ESTIMATION SNOW RESERVES IN THE UKRAINIAN CARPATHIANS

Transcription

1 ESTIMATION SNOW RESERVES IN THE UKRAINIAN CARPATHIANS Gryshchenko V. 1, Aksyuk O. 1, Shcherbak A. 1, Tavrov Y. 2 1 Ukrainian Hydrometeorological Research Institute Kyiv, Ukraine 2 Kyiv Slavonic University Kyiv, Ukraine uhmi@uhmi.org.ua, tavrov@ukr.net Abstract The purpose of the work was clarification of possibility the exactest estimation of water reserve in the Carpathian Mountains snow on the territory of Ukraine. The analysis observed data of station main and posts showed, that they reflect provision of snow accumulation predominantly the bottom mountains districts (till 7-8 m). The special routing snow shooting cower the areas predominantly in the high-rise area till 1-13 m abs. The fuller picture of the features allocation of the snow cover in the highland allow to take observed data of the snow avalanche stations on remote battens on the absolute heights within the limits of m abs. Obtained data allowed constructing detailed map of average maximal snow reserves and map of dates maximal snow reserves for territory of the Ukrainian Carpathians. Keywords: snow reserves, snow shootings, snow measurement. 1 HYDRO-METEOROLOGICAL EXTREMES, FLOODS AND DROUGHTS 1.1 Meteorological data and hydrological modeling The estimation of snow reserves is the great importance at hydrological and avalanches calculations, at designing and construction of constructions (for definition of loadings on constructions), at a tentative estimation of conditions of a winter recreation, etc. In connection with growth of water consumption and development of mountain territories there is a necessity of increase of accuracy of an estimation of water resources, including snow reserves which share makes up to 4 % of all deposits. And studying of its stocks becomes complicated significant variability of its characteristics as during the winter periods, and year by year. Till now the question on distribution snow reserves in the Ukrainian Carpathians has been partially shined in work in which characteristics of average sizes of the greatest snow reserves last day decades and their statistical parameters for 24 stations and posts on the territories of the Ukrainian Carpathians received according to supervision inclusive for Unfortunately are resulted, in it the high mountains of Carpathians is poorly shined - the prevailing part of items is located within the limits of up to 6 m and only two items characterized above located areas: Pozhezevska and Solonzovka, had by the moment of the publication of work a short number of supervision (till 1 years).

2 The given research is executed in connection with necessity of reception of more detailed characteristic of distribution snow reserves high mountains of Carpathians, on the basis of the data saved up in last years on a snow cover. The initial information for researches data s decade and pentade snow shootings of 49 meteorological stations and posts, supervision on 11 mountain snow measurement routes, as extent from 3 up to 6 km have served. On them are equipped 98 snow points within the limits of high-altitude zones mainly from 6 up to 14 m abs. Also data of supervision on avalanche stations Plaj and Pozhezevska with measurement of height of a snow on 35 and 4 remote battens, established on the area 5-6 км 2 within the limits of high-altitude zones of 1-14 m abs are used the first station and m abs on the second. Specialized routing snow shootings are spent, as a rule, once (less often two times) for a winter on snow points and linear routes by extent from 2 up to 6 km, high-altitude zones covering some in pool. Conditions of carrying out snow shootings in the bottom zones up to height of 8 m favourable, above - are complicated by a significant steepness of slopes and strong winds. On linear routes thickness of a snow cover is measured by means of snow measurement batten through everyone. m, density of a snow - by means of weight snow measure through everyone of 5 m. On mountain snow shootings routes of measurement are made on the constants fixed by labels on district snow points, on each of which is available one or the several snow shootings ground, located on terraces and slopes of valleys of different expositions. The distance between snow points 2-8 km, excess of one over another about -2 m. Thickness of a snow cover on snow points is measured not less than in 2, and a stock of water in a snow - in 5 points. Specialized supervision (including measurement of height of a snow by means of remote battens, definition of stocks of water in snow thicknesses) are made on avalanche stations Plaj and Pozhezevska and in areas of works avalanche group of UHMI. At carrying out of the analysis existing snow shootings networks all mountain territories of the Ukrainian Carpathians have been divided into 1 areas - pools (fig 1) of the rivers or groups of pools within the limits of which, conditions accumulate of now and a mode of a snow cover are approximately identical (Grischenko V., 1988).

3 Figure1. Map-scheme of a network of supervision over a snow cover in the Ukrainian Carpathians The analysis of data of a network of stations and posts in the Ukrainian Carpathians has shown, that they reflect conditions accumulate of now mainly lower areas (up to 7-8); routing snow shooting cover basically zones up to 1-13 m abs. For reception of characteristics of a snow cover above the located zones data of supervision of avalanche stations behind height of a snow cover on remote battens and density of a snow in zones of avalanches as decade snow measurement are spent on avalanche stations Plaj and Pozhezevska on not the representative sites located in places of snow blow off have been used (fig.2) x, mm mm yars

4 (a) x, mm years Figure 2. Dynamics of atmospheric precipitation during the winter period: (a) - Pozhezevska; (b) - Plaj. mm (b) As in high mountains very strong influence on redistribution of a snow cover renders a wind, and remote battens are established both in zones of accumulation, and in zones of snow blow off, for definition of average long-term sizes maximal snow reserves measurements of height of a snow is average for group of battens located in one highaltitude zone. Supervision on remote battens in area avalanche station Pozhezevska is spent from For calculations water values of density and average height of a snow on groups of towers, located in the certain high-altitude belt (both in a carrying down zone and in a zone of accumulation of a snow) were used. Estimation of water in the snow was made on dependence W mm = 1Н sm x Р g/cm3, where Н sm the snow high, Рg/cm3 - snow density, produce the estimation of water reserve in the snow. The basic way of generalization of averages for the period of supervision maximal snow reserves was construction of graphic communications of these characteristics with height of district. Average values of the maximal stocks of water in a snow for the Ukrainian Carpathians have been received up to height of 175 m. the area of territory with higher marks is insignificant, small and if necessary snow reserves on it is possible to define by extrapolation of the revealed dependence up to the uppermost high-altitude zones. Thus, by means of schedules of communication of averages long-term maximal snow reserves with absolute height in various pools there was possible a definition of these sizes for any high-altitude zone

5 Errors of definition of average size maximal snow reserves, as is known, depend on factor of their variation and duration of the period of supervision. For items factors of a variation snow reserves are equal the bottom parts of pools where snow reserves do not exceed mm, and above,4-,5 (fig. 3). In such cases the greatest mistakes of definition of average sizes for the 2-years period average 15-2 %, However in top, more multisnow zones in spite of the fact that here shorter numbers of supervision, factors of a variation decrease up to,3, and mistakes of definition of average values snow reserves make 1-15 %. Figure 3. Average long-term maximal water reserves in a snow cover Obtained data allowed constructing detailed maps of average maximal snow reserves for territory of the Ukrainian Carpathians (fig. 3). Data about date's maximal snow reserves are similarly processed and generalized. As dates maximal snow reserves a steady snow cover less able for changing on territory, than snow reserves, dependences of such dates on height of district were under construction but for separate pools, and as a whole for territory of the Ukrainian Carpathians. On the basis of actual and settlement dates the map of dates maximal snow reserves (fig. 4, 5, 6) by means of which definition of optimum terms of carrying out snow shootings for the forecast of a spring drain for each concrete reservoir is possible has been constructed. Isolines on a map are lead with the step equal to 1.

6 Figure 4. Average long-term dates maximal snow reserves y =,419x 2-337,3x + 7E+7 y =,416x ,8x + 6E+7 n, formation destruction data Figure 5. Dependence of quantity of with a snow cover n with dates of formation D f and destructions D d of a steady snow cover in the Ukrainian Carpathians

7 h, sm y = -,2x 2 +,395x + 3,4833 Q max, mm Figure 6 Dependence of height and average maximal stocks of a snow in the Ukrainian Carpathians For calculation maximal snow reserves the set security in any item, proceeding from an assumption about normal distribution of characteristics of a snow cover, the size of factor С s was accepted equal 2С v. References Grischenko V. (1978). Estimation of the maximal height of a snow covers in the Ukrainian Carpathians. - UHMI, vol. 168, pp Grischenko V. (198). Spatial variability of a snow covers in the Ukrainian Carpathians. - UHMI, vol. 181, pp Grischenko V. (1988). Maximal water reserves in snow in the Ukrainian Carpathians. - UHMI, vol. 231, pp Tokmakov A. (1977). Stocks of water in a snow cover in the Ukrainian Carpathians. UHMI, vol. 157, pp