Estimates of annual surface mass balance from radar for the West Antarctic Divide using an automated layer picker
Abstract
47687">Sea47687"> level rise remain47687">s47687"> one of the most pressing and widespread risks of climate change, with the 47687">potential 47687">to directly impact hundreds of millions of individuals. The polar 47687">ice sheets47687"> 47687">will 47687">play an 47687">increasingly 47687">large 47687">role in 47687">this issue47687"> 47687">over time47687">, with 47687">current research focused on understanding 47687">the47687"> relative contribution47687">s of various components47687"> of ice sheet mass balance47687">.47687"> 47687">Specifically, t47687">he l47687">arge spatiotemporal variability in 47687">surface mass balance (SMB) 47687">presents unique challenges in 47687">understanding its 47687">future effect on sea level47687">.47687"> 47687">A47687"> lack of spatially distributed 47687">SMB observations 47687">over polar 47687">regions47687"> compounds these complexities47687">.47687"> 47687">Previous studies 47687">demonstrate47687"> the efficacy of u47687">l47687">tra-high frequency (UHF) radar 47687">to estimate47687"> annual47687"> 47687">SMB 47687">in 47687">ice sheets, but traditional techniques involve laborious manual 47687">selection of annual layers, limiting 47687">the 47687">applicability47687"> 47687">of 47687">large 47687">existing 47687">radar data47687">sets47687"> 47687">(e.g. NASA's Operation 47687">IceBridge47687">)47687"> to SMB studies47687">.47687"> 47687">To help address 47687">this47687"> issue, we present 47687">a 47687">probabilistic, 47687">fully automated approach47687"> to47687"> estimate 47687">annual 47687">SMB47687"> from 47687">UHF47687"> 47687">radar47687"> using47687"> a weighted nearest neighbor algorithm to find continuous return horizons47687"> and47687"> assign47687">ing47687"> annual layer likelihood scores based on layer length and return strength. 47687">We apply this method 47687">to47687"> ground-based Ku47687">-47687">band 47687">and airborne Operation 47687">IceBridge47687"> 47687">data 47687">in 47687">a47687"> 47687">10047687"> 47687">x47687"> 47687">200 km 47687">section of the West Antarctic interior47687"> straddling the 47687">Amundsen47687"> Sea47687">-47687">Ross 47687">Sea 47687">ice divide47687">. 47687">T47687">he 47687">results show good agreement 47687">between 47687">both radars47687">, 47687">firn47687"> cores, and manual 47687">counts of radar layers47687">, and47687"> 47687">confirm the negative 47687">SMB 47687">trend 47687">prev47687">iously observed in 47687">the 47687">region47687">.47687"> 47687">P47687">reliminary results 47687">of spatiotemporal patterns 47687">suggest 47687">more negative47687"> 47687">SMB 47687">trends 47687">on the 47687">Amundsen 47687">side 47687">of the divide 47687">relative to the interior47687">, even after accounting for higher accumulation rates 47687">on 47687">the 47687">Amundsen47687"> side47687">.47687"> 47687">These results 47687">highlight the importance of dynamic changes to 47687">moisture transport in the region overwhelming the recent warming47687">,47687"> 47687">causing47687"> a decline in SMB rates. 47687">Furthermore, this new approach 47687">would permit 47687">the autonomous extraction of annual accumulation rates from previously-collected and ongoing 47687">radar 47687">datasets in both hemispheres47687"> 47687">to produce an47687"> unprecedented spatiotemporal 47687">record47687"> of47687"> 47687">polar47687"> 47687">SMB 47687">that 47687">would 47687">greatly 47687">facilita47687">te47687"> 47687">our 47687">understanding 47687">of 47687">rece47687">nt changes in atmospheric 47687">moisture transport47687">, 47687">enhanc47687">ing47687"> 47687">our ability to 47687">forecast 47687">future sea level rise 201341983":0,"335559739":160,"335559740":259}"">
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.C43E1847K
- Keywords:
-
- 0726 Ice sheets;
- CRYOSPHEREDE: 0728 Ice shelves;
- CRYOSPHEREDE: 0762 Mass balance;
- CRYOSPHEREDE: 0776 Glaciology;
- CRYOSPHERE