Wednesday, March 27, 2013

long-duration climate observations

PNAS recently published an important opinion piece by Carl Wunsch et al. that is well worth a read. It is freely available in HTML and PDF format from the Academy website, and less than a page and a half in length. They argue convincingly that "understanding of climate change is a problem for multiple generations" - stressing that an increased emphasis must be placed on long-duration observations of the climate system.

My favorite sentence takes nothing away from the value of modeling, yet emphasizes their key point:  "Today's climate models will likely prove of little interest in 100 years. But adequately sampled, carefully calibrated, quality controlled, and archived data for key elements of the climate system will be useful indefinitely."

Wunsch et al. point out numerous obstacles to obtaining adequate observations, lamenting that "governments have not done well in sustaining long-term observations." Some of us are all too familiar with this problem, yet this is not universally the case. One of NOAA's most far-sighted undertakings - the U.S. Climate Reference Network - has just achieved a decade of operation, thanks to staff and managers at NOAA whose vision has been laser-sharp. A paper reviewing this program is about to be published by the American Meteorological Society, and available here now.

The USCRN program can be a model for measurements of other climate system elements, domestically and internationally. Broadly implementing the USCRN approach would be an excellent way to address the intergenerational problem highlighted by Wunsch et al.

Friday, March 1, 2013

New aerial images

During the Wings of Kilimanjaro (WoK) expedition in early February, a helicopter flew to the summit with supplies for the group. The pilot was Ben Simpson of Tropic Air, a company based at the foot of Mt. Kenya and experienced in carrying out rescues there. Tropic Air uses the French-made Eurocopter AS 350 B3, from which WoK videographer Anika Craney got some great footage. A 12.5-minute clip of the flight is posted on the WoK FaceBook page, available here.

The following captures are from Anika's video, posted here to provide an update on recession of the glaciers; several of the perspectives she obtained are quite unique.

Below is the less-commonly seen half of the Northern Ice Field, with the eastern edge at left. The crater is behind the upper ice as seen here. Despite extensive snowcover (for early February) the split between the two halves is clearly visible; this did not exist and/or was not known prior to ~1989.

At the bottom edge of the image below is Stella Point. Trails to both the summit and crater camp are visible. The eastern end of the Rebmann Glacier is in the foreground. The apparent "hole" was recently observed on satellite imagery, and may have developed due to anomalous geothermal heat flux. Alternatively, it may have begun as a supraglacial pond which enhanced shortwave radiation receipt.

Fragments of the Southern Ice Field are seen in the next image. Beginning on the right-hand side, the Rebmann Glacier used to extend downslope but is primarily confined to the crater rim these days. Although partially obscured by cloud, this view provides a context for the image above. The narrow Decken Glacier becomes thinner each year, and may soon be cut off from the ice above. The largest ice body remaining is the Kersten Glacier, which is also seen in the fourth image. Within the past couple years the Kersten has become detached both from ice above and from the Decken Glacier to the right. Lastly, the Heim Glacier is the small sun-lit body of ice beyond the lower Kersten. As recently as 10 years ago the upper portion of this glacier began not far below the crater rim.  

Below is detail of the view above, showing how the Kersten Glacier has fragmented from the Decken, and into an upper and lower portion. Uhuru Peak is the high point behind the upper section and obscured by cloud in this view.

Many thanks to WoK and Anika for posting this video!