Ice Features Of The Northern Caspian Under Sea Level Fluctuations And Ice Coverage Variations

Abstract

The Caspian Seaseasonal ice cover develops each winter despite of it being in mid-latitudes. Increasing development of oil and gas fields challenges researchers to ensure operational safety. TheCaspian Seahas seen significant water level fluctuations in its recent history. And in the same time, it is vulnerable to effects of climate change. Extensive studies on ice conditions conducted in the region don’t provide insights on influence of these factors in combination to describe ice cover behavior and ice features distribution. We classify winter seasons of theNorthern Caspianby their severity calculating the cumulative freezing-degree days (CFDD). Ice charts based on aerial reconnaissance with support of the OSI-450 reanalysis provided data on the ice coverage, the timing of ice formation and destruction, the duration of the ice seasons from 1979 to 2015. We analyzed the stamukhi distribution on theNorthern Caspianfrom aerial reconnaissance for 1973–1980 and satellite imagery deciphering for 2013–2019 periods along with sea level dynamics. We found out that the amount of severe and moderate winters reduces while mild winters number increases. This leads to a decrease in the mean ice area and ice duration at theNorthern Caspian. Comparison of two periods with different sea levels and ice coverage showed that both factors affect the distribution of stamukhi by depth and distance to coast in theNorthern Caspian. Comparison of stamukhi locations in moderate winter seasons showed that their distribution is determined by the area of ice cover. In case of similar ice conditions, the stamukhi distribution is determined by sea level. The zone of their highest concentration shifts along with the coastline offset.

Influence of Long-Term Wind Variability on the Storm Activity in the Caspian Sea

“…The total storm duration increased not only for storms with SWH > 3 m but also for SWH > 2 m. The maximum trend value was 2 days in 10 years and this trend was positive and significant. According to [47][48][49], the number of mild winters increased in the second half of the 20th century and early 21st century, which reduced the sea ice in the North Caspian Sea, which was associated with the presence of positive trends of number of storms and their duration in the NC. In the Middle Caspian, the mean number of storms with SWH > 2 m was 85 and 41 for SWH > 3 m (Figure 12).…”

Digital Elevation Model Development Of The Volga And Don River’s Delta And Application In Hydrological Modeling

“…Most of the mouth coast of the Volga is a vast shallow area up to 200 km wide and 30-35 km long with depths of less than 1 m, significantly overgrown with aquatic vegetation. The rest of the coast, 15-20 km long, has depths from 1 to 10 m. Due to the Caspian Sea level fluctuations in the XX-XXI centuries the Delta area has changed several times over the past 130 year (Ogorodov et al 2020). The Volga Delta is characterized by water level fluctuations up to 4-5 m, leading to flooding of large areas due to the flatness of the land surface characteristic of river Deltas.…”