Wednesday, October 19, 2011

More ice sampling

In 2009 we collaborated with researchers at Paul Scherrer Institute (Switzerland) to test new techniques for dating glacier ice (more here). Encouraging results justified further investigation, which was part of our recent fieldwork. Here is a short clip illustrating this year's approach to sampling; note that September weather wasn't quite as dry as normal!

Early Short Rains?

A recent posting here discussed a multi-day August snowfall event which resulted in ~5cm of accumulation on the Northern Ice Field. The next month or so was relatively dry, as typically the case at this time of year, with only about 14cm of ablation due to relatively high albedo following the mid-August snowfall event.

At the Northern Ice Field AWS, the next snowfall event appears to have occurred on 20 September, the day our team arrived in Tanzania. More snowfall was recorded on the 23rd, when we waited - in the rain - for our final permits at park headquarters in Marangu. Ascending the mountain we encountered light precipitation on a few days. However, while setting up camp in the crater on the 29th, a snow squall brought another 3-4cm of accumulation to the glacier.

The next snowfall occurred during the night of October 1st, apparently associated with tremendous convection visible to the East and accompanied by lightning and thunder, the most we have ever seen from the summit. By morning, camp was blanketed by a uniform 6cm of new snow, with more variable accumulation on the glacier. Rather fortuitously, the AWS had been reset into the ice the previous day; disturbance of the glacier surface is unavoidable during this process. Perfect timing for a snowfall event!

Telemetry from the AWS indicates continuing accumulation since we departed on the 4th, with snowfall on the 5th and a multiday event from ~11-15 October. With net accumulation of ~5cm to mid-October, little additional ablation is likely in the next few months - especially if the Short Rains have indeed begun.

Finally, anecdotal reports from around the mountain support the idea of an early Short Rain season. For example, a note from 17 October indicated "lots of rain on Kilimanjaro" which made climbing very difficult for some clients (Ngorogoro Camp and Lodge). Also from the 17th, several reports of rain "every day" in Arusha. In the week prior, perhaps coinciding with the multiday event on Kilimanjaro, a storm over Kibwezi, Kenya (just north of Kilimanjaro) "was so intense that it prevented small aircraft from going to the coast."

Tuesday, October 11, 2011

Fieldwork!

We are just back from a productive trip to the mountain, spending 6 days at the summit glaciers. Typically, the dry season extends into October, but this year, rain and snow were a near-daily occurrence. One evening, snowfall accompanied by lightning and thunder collapsed our dining tent. Such variability keeps the work interesting!

Our primary objective was recovering data, changing-out instruments, and servicing the weather stations for another year of autonomous operation. For example, surface lowering of the ice (due ablation) required us to lower one of the stations further into the glacier. This was accomplished by considerable chiseling of ice, to create a one-meter deep hole. We also measured and re-drilled mass balance stakes, conducted GPS surveys, and re-photographed glaciers. This year we recovered 48 additional ice cores, which were kept frozen until reaching the laboratory freezer.

A selection of images from the fieldwork is below. For a day-by-day account of the adventure, check the "Kibo2011" group on Facebook. Additional images can be seen here.

Special thanks this year to Carsten Braun (Westfield State University), Tanzania National Parks, the Tanzania Wildlife Research Institute, and to Simon and crew at Summit Expeditions and Nomadic Experience (SENE). All were extremely helpful, for which we are most grateful.

Image #1 (above).  Northern Ice Field margin.

Image #2.  Kersten Glacier, just below Uhuru Peak. One year ago the upper and lower sections were still connected!

Image #3.  Little Penck Glacier, continuing to retreat and now clearly separated into two parts.

Image #4.  Northern Ice Field (distant) and the two sections of Furtw√§ngler Glacier (foreground). Compare the Furtw√§ngler image with that from 2002 (click here).

Image #5.  One component of the UMass station, including instruments compatible with the U.S. Climate Reference Network (CRN). Note mass balance stake to left.

Image #6.  The original UMass AWS, with Uhuru Peak in distance. Barely visible against the rock background is the "RimeCam" - acquiring 3-hourly images to help assess measurement quality.

Image #7.  Swiss collaborators from Paul Scherrer Institute working through heavy snowfall, coring the Northern Ice Field's vertical wall. Our objective here is refining the history (chronology) of glaciers on Kilimanjaro.

Image #8.  A less-fortunate visitor to Kibo's glaciers... reminding us how important safety is at nearly 6,000 meters elevation.