Storm surges in the water level variation in the New Port (gulf of Ob)

Le résumé fourni par la source

The processing of 6-hourly intervals level measurements at the New Port polar station was previously difficult due to poor data quality and the lack of methodology for assessing them and bringing observations into uniform rows. Therefore, since the second half of the 20th century, no research of wind-induced water has been carried out. In 2015, for the first time, the authors formed a base of residual levels (observations minus forecasting) for 1977–2012 on 6-hourly intervals observations of water level at the New Port station using the method of tide calibration. In the present work, a period of observations with relatively reliable data for 1977–1991 was selected for the research of the storm surges in the water level fluctuations. Surges are considered in comparison with the 5 % probability, and ranges with 95 % probability. The annual distribution of the number of surges and ranges showed an average of 12.4 surges and 11.2 ranges per year. The maximum number of surges and ranges was observed in 1981 and was 21 surges and 27 ranges. In the time course of fluctuations of residual levels during the above period, the maximum with the value of 634 cm was noted in 1987 and occurred during the autumn period (ice composition). The length of the surges varied between 0.25 days and 13.5 days. Most of the surges occurred in the period June-October (78.8 %) with the largest number in September (22,8 %). In the period January-May the number of surges decreases to 7.6 % and is zero in April. The lowest ranges residual level was observed in 1986 (343 cm above zero fasting). The total fluctuation of the residual level in New Port during the period of 6-hourly intervals level observations in 1977–1991 was 291 cm. This is 23 cm more than was recorded at the Cape Kamenny station. The length of the ranges varied from 1 day to 8 days. The majority of the intra-annual distribution of the number of ranges over a multi-year period was observed in July–October (83.7 %) with the maximum number in September (28.1 %). A small number of ranges were observed in January and March, and their total absence in April and May. The duration of surges and ranges is inversely dependent on their growth rate. Thus, the highest growth rate of the residual level at the deposit of 5.1 cm/hour corresponds to the duration of the deposit of 0.25 days. The greatest duration of growth of the surge level (9.25 days) corresponds to a speed of 0.14 cm/h. The drop in the level during the range occurred at the highest speed of 11.6 cm/h, the rise from the minimum residual level – at the speed of 6.97 cm/h. Corresponding to these rates, the duration of the decline and rise of the range level was 0.15 cm/h. The highest rise time of the residual range level was 5.25 days at an intensity of 0.44 cm/h. The authors declare that they have no competing interests.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.