Estimation of mass balance from snowline monitoring in Central Asia Martina Barandun (1), Matthias Huss (1, 2), Kathrin Naegeli (1, 3), Robert McNabb (4), Pete Bunting (3), Etienne Berthier (5), Martin Hoelzle (1) (1) Department of Geoscience, University of Fribourg, Fribourg, Switzerland (martina.barandun@unifr.ch), (2) Laboratory of Hydraulics, Hydrology and Glaciology (VAW), ETH Zurich, Zurich, Switzerland, (3) Centre for Glaciology, Department of Geography and Earth Sciences, Aberystwyth University, Wales, UK (4) Department of Geoscience, University of Oslo, Norway, (5) CNRS, LEGOS, University of Toulouse, Toulouse, France M.Barandun, WGMS Expert Workshop 2018 on Regional Mass Balance Estimates

region-wide estimate of annual glacier mass balance for Central Asia Discussion Introduction Methods Results Conclusion region-wide estimate of annual glacier mass balance for Central Asia geodetic Method + good spatial resolution restricted temporal resolution glaciological Method + good temporal resolution restricted spatial resolution Introd kyrgyzstan : old monitoring  aprupt breakdown  reestablishment in 2011 Motiviation: underrepresented in WGMS Need of monitoring: glacier retreat patter/climate influence/hydorlogical porpose mass balance modelling constrained with transient snowline observations + good temporal resolution + applicable on extended, remote areas M.Barandun, WGMS Expert Workshop 2018 on Regional Mass Balance Estimates

combining different approaches Discussion Introduction Methods Results Conclusion combining different approaches simple accumulation and temperature-index model  calibration with TSL observations validation with glaciological measurements and high-resolution geodetic mass changes region-wide geodetic mass balances (ASTER DEMs) to constrain snowline based, modelled mass balances  annual surface mass balance time series for all glaciers > 2km2 Introd kyrgyzstan : old monitoring  aprupt breakdown  reestablishment in 2011 Motiviation: underrepresented in WGMS Need of monitoring: glacier retreat patter/climate influence/hydorlogical porpose M.Barandun, WGMS Expert Workshop 2018 on Regional Mass Balance Estimates

study site BARKRAK BATYSH SOOK Discussion Introduction Methods Results Conclusion study site BARKRAK Introd kyrgyzstan : old monitoring  aprupt breakdown  reestablishment in 2011 Motiviation: underrepresented in WGMS Need of monitoring: glacier retreat patter/climate influence/hydorlogical porpose BATYSH SOOK M.Barandun, WGMS Expert Workshop 2018 on Regional Mass Balance Estimates

glaciological measurements Discussion Introduction Methods Results Conclusion glaciological measurements geodetic method + good spatial resolution restricted temporal resolution glaciological method + good temporal resolution restricted spatial resolution Introd kyrgyzstan : old monitoring  aprupt breakdown  reestablishment in 2011 Motiviation: underrepresented in WGMS Need of monitoring: glacier retreat patter/climate influence/hydorlogical porpose mass balance modelling constrained with transient snowline observations + good temporal resolution + applicable on extended, remote areas M.Barandun, WGMS Expert Workshop 2018 on Regional Mass Balance Estimates

glaciological measurements Discussion Introduction Methods Results Conclusion glaciological measurements Glacier No. 354 (6.4 km2) Golubin Glacier (5.5 km2) Abramov Glacier (24 km2) Introd kyrgyzstan : old monitoring  aprupt breakdown  reestablishment in 2011 Motiviation: underrepresented in WGMS Need of monitoring: glacier retreat patter/climate influence/hydorlogical porpose Barkrak Glacier (2.4 km2) Batysh Sook Glacier / Suyok Zapadniy (1.2 km2) Hoelzle et al. (2017) M.Barandun, WGMS Expert Workshop 2018 on Regional Mass Balance Estimates

mass balance model constrained with TSL Discussion Introduction Methods Results Conclusion mass balance model constrained with TSL geodetic method + good spatial resolution restricted temporal resolution glaciological method + good temporal resolution restricted spatial resolution Introd kyrgyzstan : old monitoring  aprupt breakdown  reestablishment in 2011 Motiviation: underrepresented in WGMS Need of monitoring: glacier retreat patter/climate influence/hydorlogical porpose mass balance modelling constrained with transient snowline observations + good temporal resolution + applicable on extended, remote areas M.Barandun, WGMS Expert Workshop 2018 on Regional Mass Balance Estimates

mass balance model constrained with TSL Discussion Introduction Methods Results Conclusion mass balance model constrained with TSL accumulation and melt model calibration with transient snowline observations step 1: a precipitation correction factor optimized by fitting the modelled winter snow accumulation to agree with the modelled cumulative melt Introd kyrgyzstan : old monitoring  aprupt breakdown  reestablishment in 2011 Motiviation: underrepresented in WGMS Need of monitoring: glacier retreat patter/climate influence/hydorlogical porpose modified after Huss et al. (2013) step 2: DDFs are optimized by comparing modelled and observed SCAF    M.Barandun, WGMS Expert Workshop 2018 on Regional Mass Balance Estimates

automatic classification of TSL Discussion Introduction Methods Results Conclusion automatic classification of TSL looking for abrupt albedo change within elevations band of all grid cells that are classified «unclear» Secondary surface type evaluation albedo < 0.25 = ice albedo > 0.55 = snow 0.25 > albedo < 0.55 = unclear Primary surface type evaluation Albedo Shortwave broadband albedo derived based on narrow-to-broadband formula by Liang 2000: Final surface type classification critical albedo = where rate of change in albedo is greatest Albedo Introd kyrgyzstan : old monitoring  aprupt breakdown  reestablishment in 2011 Motiviation: underrepresented in WGMS Need of monitoring: glacier retreat patter/climate influence/hydorlogical porpose albedo based classification Naegeli et al., (2018) M.Barandun, WGMS Expert Workshop 2018 on Regional Mass Balance Estimates

gecadal geodetic mass balance Discussion Introduction Methods Results Conclusion gecadal geodetic mass balance geodetic method + good spatial resolution restricted temporal resolution glaciological method + good temporal resolution restricted spatial resolution Introd kyrgyzstan : old monitoring  aprupt breakdown  reestablishment in 2011 Motiviation: underrepresented in WGMS Need of monitoring: glacier retreat patter/climate influence/hydorlogical porpose mass balance modelling constrained with transient snowline observations + good temporal resolution + applicable on extended, remote areas M.Barandun, WGMS Expert Workshop 2018 on Regional Mass Balance Estimates

ASTER derived geodetic mass balance Discussion Introduction Methods Results Conclusion ASTER derived geodetic mass balance all available ASTER scenes with cloud cover lower than 50% are processed elevation change is calculated for all scene-combinations with time difference higher than 5 years and overlap of 50% range of geodetic mass balances summarized for reference period based on annual variability of regional glaciological measurements Introd kyrgyzstan : old monitoring  aprupt breakdown  reestablishment in 2011 Motiviation: underrepresented in WGMS Need of monitoring: glacier retreat patter/climate influence/hydorlogical porpose using MicMAC ASTER (MMASTER) (Girod et al., 2017) M.Barandun, WGMS Expert Workshop 2018 on Regional Mass Balance Estimates

combining the different approaches Discussion Introduction Methods Results Conclusion combining the different approaches geodetic method + good spatial resolution restricted temporal resolution glaciological method + good temporal resolution restricted spatial resolution Introd kyrgyzstan : old monitoring  aprupt breakdown  reestablishment in 2011 Motiviation: underrepresented in WGMS Need of monitoring: glacier retreat patter/climate influence/hydorlogical porpose mass balance modelling constrained with transient snowline observations + good temporal resolution + applicable on extended, remote areas M.Barandun, WGMS Expert Workshop 2018 on Regional Mass Balance Estimates

snowline-constrained model - validation Discussion Introduction Methods Results Conclusion snowline-constrained model - validation reconstructed mass balance for 3 Kyrgyz glaciers with snowline-constrained mass balance model for the past 1-2 decades Introd kyrgyzstan : old monitoring  aprupt breakdown  reestablishment in 2011 Motiviation: underrepresented in WGMS Need of monitoring: glacier retreat patter/climate influence/hydorlogical porpose Barandun et al., in review M.Barandun, WGMS Expert Workshop 2018 on Regional Mass Balance Estimates

snowline-constrained model - validation Discussion Introduction Methods Results Conclusion snowline-constrained model - validation Introd kyrgyzstan : old monitoring  aprupt breakdown  reestablishment in 2011 Motiviation: underrepresented in WGMS Need of monitoring: glacier retreat patter/climate influence/hydorlogical porpose model performance  evaluated with direct glaciological measurements / high-resolution geodetic mass balance for three selected glaciers in Central Asia Barandun et al., in review M.Barandun, WGMS Expert Workshop 2018 on Regional Mass Balance Estimates

ASTER based elevation changes - validation Discussion Introduction Methods Results Conclusion ASTER based elevation changes - validation Introd kyrgyzstan : old monitoring  aprupt breakdown  reestablishment in 2011 Motiviation: underrepresented in WGMS Need of monitoring: glacier retreat patter/climate influence/hydorlogical porpose elevation change from high-resolution images from 2003 to 2012 (QuickBird – GeoEye) elevation change from ASTER images from 2003 to 2012 difference M.Barandun, WGMS Expert Workshop 2018 on Regional Mass Balance Estimates

geodetic mass balance for a reference period 2004-2012 Discussion Introduction Methods Results Conclusion geodetic mass balance for a reference period 2004-2012 comparison between Bgeod from high-resolution and ASTER images: RMSE = 0.26 m w.e. yr-1 Introd kyrgyzstan : old monitoring  aprupt breakdown  reestablishment in 2011 Motiviation: underrepresented in WGMS Need of monitoring: glacier retreat patter/climate influence/hydorlogical porpose No. 354 all possible combinations of ASTER scenes (period > 5 years) summarized for reference period M.Barandun, WGMS Expert Workshop 2018 on Regional Mass Balance Estimates

mass balance comparison for selected glaciers in m w.e. yr-1 Discussion Introduction Methods Results Conclusion comparison to other studies mass balance comparison for selected glaciers in m w.e. yr-1 from 2004 to 2012 Glacier Bsnl Bglac/mod Bgeod_aster Bgeod_HR Abramov -0.28 ±0.35 -0.64 ±0.50 -0.36 ±0.32 -0.39 ±0.16 (Barandun et al., in review) Golubin2006-14 -0.42 ±0.35 -0.40 ±0.36 -0.22 ±0.33 -0.30 ±0.37 (Barandun et al., in review) No. 354 -0.25 ±0.31 -0.40 ±0.10 -0.61 ±0.30 -0.48 ±0.10 (Barandun et al., in review) Urumqi -0.72 (WGMS) -0.39 ±0.13 -0.64 ±0.402001-2009 (Wang et al.2014) Introd kyrgyzstan : old monitoring  aprupt breakdown  reestablishment in 2011 Motiviation: underrepresented in WGMS Need of monitoring: glacier retreat patter/climate influence/hydorlogical porpose Region Bsnl Baster Bmod (2003-2009) (Farinotti et al. 2015) Bgeod (2000-2012) (Brun et al. 2017) North Tien Shan ? -0.24±0.37 -0.33±0.16 to -0.49±0.22 -0.26+0.34 -0.28+0.30 West Tien Shan -0.26±0.30 East Tien Shan -0.40±0.41 -0.41±0.28 Central Tien Shan -0.20±0.33 -0.31±0.32 Pamir Alay -0.11±0.27 -0.04±0.07 M.Barandun, WGMS Expert Workshop 2018 on Regional Mass Balance Estimates

comparison to other studies Discussion Introduction Methods Results Conclusion comparison to other studies Comparison of mass balance constrained with transient snowline observations to other studies for three Benchmark glaciers and region-wide studies Was kann man tun, wenn es zu wenige SL Beobachtungen gibt um gute rating curve herzuleiten? => idealized curve. Ausserdem musst Du betonen (vorne), dass die Kurve (im Normalfall) jährlich hergeleitet wird, kommt momentan nicht raus Outlook: Region-wide estimate based on mass balance model constrained with transient snowline observations SNL-model for individual glacier = this study Barandun et al., in review M.Barandun, WGMS Expert Workshop 2018 on Regional Mass Balance Estimates

conclusions and outlook Discussion Introduction Methods Results Conclusion conclusions and outlook first results of snowline-constrained model region-wide decadal geodetic mass balance from ASTER data for a reference period validation through in situ measurements and geodetic mass balance based on high-resolution DEMs Introd kyrgyzstan : old monitoring  aprupt breakdown  reestablishment in 2011 Motiviation: underrepresented in WGMS Need of monitoring: glacier retreat patter/climate influence/hydorlogical porpose M.Barandun, WGMS Expert Workshop 2018 on Regional Mass Balance Estimates

conclusions and outlook Discussion Introduction Methods Results Conclusion conclusions and outlook Next step: region-wide application of snowline-constrained model to derive annual mass balances automatically classified snowlines on a large amount of Landsat images  reliable annual SMB time series coupled to decadal geodetic mass balance for remote regions No. 354: Introd kyrgyzstan : old monitoring  aprupt breakdown  reestablishment in 2011 Motiviation: underrepresented in WGMS Need of monitoring: glacier retreat patter/climate influence/hydorlogical porpose M.Barandun, WGMS Expert Workshop 2018 on Regional Mass Balance Estimates

Thank you for your attention Photo: L. Sold Thank you for your attention Introd kyrgyzstan : old monitoring  aprupt breakdown  reestablishment in 2011 Motiviation: underrepresented in WGMS Need of monitoring: glacier retreat patter/climate influence/hydorlogical porpose Many Thanks to all people contributing to this work Marlene Kronenberg, Tomas Saks, Bolot Moldobekov, Erlan Azisov, Ruslan Kenzhebaev, Abror Gafurov, Stefan, Anton, David Sciboz, Aleksandr Merkushkin, Mario, Mauro, Daniel Farinotti, Fanny Brun, Sergiy Voroguhsyn, Willi Hagg, Horst Machguth, Nadine Salzmann, Philipp, Kathrin, Michi, Nico, Atoine, Julia, Helena, Lena, Helene, Victor, Aichurok, Muhamed, Almas, Avas, Perizat, Zarilbek, Shagymbek, Emil, Vektur, Alina, Aizhan, Seba, Silas …