Relationships between aerodynamic roughness and land use and land cover in Baltimore, Maryland

Nicholas, F.W.; Lewis, John E.

doi:10.3133/pp1099c

Cited by 12 publications

(6 citation statements)

References 30 publications

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“…Lettau did not specify limits for his formula; however, it is widely recognized that it fails when roughness area density P or F increases beyond 0.2-0.3 (see discussion in Macdonald et al 1998). Lettau's formula is often quoted in relation to urban roughness estimates and has been implemented for whole cities using detailed morphometric inventories, for example, Baltimore, Maryland (Nicholas and Lewis 1980), and Ogaki City, Japan (Takahashi et al 1981).…”

Section: ) Methods That Consider Height and Frontal Area Index ( F )mentioning

confidence: 99%

Aerodynamic Properties of Urban Areas Derived from Analysis of Surface Form

Grimmond¹,

Oke²

1999

J. Appl. Meteor.

1,016

702

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Several methods to determine the aerodynamic characteristics of a site through analysis of its surface form (morphometry) are considered in relation to cities. The measures discussed include zero-plane displacement length (z d), roughness length (z 0), depth of the roughness sublayer, and aerodynamic conductance. A sensitivity analysis is conducted on seven formulas to estimate z d and nine to estimate z 0 , covering a wide range of probable urban roughness densities. Geographic information systems developed for 11 sites in 7 North American cities are used to characterize their morphometry-the height, shape, three-dimensional area, and spatial distribution of their roughness elements (buildings and trees). Most of the sites are in residential suburbs, but one is industrial and two are near city centers. This descriptive survey of urban geometric form is used, together with the morphometric formulas, to derive the apparent aerodynamic characteristics of the sites. The resulting estimates of z d and z 0 are compared with values obtained from analysis of wind and turbulence observations. The latter are obtained from a survey of approximately 60 field studies and 14 laboratory studies of real and scale model cities. Despite the comprehensive nature of the survey, very few studies are found to be acceptable and their scatter is large, hence they do not provide a standard against which to test the morphometric algorithms. Further, the data show only weak relations between measured z d and z 0 and roughness density. The relative merits of morphometric and wind-based estimates of aerodynamic parameters are discussed. Recommendations are made concerning the choice of method to estimate z d and z 0 in urban areas and their most likely magnitude.

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Section: ) Methods That Consider Height and Frontal Area Index ( F )mentioning

confidence: 99%

Aerodynamic Properties of Urban Areas Derived from Analysis of Surface Form

Grimmond¹,

Oke²

1999

J. Appl. Meteor.

1,016

702

View full text Add to dashboard Cite

show abstract

“…Most of the R 2 values lie within 0.5-0.8, which reveals the strong correlation between the two variables. The termĥ 0 is estimated using a transfer function evaluated between z 0 and h 0 Nicholas and Lewis (1980): log 10 z 0 5 a 3 log 10 h 0 1 a 4 .…”

Section: Wind Speedmentioning

confidence: 99%

A Physically Based Atmospheric Variables Downscaling Technique

Rouf

Mei

Maggioni

et al. 2020

Journal of Hydrometeorology

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This study proposes a physically based downscaling approach for a set of atmospheric variables that relies on correlations with landscape information, such as topography, surface roughness, and vegetation. A proof-of-concept has been implemented over Oklahoma, where high-resolution, high-quality observations are available for validation purposes. Hourly North America Land Data Assimilation System version 2 (NLDAS-2) meteorological data (i.e., near-surface air temperature, pressure, humidity, wind speed, and incident longwave and shortwave radiation) have been spatially downscaled from their original 1/8° resolution to a 500-m grid over the study area during 2015. Results show that correlation coefficients between the downscaled products and ground observations are consistently higher than the ones between the native resolution NLDAS-2 data and ground observations. Furthermore, the downscaled variables present smaller biases than the original ones with respect to ground observations. Results are therefore encouraging toward the use of the 500-m dataset for land surface and hydrological modeling. This would be especially useful in regions where ground-based observations are sparse or not available altogether, and where downscaled global reanalysis products may be the only option for model inputs at scales that are useful for decision-making.

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“…For the Baltimore area, a program entitled CARETS (Central Atlantic Regional Ecological Test Site) was initiated in the 1970s, when the city was at its highest level of its population. The purpose was to define the relations between land use and land cover and several important climatic factors through remote sensing, and to verify numerical simulations of surface climate (Reed & Lewis 1978, Greene 1980, Nicholas & Lewis 1980. These studies utilized remotely sensed data from low-level flights over Baltimore along set paths for sunrise, mid-morning, and the warmest period of summer days in 1972-73, employing the M-7 multispectral scanner of ERIM and Sky Lab's S-192 multispectral scanner.…”

Section: Surface Remote Sensing and Process Studiesmentioning

confidence: 99%

The tale of two climates-Baltimore and Phoenix urban LTER sites

Selover²,

et al. 2000

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Two Long-Term Ecological Research (LTER) sites now include urban areas (Baltimore, Maryland and Phoenix, Arizona). A goal of LTER in these cities is to blend physical and social science investigations to better understand urban ecological change. Research monitoring programs are underway to investigate the effects of urbanization on ecosystems. Climate changes in these urban areas reflect the expanding population and associated land surface modifications. Long-term urban climate effects are detectable from an analysis of the GHCN (Global Historical Climate Network) database and a comparison of urban versus rural temperature changes with decadal population data. The relation of the urban versus rural minimum temperatures (∆Tmin u-r ) to population changes is pronounced and non-linear over time for both cities. The ∆Tmax u-r data show no well-defined temporal trends.

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Relationships between aerodynamic roughness and land use and land cover in Baltimore, Maryland

Cited by 12 publications

References 30 publications

Aerodynamic Properties of Urban Areas Derived from Analysis of Surface Form

Aerodynamic Properties of Urban Areas Derived from Analysis of Surface Form

A Physically Based Atmospheric Variables Downscaling Technique

The tale of two climates-Baltimore and Phoenix urban LTER sites

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