Albania (ALBGEOID2024)
|
Authors: D.A. Natsiopoulos, et al.
|
Created: 2024
|
Resp: O. Balliu
|
Description:
The geoid model for Albania (ALBGEOID2024) was computed in the framework of the modernization of the Albanian geodetic
reference system, promoted by the State Authority for Geospatial Information (ASIG). The model covers the area between 38.5°N and 43.5°N in
latitude and 18.0°E and 22.0°E in longitude, with a spatial resolution of 1′ × 1′. The gravity database consists of 52,517 free-air gravity
anomalies from terrestrial and marine sources. The terrestrial dataset includes 300 newly observed gravity points and 264 historical measurements
in Albania, together with 2,246 gravity observations from Greece. Marine gravity data were derived from the DTU2021 and SIO29.1 models, while EGM2008
was used to provide additional gravity information in neighboring regions and reduce boundary effects. The geoid computation was performed according
to the remove-compute-restore (RCR) procedure. The long- and medium-wavelength components of the gravity field were represented using the EIGEN6C4
global geopotential model up to degree and order 2190. The effects of topography were evaluated using spectral residual terrain modelling (RTM) based
on a combination of national and global digital terrain models. The gravimetric geoid solution was computed using the two-dimensional Fast Fourier
Transform (FFT) technique, with a modified Stokes kernel, and Least-Squares Collocation (LSC). This model was validated using 225 GNSS/levelling
benchmarks distributed over Albania and additional observations along newly established precise levelling lines. The comparison with GNSS/levelling
data showed a mean difference of approximately 3.4 cm and a standard deviation of 14.1 cm. ALBGEOID2024 is a preliminary hybrid geoid, obtained by fitting
a third-order polynomial surface to the GNSS/levelling residuals, thus reducing the standard deviation of the differences to 12.7 cm. It enables the direct
transformation of ellipsoidal heights into orthometric heights within the Albanian vertical reference system (ALB86).
References:
D.A. Natsiopoulos, G.S. Vergos, K. Qirko, O. Balliu, E. Qershija, L. Kasnec, P. Ndoj (2026). A new gravimetric and hybrid geoid model in Albania.
International Association of Geodesy Symposia, pp. 1–13. DOI: 10.1007/1345_2026_337
|
|
