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At least 235 records · Page 13

Methane production and consumption in grassland and boreal ecosystems

The objectives of the this project were to develop a mechanistic understanding of methane production and oxidation suitable for incorporation into spatially explicit models for spatial extrapolation. Field studies were undertaken in Minnesota, Canada, and Colorado to explore the process controls over the two microbial mediated methane transformations in a range of environments. Field measurements were done in conjunction with ongoing studies in Canada (the Canadian Northern Wetlands Projects: NOWES) and in Colorado (The Shortgrass Steppe Long Term Ecological Research Project: LTER). One of the central hypotheses of the proposal was that methane production should be substrate limited, as well as being controlled by physical variables influencing microbial activity (temperature, oxidation status, and pH). Laboratory studies of peats from Canada and Minnesota (Northern and Southern Boreal) were conducted with amendments of a methanogenic substrate at multiple temperatures and at multiple pHs (the latter by titrating samples). The studies showed control by substrate, pH, and temperature in order in anaerobic samples. Field and laboratory manipulations of natural plant litter, rather than an acetogenic substrate, showed similarly large effects. The studies concluded that substrate is an important control over methanogenesis, that substrate availability in the field is closely coupled to the chemistry of the dominant vegetation influencing its decomposition rate, that most methane is produced from recent plant litter, and that landscape changes in pH are an important control, highly correlated with vegetation.

Schimel, David S.↗

Breaking the Language Barrier

Preparation for the Apollo Soyuz mission entailed large-scale informational exchange that was accomplished by a computerized translation system. Based on this technology of commercial machine translation, a system known as SYSTRAN II was developed by LATSEC, Inc. and the World Translation Company of Canada. This system increases the output of a human translator by five to eight times, affording cost savings by allowing a large increase in document production without hiring additional people. Extra savings accrue from automatic production of camera-ready copy. Applications include translation of service manuals, proposals and tenders, planning studies, catalogs, list of parts and prices, textbooks, technical reports and education/training materials. System is operational for six language pairs. Systran users include Xerox Corporation, General Motors of Canada, Bell Northern Research of Canada, the U.S. Air Force and the European Commission. The company responsible for the production of SYSTRAN II has changed its name to SYSTRAN.

Source record↗

Distributions of Orbital Elements for Meteoroids on Near-Parabolic Orbits According to Radar Observational Data

Some results of the International Heliophysical Year (IHY) Coordinated Investigation Program (CIP) number 65 Meteors in the Earth Atmosphere and Meteoroids in the Solar System are presented. The problem of hyperbolic and near-parabolic orbits is discussed. Some possibilities for the solution of this problem can be obtained from the radar observation of faint meteors. The limiting magnitude of the Kharkov, Ukraine, radar observation program in the 1970 s was +12, resulting in a very large number of meteors being detected. 250,000 orbits down to even fainter limiting magnitude were determined in the 1972-78 period in Kharkov (out of them 7,000 are hyperbolic). The hypothesis of hyperbolic meteors was confirmed. In some radar meteor observations 1 10% of meteors are hyperbolic meteors. Though the Advanced Meteor Orbit Radar (AMOR, New Zealand) and Canadian Meteor Orbit Radar (CMOR, Canada) have accumulated millions of meteor orbits, there are difficulties in comparing the radar observational data obtained from these three sites (New Zealand, Canada, Kharkov). A new global program International Space Weather Initiative (ISWI) has begun in 2010 (http://www.iswi-secretariat.org). Today it is necessary to create the unified radar catalogue of nearparabolic and hyperbolic meteor orbits in the framework of the ISWI, or any other different way, in collaboration of Ukraine, Canada, New Zealand, the USA and, possibly, Japan. Involvement of the Virtual Meteor Observatory (Netherlands) and Meteor Data Centre (Slovakia) is desirable too. International unified radar catalogue of near-parabolic and hyperbolic meteor orbits will aid to a major advance in our understanding of the ecology of meteoroids within the Solar System and beyond.

Kolomiyets, S. V.↗

Newly Identified Climatically and Environmentally Significant High-Latitude Dust Sources

Dust particles from high latitudes have a potentially large local, regional, and global significance to climate and the environment as short-lived climate forcers, air pollutants, and nutrient sources. Identifying the locations of local dust sources and their emission, transport, and deposition processes is important for understanding the multiple impacts of high-latitude dust (HLD) on the Earth’s systems. Here, we identify, describe, and quantify the source intensity (SI) values, which show the potential of soil surfaces for dust emission scaled to values 0 to 1 concerning globally best productive sources, using the Global Sand and Dust Storms Source Base Map (G-SDS-SBM). This includes 64 HLD sources in our collection for the northern (Alaska, Canada, Denmark, Greenland, Iceland, Svalbard, Sweden, and Russia) and southern (Antarctica and Patagonia) high latitudes. Activity from most of these HLD sources shows seasonal character. It is estimated that high-latitude land areas with higher (SI ≥ 0.5), very high (SI ≥ 0.7), and the highest potential (SI ≥ 0.9) for dust emission cover > 1 670 000 km 2 , > 560 000 km 2 , and > 240 000 km 2 , respectively. In the Arctic HLD region (≥ 60◦ N), land area with SI ≥ 0.5 is 5.5 % (1 035 059 km 2 ), area with SI ≥ 0.7 is 2.3 % (440 804 km 2 ), and area with SI ≥ 0.9 is 1.1 % (208 701 km 2 ). Minimum SI values in the northern HLD region are about 3 orders of magnitude smaller, indicating that the dust sources of this region greatly depend on weather conditions. Our spatial dust source distribution analysis modeling results showed evidence supporting a northern HLD belt, defined as the area north of 50◦ N, with a “transitional HLD-source area” extending at latitudes 50–58◦ N in Eurasia and 50–55◦ N in Canada and a “cold HLD-source area” including areas north of 60◦ N in Eurasia and north of 58◦ N in Canada, with currently “no dust source” area between the HLD and low-latitude dust (LLD) dust belt, except for British Columbia. Using the global atmospheric transport model SILAM, we estimated that 1.0 % of the global dust emission originated from the high-latitude regions. About 57 % of the dust deposition in snow- and ice-covered Arctic regions was from HLD sources. In the southern HLD region, soil surface conditions are favorable for dust emission during the whole year. Climate change can cause a decrease in the duration of snow cover, retreat of glaciers, and an increase in drought, heatwave intensity, and frequency, leading to the increasing frequency of topsoil conditions favorable for dust emission, which increases the probability of dust storms. Our study provides a step forward to improve the representation of HLD in models and to monitor, quantify, and assess the environmental and climate significance of HLD.

high latitude dust↗

Threats to North American Forests from Southern Pine Beetle with Warming Winters

In coming decades, warmer winters are likely to lift range constraints on many cold-limited forest insects. Recent unprecedented expansion of the southern pine beetle (SPB, Dendroctonus frontalis) into New Jersey, New York, Connecticut, and Massachusetts in concert with warming annual temperature minima highlights the risk that this insect pest poses to the pine forests of the northern United States and Canada under continued climate change. Here we present the first projections of northward expansion in SPB-suitable climates using a statistical bioclimatic range modeling approach and current-generation general circulation model (GCM) output under the RCP 4.5 and 8.5 emissions scenarios. Our results show that by the middle of the 21st century, the climate is likely to be suitable for SPB expansion into vast areas of previously unaffected forests throughout the northeastern United States and into southeastern Canada. This scenario would pose a significant economic and ecological risk to the affected regions, including disruption oflocal ecosystem services, dramatic shifts in forest structure, and threats to native biodiversity.

risk↗

Identification of geostructures of continental crust, particularly as they relate to mineral-resource evaluation

The authors have identified the following significant results. As a precursor to the ERTS-1 investigation, the spatial relationship of geostructures seen on Nimbus IDCS photographs to the distribution of mineralized areas in Alaska and western Canada was analyzed to determine the possible metallogenic significance of the geostructures. In Canada, mercury and porphyry molybdenum deposits are closely associated with strong northwest-trending fault systems; the development of mineralized regions seems related to major crustal zones or fractures trending southwestward across the Cordillera from the Precambrian shield. In Alaska, comparison of the northeast- and northwest-trending set of possible crustal structures shown on the Nimbus photo, with the distribution of known mineral deposits suggests a similar relationship. The mineralized region of massive sulfides in Prince William Sound and upper Copper River areas and of porphyry coppers in the Nabesna area forms a broad northeast-trending belt possibly related to the Minto Arch on the Shield. The belt of metalliferous deposits in the western Alaska Range follows a comparable northeast trend. Mercury deposits, suggested by many to be fault-controlled, together with most tin and tungsten deposits, occupy a northeast-trending belt between the Bristol Bay-Mackenzie Bay linear and extensions of a linear along the lower Yukon River. This belt intersects the northwest-trending Canadian belt of similar deposits in the Fairbanks area.

Gryc, G.↗

Identification of geostructures of continental crust, particularly as they relate to mineral resource evaluation

The author has identified the following significant results. The southeastward continuation of a fault that has been mapped in the vicinity of Dan Creek, Alaska, shows up as a lineament on ERTS-1 image 1043-20163 that can be traced for more than 50 miles southeastward to beyond the Alaska-Canada boundary. The lineament probably reflects a major fault that is significant in understanding the complicated tectonics of the Wrangell Mountains-Saint Elias Mountains complex. From a study of the ERTS-1 image, low level vertical photography, and limited field work in the largely unmapped region, E.M. Mackevett, Jr., speculates that the eastern part of the fault may mark the southern boundary of a mild-Paleozoic metamorphic terrane that constitutes the westernmost known extent of the Alexander terrane of Berg, Jones, and Richter (1972) and correlates with the Kaskawulsh Group in Canada. This terrane, which consists dominantly of marble, was recognized during 1972 reconnaissance mapping in the eastcentral part of the McCarthy quadrangle by MacKevett, D.L. Jones, and D.H. Richter and contrasts strongly with the dominantly volcanic and volcanoclastic terrane of Pennsylvanian and Permian age that forms the basement in most of the McCarthy quadrangle.

Gryc, G.↗

Retransmission of water resources data using the ERTS-1 data collection system

The Water Survey of Canada operates a network of approximately 2400 gauging stations at which water level data are collected. Nine DCPs were installed in isolated areas of northern and western Canada. It was felt that DCPs in these locations would be exposed to climatic conditions severe enough to provide a check on system reliability. Water level data are transmitted from all sites and, also, some of the DCPs are used to transmit ice break-up, water velocity, precipitation, air temperature, water stage recorder clock operation or DCP battery voltage. Consideration is being given to transmitting other parameters that would be of value in flood or flow forecasting. Results of the project have been excellent. There has been no data loss that can be attributed to failure of a DCP although data were lost because of sensor malfunctions. The quality of data collected compares favourably with that of the hard record obtained at the remote sites. Costs of using the ERTS Data Collection System are reasonable.

Halliday, R. A.↗

The Communications Technology Satellite and the associated ground terminals for experiments

The CTS project is a joint effort between the Communications Research Centre in Canada and National Aeronautics and Space Administration in the United States with both nations equally sharing available spacecraft communication time. The CTS spacecraft will be placed in synchronous orbit at 116 deg west longitude. General spacecraft operational characteristics are discussed with particular emphasis on communication system parameters. The associated Canadian and United States user ground terminals are reviewed with particular emphasis on wideband communications. In Canada the experimenter (user) ground terminal communication equipment is government owned whereas in the United States the user terminal equipment is the responsibility of each user.

Wright, D. L.↗

The use of LANDSAT DCS and imagery in reservoir management and operation

The author has identified the following significant results. A graph that shows the snow water equivalent data during the 1975-76 winter season for the Ninemile and Michaud Farms snow pillows located in northern Maine is shown. The Bournes transducers used in the snow pillow interface were tested after field use under controlled laboratory conditions of temperature and pressure. It was found that the temperature calibration curve for the Bournes transducers became erratic below 0 C. On 8-10 August 1976, the remainder of hurricane, Belle, travelled through Vermont, New Hampshire, northern Maine, and on into Canada's Maritime Provinces dumping three inches of rain in many areas. In Canada and Maine, local storms dropped up to two inches during the following week. The Saint John River reached near flood stages at Fort Kent, Maine. During this storm, DCP data were received from Fort Kent, Ninemile Bridge, and Saint Francis River in New Brunswick. Resulting high runoff after these storms was studied in connection with the proposed Dickey-Lincoln School dams to be built in that area, and significantly, it was found that creditable flood hydrographs could be generated from LANDSAT DCP data in spite of the voids caused by the satellite being below the horizon.

Cooper, S.↗

US Search and Rescue Mission Control Center functions

A satellite aided Search and Rescue (SAR) Mission concept consisting of a local coverage bent pipe system, and a global coverage system is described. The SAR instrument is to consist of a Canadian repeater and a French processor for which Canada and France, respectively are to evaluate health and trends. Performance evaluations of each system were provided. The United States and Canada will each have a Search and Rescue Mission Control Center (MCC) and their functions were also examined. A summary of the interface requirements necessary to perform each function was included as well as the information requirements between the USMCC and each of its interfaces. Physical requirements such as location, manning etc. of the USMCC were discussed.

Source record↗

Review of Canadian experience in precise gravimetry

Results of gravity observations made in Canada from 1974 to 1978 reviewed, in order to estimate the true accuracy of present-day gravimetry and thereby assess the potential capability of the method for detecting crustal movements. The standard error of the mean of ties is 15-20 nm/s squared. Inter-instrument comparisons and other tests show, however, that a more realistic estimate of D meter accuracy is 30-40 nm/s squared. This accuracy can only be maintained over the long term where uncertainties in gravimeter calibration curves are minimized by resetting to the same dial reading on the resurveys. A further deterioration in accuracy to 40-50 nm/s squared occurs where reliance is placed on presently available D meter calibration curves. Despite the present accuracy limitations significant time variations in gravity of 100-150 nm/s squared are seen over spatial scales of 10-100 kilometers in Canada over a period of several months.

Lambert, A.↗

Selection of USSR foreign similarity regions

The similarity regions in the United States and Canada were selected to parallel the conditions that affect labeling and classification accuracies in the U.S.S.R. indicator regions. In addition to climate, a significant condition that affects labeling and classification accuracies in the U.S.S.R. is the proportion of barley and wheat grown in a given region (based on sown areas). The following regions in the United States and Canada were determined to be similar to the U.S.S.R. indicator regions: (1) Montana agrophysical unit (APU) 104 corresponds to the Belorussia high barley region; (2) North Dakota and Minnesota APU 20 and secondary region southern Manitoba and Saskatchewan correspond to the Ural RSFSR barley and spring wheat region; (3) Montana APU 23 corresponds to he North Caucasus barley and winter wheat region. Selection criteria included climates, crop type, crop distribution, growth cycles, field sizes, and field shapes.

Disler, J. M.↗

Weight and structural analysis of four structural concepts for a land mobile satellite system

The present study is concerned with a Land Mobile Satellite System (LMSS) which can provide mobile communications for commercial and government applications in nonmetropolitan areas of the continental U.S. and Canada as an augmentation to existing and planned terrestrial systems. The satellite system would provide 'narrow band' telecommunications services, thin-route fixed telephone and data services in the 806-890 MHz band, and continuous emergency beacon monitoring in the 406-406.1 MHz band. It is pointed out that a satellite system operating in concert with terrestrial cellular systems could provide truly ubiquitous mobile communications services in the U.S. and Canada. A single shuttle shuttle launch could place the LMSS spacecraft in geosynchronous orbit over the continental U.S. in 1995 with a 10-year lifetime. Attention is given to the structural concepts, a weight analysis, and a structural analysis.

Ferebee, M. J.↗

Alouette-ISIS program summary

The Alouette-ISIS program was a joint undertaking between Canada and the United States. Canada provided the Alouette and ISIS spacecraft, data acquisition, and satellite control. The USA provided launch capability, satellite tracking, and data acquisition. Brief descriptions of the six spacecraft and of the investigations on each spacecraft are given. The Alouette-ISIS bibliography, order alphabetically by first author's name, is contained.

Jackson, John E.↗

The Frasnian-Famennian mass killing event(s), methods of identification and evaluation

The absence of an abnormally high number of earlier Devonian taxa from Famennian sediments was repeatedly documented and can hardly be questioned. Primary recognition of the event(s) was based on paleontological data, especially common macrofossils. Most paleontologists place the disappearance of these common forms at the gigas/triangularis contact and this boundary was recently proposed as the Frasnian-Famennian (F-F) boundary. Not unexpectedly, alternate F-F positions were suggested caused by temporary Frasnian survivors or sudden post-event radiations of new forms. Secondary supporting evidence for mass killing event(s) is supplied by trace element and stable isotope geochemistry but not with the same success as for the K/T boundary, probably due to additional 300 ma of tectonic and diagenetic overprinting. Another tool is microfacies analysis which is surprisingly rarely used even though it can explain geochemical anomalies or paleontological overlap not detectable by conventional macrofacies analysis. The combination of microfacies analysis and geochemistry was applied at two F-F sections in western Canada and showed how interdependent the two methods are. Additional F-F sections from western Canada, western United States, France, Germany and Australia were sampled or re-sampled and await geochemical/microfacies evaluation.

Geldsetzer, H. H. J.↗

The 10.7-cm microwave observations of AR 5395 and related terrestrial effects

The 10.7 cm flux patrols in Canada recorded 4 Great Bursts (peaks greater than 500 sfu) during the disk passage of AR 5395 in March 1989. The Great Bursts of 16 and 17 March were simple events of great amplitude and with half-life durations of only several minutes. Earlier Great Bursts, originating on 6 March towards the NE limb and on 10 March closer to the central meridian, belong to an entirely different category of event. Each started with a very strong impulsive event lasting just minutes. After an initial recovery, however, the emission climbed back to level as greater or greater than the initial impulsive burst. The events of 6 and 10 March stayed above the Great Burst threshold for at least 100 minutes. The second component of long duration in these cases is associated with Type 4 continuum emission and thus very likely with CMEs. Major geomagnetic disturbances did not occur as a result of the massive complex event of 6 March or the two simple but strong events of 16 and 17 March. But some 55 hours after the peak in the long-enduring burst of 10 March, a storm began which qualifies as the fourth strongest geomagnetic storm in Canada since 1932. The vertical component of the earth's field measured during the storm by a fluxgate magnetometer at a station in Manitoba is presented. Within a minute of the sudden commencement of this storm, a series of breakdowns began in the transmission system of Hydro-Quebec which resulted in a total loss of power, on a bitterly cold winter's day, for at least 10 hours. The loss of power provoked an enormous outcry from the public resulting in the power utilities being more receptive to the need to monitor solar as well as geomagnetic activity.

Gaizauskas, V.↗

Satellite measurements of large-scale air pollution - Measurements of forest fire smoke

The transport, optical properties, total mass, and removal of smoke produced by forest fires in western Canada during late July and early August 1982 are studied using NOAA 7 AVHRR data. Color composite imagery is produced to track the movement of the smoke over Canada and the U.S. as the smoke traveled thousands of km from the source region. Smoke optical thickness, particle size, and single scattering albedo are computed using radiances measured by AVHRR bands 1 and 2. Results show that smoke optical thickness ranged from less that 0.1 to greater than 3.7 and the geometric mean mass radii ranged from 300 to 900 nm. The smoke single scattering albedo ranged from 0.9 to nearly 1.0. The total smoke mass over the eastern U.S. ranged from 0.1 to 0.5 Tg, which is close to the 0.5 Tg estimated from the forest fuel content. The smoke lifetime is estimated to be between 15 and 20 days.

Ferrare, Richard A.↗