1 / 18

EGU General Assembly, Vienna, AT, 9 April 2018

EGU General Assembly, Vienna, AT, 9 April 2018. A review of methods to estimate regional and global glacier mass balances

rburket
Download Presentation

EGU General Assembly, Vienna, AT, 9 April 2018

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. EGU General Assembly, Vienna, AT, 9 April 2018 A review of methods to estimate regional and global glacier mass balances Michael Zemp, Laura Thomson, Emmanuel Thibert, Frank Paul, Samuel U. Nussbaumer, Robert McNabb, Fabien Maussion, Horst Machguth, Matthias Huss, Jacqueline Huber, Isabelle Gärtner-Roer, Nicolas Eckert, and Martina Barandun March 2018 @ Ibergeregg, CH

  2. How best assess regional mass balance from few observation series? The Alps Kääb et al. (2013) Photo: M. Zemp

  3. review AR4 and AR5 methods ¦ new method ¦ preliminary results Pleiades, CNES Airbus Cryosat-2, ESA TanDEM-X, DLR Graphic: P. Joerg

  4. review AR4 and AR5 methods ¦ new method ¦ preliminary results Mass balance estimates in past IPCC Reports IPCC WGI AR5 (2013) Gardner et al. (2013) • glac. and geod. estimates based on: Cogley (2009) • arithmetic mean of glac. balances • spatial interpolation of glac. balances at 1°x1°grid • spatial interpolation of glac. and geod. balances at 1°x1°grid IPCC WGI AR4 (2007) Kaser et al. (2013) • glac. estimates based on: • Cogely (2005): arithmetic averaging and polynomial spatial interpolation • Dyurgerov & Meier (2005), Ohmura (2004): area-weighting => Time resolution: pentades

  5. review AR4 and AR5 methods ¦ new method ¦ preliminary results Review methods used in AR4 and AR5 in sandbox experiment

  6. review AR4 and AR5 methods ¦ new method ¦ preliminary results Method evaluation in the Swiss “sandbox”: B.geodetic Time period: 1980-2010 No. of glaciers: 1385 S1980: 1255 km2 S2010: 948 km2 Savg: 1102 km2 ρ: 850 kg m-3 Sum of Bgeod: -19.13 Gt + increasing number of observations+ representative samples allow for validation & calibration over longer periods “Arithmetic Mean of Geodetic Balances”: -15 Gt Strong underestimation when calculating Bgeod from dVavg and Savg! - common time periods- completeness of inventory- area changes - density conversion Fischer et al. (2014, 2015)

  7. review AR4 and AR5 methods ¦ new method ¦ preliminary results B.glac using arithmetic mean Time period: 1980/81-2009/10 No. of glaciers: 4 Savg: 1102 km2 Bglac.cum: -18.8 m w.e. Bglac.cum: -20.7 Gt + simple & fast method + few information required - very sensitive to sample- changing sample over time

  8. review AR4 and AR5 methods ¦ new method ¦ preliminary results B.glac using arithmetic mean at 1° x 1° grid Time period: 1980/81-2009/10 No. of glaciers: 4 Savg: 1102 km2 Bglac.cum: -18.8 m w.e. Bavg.centerpoints: -18.7 m w.e. Bglac.cum: -20.6 Gt

  9. review AR4 and AR5 methods ¦ new method ¦ preliminary results B.glac using area-weigthed mean at 1° x 1° grid Time period: 1980/81-2009/10 No. of glaciers: 4 Savg: 1102 km2 Bglac.cum: -18.7 Gt

  10. review AR4 and AR5 methods ¦ new method ¦ preliminary results B.glac interpolated to inventory points multiplied with indv. S Time period: 1980/81-2009/10 No. of glaciers: 4 / 1385 Savg: 1102 km2 Bglac.cum: -20.1 Gt + regional climatic variability + glacier distribution in space - ignores effect of hypsography- extrapolation of absolute Ba values

  11. review AR4 and AR5 methods ¦ new method ¦ preliminary results Swiss balance estimates 1980-2010 in comparison excluding GRIES???

  12. review AR4 and AR5 methods ¦ new method ¦ preliminary results Swiss balance estimates 1980-2010 in comparison excluding GRIES!!!

  13. review AR4 and AR5 methods ¦ new method ¦ preliminary results Swiss balance estimates 1980-2010 in comparison Combine the temporal variability of the glaciological with the absolute value of the geodetic balance! cf. Zemp et al. 2013, The Cryosphere fotomelia.com

  14. review AR4 and AR5 methods ¦ new method ¦ preliminary results Temporal signal: variance analysis of glac. data building on Lliboutry’s linear model J. Glaciol. 1974

  15. review AR4 and AR5 methods ¦ new method ¦ preliminary results Temporal signal: variance analysis of glac. data

  16. review AR4 and AR5 methods ¦ new method ¦ preliminary results Absolute value: calibrate glaciological with geodetic

  17. review AR4 and AR5 methods ¦ new method ¦ preliminary results Very preliminary results for 2003-2009 avg diff. to Gardner et al. (2013) arithm. avg ¦ area-weighted avg ¦ interpolated to RGI glaciers ¦ Gardner et al. (2013)

  18. review AR4 and AR5 methods ¦ new method ¦ preliminary results Thanks for your attention! SROCC swr.de Kahlitna Glacier, Alaska, from www.swisseduc.ch/glaciers/

More Related