Examining the Variability of Crossing Times for Canadian Trucks at the Three Major Canada–U.S. Border Crossings     

Hanna Maoh  Kevin Gingerich  Rahaf Husein  William Anderson 《The Professional geographer》2018,70(3):350-362

Land borders connecting Canada and the United States are vital transportation facilities for the two countries. Truck crossing times at these facilities can have a significant impact on the performance of the economy. To date, knowledge about border crossing times has been limited due to lack of detailed data on the Canadian border. This article explores and models the patterns of crossing times at the three major land crossings connecting Canada to the United States: Ambassador Bridge, Blue Water Bridge, and Peace Bridge. The analysis is based on 387,775 border crossing truck trips that were generated between Canada and the United States over a course of twelve months. Seemingly unrelated regression (SUR) models are estimated to evaluate the seasonal and hourly crossing times of Canada- and U.S.-bound trips on each border crossing, controlling for traffic intensity in the models. The SUR modeling approach is chosen to control for potential cross-model correlations. The results suggest that crossing times at the border vary by season and hour of the day. Crossing times also vary by direction of traffic and by type of day (i.e., weekday vs. weekend). Traffic intensity has a significant influence on crossing times at two of the crossings but not the Blue Water Bridge. Finally, crossing times are more variable during the summer season and tend to be higher during the late evening hours and past midnight.  相似文献   

Reply to comments by D. Netterville     

Steven R. Hanna 《Boundary-Layer Meteorology》1986,34(1-2):209-209

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Twenty-one years of German geomorphology     

Hanna Bremer 《地球表面变化过程与地形》1984,9(3):281-287

In recent decades, German geomorphology has been mainly concerned with climatic and climato-genetic geomorphology. The first is the study of processes, especially of process combinations in different climato-morphological zones. The second is concerned with the way exogenic forces control the evolution of relief in a certain region. This study of relief generations differs fundamentally from denudation chronology. Certain principles developed as knowledge of these fields has grown, such as the variability of rock resistance with climate and discontinuity of processes in both space and time, are considered. In recent years new trends, based mainly on climatic geomorphology, have been towards greater specialization in fields such as quantitative geomorphology, geomorphological mapping, and laboratory analysis of regolith and soil samples.  相似文献   

Estrogen reduction in a coupled wetland and ground water flow-through system     

Eric W. Peterson  Laura A. Hanna 《Environmental Earth Sciences》2016,75(5):384

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The role of radiative-convective interaction in creating the microclimate of urban street canyons   总被引：2，自引：2，他引：2  

Hanna Swaid 《Boundary-Layer Meteorology》1993,64(3):231-259

An approximate sky view factor (SVF) has been developed, which is capable of estimating the mean rate of net longwave radiant energy loss from urban street canyons. Reduced scale models of typical canyon geometries were used in outdoor tests to verify the predictions of radiant fluxes obtained using the proposed SVF. Air-surface temperature differences from the scale models are used together with hypothesized within-canyon airflow patterns to determine some quantitative characteristics of the wind field in canyons. Simple correlations are proposed for the relationship between mean in-canyon and pedestrian-level flow speeds on the one hand, and the ambient (above roof-level) wind speed on the other hand. As expected, the height/width ratio of a canyon controls the form and magnitude of the flow within.  相似文献   

The round table discussion: Interactions and feedback between theory and experiment     

Philip Chatwin  Han van Dop  Steven Hanna  Michael Poreh  Brian Sawford  Roland Stull 《Boundary-Layer Meteorology》1993,62(1-4):435-448

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Twenty years in the water well industry: where are we?     

Sterrett R  Mehmert M  Hanna T 《Ground water》2008,46(5):659-659

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Simulated asteroid materials based on carbonaceous chondrite mineralogies     

Daniel T. Britt  Kevin M. Cannon  Kerri Donaldson Hanna  Joanna Hogancamp  Olivier Poch  Pierre Beck  Dayl Martin  Jolantha Escrig  Lydie Bonal  Philip T. Metzger 《Meteoritics & planetary science》2019,54(9):2067-2082

A set of high‐fidelity simulated asteroid materials, or simulants, was developed based on the mineralogy of carbonaceous chondrite meteorites. Three varieties of simulant were developed based on CI1 chondrites (typified by Orgueil), CM2 chondrites (typified by Murchison), and CR2/3 chondrites (multiple samples). The simulants were designed to replicate the mineralogy and physical properties of the corresponding meteorites and anticipated asteroid surface materials as closely as is reasonably possible for bulk amounts. The simulants can be made in different physical forms ranging from larger cobbles to fine‐grained regolith. We analyzed simulant prototypes using scanning electron microscopy, X‐ray fluorescence, reflectance spectroscopy at ambient conditions and in vacuum, thermal emission spectroscopy in a simulated asteroid environment chamber, and combined thermogravimetry and evolved gas analysis. Most measured properties compare favorably to the reference meteorites and therefore to predicted volatile‐rich asteroid surface materials, including boulders, cobbles, and fine‐grained soils. However, there were also discrepancies, and mistakes were made in the original mineral formulations that will be updated in the future. The asteroid simulants are available to the community from the nonprofit Exolith Lab at UCF, and the mineral recipes are freely published for other groups to reproduce and modify as they see fit.  相似文献   

Measurement of solifluction rates using multi‐temporal aerial photography     

Hanna Ridefelt  Jan Boelhouwers  Trond Eiken 《地球表面变化过程与地形》2009,34(5):725-737

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Ice table depth variability near small rocks at the Phoenix landing site, Mars: A pre-landing assessment     

Hanna G. Sizemore  Michael T. Mellon 《Icarus》2009,199(2):303-309

We combine thermal simulations of ground ice stability near small rocks with extrapolations of the abundance of rocks at the Phoenix landing site based on HiRISE rock counts to estimate the degree of ice table depth variability within the 3.8 m² workspace that can be excavated during the mission. Detailed predictions of this kind are important both to test current ground-ice theory and to optimize soil investigations after landing. We find that Phoenix will very likely have access to at least one rock in the diameter range 5 cm to 1 m. Our simulations, which assume the ice to be in diffusive equilibrium with atmospheric water vapor, indicate that all rocks in this size range are associated with an annulus of deep ice-free soil. Ice table depth variability of 1-5 cm is very likely at the landing site due to the presence of small rocks. Further, there are scenarios in which Phoenix might exploit the presence of individual large rocks and/or the arrangement of small rocks to sample soils at depths >10 cm below the average depth predicted from orbit (∼4 cm). Scale analysis to constrain uncertainties in simulation results indicates that estimates of maximum depths may be somewhat conservative and that ice table depressions associated with individual rocks could be deeper and laterally more extended than indicated by formal predictions by mm to cm.  相似文献