Accurate Linking of Lake Erie Water Level with Shoreline Datum Using GPS Buoy and Satellite Altimetry

Abstract

There is a need to accurately link the water level to the shoreline vertical datum for various applications including coastal management, lake/river/estuary/wetland hydrological or storm surge modeling/forecasting. Coastal topography is historically surveyed and referenced to the predetermined vertical datum in terms of orthometric heights, or the heights above the geoid, which is poorly known in terms of accuracy and lack of adequate spatial resolution for coastal applications such as estuary or storm surge modeling. We demonstrate an accurate linking of the lake surface to a shoreline datum using satellite techniques, including GPS buoy and satellite altimetry, water level gauges, and local geoid and lake circulation models. The possible error sources are analyzed and an error budget is reported in this study. An innovated method to estimate geoid height near the water level gauge using a GPS buoy is proposed. It is found that at a 95% confidence interval, the method is consistent with the National Geodetic Survey GEOID03 geoid model. The lake surface represented using a lake circulation model provided by the Great Lakes Forecasting Systems is also verified with kriging based on the data (1999 -2001) from the water level gauge, and TOPEX/POSEIDON altimeter. Mean discrepancies of 2.7 and 7.2 cm are found with the data from the gauges around Lake Erie, and from the combination of the gauges and the altimeter, respectively. It reveals that the current dominant limitation of more accurate linking of water surface to shoreline is the insufficient knowledge of geoid in the current models. Further improvement is feasible through more accurate and higher resolution modeling of the lake geoid.Key words: Satellite altimetry, GPS buoy, Water level gauges, Geoid Citation: Cheng, K. C., C. Y. Kuo, C. K. Shum, X. Niu, R. Li, and K. W. Bedford, 2008: Accurate linking of Lake Erie water level with shoreline datum using GPS buoy and satellite altimetry.

Vertical Motion Determined Using Satellite Altimetry and Tide Gauges

“…The IGLD85 heights must be converted to Helmert orthometric heights (Hofmann-Wellenhof and Moritz 2006) in order to make comparisons with the TOPEX data. The conversion of water gauge records from IGLD85 heights to orthometric heights is an approximately 1 : 1 ratio (Cheng et al 2008), which does not significantly affect estimates of vertical motion. For instance, the average change rate of the differences in form of time series between two height systems (IGLD85 and orthometric heights) at Holland West, Lake Michigan, is smaller than 0.05 mm yr -1 , which is smaller than the uncertainties of the estimated vertical motion.…”

Lake Level and Surface Topography Measured With Spaceborne GNSS‐Reflectometry From CYGNSS Mission: Example for the Lake Qinghai

“…The water levels in lakes and rivers have been observed successfully from different radar altimeter (RA) missions (e.g., Berry et al, 2005;Birkett, 1995;Frappart et al, 2006;Jiang et al, 2017;Kleinherenbrink et al, 2015;Nielsen et al, 2015;Tseng et al, 2013), making it possible to study continental surface hydrology at global scale. In addition, the geodetic height profiles of the lake surface along the altimeter ground tracks can be used to assess and improve various gravitational models that underpin the gravimetric geoid models (e.g., Cheng et al, 2008;X. Li, Crowley, et al, 2016;Schwatke et al, 2011).…”

Accurate Forecasting of the Satellite-Derived Seasonal Caspian Sea Level Anomaly Using Polynomial Interpolation and Holt-Winters Exponential Smoothing

“…Tide gauge records relative to the crustal surface at the local coast are considerably affected by a number of geographical and meteorological phenomena, including vertical crustal movements, changes in atmospheric pressure, wind, river discharge, water circulation, water density, and increscent water mass due to melting ice (Kostianoy and Kosarev 2005). In the last two decades, satellite-based sensors in particular satellite altimetry have offered a promising alternative for monitoring water surface heights with unprecedentedly high accuracy from inter-seasonal to inter-annual time scales and spatial coverage regardless of meteorological and geological constraints (Campos et al 2001;Cheng et al 2008). Satellite altimetry has been applied in a wide variety of studies Crétaux et al 2011;Kuo and Kao 2011).…”