http://users.monash.edu.au/~kerryn/ kerry.nice@monash.edu

Kerry NiceProgram B - Water Sensitive

UrbanismProject B3 Water Sensitive UrbanDesign and Urban Micro-climate

VTUF-3D: An urban micro-climate model to assess temperaturemoderation from increased vegetation and water in urban canyonsIntroductionI Assessing positive climatic impacts on human thermal comfort (HTC) of Water Sensitive Urban Design (WSUD), through associated

increases in vegetation and water in urban areas, requires a suitable modelling toolI Observation studies have shown that increased tree cover is effective in promoting positive HTC in urban areas (White et al., 2012).I Modelling HTC at a microscale must fully account for both physical and physiological properties of vegetation, as well as the full

soil/plant/atmosphere water cycle. No models were found which fulfilled this requirement.I The TUF-3D model (Krayenhoff and Voogt, 2007) was modified in a novel way to tile the MAESPA tree model (Duursma and

Medlyn, 2012) within the TUF-3D urban canyon and calculate vegetation radiation transmission.I The modified model, VTUF-3D, provides parameters of air temperature, surface temperatures, wind, and humidity at a suitable scale

to assess HTC (measured by UTCI) in urban canyon simulations.I This tool can be used to determine optimal positioning of vegetation to maximize the impact, as well as determining the climate

response of each tree and its relative value in urban canyons.

Validations of VTUF-3DI Validations compared modelled results to flux observations in Preston (Coutts

et al., 2007), HTC observations in Melbourne (White et al., 2012), and Tsfcand UTCI in Lincoln Square, Melbourne (Motazedian, 2015) and found tobroadly reproduce their spatial and temporal variations.

I Ongoing model development aims to further increase predictive accuracy.

Figure 1 : Modelled Preston street

Figure 2 : Modelled UTCI of 4 scenarios over 13-14 February 2004 /UTCI differences between 200% trees and other scenarios

Modelling Preston vegetation scenarios with VTUF-3DI 4 scenarios for Preston (Figure 1) (configurations, Figure 3) of 0% trees, 50% trees, existing

100% Preston tree canopy cover, and 200% trees.I UTCI (averaged at 0m height, Figure 2) maximum variations of 0.9◦C between no tree

scenario and 200% treesI 200% trees scenario gives 0.3◦C UTCI reduction over existing 100% Preston tree canopy

Figure 3 : Preston 0%, 50%, 100%, 200% trees configuration (top)/UTCI at 0m height at 14 Feb 2004 1400 (below)

ConclusionsI Integration of MAESPA and TUF-3D into VTUF-3D creates a tool suitable to model human thermal comfort impacts of WSUD.I Modelling shows UTCI temperature reductions of 0.3◦C to 0.9◦C between varying tree cover scenarios.I Future work includes furuther model refinement for added accuracy and running comprehensive sets of WSUD scenarios to further

quantify HTC impacts of WSUDCoutts, A.M.,

Beringer,J.andTap-per,N.J.(2007),Im-pactofIn-creas-ingUr-banDen-sityonLo-calCli-mate:Spa-tialandTem-po-ralVari-a-tionsintheSur-faceEn-ergyBal-anceinMel-bourne,Aus-tralia.Jour-nalofAp-pliedMe-te-o-rol-ogyandCli-ma-tol-ogy,46(4):pp.477–493.

Duursma, R.A. andMed-lyn,B.E.(2012),MAESPA:amodeltostudyin-ter-ac-tionsbe-tweenwa-terlim-i-ta-tion,en-vi-ron-men-taldriversandveg-e-ta-tionfunc-tionattreeandstandlev-els,withanex-am-pleap-pli-ca-tionto[CO2]xdroughtin-ter-ac-tions.Geo-sci-en-tificModelDe-vel-op-ment,5(4):pp.919–940.

Krayenhoff, E.S.andVoogt,J.A.(2007),Ami-croscalethree-dimensionalur-banen-ergybal-ancemodelforstudy-ingsur-facetem-per-a-tures.Boundary-LayerMe-te-o-rol-ogy,123(3):pp.433–461.

Motazedian, A.(2015),Ob-ser-va-tionsfromLin-colnSq,Mel-bourne.

White, E., Coutts,A.,Tap-per,N.andBeringer,J.(2012),Ur-banmi-cro-cli-mate&streettrees:Un-der-stand-ingtheef-fectsofstreettreesonhu-manther-malcom-fort.Tech-ni-calre-port,CRCforWa-terSen-si-tiveCities,MonashUni-ver-sity.