Progress in Urban Meteorology :A Review

Kanda, Manabu

doi:10.2151/jmsj.85b.363

Cited by 101 publications

(66 citation statements)

References 213 publications

(228 reference statements)

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“…Ashworth, 1929) and an increased activity during the 50's and 60's of the 20th century (e.g. see review in Lawrence, 1971;Kanda, 2007) was observed. These previous studies focused on the impact of human activities near the major sources of heat and air pollution emissions, which are mainly concentrated in urban, semi-urban and industrial areas.…”

Section: A Sanchez-lorenzo Et Al: Assessing Large-scale Weekly Cyclmentioning

confidence: 99%

“…4.2.2). This paper will focus on a review of studies about "large-scale" WCs (for a review of urban WC's see Arnfield, 2003 andKanda, 2007), which is a more recent topic in scientific literature, thus holding major uncertainties and some confusion. Also, to our knowledge, a review of this subject is still lacking.…”

Section: A Sanchez-lorenzo Et Al: Assessing Large-scale Weekly Cyclmentioning

confidence: 99%

See 1 more Smart Citation

Assessing large-scale weekly cycles in meteorological variables: a review

Sánchez-Lorenzo¹,

Laux

Franssen³

et al. 2012

Atmos. Chem. Phys.

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Abstract. Several studies have claimed to have found significant weekly cycles of meteorological variables appearing over large domains, which can hardly be related to urban effects exclusively. Nevertheless, there is still an ongoing scientific debate whether these large-scale weekly cycles exist or not, and some other studies fail to reproduce them with statistical significance. In addition to the lack of the positive proof for the existence of these cycles, their possible physical explanations have been controversially discussed during the last years. In this work we review the main results about this topic published during the recent two decades, including a summary of the existence or non-existence of significant weekly weather cycles across different regions of the world, mainly over the US, Europe and Asia. In addition, some shortcomings of common statistical methods for analyzing weekly cycles are listed. Finally, a brief summary of supposed causes of the weekly cycles, focusing on the aerosol-cloud-radiation interactions and their impact on meteorological variables as a result of the weekly cycles of anthropogenic activities, and possible directions for future research, is presented.

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Section: A Sanchez-lorenzo Et Al: Assessing Large-scale Weekly Cyclmentioning

confidence: 99%

Section: A Sanchez-lorenzo Et Al: Assessing Large-scale Weekly Cyclmentioning

confidence: 99%

Assessing large-scale weekly cycles in meteorological variables: a review

Sánchez-Lorenzo¹,

Laux

Franssen³

et al. 2012

Atmos. Chem. Phys.

View full text Add to dashboard Cite

show abstract

“…While this ensured that all sites observed emissions from similarly sized source areas, each instrument was likely located at a different vertical position within its respective boundary layer. For example, observations from urban Boston and Worcester were likely affected by building topography and the corresponding changes in micrometeorology and atmospheric mixing [60,61]. Methodological challenges (e.g., urban tall tower construction) in elevating instruments above the roughness layer combined with differences in boundary layer height at each location prevented similar instrument positioning within each plume/boundary layer.…”

Section: Instrumentation and Data Analysismentioning

confidence: 99%

Variations in Atmospheric CO2 Mixing Ratios across a Boston, MA Urban to Rural Gradient

Briber

Hutyra

Dunn

et al. 2013

Land

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Urban areas are directly or indirectly responsible for the majority of anthropogenic CO 2 emissions. In this study, we characterize observed atmospheric CO 2 mixing ratios and estimated CO 2 fluxes at three sites across an urban-to-rural gradient in Boston, MA, USA. CO 2 is a well-mixed greenhouse gas, but we found significant differences across this gradient in how, where, and when it was exchanged. Total anthropogenic emissions were estimated from an emissions inventory and ranged from 1.5 to 37.3 mg· C· ha −1 · yr −1 between rural Harvard Forest and urban Boston. Despite this large increase in anthropogenic emissions, the mean annual difference in atmospheric CO 2 between sites was approximately 5% (20.6 ± 0.4 ppm). The influence of vegetation was also visible across the gradient. Green-up occurred near day of year 126, 136, and 141 in Boston, Worcester and Harvard Forest, respectively, highlighting differences in growing season length. In Boston, gross primary production-estimated by scaling productivity by canopy cover-was ~75% lower than at Harvard Forest, yet still constituted a significant local flux of 3.8 mg· C· ha −1 · yr −1 . In order to reduce greenhouse gas emissions, we must improve our understanding of the space-time variations and underlying drivers of urban carbon fluxes.

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“…The computational fluid dynamics (CFD) technique in its many forms provides a wide range of technical options for investigation [9]. While RANS based models still have a role to play, the use of LES modelling can explicitly resolve atmospheric flows of various scales ranging from an individual roughness element to an entire boundary layer [10]. Various urban flow and dispersion models have been developed based on CFD to simulate the complicated wind pattern and pollutant transport [9].…”

Section: Introductionmentioning

confidence: 99%

Transport processes in and above two-dimensional urban street canyons under different stratification conditions: results from numerical simulation

Britter

Norford

2014

Environ Fluid Mech

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Thermal stratification (neutral, unstable and stable) plays an important role in determining the transport processes in and above urban street canyons. This paper summarizes the recent findings of the effect of thermal stratification on the transport of momentum, heat, and pollutants in the two-dimensional (2D) urban street canyons in the skimming flow regime. Special attention is paid to the results from large-eddy simulations (LESs), while other experimental and numerical results are referred to when necessary. With increasing Richardson number, Ri, the drag coefficient of the 2D street canyon as felt by the overlying atmosphere decreases in a linear manner. Under neutral and stable stratification, a nearly constant drag coefficient of 0.02 is predicted by the LESs. Under unstable stratification, the turbulent pollutant transport is dominated by organized turbulent motions (ejections and sweeps), while under stable stratification, the unorganized turbulent motion (inward interactions) plays a more important role and the sweeps are inhibited. The unstable stratification condition also enhances the ejections of turbulent pollutant flux, especially at the leeward roof-level corner, where the ejections dominate the turbulent pollutant flux, outweighing the sweeps. With increasing Ri, both the heat (area active scalar source) and pollutant (line passive scalar source) transfer coefficients decrease towards a state where the transfer coefficients become zero at Ri ≈ 0.5. It should be noted that, due to the limit of the 2D street canyon configuration discussed in this paper, great caution should be taken when generalising the conclusions drawn here.

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Progress in Urban Meteorology :A Review

Cited by 101 publications

References 213 publications

Assessing large-scale weekly cycles in meteorological variables: a review

Assessing large-scale weekly cycles in meteorological variables: a review

Variations in Atmospheric CO2 Mixing Ratios across a Boston, MA Urban to Rural Gradient

Transport processes in and above two-dimensional urban street canyons under different stratification conditions: results from numerical simulation

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