|Review - King et al (tc-2016-99-R1)|
This is an substantially-improved version of the original manuscript. King et al. have addressed most of the comments given by previous reviewers, and Figure 7 (changes in AAR for different glacier types and temperature scenarios) is a great addition. The manuscript is well-written and will be a valuable contribution to ongoing glacier-climate studies in the region.
1. Mass loss calculations: how are missing areas in the SRTM dealt with, particularly in accumulation areas? And why not use the slightly lower and generally more accepted density of 850 +/- 60 kg/m3 (Huss, 2013)?
Also: a mass balance can be calculated for the entire glacier/region, but for vertical profiles (e.g. Figure 5 in the revised manuscript) it must be kept as surface elevation differences - the conversion to mass change can only be done if dynamics are taken into account (or they cancel each other out, as in the case for the whole glacier). As Gardelle et al. note in their 2013 paper: "Note, elevation changes over separate sections of a glacier cannot be treated as mass changes due to the disregard of glacier dynamics."
As a result, mass loss rates cannot be compared for different elevations (P10L15-27). This will need to be treated as elevation differences. And ablation gradients should be 'surface lowering' or 'elevation change' gradients (P11L1-10).
2. Derivation of ELA from mass balance (Sec. 3.7). In the previous version of the mansucript, both reviewers pointed to this as a potentially weak point in the methods. The authors have not provided any additional support for the assumption that the ELA can be determined from geodetic mass balance observations (other than Nuth et al., 2007). I think the method of estimating future ELAs/AARs is useful but the method for current ELA calculation needs to be further justified. Also, as the authors calculate mean geodetic mass balance for 100 m elevation bands to estimate ELA the submergence/emergence velocities again become an issue that needs to be considered.
Abstract: just a suggestion to shorten to the recommended 100 - 200 words
P2L23: Central Himalayan glaciers have less negative mass balances (as opposed to more stable).
P3L24: clarify - do the 40 largest glaciers comprise 70% of the total glacierized area?
P3L29: New paragraph for Tama Koshi.
P4L1: "The Tama Koshi is a poorly studied catchment..."
P4L3: New paragraph for Pumqu catchment.
P9L25: By definition, lapse rates are positive. I'd personally keep it negative and use 'vertical temperature gradient'.
P11L28: Thakuri et al (2014) also examine smaller glaciers, which might help explain the greater rates of area change.
P12L24: 'elevation change' instead of 'mass loss' (and elsewhere)
P12L26: 'here' - be specific again, e.g. 'north of the divide'
P13L1: Measured precipitation is actually low - suggest 'delivers a large proportion of total annual precipitation'
P13L25: Shrestha et al., (1999)
P14L17: (Barundun et al., 2015)
P14L17: 'Our results'...re-state the regional mass loss estimates here for comparison. A table with the current results and those from previous studies would also be helpful.
P14L27: 'surface lowering' instead of 'mass loss'
P15L26: awkward phrasing. Perhaps: '...suggests large glacier mass losses."
P16L5-120: Expand on Figure 7! E.g. at high-end temperature projections, AARs go to zero and ELAs are above the head of glaciers in the Tama Kosi. Initial response to temperature change is greater for Dudh Kosi...
P18L3. "Projected warming in the Everest region will lead to increased ELAs and, depending on glacier hyspometry, substantial increases in ablation areas.'
Figure 1: Glacier names still too small to read.
Figure 2: Glacier names too small, and are the grey regions on the glaciers areas with no data?
Figure 7: What does each point represent?