Beschreibung:
<jats:p>Abstract. The Antarctic Peninsula (AP) is one of the widely studied
polar regions because of its sensitivity to climate change and potential
contribution of its glaciers to global sea level rise. Precise digital elevation models (DEMs) at a high
spatial resolution are much demanded for investigating the complex glacier
system of the AP at fine scales. However, the two most recent
circum-Antarctic DEMs, the 12 m TanDEM-X DEM (TDM DEM) from bistatic interferometric synthetic aperture radar (InSAR)
data acquired between 2013 and 2014 and the Reference Elevation Model of
Antarctica mosaic (REMA mosaic) at an 8 m spatial resolution derived from
optical data acquired between 2011 and 2017 have specific individual
limitations in this area. The TDM DEM has the advantage of good data
consistency and few data voids (approx. 0.85 %), but there exist residual
systematic elevation errors such as phase-unwrapping errors in the
non-edited DEM version. The REMA mosaic has high absolute vertical accuracy,
but on the AP it suffers from extended areas with data voids (approx. 8 %). To
generate a consistent, gapless and high-resolution topography product of the
AP, we fill the data voids in the TDM DEM with newly processed TDM raw DEM data
acquired in austral winters of 2013 and 2014 and detect and correct the
residual systematic elevation errors (i.e., elevation biases) in the TDM DEM
with the support of the accurately calibrated REMA mosaic. Instead of a
pixelwise replacement with REMA mosaic elevations, these provide
reference values to correct the TDM elevation biases over entire regions
detected through a path propagation algorithm. The procedure is applied
iteratively to gradually correct the errors in the TDM DEM from a large to
small scale. The proposed method maintains the characteristics of an InSAR-generated DEM and is minimally influenced by temporal or penetration
differences between the TDM DEM and REMA mosaic. The performance of the
correction is evaluated with laser altimetry data from Operation IceBridge
and ICESat-2 missions. The overall root mean square error (RMSE) of the
corrected TDM DEM has been reduced from more than 30 m to about 10 m which
together with the improved absolute elevation accuracy indicates comparable
values to the REMA mosaic. The generated high-resolution DEM depicts the
up-to-date topography of the AP in detail and can be widely used for
interferometric applications as well as for glaciological studies on
individual glaciers or at regional scales.
</jats:p>