High-impact winter compound events and their links to large-scale atmospheric circulation

0508584 - ÚFA 2020 DE eng A - Abstrakt
Plavcová, Eva - Lhotka, Ondřej - Stryhal, Jan
High-impact winter compound events and their links to large-scale atmospheric circulation.
EMS Annual Meeting Abstracts, Vol. 16. Berlin: European Meteorological Society, 2019.
[EMS Annual Meeting 2019. 09.09.2019-13.09.2019, Copenhagen]
Institucionální podpora: RVO:68378289
Klíčová slova: large-scale atmospheric circulation * lcirculation patterns * extreme winter weather * reanalysis * Central Europe
Obor OECD: Climatic research
https://meetingorganizer.copernicus.org/EMS2019/EMS2019-84.pdf

Compound events of meteorological variables considerably affect various sectors of human society and natural
environment. We focus on winter extreme events since combinations of low temperatures with heavy snowfalls
and/or strong winds (e.g., winter storms and blizzards) represent high-impact weather phenomena for transportation, public health sectors, and many other areas of human activity. We aim to expand the understanding of
extreme winter weather with respect to its driving mechanisms.
In this study, we analyze frequency of winter compound events and their links to large-scale atmospheric
circulation. The study is performed over Central Europe, defined roughly between 48–52◦N and 10–20◦E. This
domain excludes high-altitude mountain ranges (Alps and Carpathians) and therefore has a relatively homogenous
climate. Data from the E-OBS database and the ERA5 reanalysis are analyzed over the 1979-2017 period. Winter
compound events are characterized as various combinations of anomalous temperatures, heavy snowfalls, strong
wind, extreme rain, and sudden temperature changes. The extremes are selected using a modified extremity index
proposed by Lhotka and Kyselý (2015) which takes into account spatial extent and severity of winter extremes.
Large-scale atmospheric circulation is represented by indices (flow direction, strength and vorticity; Jenkinson
and Collison 1977) and classifications derived from circulation patterns produced by the reanalysis. We aim to
find useful methods to detect significant synoptic links in observed climate, which could be subsequently used
as reference for an evaluation of high-impact winter compound events and their driving mechanisms in historical
runs and projections of climate models.
Trvalý link: http://hdl.handle.net/11104/0299450