Measuring nocturnal near-surface urban heat island intensity in the small, mid-latitude city of Inverness, Scotland

Figures & data

Figure 1. Location of the city of Inverness, Scotland and its main former townships and villages. Created using LiDAR DTM data – crown copyright Scottish Government, SEPA and Scottish Water, and aerial imagery – copyright Getmapping plc.

Figure 2. Climate of Inverness, Scotland. Created using 1991–2020 climate data courtesy of the Met Office.

Figure 3. Location of the transect route within the study area, detailing air temperature observation sites with local climate zones (LCZs). Dominant surface type determined using data from Morton et al. (2020).

Figure 4. Mean near-surface air temperature profiles for each of the 5 traverses measured along the study transect route from Inverness, Scotland to the surrounding rural countryside over 30 dates between 01/06/2019 and 31/08/2019.

Table 1. Statistical analysis of nocturnal near-surface UHI intensity (UHII) study transect results collected in Inverness between June and August 2019.

	Near-surface UHII (°C)
Mean	1.6
Minimum	0.7
Maximum	3.5
Median	1.3
Sample variance	0.5
Skewness	1.4
Standard deviation	0.7

Figure 5. Observed nocturnal near-surface urban heat island intensity in Inverness, Scotland on each observation date between 01/06/2019 and 31/08/2019.

Figure 6. Near-surface air temperature difference between the local climate zones (LCZs) studied in Inverness, Scotland over 30 dates between 01/06/2019 and 31/08/2019.

Figure 7. Relationship between mean near-surface air temperature and fraction of impervious surface within 250 m of the observation points studied, by local climate zone (LCZ).

Table 2. Summary of wind and cloud cover conditions at Inverness during the study period.

Observation date	Maximum UHII (°C)	Mean windspeed (ms^−1)	Dominant wind direction	Cloud cover	Cloud base height (m)	Mean relative humidity (%)	Precipitation (mm)	Frontal passage
01/06/2019	3.5	0.6	Variable	No cloud	n/a	86.5	0.0	None
02/06/2019	2.8	0.8	SW	Few	400	86.5	1.0	Warm
08/06/2019	1.5	0.8	Variable	Few	1,600	93.6	1.5	None
09/06/2019	1.3	0.5	Variable	Broken	400	93.9	0.7	None
15/06/2019	2.2	1.2	Variable	No cloud	n/a	71.7	0.0	None
16/06/2019	1.8	1.0	SE	No cloud	n/a	73.3	0.0	None
22/06/2019	2.9	0.9	WNW	Few	2,400	86.0	0.8	None
23/06/2019	1.2	0.9	Variable	Few	600	91.5	0.0	None
29/06/2019	1.3	1.0	ENE	Overcast	0	96.2	0.5	None
30/06/2019	1.3	3.1	WSW	Scattered	1,200	77.0	0.0	Occluded
05/07/2019	1.3	2.2	W	Broken	1,200	79.6	0.0	None
06/07/2019	1.4	0.9	Variable	Scattered	1,200	82.5	0.0	None
14/07/2019	1.9	1.2	Variable	No cloud	n/a	81.0	0.0	None
15/07/2019	1.4	1.9	ESE	Overcast	400	91.2	0.0	None
20/07/2019	1.3	1.6	WSW	Few	400	78.5	0.0	None
21/07/2019	1.3	0.9	Variable	Broken	1,000	85.4	0.0	Warm
27/07/2019	1.6	2.0	Variable	No cloud	n/a	88.6	0.0	None
28/07/2019	2.0	1.9	ENE	No cloud	n/a	91.6	0.0	None
30/07/2019	1.2	1.2	Variable	Overcast	100	95.2	1.0	None
31/07/2019	0.8	0.5	Variable	Overcast	600	96.6	1.0	None
03/08/2019	2.9	1.3	ENE	No cloud	n/a	85.9	0.0	None
04/08/2019	1.4	1.3	Variable	Few	300	90.0	0.0	None
10/08/2019	1.3	1.2	Variable	Overcast	600	84.8	0.0	None
11/08/2019	0.9	0.2	Variable	Broken	400	93.6	0.3	None
17/08/2019	0.7	2.4	SW	Scattered	400	79.8	0.0	None
18/08/2019	0.7	1.9	WSW	Scattered	300	86.6	0.0	None
24/08/2019	1.3	0.3	Variable	Few	1,400	92.3	0.0	None
25/08/2019	1.4	0.5	Variable	No cloud	n/a	90.2	0.0	None
30/08/2019	1.3	0.5	Variable	Few	600	91.8	0.2	None
31/08/2019	0.9	1.8	W	Broken	300	93.4	0.8	None

Note: Created using data from field notes and hourly reporting obtained post hoc from Munlochy PWS (Met Office ID: 882856001).

Figure 8. Relationship between daily nocturnal near-surface urban heat island intensity and (a) wind speed, (b) cloud base height, and (c) mean relative humidity on each of the 30 dates studied between 01/06/2019 and 31/08/2019.

Table 3. Review of near-surface UHI intensity (UHII) in selected cities, by population, latitude, Köppen climate classification and season recorded.

Settlement	Study	Population	Latitude	Köppen climate classification	Season	UHII (°C)
Ipora, Brazil	Alves and Lopes (2017)	31,274	16°S	Aw	Autumn	3.0
Hania, Greece	Kolokotsa et al. (2009)	53,000	35°N	Csa	Summer	2.6
Glasgow, Scotland	Hartley (1977)	940,400	55°N	Cfb	Autumn	8.3 (maximum)
Fairbanks, USA	Magee et al. (1999)	31,427	64°N	Dfb	All	0.3
Brandon, Canada	Suckling (1981)	37,000	50°N	Dfb	Spring/Summer	3.2
Aveiro, Portugal	Pinho and Orgaz (2000)	38,000	39°N	Csb	Autumn	7.5 (maximum)
Ljutomer, Slovenia	Ivajnšič et al. (2014)	3,270	46°N	Cfb	Winter	1.0
Agrinio, Greece	Vardoulakis et al. (2013)	93,000	38°N	Csa	Summer	3.8
Geisenheim, Germany	Diesnst et al. (2018)	11,500	50°N	Cfb	Summer	0.8
Dublin, Ireland	Graham (1993)	931,582	53°N	Cfb	Summer	8.0 (maximum)
Bodø, Norway	Miles et al. (2023)	52,000	67°N	Cfb/Dfb	Summer	0.7
Melbourne, Australia	Wai et al. (2022)	4,963,000	38°S	Cfb	All	1.0
Glasgow, Scotland	Hartley (1977)	940,400	55°N	Cfb	Autumn	8.3 (maximum)
Manchester, England	Levermore et al. (2015)	2,685,400	53°N	Cfb	Winter	6.0 (maximum)
Seattle, USA	Ramamurthy and Sangobanwo (2016)	710,687	48°N	Cfb	Summer	3.4
Stuttgart, Germany	Ketterer and Matzarakis (2015)	600,000	49°N	Cfb	Summer	5.4
Utrecht, Netherlands	Brandsman and Wolters (2012)	311,000	52°N	Cfb	All	1.5
Portland, USA	Hart and Sailor (2009)	549,781	46°N	Cfb	Summer	2.0
Reading, England	Nicholson (2020)	160,000	51°N	Cfb	Summer	1.0
Inverness, Scotland	Current study	63,220	57°N	Cfb	Summer	1.6

Note: Mean UHII is presented unless otherwise stated and rounding applied for consistency.

Morton, R. D., Marston, C. G., O’Neil, A. W., & Rowland, C. S. (2020). Land cover map 2019 (20 m classified pixels, GB) [Data set]. NERC Environmental Information Data Centre. https://doi.org/10.5285/643EB5A9-9707-4FBB-AE76-E8E53271D1A0

 Google Scholar

Alves, E. D. L., & Lopes, A. (2017). The urban heat island effect and the role of vegetation to address the negative impacts of local climate changes in a small Brazilian city. Atmosphere, 8(2), 1–14. https://doi.org/10.3390/atmos8020018

 Web of Science ®Google Scholar

Kolokotsa, D., Psomas, A., & Karapidakis, E. (2009). Urban heat island in Southern Europe: The case study of Hania, Crete. Solar Energy, 83(10), 1871–1883. https://doi.org/10.1016/j.solener.2009.06.018

 Web of Science ®Google Scholar

Hartley, M. (1977). Glasgow as an urban heat island. Scottish Geographical Magazine, 93(2), 80–89. https://doi.org/10.1080/00369227708736365

 Web of Science ®Google Scholar

Magee, N., Curtis, J., & Wendler, G. (1999). The urban heat island effect at Fairbanks, Alaska. Theoretical and Applied Climatology, 64(1-2), 39–47. https://doi.org/10.1007/s007040050109

 Web of Science ®Google Scholar

Suckling, P. W. (1981). Nocturnal observations of incoming longwave radiation and the urban heat island for a small prairie city. Archives for Meteorology, Geophysics and Bioclimatology Series B, 29(1-2), 23–27. https://doi.org/10.1007/BF02278187

 Google Scholar

Pinho, O. S., & Orgaz, M. D. M. (2000). The urban heat island in a small city in coastal Portugal. International Journal of Biometeorology, 44(4), 198–203. https://doi.org/10.1007/s004840000063

 PubMed Web of Science ®Google Scholar

Ivajnšič, D., Kaligarič, M., & Žiberna, I. (2014). Geographically weighted regression of the urban heat island of a small city. Applied Geography, 53, 341–353. https://doi.org/10.1016/j.apgeog.2014.07.001

 Web of Science ®Google Scholar

Vardoulakis, E., Karamanis, D., Fotiadi, A., & Mihalakakou, G. (2013). The urban heat island effect in a small Mediterranean city of high summer temperatures and cooling energy demands. Solar Energy, 94, 128–144. https://doi.org/10.1016/j.solener.2013.04.016

 Web of Science ®Google Scholar

Diesnst, M., Lindén, J., & Esper, J. (2018). Determination of the urban heat island intensity in villages and its connection to land cover in three European climate zones. Climate Research, 76(1), 1–15. https://doi.org/10.3354/cr01522

 Web of Science ®Google Scholar

Graham, E. (1993). The urban heat island of Dublin city during the summer months. Irish Geography, 26(1), 45–57. https://doi.org/10.1080/00750779309478717

 Google Scholar

Miles, V., Esau, I., & Miles, M. W. (2023). The urban climate of the largest cities of the European Arctic. Urban Climate, 48, 1–12. https://doi.org/10.1016/j.uclim.2023.101423

 Web of Science ®Google Scholar

Wai, C. Y., Muttil, N., Tariq, M. A. U. R., Paresi, P., Nnachi, R. C., & Ng, A. W. M. (2022). Investigating the relationship between human activity and the urban heat island effect in Melbourne and four other international cities impacted by COVID-19. Sustainability, 14(7), 1–25. https://doi.org/10.1108/SAMPJ-07-2021-0268

 Google Scholar

Levermore, G. J., Parkinson, J. B., Laycock, P. J., & Lindley, S. (2015). The urban heat island in Manchester 1996-2011. Building Services Engineering Research and Technology, 36(3), 343–356. https://doi.org/10.1177/0143624414549388

 Web of Science ®Google Scholar

Ramamurthy, P., & Sangobanwo, M. (2016). Inter-annual variability in urban heat island intensity over 10 major cities in the United States. Sustainable Cities and Society, 26, 65–75. https://doi.org/10.1016/j.scs.2016.05.012

 Web of Science ®Google Scholar

Ketterer, C., & Matzarakis, A. (2015). Comparison of different methods for the assessment of the urban heat island in Stuttgart, Germany. International Journal of Biometeorology, 59(9), 1299–1309. https://doi.org/10.1007/s00484-014-0940-3

 PubMed Web of Science ®Google Scholar

Brandsman, T., & Wolters, D. (2012). Measurement and statistical modelling of the urban heat island of the city of Utrecht (The Netherlands). Journal of Applied Meteorology and Climatology, 51(6), 1046–1060. https://doi.org/10.1175/JAMC-D-11-0206.1

 Web of Science ®Google Scholar

Hart, M. A., & Sailor, D. J. (2009). Quantifying the influence of land-use and surface characteristics on spatial variability in the urban heat island. Theoretical and Applied Climatology, 95(3-4), 397–406. https://doi.org/10.1007/s00704-008-0017-5

 Web of Science ®Google Scholar

Nicholson, A. (2020). Analysis of the diurnal cycle of air temperature between rural Berkshire and the University of Reading: Possible role of the urban heat island. Weather, 75(8), 235–241. https://doi.org/10.1002/wea.3807

 Web of Science ®Google Scholar