Trends of Changes in Salinity in the Indian Ocean and Adjacent Areas of the South Ocean in 2005–2023 in Conditions of Strengthening the Hydrological Cycle

Using climate data from the USA National Oceanic and Atmospheric Administration (NOAA), as well as atmospheric reanalysis of precipitation and evaporation from the European Weather Forecast Center ERA5, trends and regional features of changes in salinity and salt content in the extratropical zone of the Indian Ocean were determined from 2005 to 2023. At the near-surface level 5 m in most of the water area, linear trends in the average annual salinity of both signs ranging from –0.44 psu/10 years to 0.20 psu/10 years were expressed, and on average, significant trends in decreasing salinity with a value of 0.01 psu/10 years prevailed. With depth, the pattern of horizontal distribution of salinity trends changes significantly, which is reflected in the characteristics of the salt content of the upper, intermediate and deep layers. In the whole region, the salt content of the upper 1000-meter layer increased by ~5 kg/m2 over 10 years, i. e. by approximately 0.03%. An analysis is given of the statistical significance of trends and possible cause-and-effect relationships of changes in the salinity field with large-scale and regional processes in the ocean and atmosphere under conditions of intensification of the hydrological cycle.