Tropical Island Urban Canopy Model Heat Flux Accuracy
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current urban canopy models inadequately account for the unique climate characteristics of tropical island cities, particularly strong horizontal ventilation, which affects the urban heat island effect, leading to inaccurate modeling of heat fluxes and storage.
Innovation Solution
A method for building an urban canopy model specifically tailored to tropical island climates, incorporating energy balance equations that account for net radiation, sensible, latent, and convective heat fluxes, as well as heat storage, considering the unique radiation and ventilation patterns of tropical islands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the classic urban canopy model is used to model urban street canyons, then the general urban heat island effect can be studied, but the model fails to accurately capture the heat island effect in tropical island cities with strong horizontal ventilation characteristics
Solution Approach 1:
The patent modifies the urban canopy model by introducing climate-specific parameterization schemes. For tropical island cities, it incorporates strong horizontal ventilation characteristics through modified momentum and heat transfer equations that account for perennial strong winds. The model uses location-specific parameters such as enhanced horizontal advection terms and adjusted stability functions that reflect tropical monsoon conditions, allowing the model to adapt its behavior to local climate characteristics while maintaining the same basic framework.
2Device complexity
If the parameterization methods in the urban canopy model are kept general, then the model structure remains simple, but the model cannot accurately represent the unique climate characteristics of tropical island cities
Solution Approach 1:
The patent introduces climate-dependent parameterization by modifying key parameters in the momentum and heat transfer equations. For tropical island conditions, it adjusts the stability functions (such as von Karman constant and roughness lengths), modifies the horizontal advection coefficients to account for strong winds, and adjusts the surface flux parameters to reflect high solar radiation and humidity conditions. These parameter changes allow the model to accurately represent tropical climate characteristics without fundamentally altering the model structure.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The model improves the accuracy of heat flux calculations in tropical island cities, enhancing the understanding and mitigation of the urban heat island effect by considering strong solar radiation, high temperatures, and high humidity, and the influence of perennial monsoons.
Implementation Method 1
Q* is a net radiation heat flux... net radiation heat flux Q*=long wave radiation+short-wave radiation
Implementation Method 2
QH is a sensible heat flux
Implementation Method 3
QE is a latent heat flux
Implementation Method 4
ΔQA is a net convective heat flux
Implementation Method 5
net long wave radiation of a pavement Lr* is: Lr*=εrΨrL↓−εrσTr4+εrεw(1−Ψr)σTw4+...
Implementation Method 6
Lr*=εrΨrL↓−εrσTr4... where σ is a standard deviation, Tr and Tw are temperatures of the pavement and the wall
Implementation Method 7
average direct solar radiant fluxes of the pavement, west wall, east wall and roof are calculated according to the perpendicular angle of the street to the sun direction
Implementation Method 8
L↓ is the amount of solar radiation
Implementation Method 9
the sky viewing angle coefficient at the w/2 position of the pavement is... the sky viewing angle coefficient at the intersection of the wall and the pavement is... where h represents the height of a street canyon, and w represents the width of the street canyon
Implementation Method 10
the horizontal wind velocity at the top of the street canyon Ucan is obtained by means of a Log approximate curve
Implementation Method 11
heat transfer equations of the three planes are written as... the thermal conductivity is calculated using a Fourier heat conduction equation
Data Source
AI summary
Provided is a method for building an urban canopy model based on tropical island climate characteristics. Adjacent regions are linked together, multiple streets of finite lengths within the regions affecting each other. Net radiation heat flux Q*=long-wave radiation+short-wave radiation. The tropical island urban canopy model considers the strong solar radiation and high temperature and high humidity climate characteristics of tropical cities and the influence of perennial monsoons on island cities, improves the methods of processing long-wave radiation flux, short-wave radiation flux, sensible and latent heat flux, street canyon wind velocity, heat storage flux, anthropogenic heat flux and horizontal heat flux on the basis of an urban canopy model, and has higher adaptability to the studies on the tropical island-type urban heat island effect.