Change 6th Assessment Report. His research examines how and why the climate has changed since the industrial revolution, and how it may change over the coming decades, particularly the interplay between natural climate variations and anthropogenic trends. He also leads Weather Rescue – a citizen science project involving thousands of volunteers – which is recovering millions of lost Victorian-era weather observations from hand-written archives and turning them into invaluable digital data. Ed also actively engages with a variety of audiences about climate change, especially through blogs, social media and graphical visualisations.

• DESCRIPTION

  Harmonic tremor signals appear in seismological records in a far wider context than on volcanoes where they have first been described. Yet, the signals typically share common characteristics: Tremor usually shows an emergent onset and lasts considerably longer than impulsive earthquake signals. Durations range between minutes and months. Harmonic tremor spectra show distinct peaks with a fundamental frequency in many cases in the range of 0.5-5 Hz and a series of harmonic overtones. These frequencies may glide over time, giving seismological tremor records converted into the audible frequency range the appearance of melodic songs. Other commonly observed characteristics are an inverse relation between the tremor amplitude and the fundamental frequency, period doubling and sudden switching into a non-harmonic, chaotic mode. The underlying sources and source mechanisms, however, may be very different: Here, I will present harmonic tremor signals caused by Antarctic icebergs by periodic stick-slip quakes during collision or by fluid flow through narrow cracks. The latter mechanism is frequently used to explain harmonic tremor in volcanoes. I will further present the properties of tidally modulated tremor presumably caused by submarine hydrothermal circulation on a mid-ocean ridge. These tremor signals may easily be confused with harmonic tremor excited by bottom currents acting on the structure of ocean bottom seismometers and thus causing unwanted disturbances in many seafloor seismological records. Finally, even the vibrations of ship hulls couple efficiently into the ground and appear on ocean bottom seismometer records as prominent harmonic tremor.

• BIOGRAPHY

  Vera Schlindwein is a senior scientist at the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research in Bremerhaven, Germany. She received her Diploma degree in geophysics at the University of Munich in 1994, where she worked on harmonic tremor signals of Semeru Volcano, Indonesia. After a first participation on a cruise of RV Polarstern to East Greenland, she moved to the AWI and did her PhD on the crustal architecture of East Greenland, graduating in 1998. After that, she obtained a DAAD and a ERC Marie Curie Fellowship for a two year project at the University of Durham, UK. In 2006, she became leader of an Emmy-Noether Junior Research Group at AWI. Her work since then mainly focused on the seismicity of polar mid-ocean ridges. In 2013 she received the Venia legendi for geophysics at the University of Bremen, where is has been teaching seismology since 2008. She participated in 10 polar expeditions. Unusual seismic signals produced by icebergs, ice floes, volcanoes and hydrothermal systems have always been a fascinating side aspect of her seismicity studies.