Abstract

Tide gauge (TG) time series and GNSS measurements have become standard datasets for various scientific and practical applications. However, the TG and geodetic networks in the Baltic Sea region are deforming due to vertical land motion (VLM), the primary cause of which is the glacial isostatic adjustment. Consequently, a correction for VLM, either obtained from a suitable VLM model or by utilizing space-geodetic techniques, must be applied to ensure compatibility of various data sources. It is common to consider the VLM rate relative to an arbitrary reference epoch, but this also yields that the resulting datasets may not be directly comparable. The common height reference, Baltic Sea Chart Datum 2000 (BSCD2000), has been initiated to facilitate the effective use of GNSS methods for accurate navigation and offshore surveying. The BSCD2000 agrees with the current national height realizations of the Baltic Sea countries. As TGs managed by national authorities are rigorously connected to the national height systems, the TG data can also be used in a common system. Hence, this contribution aims to review the treatment of TG time series for VLM and outline potential error sources for utilizing TG data relative to a common reference. Similar consideration is given for marine GNSS measurements that likewise require VLM correction for some marine applications (such as validating marine geoid models). The described principles are illustrated by analyzing and discussing numerical examples. These include investigations of TG time series and validation of shipborne GNSS determined sea surface heights. The latter employs a high-resolution geoid model and hydrodynamic model-based dynamic topography, which is linked to the height reference using VLM corrected TG data. Validation of the presented VLM corrected marine GNSS measurements yields a 1.7 cm standard deviation and −2.7 cm mean residual. The estimates are 1.9 cm and −10.2 cm, respectively, by neglecting VLM correction. The inclusion of VLM correction thus demonstrates significant improvement toward data consistency. Although the focus is on the Baltic Sea region, the principles described here are also applicable elsewhere.

Highlights

  • This article is an open access articleTide gauge (TG) time series has become a standard dataset for various scientific and practical applications, whereby the sea level records refer to local solid Earth

  • BSCD2000 will be realized through global navigation satellite system (GNSS) and high-resolution (0.01 × 0.02 arc-deg) geoid modeling, while onshore, BSCD2000 will be compatible with the national height system realizations of the Baltic Sea countries (e.g., EH2000, N2000, and RH 2000) and will coincide with national geoid models to allow seamless height transitions

  • In the Baltic Sea region, a strong Glacial isostatic adjustment (GIA)-induced vertical land motion (VLM) signal deforms the TG and geodetic networks, the effect of which appears in the TG and GNSS records

Read more

Summary

Introduction

Tide gauge (TG) time series has become a standard dataset for various scientific and practical applications, whereby the sea level records refer to local solid Earth. 2022, 14, 920 the primary (scientific) applications of TG data is to study sea level and its variations [1,2,3,4], a common approach is to estimate the VLM rate at a TG station, which is removed from a TG time series before further data utilization. Glacial isostatic adjustment (GIA) induced VLM is commonly expressed as a spatially dependent linear trend (i.e., constant in time considering the proportionately short time extent of TG time series) due to the long-lasting viscoelastic response of the Earth [15,16] It is the primary cause of linear VLM. VLM-generated coordinate differences will be introduced to a GNSS measurement at epoch t because a determined height difference dh(t) (between measurement station and GNSS-CORS) is from the positions at the defining epoch (e.g., in elevation due to VLM).

Simplified
Treatment of Tide Gauge Time Series for Vertical Land Motion
Baltic Sea Chart Datum 2000
Tide Gauge Time Series in Relation to the Baltic Sea Chart Datum 2000
Numerical Examples
Treatment of Marine GNSS Measurements for Vertical Land Motion
A Numerical Example
Derivation of Offshore Dynamic Topography
Determination of Residuals
Correction for Vertical Land Motion
Discussion
Conclusions
Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call