CALM
Program Description
The
active layer is the layer of earth materials between the ground surface and
permafrost that freezes and thaws on an annual basis. The active layer is extremely
important in many of Earth’s cold regions because the permafrost immediately
below it can form an impermeable layer that restricts the majority of
geomorphic, hydrologic, and biogeochemical processes to this relatively thin
layer.
Climate
models indicate that sustained warming will be more pronounced in the high
latitudes than in other regions. Given the temperature dependence of ice and
its mechanical properties, warming or thawing of ice-rich permafrost can result
in very substantial impacts on natural and human systems in cold environments.
Considerable evidence exists that warming is well underway in the high-latitude
regions (e.g., Hinzman et al. 2005). The roles of
permafrost in climate-change science are discussed in a report by the U.S. Arctic
Research Commission’s Permafrost Task Force (2003).
In
regions underlain by ice-rich permafrost, sustained climatic warming could lead
to a widespread increase in the thickness of the active layer. This, in turn,
can result in differential settlement of the ground surface and cause damage to
roads, structures, and utility lines. Thaw subsidence can also alter local
hydrological patterns and lead to profound ecological changes (e.g., Jorgenson
et al. 2006, Shur and Jorgenson 2007). Another
important consequence of increased active-layer thickness is that carbon
sequestered in the uppermost permafrost reservoir can be released to the
atmosphere in the form of greenhouse gases. A net increase in the efflux of CO2
and CH4 to the atmosphere provides a positive feedback effect on
climatic warming (Shuur et al. 2008).
In
light of these challenges, it is necessary to monitor and model interannual, decadal, and secular variations in the active
layer at a variety of geographic scales, ranging from local to global. To
achieve these goals, the CALM (Circumpolar Active Layer Monitoring) program was
established in the early 1990s. CALM’s goals include monitoring the thickness
of the active layer (e.g., Hinkel and Nelson 2003; Streletskiy et al. 2012), the temperature in the
near-surface layers of the permafrost regions (e.g., Hinkel
et al. 2001; Nyland et al. 2012), and surface movements attributable to frost
heave and thaw
settlement (Shiklomanov et al. 2013).
Observations are made in both built and natural environments (e.g., Klene et al. 2013; other references).
CALM is among the international permafrost community’s first large-scale
efforts to construct a coordinated monitoring program capable of producing data
sets suitable for evaluating the effects of climate change. Together with its
sister program, the IPA’s Thermal State of Permafrost (Romanovsky
et al. 2010, Vieira et al. 2010), CALM comprises GTN-P, the Global Terrestrial Network for
Permafrost, itself a component of the Global Terrestrial Observation System
and the Global Climate Observation System (GTOS/GCOS). The CALM network’s
history, organizational structure, site
descriptions, and initial analytical
results were reported in Brown et al. (2000), Burgess et al. (2000), and
Nelson et al. (2008, 2011), and can be found elsewhere on this site.
CALM
investigators measure the seasonal depth of thaw at plots of various dimensions
using standardized protocols (Nelson and Hinkel
2005). Soil and air temperature, soil moisture content, and vertical movement
are also measured at many sites. These
measurements, combined with site-specific information about soils, landscape,
and vegetation, can be used to “scale up” assessments of the stability and
projected changes to regional and circumpolar scales (e.g., Nelson et al. 1997; Shiklomanov and Nelson 2002). They also perform an
important role in model validation (e.g., Shiklomanov
et al., 2007, other
references).
CALM
currently consists of more than 240 field installations operated by researchers
from Canada, China, Denmark/Greenland, Italy, Kazakhstan, Mongolia, New
Zealand, Norway, Poland/Svalbard, Portugal, Russia, Spain, Sweden, Norway, Switzerland, and
the United States. The CALM program began as a voluntary effort in 1991,
initially as part of ITEX, the International Tundra Experiment. CALM was
formalized in late 1997 with a five-year grant from the U.S. National Science Foundation’s
Arctic System Science program to the University of Cincinnati (K.M. Hinkel, Project Director). After a bridging year
supported by the University of Delaware’s
Center for International Studies, a second five-year block of support
was awarded by the NSF Arctic Logistics and Research Support program, with the
University of Delaware acting as lead institution (F.E. Nelson and N.I. Shiklomanov, co-PIs). Known as CALM II, this project
expanded CALM’s mission to include measurements of movement at the ground
surface, anthropogenic-impacts studies, and more extensive thermal monitoring.
Two further five-year blocks of support from NSF’s Arctic Observing Program
(CALM III (2009-2014) and CALM IV (2014-2019)) are administered through The
George Washington University (N.I. Shiklomanov and
D.A Streletskiy, co-PIs), with subcontracts to the
University of Montana (A.E. Klene) and Northern
Michigan University (F.E. Nelson).
CALM
is currently administered through The George Washington University’s Department
of Geography. Program participants collect temperature and thaw depth
measurements and provide them to the CALM office at GWU. Data are subsequently
incorporated into several databases. Analysis, archiving, and distribution of
CALM’s long-term observations are integral components of the project. Data
analysis is performed in the first instance by the field investigators, and
further processing and standardization occur at the grant-holding universities.
CALM data are freely available to interested parties on the GTOS Terrestrial
Ecosystem Systems (TEMS) website, on the
National Snow and Ice Data Center’s Frozen Ground website, on CD through the
International Permafrost Association’s Global Geocryological
Data (GGD) system (Parsons et al., 2003), and through the Joint Office for
Scientific Support. Scientific results are presented at national and
international meetings, and published in international peer-reviewed journals.
CALM’s
observing protocols and management practices are developed through consensus.
Investigators discuss the program at various scientific meetings, including the
IPA’s international and regional conferences, the American Geophysical Union’s
Fall Meetings in San Francisco, and the permafrost conferences held
periodically in Pushchino, Russia. International
workshops concerned exclusively with the CALM program were held in Lewes,
Delaware in 2002 and Fairbanks, Alaska in 2008. A third workshop is planned in
association with the International Permafrost Conference scheduled for the
summer of 2016 in Potsdam, Germany. More information about the CALM workshops
and resulting resolutions can be found at CALM WORKSHOPS page.
CALM
is a joint effort by the world permafrost community, with abundant help from
colleagues engaged in related branches of science. These individuals contribute
their time and effort, in most cases without financial compensation. Our
results and data are available to all interested parties. The CALM community
asks only that our data and resources be used in a scientifically responsible
manner, and that users give formal acknowledgment to the program and to
individual investigators in any publication, press releases, or web-based
activity.
Literature Cited
Brown, J., Hinkel, K.M., and Nelson,
F.E. (2000). The Circumpolar Active Layer Monitoring
(CALM) program: historical perspectives and initial results. Polar Geography 24: 165-258.
Hinkel, K.M. and Nelson, F.E. (2003). Spatial
and temporal patterns of active layer thickness at CALM sites in northern
Alaska, 1995-2000. Journal of Geophysical Research-Atmospheres,
108(D2), 10.129/2001JD000927.
Hinzman, L., Bettez, N., Bolton, W.R., Chapin, F.S., and 31 others
(2005). Evidence
and implications of recent climate change in northern Alaska and other Arctic
regions. Climatic Change, 72: 251-298.
Jorgenson, M.T., Shur, Y., and Pullman, R.R. (2006). Abrupt increase in
permafrost degradation in Arctic Alaska. Geophysical Research Letters 33: doi:
10.1029/2005GL024960.
Klene, A.E., Nelson, F.E., and Hinkel,
K.M. (2013). Urban
- rural contrasts in summer soil-surface temperature and active-layer
thickness, Barrow, Alaska, U.S.A. Polar
Geography 36(3): 183-201.
Nelson, F.E.,
and Hinkel, K.M. (2003). Methods
for measuring active-layer thickness. In: Humlum,
O. and Matsuoka, N. (eds.) A Handbook on Periglacial
Field Methods. Longyearbyen, Norway: University of the North in Svalbard,
currently online at:< http://www.unis. no/RESEARCH/GEOLOGY/Geo_research/Ole/PeriglacialHandbook/ActiveLayerThicknessMethods.htm>.
Nelson, F.E. and Shiklomanov, N.I. (2011). The Circumpolar Active Layer
Monitoring Network—CALM III (2009-2014): Long-term Observations on the Climate-Active
Layer-Permafrost System. pp. 9-21 in: Ambientes Periglaciares, Permafrost y Variabilidad
Climática: II Congreso Ibérico de la International Permafrost Association. Alcalá, Spain: Universidad de Alcalá
Servicio de Publicaciones.
Nelson,
F.E., Shiklomanov, N.I., Hinkel,
K.M., and Brown, J. (2008). Decadal results from the Circumpolar
Active Layer Monitoring (CALM) program. Proceedings of the Ninth International Conference on Permafrost.
Fairbanks: University of Alaska Press, pp. 1273-1280.
Nelson,
F.E., Shiklomanov, N.I., Mueller, G.R., Hinkel, K.M., Walker, D.A., and Bockheim,
J.G. (1997). Estimating active-layer thickness over a large
region: Kuparuk River basin, Alaska, U.S.A. Arctic and Alpine Research 29: 367-378.
.Nyland, K.E., Shiklomanov,
N.I., Streletskiy, D.A., Klene,
A.E., and Nelson, F.E. (2012).
Thermal insulating properties of northern Alaskan vegetation
and their effects on ground thermal regimes. Proceedings of the Tenth International
Conference on Permafrost. Salekhard, Russia: The Northern Publisher, 295-300.
Romanovsky,
V.E., Smith, S.L., and Christiansen, H.H. (2010).
Permafrost thermal state in the polar Northern Hemisphere during the
International Polar Year 2007-2009: a synthesis. Permafrost and Periglacial
Processes. 21: 106-116.
Schuur, E.A.G, J. Bockheim,
J.G. Canadell, E. Euskirchen,
C.B. Field, S.V Goryachkin, S. Hagemann,
P. Kuhry, P.M. Lafleur, H.
Lee, G. Mazhitova, F. E.
Nelson, A. Rinke, V.E. Romanovsky,
N. Shiklomanov, C. Tarnocai,
S. Venevsky, J. G. Vogel, and S.A. Zimov (2008). Vulnerability of permafrost carbon
to climate change: implications for the global carbon cycle. BioScience 58:
701-714.
Shiklomanov, N.I. and Nelson, F.E.
(2002).
Active-layer mapping at regional scales: a 13-year spatial time series for the Kuparuk region, north-central Alaska. Permafrost and Periglacial Processes, 13:
219-230.
Shiklomanov, N.I., Anisimov, O.A., Zhang, T., Marchenko,
S., Nelson, F.E., and Oelke, C. (2007). Comparison of model-produced active
layer fields: Results for northern Alaska. Journal
of Geophysical Research—Earth Surface 112(F2); F02S10, doi:
10.1029/2006JF000571.
Shiklomanov, N. I., Nelson, F. E., and Streletskiy, D.A., Hinkel, K. M.,
and Brown, J. (2008). The Circumpolar
Active Layer Monitoring (CALM) program: data collection, management, and
dissemination strategies. Proceedings
of the Ninth International Conference on Permafrost.
Fairbanks: University of Alaska Press, pp. 1647-1652.
Shiklomanov, N.I., Streletskiy,
D.A., and
Nelson, F.E. (2012). Northern Hemisphere component of the
global Circumpolar Active Layer Monitoring (CALM) program. Proceedings of the Tenth
International Conference on Permafrost. Salekhard,
Russia: The Northern Publisher, 377-382.
Shiklomanov, N.I., Streletskiy, D.A., Little, J.D., and Nelson, F.E. (2013). Isotropic thaw
subsidence in undisturbed permafrost landscapes. Geophysical Research Letters, 40: 1-6. doi:10.1002/2013GL058295.
Shur, Y., and Jorgenson, M.T. (2007). Patterns
of permafrost formation and degradation in relation to climate and ecosystems.
Permafrost and Periglacial
Processes 18: 7-19.
.Streletskiy, D.A., Shiklomanov,
N.I., and Nelson, F.E. (2012).
Spatial variability of permafrost active-layer thickness
under contemporary and projected climate in northern Alaska. Polar Geography 35(2): 95-116.
U. S. Arctic Research Commission Permafrost Task Force (F.E.
Nelson and L.W. Brigham, Lead Authors, 2003). Climate Change, Permafrost,
and Impacts on Civil Infrastructure. Washington, D.C.: U.S. Arctic
Research Commission, 62 + vi pp.
Vieira,
G. Bockheim, J., Guglielmin,
M., and 16 others (2010).
Thermal state of permafrost and active-layer monitoring in the Antarctic:
advances during the International Polar Year 2007-2008. Permafrost and Periglacial Processes, 21:
182-197
The extended list of
references available at http://www.gwu.edu/~calm/publications/calm.html