Hydrogeology, geology & engineering aspects of surficial materials on the Lake Michigan shore in Illinois

Other titles: Geologic, Hydrogeologic, and engineering aspects of surficial materials on the Lake Michigan shore in IllinoisOpe

Internal and external forcing of multidecadal Atlantic climate variability over the past 1,200 years

The North Atlantic experiences climate variability on multidecadal scales, which is sometimes referred to as Atlantic multidecadal variability. However, the relative contributions of external forcing such as changes in solar irradiance or volcanic activity and internal dynamics to these variations are unclear. Here we provide evidence for persistent summer Atlantic multidecadal variability from AD 800 to 2010 using a network of annually resolved terrestrial proxy records from the circum-North Atlantic region. We find that large volcanic eruptions and solar irradiance minima induce cool phases of Atlantic multidecadal variability and collectively explain about 30% of the variance in the reconstruction on timescales greater than 30 years. We are then able to isolate the internally generated component of Atlantic multidecadal variability, which we define as the Atlantic multidecadal oscillation. We find that the Atlantic multidecadal oscillation is the largest contributor to Atlantic multidecadal variability over the past 1,200 years. We also identify coherence between the Atlantic multidecadal oscillation and Northern Hemisphere temperature variations, leading us to conclude that the apparent link between Atlantic multidecadal variability and regional to hemispheric climate does not arise solely from a common response to external drivers, and may instead reflect dynamic processes

Geology for planning in Northeastern Illinois. IV

Cover title."Prepared for the Northeastern Illinois Planning Commission.""This study has been financed in part by a grant from the U.S. Environmental Protection Agency under provisions of PL 92-500.""August 15, 1976."Includes bibliographical references

Foundation and earth materials of the Lake Michigan till bluffs : preliminary report

Ope

Breeding Home Ranges of Migratory Turkey Vultures Near Their Northern Limit

We used Global Positioning System (GPS) satellite transmitters to estimate the breeding home ranges of Turkey Vultures (Cathartes aura) in Saskatchewan, Canada from 2005 to 2009. Breeding ranges calculated using 95% Minimum Convex Polygons (MCP) ranged from 47 to 953 km2 and averaged (± SD) 371 ± 340 km2. Fixed-kernel home ranges (95%) ranged from 49 to 1,992 km2 and averaged 648 ± 731 km2. These ranges include both the smallest and largest summer ranges reported for the species. Spatial variation in range size may have been due to differences in availability of food and the quality of the home ranges involved, amplified by the species\u27 extremely low-cost soaring flight. Adults used all-night perches in varying locations up to 38 km from their nest house while traveling substantial distances to available carcasses to obtain food for their young. Identifying home range sizes for Turkey Vultures is a first step toward understanding how the species is increasing and expanding its distribution in Saskatchewan and elsewhere in Canada

Winter Ranges of Migratory Turkey Vultures in Venezuela

We used four Global Positioning System (GPS) satellite transmitters to calculate the wintering ranges of migratory Turkey Vultures (Cathartes aura) that breed in Saskatchewan, Canada, and winter in Venezuela. Between 2007 and 2011, 95% fixed-kernel estimators of range size varied from 54 to 76 731 km2 with an average of 16 814 ± 28 606 km2 (SD), while those calculated with 95% Minimum Convex Polygons ranged from 22 to 46 778 km2 and averaged 9545 ± 17 356 km2. The smallest wintering range was comparable to previously reported range sizes, but our largest wintering range greatly exceeded anything yet recorded. Variation in winter range sizes may be attributed to resource availability, migration costs, and the absence of obligations associated with breeding. Each vulture had a “primary nocturnal roost” to which it returned frequently; each spent more hours (evenings, nights, and mornings) at and within 1 km of such roosts, than it did foraging during midday. Our results increased our understanding of the feeding and movement ecology of North American migratory Turkey Vultures overwintering in South America