Relationship between Climatic and Glaciologic Parameters in Northeastern Siberia

1. Relationship of climatic and glaciologic parameters to circulation types and modern dynamic of nature hazards in Northeastern Siberia mountains ANANICHEVA, M.D., KONONOVA, N.K. Institute of geography, RAS Staromonetny per 29, Moscow 119017, Russia cest@online.ru, NinaKononova@yandex.ru

2. Introduction • The assessment of dynamics of land-based glaciation regime for the period of instrumental observation has become quite up-to-date in relation to the current climate warming and the glacier shrinkage in Northern Eurasia. This paper is aimed at understanding the relationship between climatic drivers of glacier regime and the atmospheric circulation. • Internal areas of north-east Siberian, distinguished by the highest climate continentality, encompass: • - wide depressions over Eurasia up to 1000-1200 m high (Oymyakonskaya, Yanskaya, Momo-Selenykhskaya), moderately elevated (up to 1500 m) uplands (Verkhoyanskoe, Kolymskoe, Elginskoe), • -high-mountainuos ranges (as high as 3500 m) – Suntar-Khayata, Chersky, Verkhoyansky (and as a part of it glaciated Orulgan range), less elevated ridges without glaciers – Segte-Daban, Ulakhan-Bom, Omsugchansky, and etc. • The climate is characterised by contrasts between very cold or dry depressions and intermountain valleys (“pole of cold” of Eurasia) and is more humidified with less severe temperature regime of the high-mountain areas.

3. Data and Analysis We have analysed relationship between the thermal and humidity regimes over north-east Siberia and the ECMs recurrence using monthly time series of summer temperature and total/solid precipitation from main weather stations, which cover the whole territory of this vast region. To understand the atmospheric circulation impact on the glacier balance of mass we used time series of the annual balance of the Glacier N31 (Northern Massif of the Suntar-Khayata mountains) from 1957 to 2000 obtained by reconstruction basing on direct measurements during the IGY (Ananicheva, Koreisha, 2005). As a complex dynamic indicator of the atmospheric circulation we used the calendar of the ECMs succession (Dzerdzeevskiy, 1967). Scheme of weather-stations’ location

4. Dynamic schemes of ECM ECM 1a - GROUP I • The total month or year ECMs duration and circulation groups were defined by this calendar: • Group I is zonal and it includes types 1 and 2 with anticyclone in Arctic without blocking. • Group II contains disturbance of zonal circulation, types from 3 to 7, anticyclone in Arctic, one blocking. • Group III is northern meridinal, types 8-12, anticyclone in Arctic, from 2 to 4 blocking over Northern Hemisphere. • Group IV – southern meridinal, type 13, which is characterized by cyclone circulation over Arctic Ocean without blocking). ECM 3 – GROUP II ECM 13z– GROUP IV ECM 12a - GROUP III

5. Methods and Analysis • Regime of cryosphere elements (including glaciers) is driven by climatic factors. The most dynamic component of climate is atmospheric circulation. Quantitative assessment of its characteristics requires a large-scale classification of macro-circulation processes. In regard to this the Dzerzeevskiy`s classification is quite helpful, being later developed to make possible understanding of regularities of the atmospheric circulation in hemispheric scale (Dzerzeevskiy, 1967). • The specific feature of the classification is that each ECM due to availability of dynamic schemes, averaged charts of atmospheric pressure both at the sea level and at 500 hPa isobaric surface, characterizes the circulation over the Hemisphere and is able to provide detailed information about barometric system movement over concrete smaller region.

6. Methods and Analysis • In accordance with this, we analyzed the circulation processes over North-Eastern Siberia (NE Siberia) basing on maximum number of correlation (relative to each other) between various ECM recurrence with mean summer temperature (Tsum), atmospheric total (Xtot) and solid precipitation (Xsol) as well as the glacier mass (net) balance (Bn). • As a rule, the obtained correlation coefficients are quite low by traditional view (R=0.3-0.6), however the analyzed time-series are rather long: ECM calendar lasts from 1988 to 2000; Tsum, Xsol, Bn, Bs, Bw – from 1930s till 2000. Reasoning from the statement, made from analysis of long series correlation in (Storm, 1967), it is possible to consider the received relationship as minimum meaningful, relative (comparable) to each other. The low correlation coefficients originate from the fact that we compare recurrence of ECM with Tsum and Xsol, different by their nature: intensity of Tsum and Xsol against availability of the ECM recurrence.

7. The study region The choice of the region was not voluntary. According to VNIIGMI-MCD (Center for geophysical data storage, Obninsk, Moscow region), the maximum absolute values of the linear trend factor (number of days in the winter or summer when mean daily temperature exceeded critical value) for the period from 1961 to 1998 are obtained between other for Eastern Yakutia (Suntar-Khayata Range inclusively). This region is anomalous enough in terms of climate warming, which started at the end of 20th century and encouraged essential retreat of glaciers there (Ananicheva, at al 2002). Mass balance of Glacier 31 in Suntar-Khayata Range is negative for the recent decades and its values continue reducing.

8. Circulation conditions and relation of ECM to Tsum, Xsol in North-Eastern Siberia • The best correlation of both parameters with ECM recurrence is with those shown in Table 1. • For the ECM 2a (Group I) the absence of Arctic invasions (blocking processes) within NH and movement of westerly cyclones along the Arctic coast and the 60th parallel are characteristic of (Dzerdzeevskii, 1968, Savina, Khmelevskaya, 1984). The small-gradient area of low pressure, promoting warming, and decrease in relative humidity of westerly air masses prevails over NE Siberia. This ECM acts in summer. • Under ECM 2b (summer) the north of the region is occupied by anticyclone, cold air from Arctic comes inhere along its eastern periphery. The “diving” cyclone from northwest drifts into this part, and brings cold dry air. • For the ECM 3 (summer) only one invasion is characteristic – towards Atlantic Ocean, this type belongs to the group of “disturbance of zonal circulation”, Group II. For NE Siberia this type as well as previously motioned has latitudinal extent; Arctic anticyclone under this ECM is quite widespread and reaches the coast of the study region. This favors penetration of cold and dry air inside the continent. In the South of the region there are western cyclones.

9. Table 1.The relationship of the Tsum , Xtot, and Xsol with the ECMs

10. The ECM 4c(summer) also belongs to Group II; it facilitates the blocking process to be located over Urals. Westerly cyclones displace inhere bringing cooling; precipitation is low due to low moisture content in continental air. Under the ECM 9а (Group III, summer) two blocking processes are formed - over the Atlantic and Pacific oceans, for NE Siberia the process has latitudinal extent, the region locates beneath the boundary of cyclonic and anti-cyclonic areas, mainly in the narrow of the cyclone with a center, south from Kamchatka. Invasion of warm and humid oceanic air to the northeast favors positive Tsum and Xsol anomalies. The ECM 12cs(here index s means summer subtype), also from Group II, makes possible three blocking processes to form: over the Atlantic Ocean, and two – over Siberia, in the Ob’ and the Enisey river basins and in the northeastern of its part. Southern cyclones can come in between these anticyclone blocking. Thus the western part of NE Siberia locates beneath a boundary of the northern invasions and southern outlets, the latter sharpens atmospheric fronts and causes plentiful precipitation. The northern part is covered with cold and dry air masses from Arctic. Such synoptic situation determines prevailing negative correlation between the ECM recurrence withTsumand – positive – withXsol. The ECM 13sfrom the Group IV: a cyclone forms over the Pole, and it “attracts” trajectories of southern cyclones from subtropics in four sectors of the hemisphere. These cyclones (originally from Mongolian branch of Polar Front) come in to NE Siberia bringing warmth and moisture.

11. Under the ECM 12аoccurring throughout a yearrelatively tight correlation between the recurrences of the ECMs is found with Xsol for a major part of the meteo-stations used. For the NH 12аrefers to Group III blocking processes are directed towards Atlantic, Enisey basin, east of the North America and the Pacific. The studied region is mainly under southern cyclones, which impact from Russian Pacific Coast that conditions positive correlation to prevail. • The duration and activity of the ECMs characteristic of meteo-regime of NE Siberia can be considered in Table 2. The most active (i.e. the total annual recurrence for the recent decades is higher then the mean of the entire observation period) are the ECMs -9a, 11d, 12a, 12bs, 13w, 13s, relatively active –(the recurrence sharply fluctuates) is also 12bs.

12. Table 2ECM (days), remarkable for North-Eastern Siberia meteo-regime and have the positive deviation from Average in last decade * ECMs, the recurrence that was maximum (and exceeds mean long-term) during recent decade.

13. Fig. 2 Dynamic scheme of ECM formed weather and balance of glacier at the resent time • The Table 2 shows that for the recent decade the total annual recurrence of the 4th ECMs (13s, 13w, 12a, and 9a) makes up 190 days a year. • There is their impact that will tell on glacier state in future. One can see the position and paths of replacement for anti- and cyclones under mentioned ECMs (Fig.2).

14. Circulation conditions of glacier accumulation and ablation in NE Siberia • We analyzed the correlation between Bn of Glacier N31 (reconstruction of Bn was made in (Ananicheva, Koreisha, 2005) and recurrence of various ECMs that can impact the formation of glacier mass balance: first of all, it is those responsible for enhanced (due to the warming, which occur there) melting (A) and also those encouraging plentiful winter precipitation – the main glacier accumulation (C) factor.

15. The ECMs determining A and C for the Suntar-Khayata Range • The ECM 10a within the NH is northern meridional, blocking processes are directed to Europe and America. There is anti-cyclone with outlet towards the NE over NE Siberia that’s why precipitation anomalies are negative under its impact. • The meteorological conditions under ECM 13s can also promote rapid glacier melting and therefore – formation of glacial freshets. The maximum heating and glacier ablation occur in a warm period under combination of the positive Tsum anomaly and clear-sky weather.. Accumulation on Glacier 31 has been revealed to be co-related to above-described ECMs 2b, 3, and 9a (Table 3). Besides ECM 6 plays a significant role it is referred to the group of zonal disturbance. The only blocking process is directed via Chukotka to the Pacific Ocean. Depending on strength and depth of blocking anti-cyclone it covers larger or lesser part of studied region in its east in concrete case. The western part is under Atlantic influence of cyclones. The Glacier 31 melting is conditioned with the ECMs 10b, 13s (described above), and 10a.

16. Fig. 3 Total duration of the ECMs of warm and cold seasons related to Bn of Glacier N31 a) Positive relation, the warm season ECMs; b) Negative relation, the warm season ECMs; c) Positive relation, the cold season ECMs; d) Negative relation, the cold season ECMs1 – annual duration; 2 – average for 1899-2003; 3 – 10-year smoothing:

17. Fig. 3 (a, b, c, d) shows the course of the total duration of the ECMs of warm and cold seasons related to Bn of Glacier N31 and demonstrates growth of recurrence of that unfavorable for glacier balance that are both in summer and winter. • Accumulation takes place in a cold period under the fronts of western and southern cyclones and its preserving is under negative air temperature mainly in Arctic cyclones. Such situation occurs in summer period in NE Siberia. • So, we may come to conclusion that synoptic processes in NE Siberia have not encouraged glacier nourishment for the recent 40 years; however the increase of glacier-unfavorable ECMs in the warm period is beginning to slow down the last decade.

18. The ECMs contribution into hazardous events in NE Siberia (Table 4)

19. Conclusions • CONCLUSIONS • 1. Mountains of NE Siberia have been undergoing by sufficient warming during last 40 years 2. Positive correlation with Tsum of NE Siberia are inherent in those ECMs where the regions are impacted by continental anticyclone or “small gradient area” of lowered pressure. In these cases during summer season heating occurs. Negative correlation relate either to the ECMs of active cyclonic activity (permanent cold air inflow, cloudiness, precipitation and heat consumption for evaporation) or invasion of Arctic air masses from Arctic High. Positive correlation with Xsol relate to precipitation fall within the fronts of westerly and southern cyclones, negative ones – to small gradient area of lowered pressure.3. The most intensive warming and ablation of glaciers take place in summer season under the combination of positive anomaly Tsum with unclouded weather. For NE Siberia it is either possible under continental (not Arctic) anticyclone condition or small-gradient of the lowered pressure area. 4. Accumulation occurs in a cold half-year period under both precipitation fall on fronts of the western or southern cyclones and snow preserving due to negative temperatures, mainly during Arctic cyclones invasion. In NE Siberia glacier accumulation is mostly related to the ECMs and responsible for Arctic invasion, which provides negative air temperatures.5. The result of the paper is allocation of the extreme-events-causing ECMs within study region. Active now ECM 9a and 13s promote formation of glacial mudflows and glacial floods. The major part of characteristic ECMs, responsible for the conditionsfavorable of avalanche formation, has the total duration that exceeds the mean level.

20. Acknowledgements: • This work was supported by the Russian Foundation for the Basic Research (grants No 03-05- 64679, 05-05-64354) • THANK YOU!