Tuesday, March 21, 2017

The value of a photograph


Measurements from our Northern Icefield AWS are transmitted to us in near-real time via the Argos system, which has proven to be extremely reliable. Telemetry is especially valuable for stations such as Kilimanjaro, for safely conducting fieldwork at 5,700 m requires considerable time simply for acclimatizing. With access to data by telemetry, conditions on the glacier can be monitored remotely, which saves on logistical costs and aids in fieldwork planning.

The figure above illustrates one measurement provided by telemetry: changes in glacier surface height. Decreases in height are due to ablation, the combined impact of melting and sublimation. Height increases are due to snow accumulation. Over time, the plot reveals both seasonal fluctuations of Northern Icefield surface height, and the on-going thinning which has been underway for decades.

For the time interval since June 2015, the bimodal wet seasons are depicted in green (Vuli = 'short rains', typically November & December) and in blue (Masika = 'long rains', typically March-May). Red circles represent the times of fieldwork in September 2015 and August 2016, and a recent visit described below. On the figure, note the lack of accumulation during the 2016 short rains, discussed in prior blog entries. Without much snowfall to add mass and brighten the glacier surface, ablation resumed in January 2017 at a rate similar to the dry season; this is not normal!


The lack of 2016 short rain precipitation on Kilimanjaro was at least partially due to a temperature contrast between the eastern and western Indian Ocean - the Indian Ocean Dipole - depicted above. During the NH summer, high ocean temperatures in the east led to more evaporation and cooling of the moister atmosphere. Easterly airflow over the western Indian Ocean resulted in less convection and less moisture delivery over East Africa during the short rains. In addition to less snowfall on the glaciers, the IOD is contributing to drought and famine in East Africa to the north of Tanzania. With over 10 million people facing food insecurity or worse, the consequences are profound (e.g., see here).


Back on the Northern Icefield, an on-site image from the AWS has provided information which measurements cannot. The image above was sent by Thomas Lämmle, who is frequently on Kilimanjaro with his company "EXTREK-africa" (website and Facebook EXTREK.AFRICA). Thomas' photo confirms the extent of ablation over the past couple months following the failed short rains. With great relief, the AWS tower appears to have remained nearly plumb, despite slackening of the guy cables. Also visible in the image are 3 ablation stakes (within blue ellipses) whose heights have been measured upon every prior visit.

Compare Thomas Lämmle's image from last month with a similar perspective ~17 months earlier, in September 2015 (below). From measurements at the AWS and the ablation stakes, we know that there was little net change in surface height between Sep. 2015 and Aug. 2016. The top figure also reveals that there was indeed no net lowering between Oct. 2011 and July 2016 (see y-axis). Not coincidentally, the AWS tower last required resetting in 2011 - the previous IOD negative event which was also associated with severe famine in East Africa, claiming 260,000 lives (link here).

Combining AWS data with photogrammetric ablation stake measurements reveals a glacier surface lowering of 40-45 cm between Sep. 2015 and the end of last month. Thanks to this recent photograph, we know that the AWS remained vertical as March began. Hopefully the long rains will bring new accumulation, which is the critical control on surface ablation at the Northern Icefield.

Thank you, Thomas!


Monday, March 13, 2017

Remembering Tharsis Magnus Hyera




“I want to be the most enlightened person on Kilimanjaro climate in Tanzania.”

So wrote collaborator and good friend Tharsis Hyera, who passed away on 15 February after battling testicular cancer. In addition to helping the people of Tanzania better understand Kilimanjaro climate, Tharsis touched the lives of all who spent time with him on the mountain, and is fondly remembered by those he met during an extended visit to New England in autumn of 2005.

Tharsis became involved in Kilimanjaro research upon the recommendation of Steven Mlote, Senior Scientific officer with COSTECH (Tanzania Commission for Science and Technology), who informed us that Tharsis had been a meteorology student of Prof. Stefan Hastenrath at the University of Nairobi, helping with analysis of data from Kilimanjaro and Mount Kenya in 1973.

We invited Tharsis to join Georg Kaser and others for a June 2001 expedition, in his professional role as a Principal Meteorologist at the Tanzania Meteorological Agency. He immediately accepted, despite virtually no mountain experience, arriving in Moshi with a huge smile and a small suitcase containing casual business attire.

During introductions, Tharsis revealed some minor health concerns and admitted that “I did not tell my doctor about my plan to climb Kilimanjaro, as he might discourage me.” Only later did he reveal to us that “my own people had discouraged me from climbing Kilimanjaro” and that one said “he would be preparing a coffin for receiving my dead body.” Nonetheless, his interest and determination appeared irrepressible, so we outfitted our new 56-year-old collaborator with all the required equipment and embarked on 10 days of fieldwork.
 
Tharsis’ foray onto the mountain was a great success, as documented in this video clip made by William Brangham and John Savage from NY Times Television. Despite considerable discomfort, he persevered to the top and spent 3 nights sleeping in the crater. In camp each night, he listened keenly to every discussion and contributed his knowledge about the regional climate of East Africa. Upon returning home, Tharsis related that “my wife and entire family were extremely overjoyed to see me walking into our home, looking a bit like a ghost due to the greyish overgrowth on my face, but alive and much healthier than when I left them.” “With me as the hero on center stage, we celebrated all night long.”

Two months after his trip, Tharsis wrote that “I am still having the euphoria of having managed to reach the Kilimanjaro summit. “I cherish the lesson that I learned from you and from the mountain—ad impossibile nemo tenetur—one only needs to shift one's paradigm and to have the perseverance to achieve one's goal.”

In subsequent years, Tharsis contributed toward a 2004 paper on Kilimanjaro glaciers and climate, spent another 4 nights at the summit (photos below), inspired and facilitated the participation of Tanzanian meteorologists Emmanuel Mpeta and Juliana Adosi (figs 5 & 6), and assisted with acquisition of our research permits. On a visit to the United States, Tharsis spent time working with Reanalysis data and jointly presenting lectures – in addition to picking apples, making cider, and singing and dancing at an Elementary school presentation (fig. 8).

As friends and collaborators of Tharsis, we cherish our memories of his enthusiasm, curiosity, and gratitude. May he rest in peace.


Fig. 2 - Tharsis on the Northern Icefield, approaching the AWS (note Mt. Meru in background)

Fig. 3 - Tharsis (right) on top of Lava Tower, Oct. 2004, with Fred Contrada & Doug Hardy (PC: Bill Duane)

Fig. 4 - Tharsis on Uhuru Peak, June 2001

Fig. 5 - Tharsis (right) with Emmanuel Mpeta (left) and Guide Erick Masawe at Machame Camp, Oct. 2004

Fig. 6 - Breakfast at Keys Hotel in Moshi, Jan. 2005 (left to right: Doug Hardy, Tharsis Hyera, Georg Kaser, Nicolas Cullen, Juliana Adosi, and Thomas Mölg)

Fig. 7 - Tharsis (left) with Paschal Nguye (former Chief Warden) at MbaheFarmhouse (SENE), Sep. 2009

Fig. 8 - Tharsis at Marion Cross School, Norwich Vermont (USA), Nov. 2005

Fig. 9 - Tharsis and family in Dar es Salaam, c. 2002

Fig. 10 - Tharsis near the summit, with Kersten Glacier, June 2001

Fig. 11 - Our most-recent visit with Tharsis, Sep. 2012 in Mbahe. Always a great listener!

Saturday, March 4, 2017

Big book for a big mountain


Whoa... this is a big book, opening to a width of 1.25 meters. Ian van Coller has assembled a stunning collection of photos taken during our 2016 fieldwork, depicting several of the summit glaciers and many of the Tanzanians on our team.

Although no substitute for the large prints, the page-through below provides a glimpse of this monumental undertaking (Kilimanjaro: The Last Glacier). Another page-through and a selection of Kilimanjaro images are posted on Instagram.

Recent summit photos


To provide a context on limited snowfall during the short rains (Nov/Dec), a previous post solicited recent images from the summit. Thanks for the submissions!

Images #1 and #3 here were taken on 2 February and sent in by Pik-Ki Fung. The above view is looking north from Uhuru Peak (summit) across the Furtwängler Glacier and the crater to the Northern Icefield. Despite a moderate snowfall event of ~5 cm on 30 and 31 January, most of that new snow had sublimated and melted prior to when Pik-Ki reached the summit. Rapid ablation of thin snowcover within the crater is typical, as solar radiation is transmitted through to the dark ash. Note that fresh snow remains on glacier surfaces.

The Furtwängler Glacier remnant circled in red above is also visible in the image below, sent in by Kshaunish Jaini of AlienAdv.com. (Kshaunish provides considerable interesting information about climbing Kilimanjaro on this webpage.) The image below from near "Crater Camp" appears to have been taken in the morning, on either 21 or 22 February, and reveals a thin snowcover within the crater. Telemetry from the NIF weather station shows no snowfall between the final days of January and the days just prior to when the image below was taken. Although a minor event, several centimeters of snow accumulated between the 18th and 20th, which is likely what is visible in this image. Even a thin snowcover reflects most of the incoming solar radiation. Thanks Kshaunish!


The image below is looking south, the opposite direction as image #1, and was taken the same day (2 February). Fresh snow is only visible in isolated patches on the ash, yet remains on the glacier and meltwater lake in the foreground. This is the upper Kersten Glacier, seen here a year earlier.
Hopefully the long rains (March-May) will bring fresh snowfall to Kilimanjaro, brightening glacier surfaces and thus reducing radiation receipt. Indeed, both human and natural systems in East Africa are in need of rain, after failure of the 2016 short rains.

Tuesday, January 31, 2017

Please share recent glacier photos!

Horizontal surfaces on Kilimanjaro glaciers are ablating rapidly at the moment (i.e., melting and sublimating), largely because the 2016 short rains "failed". Typically, a short wet season occurs during November and December, when snowfall at the summit dramatically raises albedo and the associated decrease in net radiation receipt decreases the energy available to drive ablation. During the 2016 short rains, a series of minor snowfall events were sufficient to end a long dry season which began in May, yet once this new snow ablated, the dark, decades- to centuries-old ice surface was exposed again. Ablation began accelerating, and since the New Year, flat areas of the Northern Ice Field have lost ~15 cm of snow and ice.

Snowfall during January and February is usually limited, and quite variable from year to year. Therefore, a high rate of ablation is likely to continue until the long rains begin, typically in March. One wildcard at this time of year due is some tropical cyclone paths in the south-west Indian Ocean, which can result in heavy snowfall on the mountain. This year, however, there has been little cyclone activity in the SWIO region - and indeed, the period 13 December to 31 January is the first on record (since 1960) without a hurricane (cyclone) somewhere on Earth, according to a @philklotzbach tweet.

Anyone visiting Kilimanjaro during February is encouraged to submit photos of the summit area. Any glacier photos would be helpful, especially looking to the south just below Uhuru Peak or across the crater to the Northern Icefield. One weather station is visible near the summit (upper slopes of Kersten Glacier) and another on the Northern Icefield should be barely visible on images taken with a telephoto lens and/or high resolution.

Thank you!

Sunday, December 18, 2016

late short-rains [updated]


New snow on Kibo! Simon Mtuy sent this photo, taken 17 December 2016. He comments:  there was considerable rain last night, bringing snow to both Kilimanjaro and Meru; the short rains have started slowly this year.

Stay tuned for an update on snow at the summit. Ablation was greater than normal during October due to the old, low-albedo surface.

[UPDATE 1/3/2017:  Telemetry from the summit indicates that snowfall during the 3-4 days prior to this image was the largest event of December. Nonetheless, only ~4 cm was measured at the AWS. Combined with minor events during both the first and last few days of the month, the net change in surface height for December was ~2 cm. The short rains essentially failed to develop during 2016 at the summit...]

Wednesday, September 14, 2016

2016 Fieldwork

Fieldwork! This year we were on the mountain slightly earlier than in recent years - during late July into early August, the core of the dry season. Our primary objective was recovering AWS data and servicing instrumentation, as well as measuring the network of ablation stakes. In addition, photographer Ian Van Coller (Montana State Univ.) was along to document the summit glaciers and shoot portraits of the Tanzanians joining us; check his wonderful photos on Instagram and his website. Fantastic logistical support was again provided by the SENE team (Summit Expeditions and Nomadic Experience)!

Below are some images from the fieldwork, with brief captions. Feel free to contact us with any questions.

1.  Kibo (left) and Mawenzi (lower peak to right) viewed from the highway west of Moshi, looking up 5,000 m through relatively clear air. The maize crop near Moshi was ready for harvest, much later than those in "home garden" villages at higher elevations on the mountain.

2.  Early-evening transport of freshly-harvested maize.

3.  At Mbahe Farm; young banana tree and us not-so-young mzungos.

4.  Mbahe Farm's cheerful, attentive, and unflappable host Wilson.

5.  Friendly Mbahe children, a highlight of every visit.

6.  On day 2 of our ascent up the Umbwe Route: Ian photographing one of our first Kibo views.

7.  Barranco Camp (4,000 m) is certainly worthy of the crowds, but fortunately for us it was one of the only camps we shared with other groups. And in case you are wondering, there are at least 137 tents visible in this image!

8.  Two south-side glaciers on Kibo:  Kersten on the left and Deckens on the right. Both have thinned and retreated dramatically in the past couple years. Note that seasonal snow is also visible - in addition to the ice - above ~5,500 m. 

9.  Glaciers slightly to the north of those above, along with the Western Breach on the left-hand side. Most interesting in this late-afternoon view is a small waterfall of meltwater, barely visible at the cliff base, just left of center. 

10.  Northwest of the Breach, Uhlig Glacier was depicted on the earliest maps of Kilimanjaro's glaciers. Contrary to what one might read on the web, this glacier endured until sometime within the last year. Although a minor ice body, the Uhlig hadn't changed much in recent years due to topographic shading and persistent, local cloud cover. The two images below are from slightly offset perspectives, yet the glacier is clearly now gone...

11.  Our ascent this year came up the mountain's north side from Pofu Camp. The final campsite on this dry, rather difficult route was a scenic perch at 5,200 m looking north to Amboseli National Park, with Mawenzi just barely visible in the other direction (over the ridge; see below).

12.  Simon Mtuy ascending toward the camp shown above.

13.  Summit glaciers! Reaching the crater rim on this trip was especially rewarding after our scramble up. Beautiful lighting then brought Ian's progress to a screeching halt.

14.  Our camp beside the Northern Ice Field. Dramatic retreat of the glacier continues all around the margin. Ironically, the mass balance on flat horizontal surfaces has been near-neutral for the past 5 years, and in places the ice is still 40+ m thick!

15.  Detail of the Northern Ice Field margin. This particular section provides an atypically-clear view of ice stratigraphy in the upper portion of this glacier. Except for a very thin veneer, this is all dense glacier ice, not firn.

16.  Another perspective on the Northern Ice Field margin, with Simon for scale.

17.  Upper margin of the Deckens Glacier, along with seasonal snowcover and a frozen meltwater pond. Dust accumulation - some of which is due climbers heading to Uhuru Peak - results in very low albedo on the vertical surface, leading to considerable absorption of solar radiation each morning.

18.  A distant view of steadily-shrinking Eastern Ice Field remnants, 2001-16.

19.  A fragment of Furtängler Glacier, vanishing without a trace almost before our eyes. A larger remnant is shown in this GigaPan image, which will soon be the only way to explore this glacier.

20.  Mawenzi from near Uhuru Peak, with convergence of trails at Stella Point.