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Baker Perry 1, Richard Poremba 1, Anton Seimon 1,2, Daniel Martin 1, Ginger Kelly 1, and Alfredo Tupayachi 3 1 Department of Geography and Planning, Appalachian State University 2 Climate Change Institute, University of Maine, 3 Universidad Nacional de San Antonio de Abd de Cusco 71 st Eastern Snow Conference Boone, NC USA 5 June 2014 SNOWFALL EVENT CHARACTERISTICS IN THE CORDILLERA VILCANOTA, PERU

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Cordillera Vilcanota

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Background and Significance Cordillera Vilcanota has been the site of significant research focused on: Paleoclimatic reconstructions from Quelccaya ice cores (e.g., Thompson et al. 1985, Seimon 2003, Thompson et al. 2006 ) Past glaciations and climate-glacier interactions (e.g., Mark et al. 2002) Ecological response to climate change (e.g., Seimon et al. 2007) Precipitation variability is a fundamental influence on past and current changes in the tropical Andes (Garreaud et al. 2003) Precipitation type, amount, and timing controls surface albedo, which is critical to glacier mass balance (e.g., Francou et al. 2003) Precipitation processes play a dominant role in influencing stable oxygen isotope ratios ( 18 O) preserved in snow/ice stratigraphy (e.g., Vuille et al. 2008, Vimeux et al. 2009) However, considerable uncertainty remains on the timing, precipitation type, and trajectories during events

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Descriptions of Central Andean Regional Precipitation Climatic FeaturePrevious StudiesThis Study Precipitation diurnality Unimodal daytime precipitation maximum Bimodal: broad nighttime maximum peaking near midnight LST with secondary late-afternoon maximum Precipitation character Exclusively deep, moist convection Primarily stratiform (nighttime) with secondary deep moist convection (daytime) Precipitating moisture trajectory E from Amazon basin Primarily NW, but with 95 % tied to trajectories from the Amazon basin Moisture source regions Amazon basin exclusively Dominantly Amazon basin, but also 5% from Pacific Ocean ENSO-related precipitation anomalies Negative anomalies with El Nio; positive anomalies with La Nia Positive anomalies with El Nio; negative anomalies with La Nia ?

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Research Questions What are the predominant precipitation types at ~ 5,000 m asl and how do they vary by season? Snow, graupel (phati in Quechua), rain/snow mix, rain What is the daily timing of snowfall events in the Cordillera Vilcanota? When is heavy snowfall most likely to occur? What are the dominant wind directions and antecedent upstream air trajectories associated with snowfall events?

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SENAMHI Stations: 2x Daily Observations 0000 and 1200 UTC Cusco International Airport: Hourly Precip Observations Perry et al. 2014, Int J Clim

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Quelccaya Icecap Don Pedro Godfredo with Precipitation Gauge (At Murmurani Alto 5,050 m asl) 10 cm diameter manual gauge August 2010

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Sonic Snow Depth Parsivel Present Weather Temp & Relative Humidity April 2012 Murmurani Alto (5,050 m)

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RM Young 05103 Alpine Wind Sensor April 2012 Osjollo Anante Icecap (5,540 m) Vaisala WXT 510 Multisensor with Sonic Wind, Temperature, Relative Humidity, and Pressure

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Snow and Graupel are the Primary Precipitation Types Rain is Very Infrequent, Less than 4% of Hours

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April 2012 Rapid Snow Ablation in Murmurani Alto

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5.9 mm/event 68% of total =Stratiform? 3.3 mm/event 32% of total =Convective? Night Day Sunrise Perry et al. 2014, Int J Clim

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73% of heavy events occur at night 59% of light events occur during day Perry et al. 2014, Int J Clim

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Night Day Sunrise

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Composite Trajectory Clusters for All Events in Cusco, 2004-2010 Cluster 1 50% of events 4.7 mm/event Cluster 3 19% of events 4.8 mm/event Cluster 6 5% of events 8.7 mm/event Cluster 2 14% of events 3.6 mm/event Cluster 4 5% of events 4.8 mm/event Cluster 5 8% of events 3.3 mm/event 58% of precipitation events at Cusco exhibit trajectories out of the NNW Infrequent, yet heavy 83% of events are tied to weak low-level flow out of NNW, NE, and E Perry et al. 2014, Int J Clim

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Wind Speed and Direction During All Precipitation Events: 2012-2013 Wind Observations from Osjollo Anante Precipitation Observations from Murmurani Alto

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Wind Speed and Direction During DJF Precipitation Events: 2012-2013 Wind Observations from Osjollo Anante Precipitation Observations from Murmurani Alto

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Descriptions of Central Andean Regional Precipitation Climatic FeaturePrevious StudiesThis Study Precipitation diurnality Unimodal daytime precipitation maximum Bimodal: broad nighttime maximum peaking near midnight LST with secondary late-afternoon maximum Precipitation character Exclusively deep, moist convection Primarily stratiform (nighttime) with secondary deep moist convection (daytime) Precipitating moisture trajectory E from Amazon basin Primarily NW, but with 95 % tied to trajectories from the Amazon basin Moisture source regions Amazon basin exclusively Dominantly Amazon basin, but also 5% from Pacific Ocean ENSO-related precipitation anomalies Negative anomalies with El Nio; positive anomalies with La Nia Positive anomalies with El Nio; negative anomalies with La Nia (Not shown) Perry et al. 2014, Int J Clim

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Summary and Conclusions Precipitation primarily falls as snow above 5,000 m, with graupel and heavily rimed snow crystals common. Rain and mixed precipitation are rare, accounting for less than 5% of total precipitation hours. How will these values change in 2014-2015, with the possibility of a major El Nio and an associated elevated freezing level? There were a total of 281 events between April 2012 and July 2013, with most of the heavy events occurring at night. No hourly precipitation totals available, only present weather. What are the meteorological mechanisms responsible for the heavy nighttime stratiform precipitation? Most precipitation events are associated with W and NW flow at Murmurani Alto and NW trajectories at Cusco. In contrast to E flow as reported at other sites in the Central Andes, including Quelccaya.

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Paleoclimatic Implications Much of the inference from the nearby Quelccaya ice core record presumes that the central Andean precipitation meteorology is fairly well understood. Our findings call that into question. A reconsideration of the climatological inferences derived from Quelccaya (and possibly other tropical Andean ice cores) may be needed. May result in improved paleoclimatic understanding? Improved correlation with other paleoclimatic proxy records?

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Research Activities: July to November 2014 Install precipitation monitoring stations on the Quelccaya Icecap and at Chacaltaya (Cordillera Real), Bolivia. Recruit and train additional citizen science precipitation observers in the Cordilleras Vilcanota and Cordillera Real. Investigate the vertical structure of precipitation with weather balloon releases and a vertically-pointing radar. Categorize snow particle type and degree of riming, which may provide insight to cloud microphysical processes. Minder et al. (2012)

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Acknowledgments Sandra Yuter, Doug Hardy, Nelson Quispe, Marcos Andrade, Tracie Seimon, Jon Webb, Preston Sowell, Brooks Fisher, Karina Yager, Charles Rodda, Skylar Haines, Nico Robles, Ben Boore, Paul Carr, Dan Slayback, Don Pedro Godfredo, and Crispin family Appalachian State University Board of Trustees International Research Travel Grant (2009), Office of International Education and Development (2010, 2012), Justin Brooks Fisher Foundation (2012), College of Arts & Sciences (2012) NSF Grant AGS-1347179 (CAREER: Multiscale Investigations of Tropical Andean Precipitation)Questions?