Timelapse: watch 129 days in 11 seconds

In early 2005 we installed a timelapse camera system near the weather station, with objectives of visually documenting the variability of weather (esp. clouds), glacier surface texture & roughness, accumulation & ablation, and crater snowcover. Images demonstrate the pronounced and typical diurnal cycle of convection on southwestern slopes, as well as interesting variability within the seasonal cycles.

A movie of 129 days worth of images is available here, spanning 8 Oct. 2009 to 14 Feb. 2010. To provide consistent lighting, these images are all from 6 PM local time, when the upper Breach Wall and the Furtwängler Glacier are illuminated. To fully appreciate the day-to-day variability of weather and snowcover depicted, try watching just one portion of the image (e.g., convection to the South, glacier in foreground).

The two images below are from the same time interval, illustrating dry conditions on a clear day, and fresh 'short rains' snowcover (respectively). Note the white ablation stake in the foreground; 42 cm was exposed in early October of 2009 (shortly prior to date of upper image), increasing a year later (8 Oct. 2010) to 120 cm.

2010 dry season ablation

June through October is typically an extended dry period at the summit of Kilimanjaro, with ablation of horizontal glacier surfaces often increasing once the seasonal snow cover is gone. During September and October this year, ablation was especially pronounced on the Northern Ice Field, despite above-average snow cover at the end of May. Ablation will continue at this pace in November until the 'short rains' begin and snow cover is restored.

To illustrate, average net surface lowering at the weather station (2 sensors) was 30 cm in both October and September, following 19 and 22 cm in August and July, respectively. New records were established for net ablation over 2-, 3-, and 4-month intervals (since 2002).

Analysis of October 2010 field measurements is just getting underway, including those from a network of ablation stakes, but it appears that surface ablation may have been more normal on the southern glaciers. With our Innsbruck colleague's full instrumentation on that side, it will be fascinating to further investigate these spatial patterns of mass and energy flux.

Success!

Back safely from fieldwork at the summit. Thanks to Simon (above) and the SENE crew (Summit Expeditions & Nomadic Experiences), as well as the Marangu Hotel team, this was a fun and productive trip. Over the course of 6 busy days amidst the penitentes, we accomplished just about every objective on the list; details will be posted soon.

Upcoming fieldwork

I haven't been on the mountain for 11 months now, and am anxious to get back. Telemetry indicates that the rate of ablation during the current dry season has been unprecedented in the 10-year record - which is somewhat perplexing. Snow accumulation began on the glaciers within a few weeks of our October 2009 fieldwork and continued without much interruption until the very end of May, bringing a net accumulation of 70 cm to the Northern Ice Field. Ablation then began, and although measurements from the two sensors differ, most of this snow appears to have now ablated. Visiting the glaciers will allow evaluation of the extent to which melting, evaporation, and superimposed ice formation is responsible.

So, we depart later this month for the summit glaciers with an ambitious program and a collaborative team, including personnel from the Univ. of Massachusetts, Innsbruck University, and NASA JPL. Simon Mtuy and Summit Expeditions are again providing logistical support on the mountain. One of my objectives will be to add reference-quality instrumentation developed by the U.S. CRN (Climate Reference Network), establishing the first CRN station outside the Americas. Operating CRN instruments alongside those which have been on Kilimanjaro since February 2000 will provide an intercomparison with which the long-term data can be adjusted. Measuring air temperature in that environment, on snow and with solar radiation typically exceeding 1,200 W/m^2, is far more difficult than might be expected.

Accompanying work at the weather station will be measurement of how ablation on the glacier has varied spatially, while NASA team members investigate microbiological diversity in the ice. And we're optimistic about getting some dates soon on ice samples collected last October. Stay tuned!

-Doug Hardy, UMass Geosciences

Science journalism

Christopher Reddy of Woods Hole Oceanographic Institution has an opinion piece in the August 25th Wall Street Journal, pertaining to media coverage of the Deepwater Horizon's subsurface oil plume. Although the situation is arguably more complex and important than the Kilimanjaro retreating glacier story, I find it to be an interesting analog in terms of scientist's differing findings, their interaction with journalists, and how the story is conveyed by the media. Reddy suggests that "...it is incumbent on scientists and journalists to keep the results in perspective" [especially those which are preliminary] "and refrain from veering into misleading waters."

Two new publications

This week, two new papers add to our knowledge of Kilimanjaro's glaciers.  Georg Kaser is first author on "Is the decline of ice on Kilimanjaro unprecedented in the Holocene?" published (appropriately enough) in The Holocene.  The paper sets forth a hypothesis that the glaciers may be only hundreds of years old, rather than 11,700 - as detailed in the only other paper published on the matter (Thompson et al., 2002).  A link to this new paper, as well as the 2002 paper in Science, are provided to the right.  The quest for definitive dates on the ice is underway!

A second new paper is primarily the work of Ph.D. student Michael Winkler (Innsbruck), and published in Erdkunde (in English). "Land-based marginal ice cliffs: focus on Kilimanjaro" will be of interest to anyone familiar with - or intrigued by - the unique vertical walls of Kilimanjaro glaciers. The paper is also available from our publications link.

Dry season underway

As typically the case, the beginning of June marked the transition from accumulation to ablation on the Northern Ice Field. Two sensors are used to measure changes in surface height, and while one indicates less than 5 cm of ablation the other shows 20-25 cm (with the average being -11.5 cm). In both cases the decrease is more-or-less continuous through the month.