CYCLONIC ACTIVITY OVER THE TERRITORY OF BELARUS UNDER ...€¦ · CYCLONIC ACTIVITY OVER THE...
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CYCLONIC ACTIVITY OVER THE TERRITORY OF BELARUS UNDER CURRENT CLIMATE CONDITIONS Inna Semenova (1), Katsiaryna Sumak (2) Vienna, 2017 (1) Odessa State Environmental University, Ukraine [email protected] (2) Center of Hydrometeorology and Control of Radioactive Contamination and Environmental Monitoring, Minsk, Belarus [email protected] 0 2 4 6 8 10 12 14 16 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 South West North-west Amount of cases Frequency of cyclones over the territory of Belarus (1995-2015) 950 960 970 980 990 1000 1010 1020 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 South West North-west Min P, hPa Interannual variability of pressure in cyclones over Belarus (1995-2015) 975 980 985 990 995 1000 1005 January February March April May June July August September October November December South West North-west Min P, hPa Seasonal variability of pressure in cyclones over Belarus (1995-2015) INTRODUCTION OBJECTIVE OF STUDY WEST CYCLONES Trajectories of cyclones through the territory of Belarus (1995 - 2015) SOUTH CYCLONES Trajectories of cyclones through the territory of Belarus (1995 - 2015) NORTH - WEST CYCLONES Trajectories of cyclones through the territory of Belarus (1995 - 2015) region of formation region of filling region of formation region of filling region of formation region of filling Cyclones are the main synoptic processes, which determine the complicated weather conditions and precipitation regime in the middle latitudes. Intensity of cyclonic activity in the center of Europe depends on dynamics of main baric centers in atmosphere of the North Atlantic (described by NAO) and location of main tropospheric flows. Therefore the current climate changes might influence to trajectories and intensity of cyclones. The Republic of Belarus is located in the center of Eastern Europe, therefore most of cyclones in this part of the continent are passing over its territory. For the territory of Eastern Europe, as well as for Belarus, three main types of cyclone trajectories are characteristic: west, north-west and south cyclones. First of them are formed under the zonal type of atmospheric circulation, the rest – under the meridional atmospheric processes. The main objective of the study is analysis of trajectories and frequency of cyclones, which moved by the territory of Belarus during the period of 1995- 2015. At present, there is not enough climatic information about these processes. During the studied period 329 cyclones moved over the territory of Belarus. So, about 15-16 cyclones per year affected the weather conditions. 22% were of western and northwestern types of cyclones separately, 56% constituted southern cyclones. The maximum number of all types of cyclones (21-23 cases per year) observed in 1998, 2004, 2008 and 2009. Minimum of cyclone activity (about 10 cases) was in 2015. Mean pressure in the center of cyclones over the territory of Belarus composed about 992 hPa for the western and northwestern types and about 997 hPa for the southern cyclones. 0 1 2 3 4 5 6 7 8 9 1995-1999 2000-2004 2005-2009 2010-2015 Spring Summer Autumn Winter Amount of cases 0 2 4 6 8 10 12 14 Amount of cases Frequency of west cyclones over Belarus (1995-2015) 0 2 4 6 8 10 12 1995-1999 2000-2004 2005-2009 2010-2015 Spring Summer Autumn Winter Amount of cases 0 2 4 6 8 10 12 14 16 January February March April May June July August September October November December Amount of cases Frequency of north-west cyclones over Belarus (1995-2015) 0 2 4 6 8 10 12 14 16 18 20 1995-1999 2000-2004 2005-2009 2010-2015 Spring Summer Autumn Winter Amount of cases Interannual variability of south cyclones frequency in certain periods 0 5 10 15 20 25 January February March April May June July August September October November December Amount of cases Frequency of south cyclones over Belarus (1995-2015) The western cyclones frequently moved over the territory of Belarus in March and in December. The north-western cyclones most observed in January and in February. The amount of southern cyclones more evenly distributed within a year. The most cases observed in warm season – in July, April and May. Minimum of southern cyclones occurred in January and December. The most of western cyclones, which moved over the territory of Belarus formed between 50N and 60N over regions of the Northwest Atlantic, the British Isles, the North Sea and south of the Baltic Sea. The main feature of these cyclones is a change of trajectories after the crossing of Belarus, further the most of cyclones turned toward northeast, but few number moved southward. The southern cyclones came to the territory of Belarus from all the Mediterranean regions, the Balkan Peninsula, the Black Sea and from Ukraine. The northwestern cyclones generally formed over the Norwegian Sea and moved through Scandinavia to the territory of Belarus, where the significant part of them turned toward northeast. The evaluation of zonal flow using the ECBI (European Continental Blocking Index, Semenova, 2013) showed that most part of west cyclones (78%) shifted under the stable west flow (ECBI<0) and without blocking episodes over Eastern Europe during the studied period. 13% cases of west cyclones were accompanied by a rearrangement of the high-altitude field from meridional to zonal flow and vice versa. North-western cyclones (60% cases) moved to the territory of Eastern Europe with the predominance of west flow on high-altitude field. However, the rest of them formed under the blocking processes (ECBI>0), or were accompanied under the meridional rearrangement of the high-altitude field of pressure. South cyclones (38% cases) went to the territory of Eastern Europe under the blocking processes, 45% of cyclones moved under the stable zonal flow. And 16% cases of south cyclones were accompanied by a rearrangement of the high-altitude field of pressure, that was revealed by the sign change of blocking index ECBI. DATA AND METHODS We used two types of data. For the period 1995- 2003 - ECMWF ERA-Interim Reanalysis (1.5×1.5°), interval 6h; 2004-2015 – surface pressure field of Offenbach weather center (Germany), interval 6h. The obtained results we visualized on the basis of a graphic package GMT (Generic Mapping Tools) (http://gmt.soest.hawaii.edu/). RESULTS OF STUDY ECBI-1995-2015 -1,0 -0,5 0,0 0,5 1,0 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 References 1. Semenova I.G. (2013). Regional atmospheric blocking in the drought periods in Ukraine. Journal of Earth Science and Engineering. V.3 (5). P. 341-348 Thus, the study showed, that cyclonic activity over the territory of Belarus under current climate conditions was very intensive that indicated by high frequency of cyclones. Meridional circulation is a pattern, which occurred often over the Eastern Europe in current period. In the limiting cases, formation and movement of cyclones by quasi-meridional trajectories indicated the end of blocking of atmospheric flow . It follows that the blocking processes were also observed often over the Eastern Europe during the study period. In the near future, we plan to assess the grade of zonality flow (using the blocking index ECBI) and set when blocking actually begins in the synoptic concept. Moreover, we will calculate the intensity of blocking (for all types of cyclones), dividing the gradation of the index ECBI. CONCLUSIONS
Transcript of CYCLONIC ACTIVITY OVER THE TERRITORY OF BELARUS UNDER ...€¦ · CYCLONIC ACTIVITY OVER THE...
CYCLONIC ACTIVITY OVER THE TERRITORY OF BELARUS UNDER CURRENT CLIMATE CONDITIONSInna Semenova (1), Katsiaryna Sumak (2)
Vienna, 2017 (1) Odessa State Environmental University, Ukraine [email protected]
(2) Center of Hydrometeorology and Control of Radioactive Contamination and Environmental Monitoring, Minsk, Belarus [email protected]
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2
4
6
8
10
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16
1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015
South West North-west
Amou
nt o
f cas
es
Frequency of cyclones over the territory of Belarus (1995-2015)
950
960
970
980
990
1000
1010
1020
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
South West North-west
Min
P, h
Pa
Interannual variability of pressure in cyclones over Belarus (1995-2015)
975
980
985
990
995
1000
1005Ja
nuar
y
Febr
uary
Mar
ch
April
May
June July
Augu
st
Sept
embe
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Oct
ober
Nov
embe
r
Dece
mbe
r
South West North-west
Min
P,h
Pa
Seasonal variability of pressure in cyclones over Belarus (1995-2015)
INTRODUCTIONOBJECTIVE OF STUDY
WEST CYCLONESTrajectories of cyclones through the territory of Belarus (1995-2015)
SOUTH CYCLONESTrajectories of cyclones through the territory of Belarus (1995-2015)
NORTH-WEST CYCLONESTrajectories of cyclones through the territory of Belarus (1995-2015)
region of formation region of filling region of formation region of filling region of formation region of filling
Cyclones are the main synopticprocesses, which determine thecomplicated weather conditions andprecipitation regime in the middle latitudes.Intensity of cyclonic activity in the center ofEurope depends on dynamics of mainbaric centers in atmosphere of the NorthAtlantic (described by NAO) and location ofmain tropospheric flows. Therefore thecurrent climate changes might influence totrajectories and intensity of cyclones.
The Republic of Belarus is located in thecenter of Eastern Europe, therefore mostof cyclones in this part of the continent arepassing over its territory.
For the territory of Eastern Europe, aswell as for Belarus, three main types ofcyclone trajectories are characteristic:west, north-west and south cyclones. Firstof them are formed under the zonal type ofatmospheric circulation, the rest – underthe meridional atmospheric processes.
The main objective of the study is analysis oftrajectories and frequency of cyclones, which movedby the territory of Belarus during the period of 1995-2015. At present, there is not enough climaticinformation about these processes.
During the studied period 329 cyclones moved over theterritory of Belarus. So, about 15-16 cyclones per yearaffected the weather conditions. 22% were of westernand northwestern types of cyclones separately, 56%constituted southern cyclones. The maximum number ofall types of cyclones (21-23 cases per year) observed in1998, 2004, 2008 and 2009. Minimum of cyclone activity(about 10 cases) was in 2015.
Mean pressure in the center of cyclones over the territory ofBelarus composed about 992 hPa for the western andnorthwestern types and about 997 hPa for the southerncyclones.
0
1
2
3
4
5
6
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8
9
1995-1999 2000-2004 2005-2009 2010-2015
Spring Summer Autumn Winter
Amou
nt o
f cas
es
0
2
4
6
8
10
12
14
Amou
ntof
cas
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Frequency of west cyclones over Belarus (1995-2015)
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4
6
8
10
12
1995-1999 2000-2004 2005-2009 2010-2015
Spring Summer Autumn Winter
Amou
nt o
f cas
es
0
2
4
6
8
10
12
14
16
January February March April May June July August September October November December
Amou
nt o
f cas
es
Frequency of north-west cyclones over Belarus (1995-2015)
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2
4
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10
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1995-1999 2000-2004 2005-2009 2010-2015
Spring Summer Autumn Winter
Amou
nt o
f cas
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Interannual variability of south cyclones frequency in certain periods
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10
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January February March April May June July August September October November December
Amou
nt o
f cas
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Frequency of south cyclones over Belarus (1995-2015)
The western cyclones frequentlymoved over the territory of Belarusin March and in December. Thenorth-western cyclones mostobserved in January and inFebruary. The amount of southerncyclones more evenly distributedwithin a year. The most casesobserved in warm season – in July,April and May. Minimum ofsouthern cyclones occurred inJanuary and December.
The most of western cyclones,which moved over the territory ofBelarus formed between 50N and60N over regions of the NorthwestAtlantic, the British Isles, the NorthSea and south of the Baltic Sea.The main feature of these cyclonesis a change of trajectories after thecrossing of Belarus, further themost of cyclones turned towardnortheast, but few number movedsouthward. The southern cyclonescame to the territory of Belarusfrom all the Mediterranean regions,the Balkan Peninsula, the BlackSea and from Ukraine. Thenorthwestern cyclones generallyformed over the Norwegian Seaand moved through Scandinavia tothe territory of Belarus, where thesignificant part of them turnedtoward northeast.
The evaluation of zonal flow using the ECBI (EuropeanContinental Blocking Index, Semenova, 2013) showed thatmost part of west cyclones (78%) shifted under the stablewest flow (ECBI<0) and without blocking episodes overEastern Europe during the studied period. 13% cases ofwest cyclones were accompanied by a rearrangement ofthe high-altitude field from meridional to zonal flow and viceversa. North-western cyclones (60% cases) moved to theterritory of Eastern Europe with the predominance of westflow on high-altitude field. However, the rest of them formedunder the blocking processes (ECBI>0), or wereaccompanied under the meridional rearrangement of thehigh-altitude field of pressure. South cyclones (38% cases)went to the territory of Eastern Europe under the blockingprocesses, 45% of cyclones moved under the stable zonalflow. And 16% cases of south cyclones were accompaniedby a rearrangement of the high-altitude field of pressure,that was revealed by the sign change of blocking indexECBI.
DATA AND METHODSWe used two types of data. For the period 1995-2003 - ECMWF ERA-Interim Reanalysis (1.5×1.5°),interval 6h; 2004-2015 – surface pressure field ofOffenbach weather center (Germany), interval 6h.The obtained results we visualized on the basis of agraphic package GMT (Generic Mapping Tools)(http://gmt.soest.hawaii.edu/).
RESULTS OF STUDY
ECBI-1995-2015
-1,0
-0,5
0,0
0,5
1,0
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
References1. Semenova I.G. (2013). Regional atmospheric blocking in the drought periods in
Ukraine. Journal of Earth Science and Engineering. V.3 (5). P. 341-348
Thus, the study showed, that cyclonic activity over the territory ofBelarus under current climate conditions was very intensive thatindicated by high frequency of cyclones.
Meridional circulation is a pattern, which occurred often over theEastern Europe in current period. In the limiting cases, formation andmovement of cyclones by quasi-meridional trajectories indicated theend of blocking of atmospheric flow. It follows that the blockingprocesses were also observed often over the Eastern Europe duringthe study period.
In the near future, we plan to assess the grade of zonality flow(using the blocking index ECBI) and set when blocking actually beginsin the synoptic concept. Moreover, we will calculate the intensity ofblocking (for all types of cyclones), dividing the gradation of the indexECBI.
CONCLUSIONS
