Snow Cover Changes in the Little Carpathians in Slovakia

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SNOW COVER CHANGES IN THE LITTLE CARPATHIANS IN SLOVAKIA

Lapin M. 1, Faško P.2

1Div. of Meteorology and Climatology, KAFZM, FMFI, Comenius University, Bratislava, SK-84248 Slovakia, E-mail: [email protected], Web: www.dmc.fmph.uniba.sk 2Slovak Hydrometeorological Institute, Bratislava, SK-83315 Slovakia E-mail: [email protected], Web: www.shmu.sk

Abstract: The Little Carpathians represent relatively isolated 80 km long mountains in south-western Slovakia with mean altitude of their ridge about 600 m and steep slopes. Observations from 20 stations have been utilized for areal and temporal snow cover analysis (3 of them with complete observations since 1921 and 6 since 1951, all other stations have shorter periods of observations, insignificantly interrupted series, or they have already closed their operation). After analysis of selected series we came into conclusion to reconstruct daily snow cover time series from October 1950 to April 1990 and from October 1990 to April 2004 (without and with influence of supposed climate change). The results showed that in spite of significant increase in temperature means and some decrease in precipitation totals in the November to March season no remarkable decrease in snow cover conditions occurred after 1990. Only selected results are presented in this extended abstract.

Keywords: climate change, variability, snow cover

1. INTRODUCTION

The Little Carpathians represent relatively isolated 80 km long mountains in south-western Slovakia (Fig. 1 left) with mean altitude of their ridge about 600 m a.s.l. and steep slopes. This mountain is surrounded by flat lowlands in the North-west and South-east with altitudes from 130 to 200 m a.s.l. The city of Bratislava lies at the southwestern edge of mountains. Also other parts of its surroundings are densely populated (more than one mil. inhabitants). That is why the Little Carpathians are very frequently visited by tourists, mainly in winter. The snow conditions are influenced there by relatively high winter precipitation totals and by temperatures near the freezing point. For example precipitation total at the Modra station (SE foot, 168 m a.s.l.) is 243 mm in the November to March season and 250 mm from May to August, while annual mean total is 696 mm for the 1901–1990 period. Mean January temperature is about -1.5°C at the southern foot of mountains and about -4.0°C in the 600 m altitude. Mean snow cover depth in 600 m altitude is about 35 cm with about 80% probability of occurrence in top winter (end of January to end of February), while near the Bratislava city it is only about 12 cm with 55% probability of occurrence by the end of January. Absolute snow cover depth maximum is about 100 cm at the ridge (measured maximum – 119 cm in February 1931) and about 50 cm at the foot of mountains (all from previous snow conditions elaboration (see references))

2. METHOD AND RESULTS

Observations from 20 stations have been utilized (Tab. 1). After analysis of selected series we came into conclusion to reconstruct temporal and areal changes in snow cover conditions for the periods from winter 1921/22 to 1949/50 (6 stations), from 1950/51 to 1989/90 (19 stations) and from 1990/91 to 2003/04 (16 stations), supposing that only the last one was significantly influenced by supposed climate change, IPCC, TAR (2001). Significant trends in air temperature means can be seen in Fig. 1 right (about 1.5°C increase in the November–March season since 1951 – this season was selected for snow conditions analysis, because of insignificant snow cover in October and April – Fig. 3 left).

658 Table 1. List of utilized stations and elaborated snow cover characteristics (Sum – mean sum of daily snow cover depths in the winter season, M SC – mean winter snow cover depth calculated from days with snow cover t1 cm, Max – maximum of daily snow cover depth in the whole selected period and the datum of maximum occurrence), * - selected period was insignificantly completed using data from other stations or there was extrapolated shorter series of observation (see comments at the foot), SE and NW – the station lies to the southeast or to the northwest from the ridge of the Little Carpathians. Station Altitude/ Measurements Winters Days Sum M SC Max Datum * calculated Location From To N N [cm] [cm] [cm] Vývrat 365 / NW XI.1921 IV.1950 29 64.3 959.2 14.9 88 7.2.1931 Vývrat* 365 / NW X.1950 IV.1990 40 56.0 748.3 13.4 71 21.2.1956 Kuchyna 252 / NW XI.1921 IV.1950 29 52.1 640.7 12.3 66 12.1.1945 Kuchyna 252 / NW X.1950 II.1990 40 46.1 432.6 9.4 70 19.2.1952 Kuchyna 236 / NW X.1990 III.2004 14 34.6 290.1 8.4 35 28.12.1993 10.3.2004 Kosariská* 380 / NW X.1950 VI.1990 40 70.6 1223.2 17.3 75 18-20.2.1952 Borinka* 230 / NW XII.1950 II.1990 40 57.0 590.9 10.4 65 18-19.2.1952 Borinka 226 / NW X.1990 III.2004 14 44.1 649.4 14.7 60 26.2.1993 Kacín* 297/ NW X.1950 IV.1990 40 61.9 1067.5 17.2 77 7.3.1970 Devín. N.V. 154 / NW XII.1950 II.1990 40 33.0 293.1 8.9 79 16.2.1952 Devín. N.V. 140 / NW X.1990 III.2004 14 27.1 186.0 6.9 40 14.2.1999 Br., Devín 169 / NW XII.1950 II.1990 40 37.7 339.8 9.0 73 18.2.1952 Br., Devín 156 / NW X.1990 III.2004 14 32.6 252.4 7.7 34 28.2.1993 Br., Kamzík 410 / SE X.1950 III.1990 40 74.7 1260.1 16.9 83 4.2.1963 Br., Kamzík 403 / SE X.1990 III.2004 14 53.1 847.0 16.0 65 20-21.2.1996 Mlyn. Dolina* 182 / NW X.1950 IV.1990 40 47.2 563.7 12.0 44 16.1.1987 Mlyn. Dolina 182 / NW X.1990 III.2004 14 40.6 349.6 8.6 30 28.12.1993 Mudronova 246 / SE X.1950 II.1990 40 44.5 486.0 10.9 55 15.1.1987 Mudronova 246 / SE X.1990 III.2004 14 42.2 477.9 11.3 35 28-29.1.1996 BR, Koliba 286 / SE I.1951 III.1990 40 53.9 639.2 11.9 71 24.1.1987 BR, Koliba 286 / SE X.1990 III.2004 14 56.2 634.6 11.3 38 29.3.1993 28.12.1993 BR, Airport 131 / SE I.1951 II.1990 40 30.3 268.5 8.9 58 22.2.1956 BR, Airport 131 / SE X.1990 III.2004 14 35.4 356.5 10.1 36 29-30.1.1996 14.2.1996 Limbach 1 315 / SE XI.1921 III.1950 29 76.9 1625.6 21.1 83 9.2.1931 Limbach 1 315 / SE X.1950 II.1990 40 60.2 851.7 14.1 87 21-22.2.1956 Limbach 1* 315 / SE X.1990 IV.2004 14 52.4 809.1 15.4 80 14.2.1996 Limbach 2* 181 / SE X.1990 IV.2004 14 37.2 371.1 10.0 29 14.2.1996 M. Javorník* 586 / SE X.1950 IV.1990 40 83.5 1227.3 14.7 81 27.1.1987 M. Javorník 586 / SE X.1990 IV.2004 14 79.1 1484.6 18.8 99 14-15.3.1996 Biely Kríz* 495 / SE X.1950 IV.1990 40 66.2 1099.5 16.6 75 27.1.1987 Mod. Piesky* 533/ SE X.1950 IV.1990 40 99.1 1696.1 17.1 90 27.1.1987 Mod. Piesky* 533/ SE X.1990 IV.2004 14 89.2 1611.3 18.1 94 14.3.1996 Panský D.* 479/ SE X.1921 IV.1950 29 93.3 3007.8 32.2 119 16-17.2.1931 Panský D.* 479/ SE X.1950 IV.1990 40 77.7 1769.3 22.8 80 27.1.1987 Modra 190/ SE XI.1921 III.1950 29 55.2 683.6 12.4 64 16.2.1940 Modra 206 / SE III.1950 III.1990 40 42.7 395.3 9.3 56 23.2.1956 Modra 168 / SE X.1990 III.2004 14 34.4 279.2 8.1 28 28.1.1996 Buková 336/ SE X.1990 III.2004 14 42.1 429.4 10.2 77 29.12.1996 Smolenice 241 / SE XI.1921 III.1950 29 56.8 619.3 10.9 46 25.2.1946 Smolenice 241 / SE X.1950 II.1990 40 49.3 478.4 9.7 60 4.3.1970 Smolenice 228 / SE X.1990 III.2004 14 43.4 478.1 11.0 42 20.2.1996

Comments: Complete observations: Vývrat – 1921-1980, Košariská – 1950-1970, Kacín – 1950-1980, BR Mlynská Dolina – 1982-2004, Limbach – 1921-2003 (moved in 1990), Biely Kríz – 1958-1973 (near Malý Javorník), Modra Piesky – 1988-2004, Panský Dom – 1926-1936, Buková – 1986-2004.

659 T[°C] Mean air temperature T at stations Hurbanovo (115) and Br. Koliba (286) and sum of precipitation R R[mm] at Modra (168) and Kuchyna (206) in the November-March seasons (1926 = 1925/26) Poland 6 800 Czech Republic HU T BK T MO R KU R 4 700 T LŠ 2 600 1000 PO

0 500

SL -2 400

300 R -4 300

Hungary Austria BR -6 200 HU -8 100

-10 0 Slovak Republic, contour lines 300 and 1000 m a.s.l., location of selected stations 1921 1926 1931 1936 1941 1946 1951 1956 1961 1966 1971 1976 1981 1986 1991 1996 2001

Figure 1. Left - map of Slovakia with contour lines 300 and 1000 m altitude, and selected stations HU (Hurbanovo), BR (Bratislava), and marked rectangle of analyzed area in the Little Carpathians; Right – November – March air temperature means T[°C] and at the stations HU in 1920/21-2003/04 and BR Ko- liba in 1951/52-2003/04, and precipitation totals at the stations Kuchyna (NW foot) and Modra (SE foot) in 1920/21-2003/04.

[cm, N] Winter snow cover maximum depths [cm], sum of daily snow cover depths [in 10 cm] and number of days [cm, N] Winter snow cover maximum depths [cm], sum of daily snow cover depths [in 10 cm] and number of days with snow cover [N] at Modra in winters 1921/1922 to 2003/2004 with snow cover [N] at Bratislava Koliba in winters 1951/1952 to 2003/2004 270 270 Max Max 240 Number 240 Number Sum 210 210 Sum Max Trend Max Trend Number Trend 180 180 Number Trend Sum Trend Sum Trend 150 150

120 120

90 90

60 60

30 30

0 0 1952 1954 1956 1958 1960 1962 1964 1966 1968 1970 1972 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 1922 1924 1926 1928 1930 1932 1934 1936 1938 1940 1942 1944 1946 1948 1950 1952 1954 1956 1958 1960 1962 1964 1966 1968 1970 1972 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004

Figure 2. Snow cover maximum (columns [cm]), number of snow cover days (simple line) and sum of daily snow cover depths (top lines, [10 cm]) at the stations Modra (left) in 1921/22-2003/04 winters and BR Koliba (right) in 1951/52-2003/04 winters, including power trends.

Means and probability of snow cover (SC) occurrence, and absolute maximum of SC calculated for callendar pentades SC [cm] Percentiles of daily snow cover (SC) depths at Bratislava Koliba station 75 in callendar pentads for 1951-2004 Bratislava Koliba, 1951-2004 40 70 Dec 6 is for December 26 - December 31 Dec 6 is for December 26 - December 31 d9 [cm] 65 Mean SC [cm] Probability of SC [%] 35 q3 [cm] 60 Max SC [cm] q2 [cm] 55 30 q1 [cm] 50 d1 [cm] 45 25 40 35 20 30 25 15 20 15 10 10 5 5 0 0 Apr 1 Apr 2 Apr 3 Apr 4 Apr 5 Okt 5 Okt 6 Jan 1 Jan 2 Jan 3 Jan 4 Jan 5 Jan 6 Feb 1 Feb 2 Feb 3 Feb 4 Feb 5 Feb 6 Mar 1 Mar 2 Mar 3 Mar 4 Mar 5 Mar 6 Nov 1 Nov 2 Nov 3 Nov 4 Nov 5 Nov 6 Nov 1 Dec 2 Dec 3 Dec 4 Dec 5 Dec 6 Dec eb 1 eb 2 eb 3 eb 4 eb 5 eb 6 an 1 an 2 an 3 an 4 an 5 an 6 Apr 1 Apr J J J J J J F F F F F F 1 Mar 2 Mar 3 Mar 4 Mar 5 Mar 6 Mar Nov 4 Nov 5 Nov 6 Dec 1 Dec 2 Dec 3 Dec 4 Dec 5 Dec 6

Figure 3. Bratislava Koliba station: Left –winter course of mean snow cover depths SC[cm] calculated from the days with SC t1 cm for calendar pentads, absolute maximum of daily SC depths and mean probability of SC occurrence in the calendar pentads from the end of October to the end of April; Right - at the stations HU, PO and LŠ, and at 850 hPa level* (2 h. p.m.) in 1951-2004 (; 71-2004)*; Right – percentiles of daily snow cover depths (upper decile, upper quartile, median, lower quartile, lover decile) calculated for calendar pentads from the middle of November to the beginning of April (the calendar pentad in October: 1 – from Oct. 1st to 5th, 2 – from Oct. 6th to 10th, … 6 – from Oct. 26th to 31st, etc).

660 SC[cm] Snowcover depth in the Little Carpathians in winter 1995/96 (stations MJ - M. Javornik, BK - B.Koliba and LE - B.Airport) SC[cm] Snowcover depth in the Little Carpathians in winter 1997/98 (stations MJ - M.Javornik, BK - B.Koliba and LE - B.Airport) 100 20

90 18

80 16

70 LE 14 MJ LE 60 12 BK MJ 50 10 BK 40 8

30 6

20 4 10 2 0 0 9.1.1996 8.2.1996 9.3.1996 8.4.1996 19.1.1996 29.1.1996 18.2.1996 28.2.1996 19.3.1996 29.3.1996 18.4.1996 4.1.1998 3.2.1998 5.3.1998 4.4.1998 31.10.1995 10.11.1995 20.11.1995 30.11.1995 10.12.1995 20.12.1995 30.12.1995 14.1.1998 24.1.1998 13.2.1998 23.2.1998 15.3.1998 25.3.1998 5.12.1997 15.11.1997 25.11.1997 15.12.1997 25.12.1997

Figure 4. Bratislava Airport (columns, LE), Malý Javorník (top line, MJ) and Bratislava Koliba (BK) – daily snow cover depths in winter 1995/96 (left, one of the highest since 1950) and in winter 1997/98 (right, one of the lowest since 1950).

From the presented snow characteristics in Table 1 it can be seen that except the stations Bratislava Koliba and Bratislava Airport (Borinka and Malý Javorník at sum of daily snow cover depths) all stations show decrease of snow cover after 1990. The most significant decrease occurred in the north western and northern part of the Little Carpathians (even more than by 30%). Increase of snow cover in the south eastern part of Bratislava since 1990 needs to be analyzed more in details. Figures 1 right and 2 show that one of the possible reason could be change in atmospheric circulation, because precipitation in the Little Carpathians is very sensitive to direction of atmospheric currents. Complete study on snow conditions in the Little Carpathians will be published in 2005.

3. CONCLUSION

Presented paper shows only a brief study on climate change detection in Slovakia using snow cover data from as much dense stations network as possible. Winter weather conditions occurred in the 1991– 2004 period were in Slovakia very unusual with several exceptional events also at snow cover. We will try to compare obtained results with characteristics from other Slovak regions (regular snow cover observations are to disposal from about 180 stations since 1921, about 400 stations since 1951 and more than 600 stations since 1961).

Acknowledgments: The authors are grateful to the Grant Agency of the Slovak Republic (project VEGA No. 1/1042/04) for supporting this study and to the Slovak Hydrometeorological Institute in Bratislava for offering climatological data.

REFERENCES

Climatic and Phenological Conditions of the West Slovakia Region. Hydrometeorological Institute, Pra- gue 1968, 343 pp. (in Slovak) Faško, P., Handzák, Š., Lapin, M., 1997: Selected Snow Cover Characteristics Change in the Low Tatras Region in Slovakia in 1921-1995. Slovak National Climate Program, 7/97, MZP SR and SHMÚ, Bratislava, 46-67. (in Slovak) Faško, P., Lapin, M., 1997: Brief Snow Cover Conditions in Bratislava in the second hals of the 20th Century. Bulletin SMS at SAV, VIII, No. 1, SHMÚ, Bratislava, 8-10. (in Slovak) IPCC, TAR, 2001: Climate Change 2001: The Scientific Basis. Contribution of Working Group I to the Third Assessment Report of the IPCC. Cambridge Univ. Press, UK, 944 p. Variability of Snow Cover Conditions in the Czechoslovak Carpathians in 1921-1985. Zborník prác SHMÚ, 34, Alfa, Bratislava 1991, 176 pp. (in Czech).

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