Spatiο-temporal variability of tropical nights over Greece. The impact of large scale atmospheric circulation patterns and meteorological anomalies on tropical nights

Postgraduate Thesis uoadl:1320800 875 Read counter

Unit:
Κατεύθυνση Πρόληψη και Διαχείριση των Φυσικών Καταστροφών
Library of the School of Science
Deposit date:
2014-09-17
Year:
2014
Author:
Τσινιάρη Ελευθερία
Supervisors info:
Δρ. Νάστος Παναγιώτης, Αν. Καθηγητής Ε.Κ.Π.Α. (Επιβλέπων), Δρ. Τσίρος Ιωάννης, Αν. Καθηγητής Γ.Π.Α., Δρ. Παλιατσός Αθανάσιος, Καθηγητής Τ.Ε.Ι. Πειραιά
Original Title:
Χωροχρονική κατανομή των τροπικών νυχτών στην Ελλάδα. Επίδραση της ατμοσφαιρικής κυκλοφορίας και των συνοπτικών μετεωρολογικών ανωμαλιών
Languages:
Greek
Translated title:
Spatiο-temporal variability of tropical nights over Greece. The impact of large scale atmospheric circulation patterns and meteorological anomalies on tropical nights
Summary:
Tropical nights (TNs) are defined as the days with a minimum air temperature
higher than 20οC. These days are of great significance due to their impact on
humans’ thermal comfort at nights, modulating the quality and quantity of
sleep. This study presents the spatio-temporal variability and trends of TNs
over the Hellenic Peninsula during the period 1951–2004. The daily minimum
temperature time series from 22 stations of the Hellenic National
Meteorological Service (HNMS) network, uniformly covering the Greek region, and
National Centers for Environmental Prediction/National Center for Atmospheric
Research (NCEP/NCAR) reanalysis datasets were used in the analysis. The Annual
Number of Tropical Nights (ANTN) recorded in each of the stations, was analyzed
along with their linkage to the atmospheric circulation indices within the
wider Greek area.
In order to examine the relationship between tropical nights and large scale
circulation, the 95th percentile of TNs was employed, in order to estimate the
composite mean and anomalies of the geopotential heights (m) at 300, 500 and
850hPa level associated with these cases, with respect to 30 years climatology
(1981-2010). It was also investigated if and how the variability of a
particular teleconnection pattern is associated with tropical nights in Greece.
The findings of our analysis shows a significant positive trend pattern over
the domain of study, which is likely due to global warming and the heat island
phenomenon. The beginning of this trend occurred in the late 1970s across most
of the examined sites. Higher trends, however, are detected in the South and
East of Greece.
The large-scale circulation anomalies associated with the TN95 cases reveals
the prevalence of higher than normal geopotential height values throughout the
whole depth of the troposphere over Greece. It was also found that the summer
North Caspian Pattern Index (NCPI) and North Atlantic Oscillation Index (NAOI)
negative phase, inversely affects the minimum temperatures and tropical nights.
Main subject category:
Natural disasters
Other subject categories:
Environment
Klimatology
Meteorology
Cartogrpaphy
Keywords:
Tropical nights, Trends, Geopotential height anomaly pattern, Atmospheric circulation
Index:
Yes
Number of index pages:
9
Contains images:
Yes
Number of references:
135
Number of pages:
148
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