Large-scale spatial patterns of forest structural diversity

2008 ◽  
Vol 38 (3) ◽  
pp. 429-438 ◽  
Author(s):  
Ronald E. McRoberts ◽  
Susanne Winter ◽  
Gherardo Chirici ◽  
Elmar Hauk ◽  
Dieter R. Pelz ◽  
...  
Keyword(s):  
Spatial Patterns ◽  
Large Scale ◽  
Structural Diversity ◽  
Diversity Indices ◽  
The United States ◽  
Shannon Index ◽  
Tree Diameter ◽  
The North ◽  
Highly Correlated ◽  
Ecological Province

Forest structural diversity was estimated for an ecological province in the north-central region of the United States of America using data for nearly 350 000 trees observed on >12 000 forest inventory plots. Each plot was 672 m2 in area, and the sampling intensity was approximately 1 plot/2400 ha. Two indices were used for each of two commonly and accurately measured inventory variables: species count and the Shannon index for tree species and standard deviation and the Shannon index for tree diameter. The primary results of the study were fourfold: (i) ranges of spatial correlation for diversity indices were small, on the order of 5–10 km, (ii) high proportions of provincewide diversity were realized for circular areas with radii as small as 15 km, (iii) diversity for both species and diameter exhibited strong northwest to southeast spatial patterns, and (iv) plot-level α diameter diversity was highly correlated with mean plot-level tree diameter.

scholarly journals Synoptic–Dynamic Climatology of Large-Scale Cyclones in the North Pacific

2006 ◽  
Vol 134 (12) ◽  
pp. 3567-3587 ◽  
Author(s):  
Linda M. Keller ◽  
Michael C. Morgan ◽  
David D. Houghton ◽  
Ross A. Lazear
Keyword(s):  
North Pacific ◽  
Large Scale ◽  
The United States ◽  
Height Anomaly ◽  
Maximum Frequency ◽  
Mean Flow ◽  
Central Pacific ◽  
The North ◽  
The Pacific ◽  
The North Pacific

Abstract A climatology of large-scale, persistent cyclonic flow anomalies over the North Pacific was constructed using the National Centers for Environmental Prediction–National Center for Atmospheric Research (NCEP–NCAR) global reanalysis data for the cold season (November–March) for 1977–2003. These large-scale cyclone (LSC) events were identified as those periods for which the filtered geopotential height anomaly at a given analysis point was at least 100 m below its average for the date for at least 10 days. This study identifies a region of maximum frequency of LSC events at 45°N, 160°W [key point 1 (KP1)] for the entire period. This point is somewhat to the east of regions of maximum height variability noted in previous studies. A second key point (37.5°N, 162.5°W) was defined as the maximum in LSC frequency for the period after November 1988. The authors show that the difference in location of maximum LSC frequency is linked to a climate regime shift at about that time. LSC events occur with a maximum frequency in the period from November through January. A composite 500-hPa synoptic evolution, constructed relative to the event onset, suggests that the upper-tropospheric precursor for LSC events emerges from a quasi-stationary long-wave trough positioned off the east coast of Asia. In the middle and lower troposphere, the events are accompanied by cold thickness advection from a thermal trough over northeastern Asia. The composite mean sea level evolution reveals a cyclone that deepens while moving from the coast of Asia into the central Pacific. As the cyclone amplifies, it slows down in the central Pacific and becomes nearly stationary within a day of onset. Following onset, at 500 hPa, a stationary wave pattern, resembling the Pacific–North American teleconnection pattern, emerges with a ridge immediately downstream (over western North America) and a trough farther downstream (from the southeast coast of the United States into the western North Atlantic). The implications for the resulting sensible weather and predictability of the flow are discussed. An adjoint-derived sensitivity study was conducted for one of the KP1 cases identified in the climatology. The results provide dynamical confirmation of the LSC precursor identification for the events. The upper-tropospheric precursor is seen to play a key role not only in the onset of the lower-tropospheric height falls and concomitant circulation increases, but also in the eastward extension of the polar jet across the Pacific. The evolution of the forecast sensitivities suggest that LSC events are not a manifestation of a modal instability of the time mean flow, but rather the growth of a favorably configured perturbation on the flow.

Linking marine fog variability in Atlantic Canada to changes in large-scale atmospheric and marine features

2020 ◽  
Author(s):  
Patrick Duplessis ◽  
Minghong Zhang ◽  
William Perrie ◽  
George A Isaac ◽  
Rachel Y W Chang
Keyword(s):  
Large Scale ◽  
Climate Model ◽  
Internal Variability ◽  
Reanalysis Data ◽  
Sea Surface ◽  
Atlantic Canada ◽  
Climate Projections ◽  
The North ◽  
Marine Traffic ◽  
Highly Correlated

<p>Marine and coastal fog forms mainly from the cooling of warm and moist air advected over a colder sea surface. Atlantic Canada is one of the foggiest regions of the world due to the strong temperature contrast between the two oceanic currents in the vicinity. Recurring periods of low visibility notably disrupt off-shore operations and marine traffic, but also land and air transportation. On longer time-scales, marine fog variability also has a significant impact on the global radiative budget. Clouds, including fog, are the greatest source of uncertainty in the current climate projections because of their complex feedback mechanisms. Meteorological records indicate a significant negative trend in the occurrence of foggy conditions over the past six decades at most airports in Atlantic Canada, with large internal variability, including interannual and interdecadal variations. Using the airport observations, reanalysis data and climate model outputs, we investigated the various variabilities on the trend, at interannual and interdecadal scales, and attempted to address what caused these changes in fog frequency. Our results show that the strength and position of the North Atlantic Subtropical High as well as the sea-surface temperature of the cold and warm waters near Atlantic Canada were highly correlated with fog occurrence. We applied the derived fog indices on climate model outputs and projected the fog trends and variability in the different future climate scenarios. The results from this study will be compared with those obtained from other methods and the implications will be discussed.</p>

Joint Canada-U.S. Survey in the Mount Kennedy Region

ARCTIC ◽  
1965 ◽  
Vol 18 (2) ◽  
pp. 70
Author(s):  
Canada. Surveys and Mapping Branch
Keyword(s):  
Large Scale ◽  
Field Measurements ◽  
The United States ◽  
Geodetic Survey ◽  
Yukon Territory ◽  
Mountain Range ◽  
National Geographic Society ◽  
National Geographic ◽  
The North ◽  
Alaskan Coast

In 1935 a National Geographic Society glaciological expedition working in the St. Elias mountain range near the Alaska-Yukon Territory boundary described an unnamed mountain in the area as "magnificent, a granite peak sheathed in snow and ice on the south and west sides, and on the north and east sides has fantastic rock cliffs." Thirty years later this same peak was officially named Mount Kennedy in honour of the late President John F. Kennedy. A surge of activity in the area followed immediately. Senator Robert Kennedy climbed the mountain, an expedition sponsored by the National Geographic Society is engaged in producing a large scale map of the mountain and its environs, and a joint U.S.-Canadian party has just completed a survey through the area which will determine the precise geographic position of the mountain's summit and its elevation. The survey party was composed of six men from the United States Coast and Geodetic Survey and two men from the Surveys and Mapping Branch of the Canadian Department of Mines and Technical Surveys. The main purpose of the work was to connect existing surveys along the Alaska Highway with similar surveys along the Alaskan coast. The work will strengthen the control surveys throughout the area and provide new control points for mapping. The decision to include Mount Kennedy in the survey, while adding a touch of glamour to the operation, greatly increased the difficulties. The survey itself consists of five main stations, connected by traverse, with auxiliary points established at alternate stations to provide additional checks on field measurements. The lengths of the four traverse courses varied from eight to thirty-nine miles; the distances were measured by electronic distance measuring equipment, and the angles were measured with precise theodolites using signal lights and heliotropes for targets. ...

Evaluating the Transfer of Care from Psychiatric Hospitals to District-Based Services

1993 ◽  
Vol 162 (S19) ◽  
pp. 6-6 ◽  
Author(s):  
Julian Leff
Keyword(s):  
Inner City ◽  
Large Scale ◽  
Medical Officer ◽  
Psychiatric Hospitals ◽  
The United States ◽  
Regional Health ◽  
North East ◽  
The North ◽  
Steady Rate ◽  
Regional Medical

In July 1983 the Regional Medical Officer of the North East Thames Regional Health Authority (NETRHA) appeared on television to announce the closure of Claybury Hospital and much of Friern Hospital over a ten-year period.When NETRHA announced its decision, the policy to be pursued was innovative because it involved psychiatric hospitals serving inner-city populations, and because there was apparently no intention to achieve its aim by decanting patients into other psychiatric hospitals, as had been done with the closures of St Wulstan's and Banstead Hospitals. Although the run-down of psychiatric hospitals had been occurring at a steady rate in the United States and in England and Wales since the early 1950s, there had been few attempts to evaluate the policy, and none had been in any sense comprehensive (this supplement, paper 7). Clinicians and research workers in the field of social psychiatry were well aware of the need for large-scale evaluative studies, since protagonists and opponents of the policy of deinstitutionalisation were locked in a polemical argument which was pursued with increasing stridency through lack of reliable information.

Spatial patterns of vegetation structure and structural diversity across edges between forested wetlands and upland forest in Atlantic Canada

2021 ◽  
Author(s):  
Karen Amanda Harper ◽  
Logan Gray ◽  
Natasha Dazé Querry
Keyword(s):  
Spatial Patterns ◽  
Vegetation Structure ◽  
Canopy Cover ◽  
Forested Wetlands ◽  
Structural Diversity ◽  
Shannon Index ◽  
Forested Wetland ◽  
Atlantic Canada ◽  
Wetland Protection ◽  
Upland Forest

Forested wetlands are an integral but understudied part of heterogeneous landscapes in Atlantic Canada, although they are known to provide habitat for species at risk. Our objectives were to explore patterns of forest structure across edges between forested wetland and upland forest, to locate changes in vegetation structure and to assess multivariate relationships in vegetation structure. Our study sites were in temperate (Acadian) forested wetland landscapes. We sampled trees and recorded canopy cover every 20 m along 120 m long transects. We estimated the cover of trees, saplings, shrubs in three height classes, Sphagnum, other bryophytes, lichens, graminoids, ferns and forbs in contiguous 1 x 1 m quadrats. We calculated structural diversity using the Shannon index and used wavelet analysis to assess spatial patterns. We found few clear patterns except for lower tree structural diversity at the edge of forested wetlands. Structural diversity was not a reliable measure for distinguishing forested wetland from upland forest. Forested wetlands are an integral part of many forested landscapes in Atlantic Canada but their detection and differentiation from surrounding ecosystem can be difficult. Policy should err on the side of caution when mapping forested wetlands and include them in wetland protection.

scholarly journals Hydro-businesses: National and Global Demands on the São Francisco River Basin Environment of Brazil

2010 ◽  
Vol 55 (S18) ◽  
pp. 203-233
Author(s):  
Lucigleide Nery Nascimento ◽  
Mimi Larsen Becker
Keyword(s):  
Large Scale ◽  
The United States ◽  
Economic Approach ◽  
Hydro Power ◽  
Federal Policies ◽  
Sao Francisco River ◽  
North East ◽  
The North ◽  
São Francisco River

SummaryThe São Francisco River provided very obvious, close-by forms of sustenance for local communities. Beginning in the mid-1950s, the river became the place for large hydro-electric facilities, large-scale flooding, and population resettlement. A decade later, the federal government began working on pilot irrigation projects that would lead to areas described today as the Brazilian California. Hydro-power for Brazilian cities such as Recife and Salvador and irrigation for grapes and mangoes destined for the United States and Europe are among the eco-system services this river supplies. The purpose of federal policies for the north-east went beyond mitigation of the consequences of droughts, the hydraulic approach, and started to follow an economic approach based upon development; as a consequence, river and user came to be distant from one another. The two major intensive uses of the river, electricity and irrigation, threaten the long-term sustainability of this system.

scholarly journals Pathogenicity of Pythium Populations from Corn-Soybean Rotation Fields

Plant Disease ◽  
2000 ◽  
Vol 84 (1) ◽  
pp. 94-99 ◽  
Author(s):  
B. Q. Zhang ◽  
X. B. Yang
Keyword(s):  
United States ◽  
The United States ◽  
Disease Index ◽  
North Central ◽  
Soybean Seedlings ◽  
The North ◽  
Soilborne Fungi ◽  
Central Regions ◽  
Highly Correlated

Corn and soybean have been rotated for decades in the north central regions of the United States, but it is unknown how the use of long-term rotation affects the population of soilborne fungi pathogenic to both crops. Pythium populations were obtained from 73 commercial corn-soybean rotation fields in Iowa from 1993 to 1995. A total of 163 Pythium isolates were obtained from soil, diseased soybean seedlings, or diseased corn seedlings, and these isolates were pooled into six populations according to the source of samples. The isolates were evaluated for their aggressiveness on corn and soybean for each population. Regardless of the source of sampling, each population had many Pythium isolates that were highly aggressive on both crops. Seventy-one percent of the isolates from soil were pathogenic, and 29% were highly aggressive on both crops. Three populations of Pythium isolates were obtained from diseased soybean seedlings. Eighty-five percent of those isolates were pathogenic, and 49 to 64% were highly aggressive on corn and soybean. Of the isolates obtained from diseased corn seedlings, 87% were pathogenic and 43% were highly aggressive on corn and soybean. For each Pythium population, aggressiveness on soybean and corn (measured by disease index) were highly correlated. Further, 23 P. ultimum isolates were identified from diseased soybean seedlings and tested for pathogenicity on corn and soybean. Disease index of the isolates varied, but the correlation between disease indices on the two crops was significant (r = 0.75, P < 0.001). The study suggests that long-term corn-soybean rotation fields contain many Pythium isolates that are highly aggressive on seedlings of both crops.

scholarly journals Simulation of the North American Monsoon by the NCAR CCM3 and Its Sensitivity to Convection Parameterization

2006 ◽  
Vol 19 (12) ◽  
pp. 2851-2866 ◽  
Author(s):  
J. Craig Collier ◽  
Guang J. Zhang
Keyword(s):  
Relative Humidity ◽  
Diurnal Cycle ◽  
North American ◽  
Large Scale ◽  
The United States ◽  
Experimental Simulation ◽  
Specific Humidity ◽  
North American Monsoon ◽  
Hourly Precipitation ◽  
The North

Abstract Two 9-yr runs of the NCAR Community Climate Model version 3 (CCM3) are compared in their simulations of the North American summer monsoon. In a control simulation, the Zhang–McFarlane deep convection scheme is used. For an experimental simulation, the following modifications to the scheme are implemented. The closure is based on the large-scale forcing of virtual temperature, and a relative humidity threshold on convective parcels lifted from the boundary layer is applied. The sensitivity to these modifications for simulating the North American monsoon is investigated. Model validation relies on hourly precipitation rates from surface gauges over the United States, hourly precipitation rates derived from the combination of microwave and radar measurements from NASA’s Tropical Rainfall Measuring Mission (TRMM) satellite over Mexico, and CAPE values as calculated from temperature, specific humidity, and pressure fields from the NCEP–NCAR reanalysis. Results show that the experimental run improves the timing of the monsoon onset and peak in the regions of core monsoon influence considered here, though it increases a negative bias in the peak monsoon intensity in one region of northern Mexico. Sensitivity of the diurnal cycle of precipitation to modifications in the convective scheme is highly geographically dependent. Using a combination of gauge-based rainfall rates and reanalysis-based CAPE, it is found that improvements in the simulated diurnal cycle are confined to a convective regime in which the diurnal evolution of precipitation is observed to lag that of CAPE. For another regime, in which CAPE is observed to be approximately in phase with precipitation, model phase biases increase nearly everywhere. Some of the increased phase biases in the latter regime are primarily because of application of the relative humidity threshold.

Nuclear Fallout, Low Birthweight, and Immune Deficiency

1994 ◽  
Vol 24 (2) ◽  
pp. 311-335 ◽  
Author(s):  
Jay M. Gould ◽  
Ernest J. Sternglass
Keyword(s):  
Immune Deficiency ◽  
Large Scale ◽  
Low Birthweight ◽  
Baby Boom ◽  
Fission Products ◽  
The United States ◽  
Immune Resistance ◽  
Incidence And Mortality ◽  
Radiation Induced ◽  
Highly Correlated

An investigation of the mortality rates of young adults born in the postwar period of large-scale atmospheric nuclear testing (1945–1965) in the United States and other western industrial nations reveals an increasingly anomalous rise in mortality from its previous secular decline. Beginning in the late 1970s and particularly since 1983, the deterioration in the health of the 25–44 age group is related to in utero exposure to fission products in the milk and diet, associated with an unprecedented rise in underweight births and neonatal mortality known to be accompanied by loss of immune resistance. The 1945–1965 rise in the percentage of live births below 2500 grams is highly correlated with the amount of strontium-90 in human bone, both peaking in the mid-1960s. In the 1980s, for the baby boom generation (those born between 1945 and 1965), cancer incidence and mortality due to infectious diseases associated with a rising degree of immune deficiency, such as pneumonia, septicemia, and AIDS, increased sharply. This process of increasing immune deficiency appears to have been exacerbated by continuing secondary exposures to accidental reactor releases and by an acceleration of radiation-induced mutation of pathogenic microorganisms increasingly resistant to drugs.

scholarly journals Spatial patterns of infauna, epifauna, and demersal fish communities in the North Sea

2009 ◽  
Vol 67 (2) ◽  
pp. 278-293 ◽  
Author(s):  
Henning Reiss ◽  
Steven Degraer ◽  
Gerard C. A. Duineveld ◽  
Ingrid Kröncke ◽  
John Aldridge ◽  
...  
Keyword(s):  
Spatial Patterns ◽  
North Sea ◽  
Ecosystem Management ◽  
Large Scale ◽  
Fish Communities ◽  
Demersal Fish ◽  
Environmental Drivers ◽  
The North ◽  
Oyster Ground ◽  
The North Sea

Abstract Reiss, H., Degraer, S., Duineveld, G. C. A., Kröncke, I., Aldridge, J., Craeymeersch, J., Eggleton, J. D., Hillewaert, H., Lavaleye, M. S. S., Moll, A., Pohlmann, T., Rachor, E., Robertson, M., vanden Berghe, E., van Hoey, G., and Rees, H. L. 2010. Spatial patterns of infauna, epifauna, and demersal fish communities in the North Sea. – ICES Journal of Marine Science, 67: 278–293. Understanding the structure and interrelationships of North Sea benthic invertebrate and fish communities and their underlying environmental drivers is an important prerequisite for conservation and spatial ecosystem management on scales relevant to ecological processes. Datasets of North Sea infauna, epifauna, and demersal fish (1999–2002) were compiled and analysed to (i) identify and compare spatial patterns in community structure, and (ii) relate these to environmental variables. The multivariate analyses revealed significantly similar large-scale patterns in all three components with major distinctions between a southern community (Oyster Ground and German Bight), an eastern Channel and southern coastal community, and at least one northern community (>50 m deep). In contrast, species diversity patterns differed between the components with a diversity gradient for infauna and epifauna decreasing from north to south, and diversity hotspots of demersal fish, e.g. near the major inflows of Atlantic water. The large-scale hydrodynamic variables were the main drivers for the structuring of communities, whereas sediment characteristics appeared to be less influential, even for the infauna communities. The delineation of ecologically meaningful ecosystem management units in the North Sea might be based on the structure of the main faunal ecosystem components.

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