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At the beginning of 21st century, Sergej Sergeevich Zilitinkevich initiated shift of the fundamental paradigm in the planetary boundary layer theory, and wider, in statistical hydromechanics of stratified flows. He held the position of the chair in meteorology at Uppsala University, Sweden in 1998—2003, where he and his colleagues consistently introduced a concept of turbulent potential and total energy and not least reviewed fundamental understanding of turbulent mixing in stratified flows. Zilitinkevich continued as a professor-emeritus at University of Helsinki, Finland, in 2004—2021, where he attracted prestigious mega-grants both in Russia and European Union. As such, he created and led a virtual international research institute — the third institute in course of his carrier in science – for development of theoretical foundations and practical implications of the new paradigm for turbulent energies. A network of researchers and practitioners established by Zilitinkevich continue their joint research in the Pan-Eurasian Experiment frameworks., В начале XXI века Сергей Сергеевич Зилитинкевич выступил инициатором смены фундаментальной парадигмы в теории планетарного пограничного слоя, и шире, в статистической гидромеханике стратифицированных турбулентных течений. Руководя знаменитой кафедрой метеорологии в Университете Уппсалы, Швеция (1998—2003), ему и его сотрудникам удалось органически ввести понятия потенциальной и полной энергии турбулентности и пересмотреть основополагающие представления о турбулентном обмене в стратифицированных течениях. Продолжив работать как профессор-эмеритус в Университете Хельсинки, Финляндия (2004—2021), и привлекая престижные мегагранты в России и Европейском Союзе, он, по сути, создал и возглавил виртуальный международный научно-исследовательский институт — третий институт в своей научной карьере — для проработки теоретических основ и практических приложений, которые вытекали из новой парадигмы энергетики турбулентности. Объединённые им ученые и практики продолжают развивать научное наследие Зилитинкевича в рамках Пан-Евразийского Эксперимента.

The northern Eurasian regions and Arctic Ocean will very likely undergo substantial changes during the next decades. The Arctic-boreal natural environments play a crucial role in the global climate via albedo change, carbon sources and sinks as well as atmospheric aerosol production from biogenic volatile organic compounds. Furthermore, it is expected that global trade activities, demographic movement, and use of natural resources will be increasing in the Arctic regions. There is a need for a novel research approach, which not only identifies and tackles the relevant multi-disciplinary research questions, but also is able to make a holistic system analysis of the expected feedbacks. In this paper, we introduce the research agenda of the Pan-Eurasian Experiment (PEEX), a multi-scale, multi-disciplinary and international program started in 2012 (https://www.atm.helsinki.fi/peex/). PEEX sets a research approach by which large-scale research topics are investigated from a system perspective and which aims to fill the key gaps in our understanding of the feedbacks and interactions between the land-Atmosphere-Aquatic-society continuum in the northern Eurasian region. We introduce here the state of the art for the key topics in the PEEX research agenda and present the future prospects of the research, which we see relevant in this context.

Dynamics of atmosphere–ice–ocean interactions in the high latitudes. What: Scientists from 13 countries involved with modeling and observing the coupled high-latitude weather and climate system discussed our current understanding and challenges in polar prediction, extreme events, and coupled processes on scales ranging from cloud and turbulent processes, from micrometers and a few hundred meters to processes on synoptic-scale weather phenomena and pan-Arctic energy budgets of hundreds to thousands of kilometers. Workshop participants also evaluated research needs to improve numerical models with usages spanning from uncoupled to fully coupled models used for weather and climate prediction (http://highlatdynamics.b.uib.no/). When: 23–27 March 2015. Where: Rosendal, Norway

It has been a decade since changes in diurnal temperature range (DTR) globally have been assessed in a stand-alone data analysis. The present study takes advantage of substantively improved basic data holdings arising from the International Surface Temperature Initiative’s databank effort and applies the National Centers for Environmental Information’s automated pairwise homogeneity assessment algorithm to reassess DTR records. It is found that breakpoints are more prevalent in DTR than other temperature elements and that the resulting adjustments have a broader distribution. This strongly implies that there is an overarching tendency, across the global meteorological networks, for nonclimatic artifacts to impart either random or anticorrelated rather than correlated biases in maximum and minimum temperature series. Future homogenization efforts would likely benefit from simultaneous consideration of DTR and maximum and minimum temperatures, in addition to average temperatures. Estimates of change in DTR are relatively insensitive to whether adjustments are calculated directly or inferred from adjustments returned for the maximum and minimum temperature series. The homogenized series exhibit a reduction in DTR since the midtwentieth century globally (-0.044 K/decade). Adjustments serve to approximately halve the long-term global reduction in DTR in the basic “raw” data. Most of the estimated DTR reduction occurred over 1960–1980. In several regions DTR has apparently increased over 1979–2012, while globally it has exhibited very little change (-0.016 K/decade). Estimated changes in DTR are an order of magnitude smaller than in maximum and minimum temperatures, which have both been increasing rapidly on multidecadal timescales (0.186 K/decade and 0.236 K/decade, respectively, since the midtwentieth century).

Недавние публикации обратили внимание на факт недостаточной чувствительности современных климатических моделей к наблюдаемым изменениям приземной температуры воздуха. Для объяснения этого факта требуется найти неучтенный в моделях физический механизм обратной связи, который бы оказывал существенное влияние на повышение чувствительности климата к небольшим изменениям внешнего форсинга. В данной работе формулируется гипотеза о том, что повышенная чувствительность климата может быть связана с изменениями в интенсивности турбулентного перемешивания и равновесной толщине планетарного пограничного слоя (ППС). С определенными упрощениями данная гипотеза позволяет провести количественные оценки ограничений на чувствительность климата, налагаемые обратными связями с ППС. Для получения таких оценок использованы теоретические разработки С. Зилитинкевича и соавторов. Парадоксально, но развитие гипотезы об обратных связях в ППС приводит к выводу, что приземные температуры могут не только расти (быстрее или медленнее) при глобальном потеплении климата, но и в отдельных случаях падать. Причем возможность падения температуры обнаружена в часто наблюдаемом интервале параметров. Обратные связи в ППС позволяют также объяснить наблюдаемую асимметрию в климатическом изменении суточных и сезонных максимальной и минимальной температур воздуха.