Abstract

During the past 25 years, the level of the Dead Sea has fallen by ~10m. This has been due primarily to diversions of its principal source, the Jordan River, for irrigated agriculture in Israel. The sea level has now fallen sufficiently that the sea has bifurcated into two basins of markedly different character. The primary data set used in verification of these changes in the Dead Sea is a suite of space photographs from Apollo through Space Shuttle missions (1969 to 1993).

These photographs were digitally scanned as 24-bit color (RGB) files. The resultant images were computer registered to a 1:250,000 base map. Cross-sectional and spatial resolution dimensions for each image were computed by counting the pixel array and calculating its corresponding geographic area extracted from the base map. The surface area of the North Basins of the Dead Sea was calculated using an automated dilation function and compared to available Israeli ground data.

Surface surveys have confirmed that the Dead Sea has dropped 10 m (39.4 ft) since 1960, and its current rate of decline has accelerated to ~1.6 m/yr. The decrease in the level of the Dead Sea has resulted in the sea bifurcating into two basins: a deep North Basin (300 m depth at an elevation of approximately −410 m), and a shallow and artifically maintained South Basin 2 to 5 m depth at an estimated elevation of approximately −401 m).

This research verifies that manned space flight photography is a scientifically useful and inexpensive alternative for monitoring large-scale global changes and for providing independent verification and correction of local, ground estimates.