Urban Effects on the Convective Boundary Layer

Hildebrand, Peter H.; Ackerman, Bernice

doi:10.1175/1520-0469(1984)041<0076:ueotcb>2.0.co;2

Cited by 69 publications

(46 citation statements)

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“…Field experiments on urban boundary layers have revealed fundamental characteristics of the mesoscale UHI structure; typical nocturnal temperature profiles including elevated inversions and the crossover phenomena (Duckworth and Sandberg 1954;Bornstein 1968;Clarke 1969;Oke and East 1971), surface wind convergence in the UHI (Schreffler 1978(Schreffler , 1979a(Schreffler , 1979b, and turbulent profiles (Hildebrand and Ackerman 1984;Clarke et al 1982;Uno et al 1988). Oke (1974Oke ( , 1979aOke ( , 1987 gives a comprehensive review of the early observational studies.…”

Section: A Urban Atmospheric Boundary Layersmentioning

confidence: 99%

Progress in Urban Meteorology :A Review

Kanda

2007

Journal of the Meteorological Society of Japan

101

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This paper reviews the progress made in urban meteorology over the past few decades. The focus is on the impact of urban surfaces on the overlying atmosphere along the conventional meteorological frameworks. Section 1 details the difficulties in generalizing urban surfaces in a meteorological sense because of surface diversity, and considers whether conventional similarity law is applicable. Section 2 describes the characteristics of urban surfaces as the bottom boundary of the atmosphere and includes a discussion of land surface parameters and the resultant surface energy partitioning. Section 3 explains characteristics of the urban atmosphere, including temperature fields, local circulations and rainfall. Section 4 describes recent progress in numerical modeling and promising new technologies, thus revealing a possible future direction for urban meteorological studies.

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Section: A Urban Atmospheric Boundary Layersmentioning

confidence: 99%

Progress in Urban Meteorology :A Review

Kanda

2007

Journal of the Meteorological Society of Japan

101

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“…The urban mean o$, is essentially equal to 2, in the mid-CBL. Hildebrand and Ackerman (1984) also showed 2, to be significantly larger over St. Louis than in the surrounding rural area, especially in the lower part of the CBL. The normalized third moment or coefficient of skewness (Sk = w'/ct) is positive for the various segments in Table II.…”

Section: Vertical Turbulent Velocity Statisticsmentioning

confidence: 87%

“…Hildebrand and Ackerman (1984) found larger vertical velocity variances and greater heat fluxes over St. Louis than at the same levels in the rural surroundings. The large differences in radiometric surface temperature among the various land uses in an urban area (Ching et al, 1983b) strongly modulate the vertical heat flux (Ching et al, 1983a).…”

Section: Introductionmentioning

confidence: 91%

Characteristics of vertical turbulent velocities in the urban convective boundary layer

Godowitch

1986

Boundary-Layer Meteorol

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Turbulence measurements of the vertical velocity component were obtained by an instrumented aircraft under fair weather conditions in the St. Louis, Missouri, metropolitan area. Time series of vertical velocity fluctuations from horizontal llight segments made in the lower part of and near the middle of the convective boundary layer (CBL) over the urban area and surrounding region were subjected to various statistical and objective analyses. Higher order vertical velocity moments, and positive and negative velocity statistics, were computed. The horizontal dimensions of updrafts and downdrafts, and related properties of these turbulent eddies were derived by conditional sampling analysis. Emphasis is on a comparison of the results from urban and selected rural measurements from the lower part of the CBL.The vertical velocity probability density distribution for each segment was positively skewed and the mode was negative. The means and standard deviations of positive and negative velocity fluctuations were greater over the urban area. The urban vertical velocity variance was 50% greater than rural values, and power spectra revealed greater production of vertical turbulent energy in the urban area over a wide frequency range.The mean and maximum widths of downdrafts were generally larger than the corresponding values for updrafts. Differences between urban and rural eddy sizes were not statistically significant. The widths of the largest updraft and downdrafi are comparable to the boundary-layer depth, Zi, and the mean value of the ratio of spectra1 peak wavelength to Z, was about 1.3 and 1.1 for urban and rural areas, respectively. Convective similarity scaling parameters appeared to order both the urban and rural measurements.

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“…The large fraction of the urban surface Impervious to water and urban runoff routing systems affect the available moisture and therefore, the partitioning of available energy into sensible and latent heat fluxes. Godowitch et al (1981), White et al (1978), Hildebrand and Ackerman (1984) and others report urban sensible heat fluxes 2-4 times higher than those in nearby rural areas.…”

Section: Qf Is the Anthropogenic Heat Fluxmentioning

confidence: 94%

“…Measurements of urban sensible heat fluxes two to four times those in the surrounding rural areas are common (e.g., Godowitch et al, 1981;White et al, 1978;Hildebrand and Ackerman, 1984). …”

Section: Sensrble and Latent Heat Fluxesmentioning

confidence: 99%

An Atmospheric Boundary Layer Stability Estimator for Urban Areas. SBIR Phase 1 Feasibility Study

Scire¹,

Hanna²

1992

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Urban Effects on the Convective Boundary Layer

Cited by 69 publications

References 0 publications

Progress in Urban Meteorology :A Review

Progress in Urban Meteorology :A Review

Characteristics of vertical turbulent velocities in the urban convective boundary layer

An Atmospheric Boundary Layer Stability Estimator for Urban Areas. SBIR Phase 1 Feasibility Study

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