Saturday, April 28, 2012

Archival video

Here is a clip produced by New York Times Science Times. The feature was filmed in June 2001 for broadcast on the National Geographic Channel, and recently turned up on YouTube. Director of Photography John Hazard was fun to have along, joining Georg Kaser, Tharsis Hyera, Erick Masawe and others!

Wednesday, April 25, 2012

Snowy April

As of yesterday, 30 cm of snow has accumulated on the Northern Ice Field this month. Not since 2006 has there been this much during April.

Any photographs of snowcover in the crater or at the summit would be appreciated!

 [UPDATE 5/1:  See above... snowfall continued.]

Wednesday, April 4, 2012

6 March snowfall

For the month of March, telemetry data indicate net snow accumulation of a paltry 2.7 cm. However, a detailed examination reveals a more interesting situation.

Telemetry shows only 2 snowfall events occurring at the summit during March. Establishing the magnitude of snowfall from telemetry data is sometimes tricky because: 1) telemetry data are only 4-hourly, 2) measurements by the 2 acoustic sensors often differ due spatial variability of accumulation, and 3) acoustic sensors sometimes yield noisy data during snowfall events. However, for the event on 6 March both acoustic sensors recorded 15-20 cm of accumulation, placing this event among the top 3 in the one-day snowfall rankings since 2000. More typically, snowfall events tend to occur over longer time periods.

The weather on 6 March contrasts sharply with that of other days last month. For example, the 4 AM and 8 AM 4-hourly mean values of temperature and humidity were the highest for both times during the month, suggesting cloud cover and moisture advection. Likewise, the temperature at noon was the lowest for any day of the month, humidity was the second highest, and 12 PM minima of both incoming and reflected solar irradiance were recorded.

Through the balance of March, lowering of the glacier surface was nearly linear, suggesting a near-constant, combined rate of ~7mm/day for settling, sublimation and melt.