Tidal and storm surges levels variation at the Cape Kamenny (Gulf of the Ob)

Abstract

Sea level observations obtained in various expeditions since 1936, as well as those made at the polar station on Cape Kamenny (the Ob Bay) from 1952 to 1994 were subjected to treatment and harmonic analysis using the least squares method (AARI version).The aim of the work was to assess the quality of hourly and 6-hourly intervals series of sea level data and to bring these data to uniform rows for the subsequent study of tidal and surge waves. As a result of this analysis, 6-hourly interval observations of 1952–1961 were considered of low quality and not suitable for further consideration in the work. Bringing 6-hourly interval observations for 1977–1994 to uniform rows was carried out first with the control of the height basis and binding to the Baltic system of heights, and then with the help of the tide calibration method the final cast was made. In the area of tidal fluctuations of the level, erroneous information about the tide, obtained during the treatment of observations for 1936, which were placed in the tide tables for 1941, was revealed. New average estimates of harmonic constants for the summer period were proposed. The study of surges of level is based on uniform series, as well as residual ones (observations minus predictions). At the same time, the tide calculation (prediction) was made according to the program developed at AARI for the average monthly values of harmonic constants (12 sets of tides lists in the annual cycle) with the inclusion of long-period tides. Statistical quantitative characteristics of non-periodic level fluctuations were obtained for the total and residual series of observations. They are calculated on a unique hourly series for the years 1947–1948. And 6-hourly interval data for 1977–1994. For the estimation of surges, the level above 5 % of estimation was used, and the drifts were distinguished by the level below 95 % of estimation. Relationships are obtained between the duration and rate of growth of the level during surges, as well as the decline and rise of the level during drifts.