## 5 Discussion  
### Comparison with Other Studies  
Glaciers have experienced a significant retreat and thinning in the Central Chilean Andes (e.g., [17; 24; 32; 60]) and other parts of the Andes (e.g., [7; 61]). However, this negative trend has been occasionally interrupted by periods with positive mass balance (e.g., [24; 33]). Our mass balance observations for the Echaurren Norte Glacier are in line with other studies. Figure 4a,b compares modeled mass balance [33] with glacier mass balances from the glaciological and geodetic approaches. In general, we observed a difference between values obtained from glaciological and geodetic methods. However, for the 2000-2013 period, a good agreement between our results and the measurements can be observed. In the long-term, the modeled mass balance between 1955 and 2013 (\(-\)0.63 m w.e. a\({}^{-1}\)) [33] was similar to our geodetic rate of \(-\)0.68 \(\pm\) 0.09 m w.e. a\({}^{-1}\) (1955-2015). [PERSON] et al. [33] identified several positive mass balances years at the Echaurren Norte Glacier, which coincident with glacier advances in the region. Other studies found elevation change rates of \(-\)0.14 m w.e. a\({}^{-1}\) and \(-\)0.20 m w.e. a\({}^{-1}\) at the Yeso and Bello glaciers in the Maipo Basin between 2012 and 2014 [62], \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Period** & **Volume Change (km\({}^{3}\))** & \
\begin{tabular}{c} **Geodetic Mass Balance** \\ **(m w.e.)** \\ \end{tabular} &
\begin{tabular}{c} **Geodetic Mass Balance** \\ **(m w.e. a\({}^{-1}\))** \\ \end{tabular} \\ \hline
1955–2000 & \(-\)0.0220 \(\pm\) 0.0010 & \(-\)38.29 \(\pm\) 3.72 & \(-\)0.85 \(\pm\) 0.08 \\
2000–2009 & 0.0020 \(\pm\) 0.0010 & \(4.87\pm 3.59\) & 0.54 \(\pm\) 0.40 \\
2000–2013 & \(-\)0.0020 \(\pm\) 0.0005 & \(-\)4.64 \(\pm\) 1.10 & \(-\)0.36 \(\pm\) 0.09 \\
2009–2015 & \(-\)0.0020 \(\pm\) 0.0001 & \(-\)7.21 \(\pm\) 0.57 & \(-\)1.20 \(\pm\) 0.09 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Summary of volume changes and geodetic mass balances for each observation period. We assumed an ice density of 850 kg m\({}^{-3}\). Figure 3: Glacier elevation change rate maps (_dh/dt_). (**a**) Elevation difference map for 1955 to 2000. (**b**) Elevation difference between 2000 and 2009. (**c**) Elevation difference map for 2000 to 2013. (**d**) Elevation differences between 2009 and 2015 (Black outline 1955 area, red outline 2009 area). which is similar our values rates between 2000-2013. We attributed this difference to the altitude of those glaciers, which are located up to 4000 m a.s.l. [PERSON] et al. [17] reported a mean area reduction of 30% in the period 1955-2013 for six major glaciers in the Olivares sub-basin (located 50 km north of Echaurren Norte Glacier). These six glaciers were larger than 5 km\({}^{2}\) in 2013. One of these glaciers, Olivares Alfa Sur, showed a remarkable area loss of 63% in the period, related at least partially to the northern aspect of the glacier. This reduction  
Figure 4: (**a**) Compilation of different mass balances data between 1955 and 2015. Comparison between mean annual mass balances (Glaciological method, WGMS) with the mean glacier mass balance derived from the hydroclimatic reconstruction from [PERSON] et al., [33] and the geodetic mass balance with uncertainty estimations in transparent (cyan and red). (**b**) Comparison between 2000–2013. (**c**) Areal changes and the cumulative mass balance of Echaurren Norte Glacier (WGMS) from 1955 to 2015.  
is similar to the 65% area loss of Echaurren Norte Glacier in the same period, coincident with the cumulative glacier downwasting (Figure 4c). Echaurren Norte Glacier has a south-eastern aspect and an altitude ranging from 3650 m to 3900 m a.s.l, whereas the glaciers around the Olivares basin have mean elevations of \(\sim\)4500 m a.s.l. Reported glaciological mass balances should be homogenized to minimize errors due to differences in operators and calculation methods [63].