Abstract. The direct glaciological method provides in situ observations of
annual or seasonal surface mass balance, but can only be implemented through
a succession of intensive in situ measurements of field networks of stakes
and snow pits. This has contributed to glacier surface mass-balance
measurements being sparse and often discontinuous in the Tien Shan.
Nevertheless, long-term glacier mass-balance measurements are the basis for
understanding climate–glacier interactions and projecting future water
availability for glacierized catchments in the Tien Shan. Riegl
VZ®-6000 long-range terrestrial laser scanner
(TLS), typically using class 3B laser beams, is exceptionally well suited
for repeated glacier mapping, and thus determination of annual and seasonal
geodetic mass balance. This paper introduces the applied TLS for monitoring
summer and annual surface elevation and geodetic mass changes of Urumqi
Glacier No. 1 as well as delineating accurate glacier boundaries for 2
consecutive mass-balance years (2015–2017), and discusses the potential of
such technology in glaciological applications. Three-dimensional changes of
ice and firn–snow bodies and the corresponding densities were considered for
the volume-to-mass conversion. The glacier showed pronounced thinning and
mass loss for the four investigated periods; glacier-wide geodetic mass
balance in the mass-balance year 2015–2016 was slightly more negative than in
2016–2017. Statistical comparison shows that agreement between the
glaciological and geodetic mass balances can be considered satisfactory,
indicating that the TLS system yields accurate results and has the potential
to monitor remote and inaccessible glacier areas where no glaciological
measurements are available as the vertical velocity component of the glacier
is negligible. For wide applications of the TLS in glaciology, we should use
stable scan positions and in-situ-measured densities of snow–firn to
establish volume-to-mass conversion.
Methodology for Bioprocess Analysis: Mass Balances, Yields and Stoichiometries