Professor Sergej Zilitinkevich, a great scientist and leader of numerous international research projects, passed away on Monday, 15 February 2021 after a lengthy illness.
At the age of 84, Prof. Zilitinkevich was still a very energetic and clear-thinking scientist, playing a key role in many ongoing international research projects, inspiring collaborations and promoting research findings. Just a few days before his death, he had discussions with colleagues in different countries, making plans for what to work on after the pandemic.
Prof. Zilitinkevich’s research focused on the theory of geophysical and astrophysical turbulence, boundary layer meteorology, the physics of the hydrosphere, and the Earth’s and planetary atmospheres. His garnered many international prizes and awards for that research, including the Vilhelm Bjerknes (2000) and Alfred Wegener (2015) medals of the European Geophysical Union, and the most prestigious IMO Prize (2019) for outstanding contributions to meteorology, climatology, and research in related fields.
He graduated from the Leningrad State University in 1959 as a physicist and earned his Ph.D. in 1962. He was appointed the Head of the Laboratory of Air Pollution of the Main Geophysical Observatory (Leningrad, USSR) in 1964. In 1966, he founded, and became the head of, the Leningrad Branch of the Institute of Oceanology of the USSR Academy of Sciences. Having earned a second academic degree of Doctor of Science in 1968, Prof. Zilitinkevich initiated inter-institutional cooperation in physics of the atmosphere and the ocean through annual workshops. In the 1970s, he served as the leader of the sub-programme on planetary atmospheres of the Soviet Space Research Programme Venera (Venus) and as the Chair of the Soviet Commission on Air–Sea Interaction. In 1972, he became Professor of Geophysics at the Leningrad State University.
Prof. Zilitinkevich published more than 200 papers and 9 books on topics such as planetary boundary layers, air-sea interaction, environmental turbulence, general circulations of the Earth’s and planetary atmospheres, theory of climate, and physical aspects of modelling water ecosystems. His first book, Dynamics of the Atmospheric Boundary Layer, published in 1970, withstood the passage of time and contains many ideas that remain innovative today. In 1972, he published intensively on Boundary-Layer Meteorology. In 2007, a hardcopy Special Issue of Atmospheric Boundary Layers: Nature, Theory, and Application to Environmental Modelling and Security was published to mark the Professor’s 70th birthday. The papers in that Special Issue reported the results from studies by Prof. Zilitinkevich and his scientific school.
In 1990, he became a visiting Professor at the Wind Energy Department of the RISØ National Laboratory in Denmark. Thereafter, he worked in several German academic institutions (1991–1997): leading and coordinating a number of research projects with the Max Planck Institute for Meteorology (Hamburg), the University of Hamburg, the Alfred Wegener Institute for Polar and Marine Research (Bremerhaven), and the Institute for Hydrophysics at GKSS Research Centre (Geesthacht). In 1998, he was elected Professor and Chair of Meteorology at Uppsala University, Sweden, where he worked until his retirement in 2003.
His retirement from Uppsala University opened a new and fruitful line for his research activities. Prof. Zilitinkevich joined the Finnish Meteorological Institute as Marie Curie Chair (2004). Shortly after, he became the Research Director at the Institute of Atmospheric and Earth System Research, University of Helsinki, Finland. He continued with the coordination of research projects funded by the European research programmes, including a prestigious Advanced Research Grant of the European Research Centre. Beginning in 2012, he was also a Chief Scientist of the International Pan-Eurasian Experiment, a scientific programme involving research groups from Western Europe, China, Japan and Russia, focused on Climate Change and Global Pollution.
From 2011, Prof. Zilitinkevich worked both in Finland and in Russia. He was the leader of several joint Russian–European research projects, including a mega-grant of the Government of the Russian Federation. He founded and was the head of the Laboratory of the Planetary Boundary Layer Physics of the N. I. Lobachevsky State University of Nizhni Novgorod. He also worked at the Moscow State University, the Tyumen State University, and the Institute of Geography of the Russian Academy of Sciences.
Among his numerous outstanding scientific achievements, only a few can be mentioned. The Zilitinkevich formula for the depth of the stably stratified planetary boundary layer is often referred to without citing the original publications, it is simply called his name. The Zilitinkevich correction to the rate equation for the depth of a convectively mixed layer, and the resistance and heat and mass transfer laws for geophysical turbulent flows are also widely known. Those results have paved the way for improved theories and parametrizations of boundary layers in geophysical flows.
Prof. Zilitinkevich remains a truly outstanding representative of the Russian, German, and Nordic scientific schools. His scientific contributions have, to a large extent, shaped present-day boundary-layer meteorology. He was an excellent mentor, prodigal of novel ideas for his students. He supervised more than 20 Ph.D. students, some become his collaborators and co-authored his publications. Apart from tackling particular problems, he always taught his students to develop a broad scientific outlook, an innovative and nonconventional way of thinking, and (not the least) lucid writing skills. All of that takes time, and in both time and effort, he was exceptionally generous with his students.
Prof. Zilitinkevich is a brilliant example of service to science and the irresistible desire to know the world around us, of striving for scientific understanding of fundamentals of the Earth System, and of deep respect for the centuries-old values and traditions of humanity. He will be greatly missed by the international scientific community, his colleagues, friends and family.