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The growing season in Carpathian region during 1961-2010
Olesya Skrynyk 1, Yurii Nabyvanets 2, Valeriya Savchenko 3 and Oleg Skrynyk 2
1 National University of Life and Environmental Sciences of Ukraine, Kyiv, Ukraine ( [email protected] ), 2 Ukrainian Hydrometeorological Institute, Kyiv, Ukraine ( [email protected], [email protected] )
3 Taras Shevchenko National University of Kyiv, Kyiv, Ukraine ([email protected])
14th EMS Annual Meeting & 10th European Conference on Applied Climatology (ECAC) | 06 – 10 October 2014 | Prague, Czech Republic
Introduction• The growing season along with seasons of other threshold temperatures (0 oC, 10 oC, 15 oC) are very important for different sectors of national economy.
• They are very important for climatological studies because they can be considered as a good indicators of climate change.• The objective of our work is to study features of the growing season (GS) in Carpathians regions during period of 1961-2010 years and reveal their possible changes.
References1. http://eca.knmi.nl/images/indices/GSL.png.2. Ped D., 1951: Definition of Dates of Steady Passage of Air Temperature through Certain Limits, Rus. Meteorol. Gidrol.,10:
38-39.3. Sladek I., 1989: Urcovani nastupu a ukonceni svorenych teplot vzduchu metodou souctovych rad odchylek.
Meteorologichne zpravy, Vol. 42.4. Skaggs RH, Baker DG, 1985: Fluctuations in the length of the growing season in Minnesota. Clim Change, 7: 403–414
Data and data processing• The area of interest included longitudes from 17oE till 27oE, latitudes from 44oN till 50oN.• Gridded data of mean and minimum daily air temperature obtained in a frame of the CARPATCLIM project were used to
calculate the beginning, end and length of the GS.• The beginning, the end and the length of the GS were calculated in every point of 0.1o X 0.1o grid and for every year of
1961-2010 period.• To obtain reliable results and with the purpose of comparison the beginning and the end of the GS were calculated by
means of three different methods which are most often used in similar studies.• Obtained time series were averaged over two periods 1961-1990 and 1981-2010. Anomalies of GS characteristics (1981-
2010 against 1961-1990) were calculated to answer a question what changes were observed.• Negative anomalies mean tendency to decrease the GS. That is, negative anomalies of the beginning of the GS mean shift
toward later dates; negative anomalies of the end of the GS mean shift toward earlier dates. • Besides, air temperature for every grid point and for every day of year was averaged over mentioned time periods. Then,
dynamical maps of averaged daily air temperature were built to study relative contribution of circulation factors in the formation of the beginning and end of the GS separately in 1961-1990 and 1981-2010.
Calculating methods for beginning/ending of season• European Climate Assessment (ECA) method (http://eca.knmi.nl/images/indices/GSL.png). Referred below as (I).
Frequently used in the European countries. Calculations are based on daily mean air temperature• Sladek’s (Ped’s) method (Sladek, 1989; Ped, 1951). Referred as (II). Frequently used in countries of the former USSR .
Calculations are based on daily mean air temperature• Method (see e.g. Skaggs and Baker, 1985), referred as (III). Frequently used in the USA and Canada. Calculations are
based on daily minimum air temperature
Results
• T
he e
nd o
f the
GS
• T
he b
egin
ning
of t
he G
S•
The
leng
th o
f the
GS
Fig. Dates of the beginning, the end and the length of the GS and their anomalies (days)
Conclusion • GS characteristics depend strongly on method used to calculate the beginning and end of the season. Differences remain even after time averaging over 30-year period.
• All methods basically give increasing of the growing season length over bigger part of studied area excepting mainly Carpathian mountains.
• Increasing of the season length is mainly due to a shift of its beginning toward more earlier dates. The end of the GS remains mainly unchanged.
• Circulation factors play more important role (comparing with radiation factors) during formation of the beginning of the season. In the autumn it seems to be vice versa.
• The most important factor what defines the growing season in the studied area is Carpathian mountains. They are a natural barrier, which stops warm air moving from south and west in Spring and cold air moving from north and east in Autumn.
