Dr. Svenja Bierstedt

Svenja Bierstedt

Küsteneinflüsse und Paläoklima
Svenja Bierstedt
Wissenschaftlerin
Tel: +49 (0)4152 87-1824
Fax: +49 (0)4152-87-2818
E-Mail Kontakt

since 01/2016
PostDoc at Institute of Coastal Research, Helmholtz-Zentrum Geesthacht, Germany

08/2012 - 12/2015
PhD student at Institute of Coastal Research, Helmholtz-Zentrum Geesthacht, Germany

08/2012 - 12/2015
Doctoral Program of School of Integrated Climate System Sciences (SICSS)

10/2009 – 07/2012
MSc. Meteorology at Free University of Berlin, Germany

10/2006 – 09/2009
BSc. Meteorology at Free University of Berlin, Germany

Project REKLIM

Doctoral Candidate of the School of Integrated Climate System Sciences SICSS within the Cluster of Excellence "Integrated Climate System Analysis and Prediction" (CliSAP)

Supervisors

Influence of atmospheric patterns on extrema over the Iberian Peninsula compared to preindustrial climate variability

The study investigates climatic changes for SRES-A1B in the Iberian Peninsula. The atmospheric circulation patterns, heat waves and droughts of this region are analyzed. The data originates from the coupled global atmosphere-ocean general circulation model ECHAM5/MPIOM. Three SRES scenarios 19C (1871-1900), 20C (1971-2000) and A1B (2071-2100) where each includes three transient model simulations and a control run are analyzed. The control run simulates an atmosphere which remains constant in the preindustrial greenhouse gas conditions for 505 years. The classification tool COST733 is used to determine 26 atmospheric circulation patterns by the method of Jenkinson and Collison (1977). Using the local 95th summer percentile (April to October) of the 2m temperature a heat wave index (HWI) is defined which allows statements about intensity and duration of heat waves during summer months (April to October). The precipitation data of 20C which is used as a reference served for anomaly calculations. Significant changes in frequency and persistence are found for some circulation patterns specifically the eastern ow patterns increase in frequency and persistence. It is also shown that both temperature and precipitation change in the A1B scenario is out of natural climate variability. The identification of dry and wet circulation patterns shows a significant change in A1B. This change can be blamed for the increasing dryness of the future scenario. The changed ow pattern alone, however, does not explain the increase in temperature. It is believed that increasing soil moisture in addition to circulation change and global warming contributes to heat intensification.

The relationship between wind storms and cyclones

The positions of wind fields with regard to the causing cyclones is examined and it is searched for a reason for the different positions. Due to the speed of displacement and the mostly southern position of the fronts there it is assumed that cyclones predominately causes wind fields to the south of their cores. This supposition is confirmed in the present work. Systems which evoke a storm field to the north of its core were localized mostly in northern latitude (> 60° N). For both kinds of wind fields a secondary maximum could be found in the Mediterranean. Hence the investigation area was divided in nine areas and the respective positions of the wind fields refer to the cyclones were shown graphically. The basic results of this study are the smaller number of the north fields,the mostly northern position of the cyclones with north wind fields and the knowledge that north wind fields mostly originate in a later development stage than south fields. The latter is based on a case study with 30 wind fields. It could be found that south fields in most cases originate at cold fronts and north fields at occlusion fronts. Proximate the temporal connection between wind fields and the life cycle of the cyclones was examined. Furthermore the strongest period of cyclone's life was checked with three parameters:the pressure trend, the core pressure and the laplacian of the pressure. Moreover for the different areas of the investigation area the life span and the way of the cyclones were compared. Another part of the work deals with the features of north wind fields and southern wind field.
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