20.11.2024 URBAN CLIMATOLOGY VIII. Urban climate classification, Local Climate Zones Paper to read 1.1 THERMAL DIFFERENTIATION OF LOCAL CLIMATE ZONES USING TEMPERATURE OBSERVATIONS FROM URBAN AND RURAL FIELD SITES lain Stewart,* Tim Oke University of British Columbia, Vancouver, Canada https://is.muni.cz/auth/el/sci/podzim2020/ZX601/um/67875456/08 local climate zones.pdf 1 20.11.2024 Types of Climate Classification Conventional (formal) type of classification. Genetic type of classification. S climatic TT ST SS PS PP AP AA AS PT Searches for boundaries between areas using variable values and simple logical rules (e.g. Kbppen climate classification) Searches for typical areas whose climate is formed (controlled) by forcing factors like relief, land-cover (e.g. Alisov, Flohn classification) Urban Climate Classification Types of Climate Classification An example of the 3D feature space and two searched categories only Feoture space - axes defined with typical characteristics used for separation of individual categories (classes) ^ buildings X - sky view factor y - albedo Z- roughness vegetation Supervised classification User defines typical occurrence of classes in the form of training sites u Unsupervised classification User defines only approx. number of classes and the algorithm identifies them in a feature space Urban climate classification using Cluster analysis Iteration algorithm - from initial position of typical „training sites" it searches repeatedly for the most similar parts (cells) of multidimensional feature space 20.11.2024 Urban Climate zones (Oke 2004) Utttan CMmateZone, UC21 1 Utensefy developed urban iwft detached close-set htgh-nse bukings wilt) daddmg. e.g. downtown timers 2 tolerrsety developed Itgh drnsrt) urbanmh2-Sstorey, attached of brick or none. e.g. aid dty care 3 Highly developed, rnediun density urban w* row a oetKfcd M ctose-set houses, stores & aparffnents eg urban tmsno_ 4 Highly developed lower mcdun density urban mth brge km buHdmgs & paved parting, pg shoppuig m,il. warehouses 5 Medium dnvhpnvnt km density suburban with J or 2 sorry bouses, eg suburban housing 6 Mxed use »Hb brgp buridngs m open landscape, eg instiutons steh as hosptal. unimsny. awpon 7 Sem-furaf A-vclopmcnt. scatered houses in natural or jqmißtural atva, p g farms. i'-i.-iV. MM nnnnnnnnn .aiSB_.fii2_ifl£..ifi.äaL.Jb.. .........—ijtflWai____ Rouglt-nest class' Key to imago symbols: [] buildings Q vegstahen, ~~ impwvKHia ground. ---pervious ground I A simplified selol classes that includes aspects ol the schemes ol Aue- i15r*6) and Ellefsen {1990/91) plus physical measures relating to mnd. thermal and morsfcire controls (columnsat Mint) Appronmateconespemrience between ucz and [iMw, urban terrain zones s 1|Dc1. DcS). 2 (A1-A4, Dei) 3 (AS D&3-S. Do2). 4 (Do1 Dof Do6| 5 (Do3) 6 (Do6). 7 (raw) * Effective le ram roughness according lo the Davenport dasnifitaton (Davenport rf at 7000) see Table 2 * Aspecl ratio = ixW e average height of the main roughness elements (buildings, trees) divided by their average spacing a tie cily centre this is the sired canyon hetghtfwidlh This measure es known lo be related lo Rcrw regime types (Oke 1987) and thermal controls (solar shading and longwave screenngl (Ohe. I98i| Tal Ines increase this rnessure s«gntim fi action 20-40ni. :o-50°.* Py^/crü i. r: 7!7" ." ^ ^ ■.' 3O-S0"-i ■5n.r#jrv admilisnee 1,000 - 2,200; in* s'^K"' Srtrfaee albedo 0.11-0.25 Airttriopogenie heal flux Local Climate Zones „feature space* Built types 1. Compact high-rise 2. Compact rnidrise 3. Compact low-rise 4. Open high-rise 5. Open midrise 6. Open low-rise 7. Lightweight low-rise 8. Large low-rise 9. Sparsely built 10. Heavy industry ■ »,<■ >,'\i'V H 1 Land cover types A Dense trees B. Scattered trees C. Bush, scrub □ . Low plants E. Bare rock or paved F. Bare soil or sand G. Water Huang et al. 2023 20.11.2024 Local Climate Zones classification system • Local climate zones are formally defined as regions of uniform surface cover, structure, material, and human activity that span hundreds of meters to several kilometers in horizontal scale. • Each LCZ exhibits a characteristic geometry and land cover that results in characteristic screen height temperature regime that is most apparent over dry surfaces, on calm, clear nights, and in areas of simple relief. • LCZ scheme consists of 17 standard LCZs, of which 15 are defined by surface structure and cover and 2 by construction materials and anthropogenic heat emissions. The standard set is divided into "built types"(l-10), and "land cover types"(A-G ) There are several methods how to define LCZ: • Method based on automatic classification of satellite imagery (WUDAPT, Bechtel et al.) • SIS method using geo-database and a set of logical rules in the form of decision tree LCZs classification algorithms WUDAPT (World Urban Database and Access Portal Tool) - automatic classification of multi-source satellite images Landsat spectra] A textural ASTER spectral 50 The keyword occurrence network of LCZ mapping papers during 2012-2021. Node size represents keywords _frequency, and colors represent the keyword's initial appearance year (Huang et al. 2023)_ LCZs of Brno (left) and Land Surface Temperature fields derived from LANDSAT 8 and TERRA-ASTER thermal images 20.11.2024 LCZs verification 2 3 9 6 7 5 10 1 14 11 12 4 8 LT8_20150320 Aii tt ■ ■■ ■. 1 i f LT8 20140520 2345689 10 ABCDEF Local Climate Zone (LCZ) 2 3 6 5 7 4 9 1 13 10 11 12 8 T i B - 2 • • 3 4 • 5 • • 6 8 • • 9 • 10 A • B • • C • • D • • • E • G LT8_20140520 2345689 10 ABCDEF Local Climate Zone (LCZ) Statistical description of land surface temperatures (LST) in individual LCZs in Brno area for two different dates (left). Blue points in right indicate no statistical difference in LST of _corresponding zones_ 8.3 Final remarks and questions 1. Why is simple Urban - rural division insufficient in urban climatology? 2. What were the main reasons to create LCZ classification scheme in urban climatology? 3. How can be LCZs used for mitigation negative effects of UHI and heat waves? 4. How can be LCZ useful e.g. to architects, planners, ecologists, and engineers? 11