Andres Tennus

Professor of Climate Science Piia Post gives inaugural lecture about global air cycle effects on weather in Estonia

On Thursday, 15 February at 16:15, Piia Post, Professor of Climate Science at the University of Tartu, will give the inaugural lecture "Atmospheric circulation as a dance of air across scales and the globe” in the assembly hall. The lecture will describe how the local Baltic Sea region is affected by the air cycle.

The uneven distribution of solar radiation on the Earth triggers the air circulation. Air is ever-moving and all around us. As it moves, it carries both energy and mass at all scales of time and space, from a fraction of a second to years and centuries, from millimetres to tens of thousands of kilometres.

According to professor Piia Post, air is often associated with oxygen essential for life, toxic emissions or greenhouse gases, but the role of air movement in our daily lives is rarely discussed. "It is known that different air masses cause different weather, but less is known about how the air creates motion in seawater and causes its level to fluctuate in the short term. This also explains why the sea is sometimes so shallow that you cannot take a ferry to Hiiumaa, or so high that it invades the streets of Pärnu," Post said.

At our latitudes, both the weather and climate are largely determined by where the air comes from, how long it stays and where it is headed. Fortunately, it is possible to notice a certain regularity in the movement of air. As mid-latitude cyclones move west to east and thunderclouds pulsate in the tropics in a circadian rhythm, it looks like a dance in the air from space. All this shapes the weather and climate, and a better understanding of this dance on its own scale will allow us to describe the climate more reliably. While global warming is foreseeable with a high degree of certainty because of the global radiation balance, there is a lot of uncertainty about what the air circulation will look like in the future climate.

In her inaugural lecture, professor Piia Post will explain the specific effects of synoptic-scale atmospheric circulation on air temperature and precipitation in the Baltic Sea region. The focus of the lecture will be on studies about the impact of air circulation on rare but important phenomena in the Baltic Sea, such as the January storm of 2005 or large salt pulses. The key question is how best to describe something that is essentially incidental.

Piia Post graduated as physicist-educator from the Department of Geophysics of the University of Tartu in 1986. In 1993, she defended her doctoral thesis on cloudiness parameters for describing the climate with the help of satellite measurements.

Since the graduation, she has been working at the Institute of Physics at the University of Tartu and its predecessors as an intern researcher, graduate student, lecturer and associate professor, and, since 1 September 2023, as professor.   She has taught dozens of subjects ranging from general physics to data processing and analysis, and is a leading lecturer in atmospheric and climate physics. In 1994–1995, Piia Post worked at the Institute of Atmospheric Physics at the GKSS Research Centre in Geesthacht, Germany. She later worked for both the Finnish and Estonian weather service and was for many years an associate scientist at the European Organisation for the Exploitation of Meteorological Satellites.

Post is involved in two very important projects for Estonia on future climate adaptation. She is in charge of the multidisciplinary project "Climate Awareness from School to Society: empowering children, youth and teachers to reduce the impacts of climate change" and is leading the preparation of new climate projections for Estonia within the project “Implementation of national climate change adaptation activities in Estonia”. Piia Post is the chair of council of the Estonian Meteorological Society and president of the Estonian Committee of Geophysics, through which she represents Estonia in several international scientific organisations. Also, she is a member of the Baltic Earth Science Steering Group.

A live webcast of the inaugural lecture will be available on UTTV.


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