Melting trends over the Greenland ice sheet ( ) from spaceborne microwave data and regional climate models Kelsey Simmons Atmospheric Science Major Published May 5, 2011 By X. Fettweis, M. Tedesco, M. van den Broeke, and J. Ettema

Authors Dr. Xavier Fettweis Dr. Xavier Fettweis University of Liege, Belgium Dr. Marco Tedesco Dr. Marco Tedesco The City College, New York, NY

Authors Dr. Michiel R. van den Broeke Dr. Michiel R. van den Broeke Utrecht University, The Netherlands Dr. Janneke Ettema University of Twente, The Netherlands

Overview Data Data Biases and Limitations Biases and Limitations Results Results What does it mean/Why does this matter? What does it mean/Why does this matter?

Collecting Data Models:RACMO2 and MAR Models:RACMO2 and MAR Instruments Instruments Algorithms Algorithms Automated Weather Station (AWS) used for the Greenland Climate Network. (GC-Net)

Algorithms Methods for detecting wet snow T19H  K-band horizontal polarized brightness temperature T19H thsd  Threshold value of T19H T37V  K-band vertical polarized brightness temperature XPGR  Cross-polarized gradient ratio

CP1 CP1 DYE DYE ETH-Camp ETH-Camp Jar1 Jar1

Melting analysis Time period Time period Years with lower snow melting vs. years with higher snow melting Years with lower snow melting vs. years with higher snow melting Regions with >100 days of melting Regions with >100 days of melting Difference between models and satellite data Difference between models and satellite data Limitations in the Algorithms Limitations in the Algorithms

T19HmeltExtXPGRXPGRMARRACMO2

Biases in Models Melting areas absent in one but not the other Melting areas absent in one but not the other Bare ice at the surface Bare ice at the surface Summer snowfall Summer snowfall

Results and Errors Significant positive trend Significant positive trend Years of Max and Min Years of Max and Min Periods of highs and lows Periods of highs and lows Response time to surface snow changes Response time to surface snow changes 2-m temperature vs surface temperature 2-m temperature vs surface temperature Minimum thickness Minimum thickness LWC sensitive algorithms LWC sensitive algorithms

What does this mean and why does it matter? Sea level rise Sea level rise Influence weather patterns Influence weather patterns Paleoclimatology Paleoclimatology

QUESTIONS?

Works Cited Fettweis, Xavier, Marco Tedesco, Michiel Van Den Broeke, and Janneke Ettema. "Melting Trends over the Greenland Ice Sheet (1958–2009) from Spaceborne Microwave Data and Regional Climate Models." TC - Abstract - Melting Trends over the Greenland Ice Sheet (1958–2009) from Spaceborne Microwave Data and Regional Climate Models. Copernicus Publications, 5 May Web. 15 Apr Fettweis, Xavier, Marco Tedesco, Michiel Van Den Broeke, and Janneke Ettema. "Melting Trends over the Greenland Ice Sheet (1958–2009) from Spaceborne Microwave Data and Regional Climate Models." TC - Abstract - Melting Trends over the Greenland Ice Sheet (1958–2009) from Spaceborne Microwave Data and Regional Climate Models. Copernicus Publications, 5 May Web. 15 Apr seas/gatefold/RS_Web_NA_15M_v3.jpg seas/gatefold/RS_Web_NA_15M_v3.jpg