A First Reliable Gravity Tidal Model for Lake Nasser Region (Egypt)

Abstract In the framework of French–Egyptian Imhotep Project, two spring gravimeters have been installed in area Lake Nasser (Egypt) with aim to establish a first reliable gravity tide model for region. The tidal stations are located Aswan, on northern edge lake and Abu Simbel south, respectively. This study was mainly aimed obtain crustal response forces and, consequently, increase accuracy geodetic observations, be used future geophysical studies this region as well investigate effect level variations deformation related changes. Nearly 3 years records (from May 2018 April 2021) were collected. Since no scale factor available gravimeters, step achieve calibration each collected signals. After removing instrumental drift, spikes, steps tares, both calibrated by fitting output signal against synthetic reference based body due Wahr-Dehant Earth FES2014 ocean loading model. signals analyzed ET34-X-V80 software analyses. enabled us retrieve set frequency-dependent factors (amplitude phase) main waves, residuals. It turns out that amplitude estimates waves is 0.2 ÷ 1% LCR_ET16 Aswan 1 10% LCR_D-218 Simbel. To improve at Simbel, stopped relocated there. 90 days recordings from ET16 provide promising results, an order 0.1% even better than results obtained Aswan. residual after subtraction range ± 50 µGal. Further analyses contribution however needed before able interpret terms surface (i.e. changes water Nasser) or underground hydrology.