En

Ecological Safety of Coastal and Shelf Zones of Sea

ISSN:24135577

2025

The paper aims to find the correlation relationship between the land-water area ratio for a fixed area of the Danube Delta and the total river discharge using Landsat series satellite products and SMHI Hypeweb hydrological model. The study period covered 1984-2010. We used a total of 132 satellite images in one band in the near-infrared spectral range with a spatial resolution of 30 m. Two study areas were selected: the delta area with channel and land (44.9-45.4°N, 29.55-29.60°E) and the control area of the mouth seashore (44.9-45.4°N and 29.80-29.85°E). For each of them a histogram was plotted which characterised the reflected light in relative units and their corresponding numbers of pixels. The signal from the first area was found to be in the range of 7000-26, 000 r.u., whereas from the second one it was 7000-8000 r.u. This distinction allowed us to separate the delta areas occupied by river water from those of land. For this purpose, we calculated the ratio between the number of pixels corresponding to a value of 7000-8000 r.u. to all pixels in the area. Then we found the correlation between the river discharge from the SMHI Hypeweb hydrological model and the proportion of pixels corresponding to areas occupied by water. The regression y = 7.78∙10-4∙x0.09 - 5.98∙10-4 was obtained. The analysis of seasonal variability showed that in the studied delta area, the share of pixels related to water-occupied areas > 0.5 corresponds to the months from March to May, and the minimum values < 0.3 correspond to July-September. All this is consistent with the period of intensity of precipitation and snowmelt in the Danube River basin area. The data from this work may be useful to researchers assessing the impact of this river discharge on the hydrological regime and condition of the Black Sea

Black Sea, Danube River, hydrological model, Landsat TM, remote sensing, river discharge, SMHI Hypeweb

2025-04-28 11:23:05