Local Circulations Developed in the Vicinity of Both Coastal and Inland Urban Areas: A Numerical Study with a Mesoscale Atmospheric Model

Ohashi, Yukitaka; Kida, Hiroshi

doi:10.1175/1520-0450(2002)041<0030:lcditv>2.0.co;2

Cited by 121 publications

(78 citation statements)

References 31 publications

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“…The horizontal wind speed over Tokyo was increased by 2.3 m s -1 relative to the pure sea breeze by the urban heat island (Yoshikado 1992). Numerical modeling has shown that the interaction of an urban heat island and the sea breeze front can result in enhanced convective forcing (Kusaka et al 2000;Ohashi and Kida 2002). Regions of enhanced vertical motion occur in a convergence zone between the sea breeze front and the urban heat island circulation (Yoshikado 1994).…”

Section: Introductionsupporting

confidence: 57%

Sea-breeze-initiated rainfall over the east coast of India during the Indian southwest monsoon

et al. 2007

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Abstract. Sea breeze initiated convection and precipitation is investigated along the east coast of India during the Indian southwest monsoon season. The sea breeze circulations are observed approximately 70 to 80% of the days during the summer months (June to August) along the Chennai coast. Observations of average sea breeze wind speeds are stronger at a rural location as compared to the wind speeds observed inside the urban region of Chennai.The sea breeze circulation is shown to be the dominant mechanism for initiating rainfall during the Indian southwest monsoon season. Roughly 80% of the total rainfall observed during the southwest monsoon over Chennai is directly related to the convection initiated by sea breeze circulation.

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Section: Introductionsupporting

confidence: 57%

Sea-breeze-initiated rainfall over the east coast of India during the Indian southwest monsoon

et al. 2007

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“…Several studies have shown that an UHI can have a significant influence on mesoscale circulations and resulting convection, e.g., warm seasonal rainfall was found to increase by 7-25 % within and 50-75 km downwind of megacities (Ohashi and Kida 2002;Shepherd 2005). There is increasing evidence that MCCZ, such as Tokyo and Houston, can influence weather (rainfall, lightning, etc.…”

Section: Hydrological Cyclementioning

confidence: 99%

“…There is increasing evidence that MCCZ, such as Tokyo and Houston, can influence weather (rainfall, lightning, etc. ) through complex urban land use-weather-climate feedbacks (e.g., Ohashi and Kida 2002). Hence, rainfall patterns and location may change in and around a MCCZ compared to an uninhabited coastline, affecting local agriculture and fresh water supply for the city.…”

Section: Hydrological Cyclementioning

confidence: 99%

Megacities and Large Urban Agglomerations in the Coastal Zone: Interactions Between Atmosphere, Land, and Marine Ecosystems

Glasow

Jickells

Baklanov

et al. 2012

AMBIO

120

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Megacities are not only important drivers for socio-economic development but also sources of environmental challenges. Many megacities and large urban agglomerations are located in the coastal zone where land, atmosphere, and ocean meet, posing multiple environmental challenges which we consider here. The atmospheric flow around megacities is complicated by urban heat island effects and topographic flows and sea breezes and influences air pollution and human health. The outflow of polluted air over the ocean perturbs biogeochemical processes. Contaminant inputs can damage downstream coastal zone ecosystem function and resources including fisheries, induce harmful algal blooms and feedback to the atmosphere via marine emissions. The scale of influence of megacities in the coastal zone is hundreds to thousands of kilometers in the atmosphere and tens to hundreds of kilometers in the ocean. We list research needs to further our understanding of coastal megacities with the ultimate aim to improve their environmental management.

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“…Since Cu-TP and Cu-NCP occur under humid conditions, the precipitation enhancement with [N a ] is also in good agreement with measurements. Observations have shown the precipitation enhancement around heavily polluted coastal urban areas (Shepherd and Burian, 2003;Ohashi and kida, 2002) or over oceans influenced by pollution aerosols (Cerveny and Balling Jr., 1998;Li et al, 2008b;Koren et al, 2012Koren et al, , 2014. When the [N a ] is increased from about 20 to 9000 cm −3 , the precipitation of Cu-TP increases from 0.13 to 0.23 mm; when the [N a ] exceeds 300 cm −3 , the precipitation becomes insensitive to the variation in [N a ].…”

Section: Response Of Convective Strength To Changes In Aerosol Concenmentioning

confidence: 89%

Aerosol effects on the development of cumulus clouds over the Tibetan Plateau

et al. 2017

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Abstract. The aerosol-cloud interaction over the Tibetan Plateau has been investigated using a cloud-resolving weather research and forecasting model with a two-moment bulk microphysical scheme including aerosol effects on cloud condensation nuclei and ice nuclei. Two types of cumulus clouds with a similar convective available potential energy, occurring over the Tibetan Plateau (Cu-TP) and North China Plain (Cu-NCP) in August 2014, are simulated to explore the response of convective clouds to aerosols. A set of aerosol profiles is used in the simulations, with the surface aerosol number concentration varying from 20 to 9000 cm −3 and the sulfate mass concentration varying from 0.02 to 9.0 µg cm −3 . Increasing aerosol concentrations generally enhances the cloud core updraft and maximum updraft, intensifying convections in Cu-TP and Cu-NCP. However, the core updraft is much stronger in Cu-TP than Cu-NCP, because of the early occurrence of the glaciation process in Cu-TP that is triggered at an elevation above 4000 m. The precipitation increases steadily with aerosol concentrations in Cu-NCP, caused by the suppression of the warm rain but occurrence of efficient mix-phased precipitation due to the reduced cloud droplet size. The precipitation in Cu-TP also increases with aerosol concentrations, but the precipitation enhancement is not substantial compared to that in Cu-NCP with high aerosol concentrations. The aerosol-induced intensification of convections in Cu-TP not only facilitates the precipitation but also transports more ice-phase hydrometeors into the upper troposphere to decrease the precipitation efficiency. Considering the very clean atmosphere over the Tibetan Plateau, elevated aerosol concentrations can remarkably enhance convections due to its specific topography, which not only warms the middle troposphere to influence the Asian summer monsoon but also delivers hydrometeors into the upper troposphere to allow more water vapor to travel into the lower stratosphere.

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Local Circulations Developed in the Vicinity of Both Coastal and Inland Urban Areas: A Numerical Study with a Mesoscale Atmospheric Model

Cited by 121 publications

References 31 publications

Sea-breeze-initiated rainfall over the east coast of India during the Indian southwest monsoon

Sea-breeze-initiated rainfall over the east coast of India during the Indian southwest monsoon

Megacities and Large Urban Agglomerations in the Coastal Zone: Interactions Between Atmosphere, Land, and Marine Ecosystems

Aerosol effects on the development of cumulus clouds over the Tibetan Plateau

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