The land surface can be shaped by different forces including climate and tectonics. Here we study how these two drivers affect the morphology of arid, carbonate watersheds in Oman. The tectonic response of a carbonate terrain in the northeastern Hajar Mountains of Oman was studied by quantifying rates of basin averaged erosion and chemical dissolution over late Pleistocene-Holocene time scales. Results indicate that the uplift rate calculated from tectonic flexural modeling (~80-200 mm/ka) and marine terraces (900-6700 mm/ka) is higher than basin averaged erosion rates of 10-15 mm/ka, and chemical dissolution rates of 0.9-1.3 mm/ka. The values of basin averaged erosion and chemical dissolution measured herein are consistent with documented denudation rates in hyper-arid climates that are limited by precipitation. The climatic forcing effects on watersheds was analyzed by studying the relationships among precipitation, vegetation, and morphological characteristics of wadis draining both sides of the Dhofar Mountains in southeastern Oman. At this location, a strong gradient in water availability is present during the monsoon season. A basins analysis shows that the hypsometric curve and statistical moments capture the morphological difference between wet and dry watersheds. Our results shed light on the geomorphic signature of water availability in a semi-arid, carbonate landscape. Finally, the potential teleconnections between climatic indices and cloud cover in the Dhofar Mountains of Oman were explored using statistical cross-correlations and Artificial Neural Networks (ANN). Cross-Correlation results show that cloud cover has a significant positive relationship (|r| > 0.460, p<0.05) with Pacific Decadal Oscillation (PDO) with a lag of 3 months, and has significant negative relationship (|r| > 0.460, p<0.05) with Indian Ocean Dipole (IOD) with a lag of 5 months. The ANN model shows that the Interdecadal Pacific Oscillation (IPO) index yields the closest prediction to the observed values of cloud cover, with the lowest prediction error. The results of this study raise the possibility of predicting in advance summer cloud cover from Pacific climatic indices.
| Identifer | oai:union.ndltd.org:bu.edu/oai:open.bu.edu:2144/43910 |
| Date | 18 February 2022 |
| Creators | Al Abri, Amani |
| Contributors | Fagherazzi , Sergio |
| Source Sets | Boston University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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