scholarly journals Climate on tundra and thoughts on causes of regional climate differences

2000 ◽  
Vol 31 ◽  
pp. 10-14 ◽  
Author(s):  
Atsumu Ohmura
Keyword(s):  
West Coast ◽  
Boreal Forests ◽  
Regional Climate ◽  
Global Scale ◽  
Scientific Investigations ◽  
Causal Processes ◽  
Mcgill University ◽  
Axel Heiberg Island ◽  
Fundamental Consideration

AbstractThe Axel Heiberg Island Expedition of McGill University, Montreal, Canada, led by the late Fritz Müller was the cradle for a number of scientific investigations, not all of them glaciological. During the four years 1969–72, the tundra climate was investigated in the Expedition Area, encompassing about 100 km2 on the mid-west coast of Axel Heiberg Island, Nunavut, Canada. This series of studies identified the main features of the tundra climate, clarified its causal processes and contributed to an understanding of the differences between tundra climates and those of the neighboring regions with glaciers, ocean surfaces and boreal forests. A fundamental consideration of climate processes on a global scale was conceived during this time. Some significant results are recorded here to commemorate Fritz Müller’s contributions as a polar scientist and a university educator.

scholarly journals Biotic stress accelerates formation of climate-relevant aerosols in boreal forests

2015 ◽  
Vol 15 (21) ◽  
pp. 12139-12157 ◽  
Author(s):  
J. Joutsensaari ◽  
P. Yli-Pirilä ◽  
H. Korhonen ◽  
A. Arola ◽  
J. D. Blande ◽  
...  
Keyword(s):  
Boreal Forests ◽  
Large Scale ◽  
Transport Model ◽  
Cloud Condensation Nuclei ◽  
Fold Increase ◽  
Global Scale ◽  
Satellite Observations ◽  
Insect Outbreaks ◽  
Voc Emissions ◽  
Scale Modelling

Abstract. Boreal forests are a major source of climate-relevant biogenic secondary organic aerosols (SOAs) and will be greatly influenced by increasing temperature. Global warming is predicted to not only increase emissions of reactive biogenic volatile organic compounds (BVOCs) from vegetation directly but also induce large-scale insect outbreaks, which significantly increase emissions of reactive BVOCs. Thus, climate change factors could substantially accelerate the formation of biogenic SOAs in the troposphere. In this study, we have combined results from field and laboratory experiments, satellite observations and global-scale modelling in order to evaluate the effects of insect herbivory and large-scale outbreaks on SOA formation and the Earth's climate. Field measurements demonstrated 11-fold and 20-fold increases in monoterpene and sesquiterpene emissions respectively from damaged trees during a pine sawfly (Neodiprion sertifer) outbreak in eastern Finland. Laboratory chamber experiments showed that feeding by pine weevils (Hylobius abietis) increased VOC emissions from Scots pine and Norway spruce seedlings by 10–50 fold, resulting in 200–1000-fold increases in SOA masses formed via ozonolysis. The influence of insect damage on aerosol concentrations in boreal forests was studied with a global chemical transport model GLOMAP and MODIS satellite observations. Global-scale modelling was performed using a 10-fold increase in monoterpene emission rates and assuming 10 % of the boreal forest area was experiencing outbreak. Results showed a clear increase in total particulate mass (local max. 480 %) and cloud condensation nuclei concentrations (45 %). Satellite observations indicated a 2-fold increase in aerosol optical depth over western Canada's pine forests in August during a bark beetle outbreak. These results suggest that more frequent insect outbreaks in a warming climate could result in substantial increase in biogenic SOA formation in the boreal zone and, thus, affect both aerosol direct and indirect forcing of climate at regional scales. The effect of insect outbreaks on VOC emissions and SOA formation should be considered in future climate predictions.

Webb, Phyllis (1927– )

2018 ◽  
Author(s):  
Melissa Dalgleish
Keyword(s):  
British Columbia ◽  
West Coast ◽  
Full Length ◽  
The West ◽  
University Of British Columbia ◽  
Mcgill University ◽  
Phyllis Webb ◽  
The University ◽  
Point Of Departure ◽  
Selection Of

Phyllis Webb, OC is a Canadian poet, teacher, and broadcaster. She was born in Victoria, British Columbia and attended the University of British Columbia and McGill University. She is the author of numerous books of poetry, a selection of prose, and a collection of broadcast scripts, essays and reviews published as Talking (1982). Her first collection of poems was published alongside work by Eli Mandel and Gael Turnbull in Trio (1954). Webb’s first full-length collection, Even Your Right Eye (1956) was followed by The Sea is Also a Garden (1962). She began working at CBC Toronto in 1964 and acted as the producer of the ‘Ideas’ programme from 1967–1969. Her 1965 collection Naked Poems marked a point of departure with its compact forms and erotic evocation of lesbian desire. After returning to the West Coast, Webb did not publish another full-length collection until Wilson’s Bowl (1980). She won the Governor General’s Award for The Vision Tree (1982). Webb’s interest in the Persian ghazal form inspired Sunday Water: Thirteen Anti-Ghazals (1982) and Water and Light: Ghazals and Anti-Ghazals (1984). Her consistent concern with form manifests itself in her formal experimentation and her meticulous crafting of poems.

Costing the Earth: A Numbers Game or a Moral Imperative?

2013 ◽  
Vol 5 (4) ◽  
pp. 378-380 ◽  
Author(s):  
Gerard Roe
Keyword(s):  
Climate Change ◽  
Regional Climate ◽  
Relative Weight ◽  
Global Scale ◽  
Climate Impacts ◽  
Economic Consequences ◽  
Economic Costs ◽  
Policy Makers ◽  
The Earth ◽  
Moral Arguments

Abstract It is a simple truism that public policy must be guided by an objective analysis of the physical and economic consequences of climate change. It is equally true that policy making is an inherently value-laden endeavor. While these two threads are interconnected, the relative weight given to each depends on the certainty that the technical analyses can deliver. For climate change, the envelope of uncertainty is best understood at the global scale, and there are some well known and formidable challenges to reducing it. This uncertainty must in turn be compounded with much more poorly constrained uncertainties in regional climate, climate impacts, and future economic costs. The case can be made that technical analyses have reached the point of diminishing returns. Should meaningful action on climate change await greater analytical certainty? This paper argues that policy makers should give greater weight to moral arguments, in no small part because that is where the heart of the debate really lies.

scholarly journals Tree-ring reconstruction of June-July mean temperatures in the northern Daxing’an Mountains, China

2020 ◽  
Vol 47 (1) ◽  
pp. 13-22
Author(s):  
Yangao Jiang ◽  
Yu Wang ◽  
Junhui Zhang ◽  
Shijie Han ◽  
Cassius E.O. Coombs ◽  
...  
Keyword(s):  
Tree Ring ◽  
Southern Oscillation ◽  
Regional Climate ◽  
Ring Width ◽  
Temperature Reconstruction ◽  
Global Scale ◽  
Spatial Correlations ◽  
Regional Study ◽  
Average Value ◽  
Daxing’An Mountains

AbstractIn this study, the mean temperature of June to July was reconstructed for the period of 1880 to 2014 by using the Larix gmelinii tree-ring width data for the Mangui region in the northern Daxing’an Mountains, China. The reconstruction accounts for 43.6% of the variance in the temperature observed from AD 1959–2014. During the last 134 years, there were 17 warm years and 17 cold years, which accounted for 12.7% of the total reconstruction years, respectively. Cold episodes occurred throughout 1887–1898 (average value is 14.2°C), while warm episodes occurred during 1994–2014 (15.9°C). Based on this regional study, the warmer events coincided with dry periods and the colder events were consistent with wet conditions. The spatial correlation analyses between the reconstructed series and gridded temperature data revealed that the regional climatic variations were well captured by this study and the reconstruction represented a regional temperature signal for the northern Daxing’an Mountains. In addition, Multi-taper method spectral analysis revealed the existence of significant periodicities in our reconstruction. Significant spectral peaks were found at 29.7, 10.9, 2.5, and 2.2 years. The significant spatial correlations between our temperature reconstruction and the El Niño–Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO) and Solar activity suggested that the temperature in the Daxing’an Mountains area indicated both local-regional climate signals and global-scale climate changes.

scholarly journals Model–data fusion across ecosystems: from multi-site optimizations to global simulations

2014 ◽  
Vol 7 (3) ◽  
pp. 2961-3011 ◽  
Author(s):  
S. Kuppel ◽  
P. Peylin ◽  
F. Maignan ◽  
F. Chevallier ◽  
G. Kiely ◽  
...  
Keyword(s):  
Land Surface ◽  
Boreal Forests ◽  
Ecosystem Respiration ◽  
Co2 Concentration ◽  
Ecosystem Model ◽  
Global Scale ◽  
Model Data ◽  
Site Specific ◽  
Output Uncertainty ◽  
Averaged Model

Abstract. This study uses a variational data assimilation framework to simultaneously constrain a global ecosystem model with eddy covariance measurements of daily net carbon (NEE) and latent heat (LE) fluxes from a large number of sites grouped in seven plant functional types (PFTs). It is an attempt to bridge the gap between the numerous site-specific parameter optimization works found in the literature and the generic parameterization used by most land surface models within each PFT. The present multi-site approach allows deriving PFT-generic sets of optimized parameters enhancing the agreement between measured and simulated fluxes at most of the sites considered, with performances often comparable to those of the corresponding site-specific optimizations. Besides reducing the PFT-averaged model–data root-mean-square difference (RMSD) and the associated daily output uncertainty, the optimization improves the simulated CO2 balance at tropical and temperate forests sites. The major site-level NEE adjustments at the seasonal scale are: reduced amplitude in C3 grasslands and boreal forests, increased seasonality in temperate evergreen forests, and better model–data phasing in temperate deciduous broadleaf forests. Conversely, the poorer performances in tropical evergreen broadleaf forests points to deficiencies regarding the modeling of phenology and soil water stress for this PFT. An evaluation with data-oriented estimates of photosynthesis (GPP) and ecosystem respiration (Reco) rates indicates distinctively improved simulations of both gross fluxes. The multi-site parameter sets are then tested against CO2 concentrations measured at 53 locations around the globe, showing significant adjustments of the modeled seasonality of atmospheric CO2 concentration, whose relevance seems PFT-dependent, along with an improved interannual variability. Lastly, a global scale evaluation with remote sensing NDVI measurements indicates an improvement of the simulated seasonal variations of the foliar cover for all considered PFTs.

scholarly journals High latitude cooling associated with landscape changes from North American boreal forest fires

2012 ◽  
Vol 9 (9) ◽  
pp. 12087-12136 ◽  
Author(s):  
B. M. Rogers ◽  
J. T. Randerson ◽  
G. B. Bonan
Keyword(s):  
Boreal Forest ◽  
High Latitude ◽  
Forest Fires ◽  
Boreal Forests ◽  
Regional Climate ◽  
Forest Composition ◽  
Energy Budgets ◽  
Surface Cooling ◽  
Functional Variation ◽  
Greenhouse Gasses

Abstract. Fires in the boreal forests of North America are generally stand-replacing, killing the majority of trees and initiating succession that may last over a century. Functional variation during succession can affect local surface energy budgets and, potentially, regional climate. Burn area across Alaska and Canada has increased in the last few decades and is projected to be substantially higher by the end of the 21st century because of a warmer climate with longer growing seasons. Here we simulated the changes in forest composition due to altered burn area using a stochastic model of fire occurrence, historical fire data from national inventories, and succession trajectories derived from remote sensing. When coupled to an Earth system model, younger vegetation from increased burning cooled the high-latitude atmosphere, primarily in the winter and spring, with noticeable feedbacks from the ocean and sea ice. Results from multiple scenarios suggest that a doubling of burn area would result in surface cooling of 0.23 ± 0.09 °C and 0.43 ± 0.12 °C for winter–spring and February–April time periods, respectively. This could provide a negative feedback to high-latitude terrestrial warming during winter on the order of 4–6% for a doubling, and 14–23% for a quadrupling, of burn area. Further work is needed to integrate all the climate drivers from boreal forest fires, including aerosols and greenhouse gasses.

scholarly journals Fritz Müller’s legacy on Axel Heiberg Island, Nunavut, Canada

2000 ◽  
Vol 31 ◽  
pp. 1-9
Author(s):  
Peter Adams
Keyword(s):  
Faculty Member ◽  
Mass Balance ◽  
Early Years ◽  
Glacier Mass Balance ◽  
Personal Account ◽  
Lake Ice ◽  
Glacier Terminus ◽  
Mcgill University ◽  
Break Up ◽  
Axel Heiberg Island

AbstractFritz Müller (1926–80) was the leader of the Jacobsen-McGill Arctic Research Expeditions to Axel Heiberg Island, Nunavut, Canada. He was a faculty member at McGill University, Montreal, Canada, from 1959 to 1970. Thereafter, he was Chair of Geography at Eidgenossische Techmsche Hochschule, Zürich, Switzerland. He conducted research on Axel Heiberg Island, mainly in the vicinity of Expedition Fiord, from 1959 until his death in 1980. This paper is a personal account of Müller’s work by one of his students, with a commentary on his contributions to Arctic science. The personal account focuses on the early years of the expeditions. The commentary includes discussion of glacier mass-balance records and lake-ice break-up from 1959 to the present, glacier-terminus records from 1948 to the present and other research focused on the region.

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