October fieldwork!

We were back on the glaciers for fieldwork in October! As previously reported (here), the pandemic and logistical issues prevented us from visiting since February 2020, and although 'automated', our weather stations on the ice are not self-maintaining. Over the course of the ensuing three years, problems and damage occurred - so one of our objectives last month was to remove weather instrumentation and mass balance stakes. With tremendous help from the porters and staff of Summit Expeditions (SENE), we were successful. The next step is examining data we recovered, and evaluating options to continue measurements with new instrumentation!

Doug Hardy (UMass), Mike Winkler (GeoSphere Austria), and Emily Collier (Univ. Innsbruck). 

Click on any image to enlarge:

Fig. 1 (above): Kibo and 5,000 meters of relief, from Moshi. Preparing to head up again was very exciting, first time in over 3 years!

Fig. 2 (above): Our first task, led by Emily and her newly-funded research, was exploring the Kilimanjaro Mountain Club archives - in search of historical observations pertaining to the impacts of Tropical Cyclones on Kilimanjaro precipitation.

Fig. 3 (above): Morning of day two, a favorite view on the Umbwe Trail. These southern slopes were once covered by the Southern Icefield. Only fragments remain today, including sections of the Kersten Glacier (center).

Fig. 4 (above): Umbwe route passes through a recently-burned area below Barranco Camp, one of several new fire scars seen on this trip.

Fig. 5 (above): Diamond Glacier, Breach Icicle, and fragments of the Balletto Glacier. The icicle is larger than in 2020* due to meltwater drainage from above. Also note extensive rockfall onto the Balletto. (*2020 image here.)

Fig. 6 (above): Mike and Emily above Karanga Camp. Kersten Glacier remnants are visible above Mike, and the Rebmann Glacier is above Emily; between them is the vanishingly meager Decken Glacier ice.

Fig. 7 (above): Team member Mathayo Melio, preparing fresh greens (Kale) at Barafu Camp.

Fig. 8 (above): Late afternoon at Barafu, where multiple helicopter pickups are now occurring daily - typically to expedite the descent of wealthy clients.

Fig. 9 (above): Wishful thinking. Simon is testing whether he can transmit a message directly from his brain through this cable. Kilimanjaro Park authorities are testing whether they can string fiber optic cable along the trails for tourists to post on Instagram. We had no success with either. Increasing rockfall and debris flows on the mountain could make unprotected fiber maintenance difficult...

Fig. 10 (above): Riming on the Uhuru sign, as the weather clears. Northern Icefield in the distance.

Fig. 11 (above): Furtwängler Glacier from above. Since 2020 the area has decreased by seventy percent (yes, in 3 yearss); the glacier's demise is imminent.

Fig. 12 (above): Upper Kersten Glacier, October 2017; find the weather station. Zoom in, as this is a panorama. Then find the relatively thick, clean stratum and compare it's position to that in 2023 (next image).

Fig. 13 (above): Kersten Glacier upper margin, where thinning and lateral retreat continue. Where is the weather station? Occasional collapses of the wall and a marginal meltwater lake has been noted for 20+ years. However, compare the thick, clean ice layer position here with that 2017 (prior image) or in 2014, 9 years ago (with Will Gadd for scale).

Fig. 14 (above): Mike investigating ice blocks where the Kersten Glacier margin most-recently collapsed. Find the weather station (we couldn't either).

Fig. 15 (above): The largest remaining fragments of the former Eastern Icefield. The right-hand block is featured in the Red Bull film.

Fig. 16 (above): Northern Icefield margin, just west of camp. Note person for scale, just right of center - and the interesting basal stratigraphy.

Fig. 17 (above): Wonderful textures photo taken by Mike.

Fig. 18 (above): Northern Icefield margin, looking west toward camp. Compare to this similar view in February 2000.

Fig. 19 (above): Northern Icefield again... but the northern margin. As evident here, in next image, and elsewhere - the ice is fracturing to a greater extent than previously seen.

Fig. 20 (above): A fresh, curious collapse feature at the Northern Icefield margin. An ice layer associated with ponded and frozen supraglacial meltwater can be seen at the top of the fracture. These have been occasionally observed on Kibo's glaciers, always frozen at the surface.

Fig. 21 (above): A portion of AWS being carried through penitentes on the Northern Icefield. These particularly-large penitentes made walking difficult!

Fig. 22 (above): The AWS tower being carried back across the crater toward Uhuru Peak, 23 years after being brought up!

Fig. 23 (above): Doug, Emily, and Simon - along with about 20 other team members - prepare for a tree-planting ceremony honoring climate research on the mountain.

Fig. 24 (above): Final preparations for a feast celebrating safe and successful fieldwork! Much of this food was grown right on Simon's farm.
 

Kibo Weather Stations - 23 years later

Our team is just back from difficult-but-stimulating fieldwork on summit glaciers, documenting Kibo's climate. Initial instrumentation at our weather station was installed in February 2000, then gradually supplemented and expanded. The configuration by 2013 is shown above. After near-annual maintenance and observation visits through 2017, we visited the stations for a Red Bull film in 2020 and then could not get back during the pandemic. Fieldwork in 2022 was foiled by bureaucratic miscommunication. By September of 2023, negative mass balance resulted in tipping and damage of equipment - the extent of which will soon be revealed by analysis of recorded data.

All the hardware, instrumentation, and ablation stakes have now been removed from the mountain and the National Park. As will be detailed in subsequent posts here, this was accomplished despite delays in departure, followed by high winds and riming precipitation. Removing everything required multiple trips to the summit by our accompanying crew, as well as an additional 19 porters to move equipment down the mountain.

We dedicate our 2023 mission to the hundreds of porters who have been essential to the success of this research since February 2000. They did the hard work transporting everything up - and then down - 5,000 meters of elevation, keeping us cheerful (most of the time) and productive. Perhaps most impressively, they were integral to a perfect safety record through the entire study. On this latest trip, we crossed paths with numerous porters from past trips, and spent time with one who was along on trip #1 back in February 2000; today he continues working as a respected mountain and safari guide. Also this month, one porter introduced himself as the son of a favorite porter, not yet born when his dad started helping. Asante sana to all the porters, guides, cooks, drivers, and support staff who have been involved - from Keys Hotel, Marangu Hotel, and since 2006, Summit Expeditions and Nomadic Experience (SENE).

2023 team:  Doug Hardy (UMass), Mike Winkler (GeoSphere Austria), and Emily Collier (Univ. Innsbruck)

September fieldwork!

With great anticipation, I'm planning to be back on Kibo's glaciers next month. After 17 years of frequent observations and measurements, circumstances beyond my control have foiled research efforts in recent years. Never take high-elevation glacier fieldwork in National Parks for granted! Chief among the issues were a major storm (October 2018), postponement of two consecutive collaborative trips (July & December 2019), a collaborative-and-fun glacier visit with limited time and deep snow (February 2020), the pandemic (2 years), and most recently - failure to get above 2200 m due to logistical/permitting difficulties (September 2022). Phew... I'm ready to get back up there!

Extensive fieldwork and AWS service was conducted in October 2017, including repairs at the station and documenting changes to summit glaciers. Accompanying us on this trip - to the Roof of Africa - was Dr. Ladislaus Chang'a, currently the Acting Director of Tanzanian Meteorological Authority.

Conditions are currently very dry at the summit. Meager high-elevation precipitation during the 2023 long rains (March-May) resulted in no snow accumulation within the caldera as the dry season began in June. By then, any snowcover remaining on glacier surfaces was continuing to thin, although without telemetry or observations, recent changes in surface mass balance remain speculative. Through June, July, and August, isolated patches of snow on Kibo's flanks have been ablating, as shown in the timelapse below - from very little, to almost none!

During this next visit, extensive glacier photography will help us better understand changes at the Northern Icefield (compare with image above). Lesser Penck Glacier (compare with image below), Furtwängler Glacier (compare with image above), and what remains of the Southern Icefield (compare with image below). Glacier images from this October will be posted here after fieldwork.

September and October fieldwork will have two objectives. The first task will be to recover AWS data from the station, extending the weather record which began over 23 years ago. These data are being stored in memory on-site, even if power to the station has been lost. In addition, the weather stations and ablation stakes (photo below) will be removed from the mountain. Both stations tipped over last year, ending the interval of high-quality measurements. Continuing a trustworthy climate record would require replacing instruments and electronics, along with sufficient funding and dedicated personnel willing to perform regular inspections and service.

Stay tuned for updates!

 

Northern Icefield weather stations, and adjacent stakes to measure ablation

Lesser Penck Glacier extent, 1930 to 2008 - continuously shrinking

Southern Icefield, 2003 (GoogleEarth image)

Summit without snow

Kibo's summit is currently snow-free, towards the end of the dry season. The two images below from the ESA Sentinel-2 satellite show virtually no snow on the mountain - the typical situation at this time of year. Back in 1889 on his first ascent, Hans Meyer observed that "in October, when all the snowfields had disappeared, there was likewise comparatively little snow to be met with on the ice-cap". This was 133 years ago! These recent images below show clouds over the west and southwest flanks of Kibo, but other white areas are glacier ice.

 

Check back in mid-October to learn more about how these dry-season conditions, and why we were unable to visit the summit weather stations in September. Planning is already underway to get up there again though!

 

Stable weather at the summit

Two months into the 2022 dry season - roughly halfway through - the extent of snowcover has remained remarkably constant. The animation below runs from 12 June through 27 July at a five-day interval (22 July not shown due clouds).

Although mass loss continues, the low rate of ablation suggests cold and dry conditions at the summit, supported by the lack of convective clouds seen on these images. With such weather conditions, sublimation is the predominant mechanism of ablation, requiring eight times more energy per unit mass lost.

Typically, an increase in atmospheric moisture marks the transition between the dry season and short rains, yet for much of eastern Africa the pattern has been disrupted in recent years. David Nash details the current and forecast situation in a short article for The Conversation.

We will be back on the mountain in September! After a 2-year COVID hiatus, we are eager to observe the glaciers, recover meteorological data - and provide a new perspective on Kilimanjaro climate variability and change (stay tuned)!

 

Kibo 2022 Dry Season begins

Throughout eastern Africa the dry season is getting underway, a period of 4-5 months with minimal precipitation. June typically begins with complete snowcover on Kilimanjaro, resulting from the March-May rainy season, which in some years supplements January snowfall events as well as snow deposited during the November-December short rains. With reduced cloud cover and lower temperatures on the mountain during the dry-season months, snow gradually sublimates and melts. This annual cycle of snowcover was roughly defined by the late 19th century:

Although Kilimanjaro lies near the equator the extent of its ice and snow varies with the season. The southern summer (December to May) is also the rainy season in the Kilimanjaro region, and it is then that the accumulations of ice and snow are greatest. In the southern winter (June to November) there is a comparative dearth of moisture, the snowfall is proportionately slight, and the process of melting goes on rapidly; hence, by the end of the season, the accumulations of ice and snow are at their smallest.
    Hans Meyer, Across East African Glaciers (1891)

Snow currently blankets only about half of the summit caldera, and only the southern flanks - as illustrated on the satellite image above, from last week (2 June). Within the caldera, this pattern of accumulation has remained quite consistent through the 2022 long rains. More noteworthy is that accumulation is clearly less than normal. Compare this year's snowcover with that of 2020 and 2018 in these images:

In a larger spatial context, snowcover on Kilimanjaro following the long rains is illustrative of the "current extreme, widespread, and persistent multi-season drought (1)" affecting East Africa, particularly in Kenya, Ethiopia, and Somalia. The figure below depicts only the most-recent wet season precipitation, as the satellite images also reflect. A joint statement by the World Meteorological Organization, UN Food and Agriculture Organization, and others states that "The 2022 March-May rainy season appears likely to be the driest on record, devastating livelihoods and driving sharp increases in food, water, and nutrition insecurity" (1). In addition, East African air temperatures have been higher than normal, and these are forecast to continue through the forthcoming dry season.

source

The current drought to the north of Kilimanjaro is both a direct and indirect consequence of climate change, and climate variability. Factors include a multiyear La Niña event (2), a longterm decrease in Long rains precipitation, more intense and severe extreme events, as well as changing large-scale patterns of convection and subsidence, driven by Sea Surface Temperature (SST) anomalies in the Indian Ocean.

Decreased snowcover on Kilimanjaro during the 2022 dry season will hasten ablation of the glaciers. Comparing the current satellite image with those of snowier years dramatically illustrates the role of snowcover in determining the reflectivity of solar radiation. Without snow, the dark volcanic surface absorbs radiation, heats up, and radiates longwave radiation to the air and adjacent ice. Kilimanjaro's summit is 5000 m above the drought-stricken plains below (primarily north of the mountain), providing information on the climate system from the mid-troposphere. These shrinking glaciers serve as a constant reminder of the importance of precipitation to human and natural systems.

A glimpse of the receding south-side glaciers

Delineating Kibo's southern slope glacier margins on satellite imagery has been difficult in recent years. This is because snow cover has persisted on both the glaciers and adjacent surfaces (see one dramatic example here). While the coverage is relatively uniform following snowfall events, ablation subsequently creates a patchy mosaic, reflecting variable snow depth (e.g., due wind redistribution) as well as topographic shading, slope, and aspect.

The issue of glacier margin delineation is nicely illustrated by the image above (Sentinel-2, acquired 19 March 2022). The southwest quadrant of the image is obscured by clouds. North of the Reusch Crater, most of the white pixels depict patchy snow cover, excepting the two remaining portions of the Northern Ice Field (NIF; labeled). The NIF southern and eastern margins are partially visible due to ablation adjacent to the near-vertical ice wall, a typical situation observed days-weeks after snowfall events.

South of the crater, Furtwängler Glacier is only ice mass entirely within the caldera, shown within the red ellipse on the image above - and likely appearing slightly larger than reality, due adjacent snow. The white arc on the image south of the crater is entirely snow, extending from west of Uhuru Peak (yellow triangle) to east of Gilman's Point (green triangle). The southern margin of this arc coincides with the steep caldera rim; snow on the north side is shaded from sun during the boreal winter, yet almost entirely ablated on the south side.

The white patches high on the southern slope, above the yellow lines, are primarily glaciers:  Kersten Glacier fragments directly south of Uhuru, the tiny Decken's Glacier finger to the east, and remnants of Rebmann Glacier just left of the label. Lower on the slope, below the yellow lines, we see a mixture of both snow-covered rock, and glacier fragments with snow cover.

Although the southern glacier margins cannot be precisely located on this image, it reveals that recession has continued despite relatively snowy conditions in recent years. For example, compare the image above with this view from July 2009.

With luck, we'll be back on Kibo in September, for a first-hand look at changes since our last fieldwork in February 2020 (including a Red Bull film).