Little snowfall to the Solstice

The 'short rains' typically bring snowcover to the summit crater by the Solstice, but not this December. One event during the second week resulted in ~10 cm of accumulation on the glacier. This was followed by drier weather, so quite likely the crater is now largely snowfree. Any first-hand observations from the summit during the holidays are welcome!

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.

Whimpy Long Rains

Telemetry from the Northern Ice Field suggests that the Long Rains ended at the end of May, consistent with previous years. Snowfall frequency was fairly regular, beginning with a relatively large event in March (see this entry), but net accumulation was only 10-15 cm. This is quite a contrast to the Short Rains of November to mid-January which netted 45-50 cm of accumulation on the glacier.

The dry interval between the rains this year was centered on February, as is typically the case. It extended from mid-January to the March snowfall mentioned above, yet included 2-3 multi-day snowfall events of 5-10 cm.

In summary, as of today (mid-June) snow depth on the Northern Ice Field is ~60 cm.

Kilimanjaro returns to PNAS

Back in November, we published a paper in Proceedings of the National Academy of Science (PNAS) which documented changes in ice-covered area on Kilimanjaro since February 2000 (see blog entry with link to paper). Collaborators at the University of Innsbruck had a different perspective on a few elements of the paper, so wrote a Letter to the Editor. Together with our response, the letter was published online April 21st in PNAS Early Edition, and both will remain there until appearing in print.

The Mölg et al. letter is also available here, and the Thompson et al. response is here.

As an active collaborator with all authors involved, I would like to point out that such discussion - in scientific literature - is normal, healthy scientific discourse. This is how the process is supposed to work, and this is one way in which science advances! Our correspondence does not demonstrate uncertainty about whether Kilimanjaro's glaciers are shrinking, or whether they are likely to disappear with a few decades, or whether global warming is likely driving recent shrinkage; we are all in complete agreement on these tenets! Nor do the letters reveal some fundamental divide between research groups. In both cases, dedicated researchers are simply articulating nuanced perspectives gained from varying combinations of arduous fieldwork, laboratory analysis, and/or computer modeling. Given the short history of quantitative measurements from Kilimanjaro, both groups are attempting to make sense of climate-glacier interactions that all agree are complex. Everyone involved is dedicated to developing a better understanding of the mountain's fascinating glaciers.

-Doug Hardy, UMass Geosciences

Singing at the summit

Here are a few audio recordings from the cook tent, by the singing crew of October 2009 (above). Only those who ascend slowly with good equipment are capable of such joyful singing at nearly 6,000 meters. Thanks to everyone at Summit Expeditions!

• cook tent track #1
• cook tent track #2
• cook tent track #3
• In Mbahe, track A
• In Mbahe, track B
• In Mbahe, track C

Long Rains begin

Here is an out-the-car-window shot of Kilimanjaro from 21 March (courtesy Michael Winkler, Innsbruck Univ.), with a mantle of fresh snow. Michael departed from a snow-free crater on the 19th. By the 21st, my telemetry data from the Northern Ice Field does not indicate accumulation (cf. this south-side view), suggesting that snowfall was primarily on the south side. This asymetry is typical of snowfall during the Long Rains (March-May). However, appreciable snowfall on the Northern Ice Field did begin in the evening of the 22nd and continued at least into the 23rd; additional smaller events continued sporatically up to today. On the 27th, Timba from Ahsante Tours & Safaris wrote that in Moshi it was "pouring big time" and that the "mountain has been on an all time white look since last week." He says that "the SE prevailing winds have begun" and the long rainy season is in "full swing."

Long Rains beginning?

After a brief dry interval, telemetry shows that snowfall is again occurring at the summit of Kilimanjaro. Could we be seeing the beginning of the "Long Rains"? Contributor Timba at Ahsante Tours & Safaris writes of "heavy rains in Moshi and surrounding areas yesterday. In town [and on the mountain], it rained the whole afternoon to early evening."  Timba suggests that the normal long rain pattern is for morning rain in Dar es Salaam, followed by afternoon and evening rain in the Kilimanjaro region, but his friend in Dar saw no rain yesterday. Stay tuned.

Ten Years!

Here we are, exactly 10 years ago this morning, after installing the AWS on Kibo's Northern Ice Field (1300 UTC or 8 am EST, 24 February 2000). Hard to believe it has been that long -- or that it function so reliably. Thanks to everyone involved in keeping the measurements going!

Kilimanjaro from space

Kibo (left) and Mawenzi (right) from the International Space Station on 21 January at ~10am (click to see larger). Note convective clouds just beginning to form to the southwest, as happens daily at this time. Although the crater is snow-free, considerable snowcover is visible on the north side of Kibo; only the brightest-white areas are glacier ice. [Image ISS022-E-33592, courtesy of Earth Sciences and Image Analysis Laboratory, NASA Johnson Space Center]

"Current weather" update

Shortly after the first of each month we provide a synopsis of current conditions at the summit, based upon data received by telemetry and processed in the UMass Climate System Research Center. However, we have been without a programmer to run the scripts since mid-December, and apologize to those who look forward to these updates.

The most recent data were accessed today, and the station looks to be working well. Here is what the partial recovery indicates:  from 1 December until mid-January, net snowfall amounted to at least 22 cm. If we can obtain early January data from the Argos archive, it may show the total to be even higher. For the entire "short rain" period, net snowfall was at least 46 cm, which is not a record but certainly above average.

Hopefully a synopsis for February can be posted on 1 or 2 March.

Rains continue to the West

Here are a couple notes about rainfall to the west of Kilimanjaro; seems like the short rains have been quite good!

Dec. 28th (Marc Baker):  "Just back from the wettest Serengeti in 10 years, first time I have had to abandon two vehicles after two days of constant rain in Piaya."

Jan. 2nd (Jo via Neil Baker) summary of Serengeti and Ngorogoro lakes:
  Lake Magadi ngng - full
  Malanja depression - filling fast
  Olbalbal depression- full and overflowing
  Lake Manyara - filling fast
  Engaruka depression - nearly full

[UPDATE 1/6 (from David Bygott):  Lake Natron also full, raining heavily in Zanzibar]
[UPDATE 1/7 (from Chris Schmeling):  Lake Eyasi close to full; 88mm precip. already this month]