Theoretical Urban Heat Island Circulation in the Temperature Inversion Profile

Li, Yaokun; Jiping, Chao

doi:10.3390/atmos9030098

Cited by 4 publications

(2 citation statements)

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“…Seo et al [11] studied the dynamics of a reversed UBC in the context of atmospheric response to specified thermal forcing. Li and Chao [12,13] emphasized the specific thermal forcing and expressed LTCs as analytic functions of the temperature distribution. Previous advances have greatly promoted the understanding of LTCs.…”

Section: Introductionmentioning

confidence: 99%

“…He then derived a fourth-order equation of temperature to assess the dynamics of UBC. Li and Chao [12,13] applied viscosity in motion equations, but they specified a complete known temperature distribution to emphasize the effect of local thermal forcing. The fact that the basic dynamics of LTCs with viscosity in both thermodynamic and motion equations have yet to be extensively studied motivates this research.…”

Section: Introductionmentioning

confidence: 99%

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A Linear Theory of Local Thermal Circulations

Jiping

2023

Atmosphere

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The dynamics of local thermal circulations (LTCs) are examined by constructing a linear theory based on Boussinesq equations in the planetary boundary layer (PBL). Linear theory arranges LTCs into a sixth-order partial differential equation of temperature, which can be solved by using the Fourier transform and inverse Fourier transform. The analytic solution suggests that the horizontal distribution of the temperature anomaly is basically determined by surface heating, while the vertical distribution of the temperature anomaly is a combination of exponential decay and an Ekman spiral. For shallow PBL cases where the Ekman elevation is much smaller than the vertical scale of motion, the higher-order partial differential terms that represent the Ekman spiral structure can be ignored so that the equations reduce to a second-order partial differential equation. Compared with the numerical results, this so-called low-order approximation does not induce dramatic errors in the temperature distribution. However, to avoid distortion in the forced atmospheric circulation, the eddy viscosity in the motion equations should be replaced with the Rayleigh form, which is the common practice in LTCs. For deep PBL cases where the Ekman elevation is comparable to the vertical scale of motion, both the exponential decay and Ekman spiral structure play roles in the forced atmospheric circulation. The most significant influence is that there exist three additional compensating forced circulation cells that surround the direct forced circulation cell.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%