Mass Balance and Climate of the Ablation Zone of the Taylor Glacier, Antarctica Andrew Bliss and Kurt Cuffey Department of Geography, University of California at Berkeley, 507 McCone Hall #4740, Berkeley, CA 94720 [email protected] http://geography.berkeley.edu/~abliss/

Abstract We explore the relationships between climate and ablation on the Taylor Glacier, Antarctica on hourly to annual timescales. A simple physically- based model that predicts ablation from weather station measurements on Map of Taylor Glacier, Antarctica. The squares identify weather the Taylor Glacier is presented along with a set of criteria to distinguish station locations. The red circles show ablation stake locations. North between predominant weather patterns on the glacier. Two case studies of is up. The equilibrium line is close to the cyan station, everything to high ablation events are presented. Advanced Very High Resolution the east is blue ice. The inset map is a digital elevation model of Radiometer imagery and NOAA-NCEP Reanalysis data are included to Antarctica, showing the location of the Taylor Glacier. give the broader context of the weather station measurements and to help connect the local scale of weather station measurements to the broader scale of climate model output. A novel method of visualizing these disparate data is also demonstrated. grees) ind Direction W (de Taylor Glacier Taylor Glacier ind Speed W (m/s)

Motivations of a katabatic wind event and is identified as such by a set of criteria we defined to distinguish among 4 grees C)

emperature The interactions between climate and the Antarctic Ice Sheet are interesting because the response of the different "modes" of weather variability on the Taylor Glacier: storm, katabatic wind, calm, and diurnal

T Antarctic Ice Sheet to anthropogenically-forced climate change may have large impacts on human mountain/valley wind. The mode indices are displayed in the figure at the far left. The next large- (de societies. We chose the Taylor Glacier as our study area in part because of the climate history record sublimation event began on March 9th and lasted until the 13th. The combination of high winds, provided by the Taylor Dome ice core. If we can understand how the Taylor Glacier has responded to consistent wind directions, and clouds is indicative of a storm. past climate changes, we will be more confident in our predictions of glacier and ice sheet response to

Rel. Humidity future climate changes. The interaction between the climate and the glacier itself takes many forms (ice Advanced Very High Resolution Radiometer Imagery (%) rheology depends on temperature, snowfall depends on storm tracks, ablation depends on temperature, The two infrared satellite images above provide a regional perspective on the weather situation and Sublimation During Different Modes ference wind speed, humidity, cloudiness). This poster focuses on the connection between weather and ablation verify our choice of mode for each sublimation event. The image on the left is from March 4th when Sublimation happens at different rates under different conditions. In the

VP dif on the Taylor Glacier where the dominant mass-loss mechanism is sublimation of ice to the katabatic winds dominated the local weather on the Taylor Glacier. The dark (warm) trace of the two examples just shown, rates were slightly higher for the katabatic (mbar) atmosphere. We present two case studies from March of 2006, one of a katabatic wind event and the katabatic wind can be seen emanating from the Skelton Glacier, just south of the Taylor Glacier. White event because the relative humidity was lower which increases the second of a storm that followed a few days later. (cold) cloud streaks are also visible, indicating fast winds aloft. The image on the right was taken moisture transport from the surface (assumed to be saturated) to the March 12th, when the Taylor Glacier was in the midst of the storm. A comma cloud is clearly visible atmosphere. The figure above shows that high-sublimation events occur

(mmWE/20 min) Weather Station Data and the Taylor Glacier is under thick clouds. The imagery comes from http://avhrr.acecrc.org.au/ during storms and katabatic events while low-sublimation events have

Each of the six weather stations that we set up on the Taylor Glacier in November of 2003 measures predominantly calm conditions. ard SW Sublimation wind speed, direction, temperature and relative humidity (shown in the figure at left). From these NOAA-NCEP Reanalysis Data

wnw variables, we predict sublimation at the weather station locations (also shown). While common low- The plots below show data from the NOAA-NCEP reanalysis corresponding to the days when the Google Maps Data Interface sublimation rate events (around 1 mm/day) account for the bulk of the sublimation on the Taylor images above were captured. All four fields are from the surface layer of the model. The blue star and The figure in the bottom right corner shows a screenshot of an AVHRR Do Glacier, less frequent, larger events are needed to explain the total observed ablation. Two of these box show the approximate locations of the Taylor Glacier and the AVHRR images respectively. The image and weather station data presented on the web using the Google (W/m^2) events are shown in the graph at left. The first started on February 26th and lasted until March 6th, synoptic conditions are remarkably similar between the two cases. In both cases the reanalysis is fairly Maps API. The data figures are inserted as a custom tile layer for the map ard SW reaching its peak intensity between the 3rd and the 6th. This pattern of wind speeds, directions, and consistent with our weather station data. Data from http://iridl.ldeo.columbia.edu/ and the AVHRR images, maps of reanalysis data, and comments on the Upw cloudiness (as observed by shortwave and longwave radiometers on 3 of our stations) is characteristic data are displayed in popup info windows. W (W/m^2) ard L wnw Do W (W/m^2) ard L Upw (W/m^2) x Storm Inde x Inde Katabatic x Inde Calm x Diurnal Inde