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

[updated] Remembering Tharsis Magnus Hyera

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

So wrote collaborator and big-hearted, good friend Tharsis Hyera, who passed away on 14 February after battling Prostrate 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.

[UPDATE 6 APRIL:  Many thanks to daughters Xaveria and Sola for getting in contact and sharing thoughts about our friend Tharsis!]

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.