Assessing the Relationship between Urban Heat Islands and Local Climate Zones during a Winter Period in the Coastal City of Balneário Camboriú/SC, Brazil

Abstract

This research seeks to understand the link between urban heat island and urban cool island, which are the Local Climatic Zones (LCZ) and atmospheric systems during the winter season in the city of Balneário Camboriú, Southern Brazil. First, meteorological data on the urban environment was collected at 11 permanent points in the Balneário Camboriú metropolitan region. Next, a synoptic analysis of the dates was performed to understand the atmospheric systems operating in the region. Finally, the LCZs map created for the city in the World Urban Database and Access Portal Tools was used to correlate the magnitudes of the heat and cool islands found in Balneário Camboriú in the winter period. The results indicate that the increasing verticalization as a result of the construction of skyscrapers in Balneário Camboriú has a significant influence on local conditions for the occurrence of heat and cold islands. The findings indicate that LCZs with sparsely distributed buildings (LCZs 6, 8 and 9) and LCZs with dense vegetation (LCZ A) have lower intensity magnitudes of heat and cool conditions. The biggest magnitudes of heat and cool islands were reported in LCZs 1 and 3 during the timeframe. The synoptic analysis supports earlier research that points to atmospheric stability (Anticyclonic domain) as a favorable atmospheric setting for the emergence of urban heat and coolness islands.

1. Introduction

Several variables influence the urban climate, including local climatic patterns and geographic features, which determine whether the climate is continental or marine. Although the first two elements are beyond human control, anthropogenic activities are directly responsible for climate change that impacts local weather. As a result, rising urbanization and urban morphology are factors directly generated by humans [1].

In this regard, the increase of urbanization and excessive human activity has resulted in a significant change in the Earth’s surface and atmospheric conditions. It is at the Earth’s surface where the most microclimate variability occurs, depending on the city’s structure (size, form, and relationships), and this influences the climatic qualities of the environment [2].

Urban Heat Islands (UHIs) are a well-known phenomenon that causes considerable increases in air temperature (Ta) [3,4]. The initial proposal of the UHI was prompted by observations of Ta disparities between urban and rural environments. This approach of contrasting urban and non-urban Ta to characterize UHI persists in contemporary research [5,6,7]. Evolution in studies on UHIs has made it possible to divide them into four types: canopy layer (CLUHI), surface (SUHI), boundary layer (BLUHI) and sub-surface (SubUHI) [8].

In general, UHIs can develop both during the day and at night, however, according to several studies it is possible to observe that their occurrence is more common during the hottest period of the year and they typically reach their peak at night [9,10]. The effects of UHIs are caused by a variety of factors, including biological, economic, and meteorological processes, changes in scaling, changes in the canopy layer, air pollution, anthropogenic heat, thermal properties of materials, building geometry and dimensions (Urban Canyon), and the reduction of green spaces [11,12,13].

The notion of Urban Cool Islands (UCIs) applies both during the day and at night. They may weaken or even invert throughout the day, such as in metropolitan regions, which may have lower Ta than rural places. This is due to variables such as skyscraper shadowing, the presence of vegetation, bodies of water, and other things that can reduce surface Ta in dense metropolitan environments as compared to rural locations. The size of UCIs changes with the seasons or throughout the daily cycle and is largely reliant on current meteorological circumstances [14,15].

Depending on the meteorological conditions at the time the measurements are collected, the presence of a UCI can be noticed in specific locations of the city. On sunny days, densely covered spaces may be cooler than outside regions, while on overcast days, these effects may be mitigated [13,16].

Urban bodies of water, such as rivers, seas, reservoirs, lakes, and tiny lagoons, are one of the variables that lead to the establishment of freshwater islands. These water bodies serve a critical role in enhancing the thermal environment of cities. Studies have shown that they have a significant cooling effect [16], and they have identified three main factors characteristics: (1) the thermal effect of water bodies compared to other types of land use; (2) the relationship between the characteristics of the water body and the water temperature; and (3) the impact of the spatial characteristics of water bodies (area, geometry) on the cooling effect.

The distribution of Ta in an urbanized region is also affected by the urban layout. Several researchers have used the Local Climatic Zones (LCZs) technique to study the association between UHI/UCI and urban morphology. The LCZs technique was created with the goal of describing urban settings for microscale Ta investigations. The landscapes were described by structure (height and spacing of buildings and trees), surface (im)permeability, and other characteristics that impact microscale measurements [17]. The World Urban Database and Access Portal Tools (WUDAPT) was created with the goal of enabling the definition of LCZs and enhancing the flow of work done using this technique. It provides free mapping of cities through LCZs [18].

In urban climatology research, it is always crucial to predict the behavior of the UHI based on factors like as urban structure, location, and (im)permeability [19]. An illustration of this may be seen in the analysis of UHI growth in Aracaju, Brazil, between 2014 and 2016, which was attributed to the city’s various climatic zones [20]. It was shown that the coldest season, which is characterized by a drop in air speed, produced the highest UHI output. Additionally, being close to water enhanced local natural ventilation while also lowering heat.

Balneário Camboriú is the most verticalized city in the Southern Hemisphere [21]. Its subtropical location implies that it is subject to the influence of several atmospheric conditions. These active systems are antagonistic forces that cause clashes throughout the year at various times. Extratropical active systems, such as polar masses and fronts, and intertropical systems, such as tropical masses and disturbed currents, are examples [22].

Previous study has demonstrated that Balneário Camboriú has varied habitats in two local climatic zones, and some interact with atmospheric systems in a complex way, resulting in diverse microclimatic environments [23,24]. In this regard, this study seeks to comprehend the link between the UHI and UCI in the Local Climatic Zones existent in the city of Balneário Camboriú, as determined by the atmospheric systems during winter days, from June 1st to 14th 2022.

2. Materials and Methods

2.1. Area Characterization

The research area is the city of Balneário Camboriú in the state of Santa Catarina (SC), Southern Brazil. Its central point is located at 26°59′42″ south latitude and 48°37′46″ west longitude. Balneário Camboriú is located in the Itajaí Valley Mesoregion and is part of the Itajaí microregion [25], in the North Coast of Santa Catarina (Figure 1).

Balneário Camboriú is bounded to the north by Itajaí, to the south by Itapema, and to the west east by Camboriú municipalities. The Atlantic Ocean lies to the east west. The primary road into the city is BR 101, which runs to the west of the municipality and acts as the border between Camboriú and Balneário Camboriú (Figure 1).

The urban area of the research object exhibits altitude changes between 0 and 24 m above sea level due to its coastal position. Elevations as high as 580 m above sea level are observed in the surrounding areas [24]. The average annual temperature of Balneário Camboriú ranges from 18.0 °C to 20.0 °C, with hot summers and an average of 1768.0 mm of precipitation. The Köppen climate classification of Balneário Camboriú is Cfa, and its climate may be categorized as humid subtropical [22].

According to the Brazilian Institute of Geography and Statistics (IBGE), the absolute population of Balneário Camboriú in the 2022 census was 139,115 people, occupying an area of 46.80 km². The whole population is concentrated in the Balneário Camboriú urban area, with a population density of 3077.70 people per squared kilometer.

In comparison to the 2010 census, the population of Balneário Camboriú increased by 28.74%. In that year, the city had 149,227 residents, accounting for 1.73% of the entire population of the state of Santa Catarina. The population distribution by gender revealed that 47.55% were men and 52.45% were women. The statistics also revealed the municipality’s age makeup, with 26.0% of the population being under the age of 18, 62.2% being adults, and 11.8% being over 65 years old. These figures are spread throughout the 14 neighborhoods of the city [25].

2.2. Points and Instruments Used for Collection

For this investigation, 11 fixed points for sample collection were chosen. Figure 2 depicts the distribution of these collecting stations in the Balneário Camboriú urban area.

The 11 points were counted from 00 to 10, being 00 the natural/rural reference for the calculations, and points from 01 to 10, the urban environments. The collection locations depicted in Figure 2 were chosen to reflect a wide range of land uses and occupations within the municipality. Chart 1 provides information on the 11 collecting stations located across the research region.

Chart 1 shows the nomenclature assigned to each location, as well as its geographic coordinates, height in respect to sea level, and a brief description of the environment in which it is located. In addition, an aerial image from Google Earth Pro (2021) in which the collecting site is placed and the land cover within a radius of 100 m may be viewed.

A low-cost polypropylene meteorological shelter was erected at the selected locations, as recommended by [26]. An HT 500 Instrutherm thermo-hygrometer was installed in each weather shelter. These gadgets, dubbed dataloggers, were set to gather Ta data every 30 min. The accuracy and precision of the equipment was measured, tested, and used in other research, including in the same city in previous research in a prior collection period, but part of the same project investigating the urban climate of Balneário Camboriú [23,24].

2.3. Analysis of the Magnitude of UHIs and UCIs

The magnitude of UHIs and UCIs were calculated using the thermal differential values between the warmest and coolest points in the research region [27]. Equation (1) expresses the thermal magnitude.

$$Mhpi=Thpi-Thpr$$

(1)

where: Mhpi is the magnitude of the UHI or UCI at a given point (pi) at time h; Thpi is the Ta recorded at a given point (pi) at time h; and Thpr is the Ta recorded at the reference point (pr) at time h (Point 00).

Because it was located in an area with dense vegetation and low urban concentration, this study used Point 00 as a reference point for determining the magnitude of UHIs and UCIs. According to the index shown in

Table 1. Classification of the magnitudes of urban heat and cool islands [27].

Magnitude (°C)	Intensity	Category
>6.0	Very strong	UHI
4.0 to 6.0	Strong
2.0 to 4.0	Moderate
0.0 to 2.0	Weak
−2.0 to 0.0	Weak	UCI
−4.0 to −2.0	Moderate
−6.0 to −4.0	Strong
<−6.0	Very strong

, the categorization of magnitudes according to intensity was developed in line with what was pointed out by [27].

It was necessary to identify the climatic types operating in the region under research in order to look into global synoptic processes. Version 3.0 of the Spatial Synoptic Classification (SSC) resource was utilized for this purpose. The SSC is a daily method that uses surface-observed meteorological data to categorize climate types [28,29]. Analyses were conducted on the climatic types recorded at the Florianópolis, Santa Catarina, meteorological station. This meteorological monitoring station, which most accurately represents the climatic parameters of the region under investigation, is located around 87.0 km from Balneário Camboriú.

At this latitude, the hours of 7 a.m. to 6 p.m. were regarded as daytime during the winter, while the hours of 6:30 p.m. to 6:30 a.m. the next day were regarded as nighttime [24].

3. Results

3.1. The LCZs in Balneário Camboriú

The World Urban Database and Access Portal Tools (WUDAPT) technique [18,23] was used in this research to determine the Local Climate Zones for Balneário Camboriú. The following LCZs were found by the authors in the research area: LCZ 1, LCZ 2, LCZ 3, LCZ 4, LCZ 5, LCZ 6, LCZ 8, LCZ 9, LCZ A, LCZ B, LCZ D, LCZ E, LCZ F, and LCZ G. As indicated in Figure 3, the data collecting locations were located in five of these LCZs: LCZ 1, LCZ 3, LCZ 6, LCZ 8, and LCZ 9.

LCZ 1 is defined as an area with a high density of tall structures [17] (more than 10 stories), few or no trees, and is located near the beach sand strip (LCZ F) and the Atlantic Ocean (LCZ G). LCZ 3 is located in the furthest part of the Atlantic Ocean and is defined as a region with a high density of low structures with up to three stories, few or no trees, and heavily paved land. LCZ 1 and LCZ 3 best depict Balneário Camboriú—urbanized areas with few or no trees and heavy traffic [24].

LCZ 6 is located in the northern portion of the municipality and is distinguished by a spaced layout of medium-sized buildings (between 3 and 9 stories) and permeable soil covering. LCZ 08 is the class that includes single-story low-rise structures. LCZ 09, on the other hand, is one of the least urbanized classes in this study, with fewer buildings, more permeable soil covering, and a larger prevalence of trees. LCZ A is made up of heavily forested vegetation that is mostly permeable.

Point 00, as indicated in Figure 3, is located in LCZ 9, which is distinguished by low-rise building designs and permeable soil. Point 01 lies near LCZ A (thick vegetation), on the Camboriú River’s right bank, LCZ 8 (big low-rise structures and impermeable soil), and LCZ 9, whereas Point 02 is completely immersed in LCZ 3, in an area of low, compact buildings with impermeable soil.

Points 03 and 04 are in LCZ 1 (skyscraper, compact, and waterproof). What distinguishes the two is that Point 04 is influenced by LCZ F, which is characterized by exposed soiland exposed soil does not occur with Point 03 because it is inserted in LCZ 1 and under its influence only. Point 05, on the other hand, is in LCZ 3, near LCZ 1, and point 06 is in both LCZ 1 and LCZ A. Point 07 sits at the bank of a creek (LCZ A) and in LCZ 6 with medium-sized structures. Point 08 is in LCZ 8 and points 09 and 10 are in LCZ 3.

3.2. Ta Data from Collection Points

Using Point 00 as the reference point for this study, the average Ta recorded at this position for the data collecting period was 16.1 °C. During the investigated time period, the absolute maximum and lowest Ta recorded at the reference site were 23.6 °C and 8.9 °C, respectively, resulting in a thermal amplitude of 14.7 °C.

Table 2. Ta data (°C): averages, absolute maximums, absolute minimums, and thermal ranges for each collection point between 1–14 June 2022.

	P00	P01	P02	P03	P04	P05	P06	P07	P08	P09	P10
Average Ta (°C)	16.1	15.9	16.6	16.6	16.8	16.6	16.5	17.0	16.5	17.2	16.4
Maximum Ta (°C)	23.6	23.3	24.9	22.3	24.5	22.6	23.9	24.6	22.9	28.8	22.7
Minimum Ta (°C)	8.9	7.8	8.5	9.5	8.8	8.9	9.0	8.6	8.9	8.2	8.7
Amplitude Ta (°C)	14.7	15.5	16.4	12.8	15.7	13.7	14.9	16.0	14.0	20.6	14.0

displays the average Ta data, absolute maximum and lowest Ta, and thermal amplitude of the 11 research-area-representative locations.

During this study, the lowest average Ta reported in Balneário Camboriú was 15.9 °C, recorded at Point 01, a location impacted by three separate local climate zones: LCZ 8, LCZ 9, and LCZ A. The highest average Ta for the data collecting period, 17.2 °C, was recorded at Point 09, as was the absolute maximum Ta, 28.8 °C. Point 09 is situated inside LCZ 3. Point 03 in LCZ 1 had the lowest absolute maximum Ta and the greatest absolute minimum Ta (22.3 °C and 9.5 °C, respectively), as well as the lowest thermal amplitude measured throughout the examined time. Point 01 had the lowest absolute minimum Ta in the study region, at 7.8 °C.

Urban areas experience Ta variability during the day and night, and this difference has been called thermal amplitude. The UHI directly impacts local temperature ranges. The low albedo and reduced soil permeability of urban surfaces result in higher daytime temperatures and nighttime heat retention, in other words: a high thermal amplitude. While UCIs can cool daytime temperatures, the overall trend is toward reduced thermal amplitudes in urban areas [1].

3.3. Magnitudes of UHI and UCI in Balneário Camboriú

Figure 4 depicts the absolute maximum and lowest magnitudes of daily UHIs and UCIs (7 a.m. to 6 p.m.) for each Ta recording station.

Maximum UHI magnitudes reached moderate intensity throughout the day in Points 01, 06, 07, 08, and 10. The UHI achieved their peak magnitude throughout the analysis period at points 02 and 04, respectively. Points 03, 05, and 09 recorded extremely intense heat islands.

During the day, the UCIs were detected with moderate intensity at the greatest number of collection places (01, 02, 04, 06, 07, 08, 09, and 10). The magnitudes of the UCIs were greatest at Points 03 and 05, with very strong magnitudes and strong intensities, respectively. The intensity of both Ta islands was found to be lower at night, between 6:30 p.m. and 6 a.m., compared to the daylight period. Figure 5 depicts the magnitudes of the nighttime UHIs and UCIs.

Moderately intense nocturnal UHIs were detected at locations 01, 02, 06, 08, 09, and 10. The UHIs of high intensity were reported at points 03, 04, and 05. Point 07 was the only one with a high UHI intensity. Five of these places had the same UHI intensities as during the day. Another four places had lesser UHI magnitudes, with just one showing an increase in heat intensity when compared to daylight.

During the night, Points 03, 04, 06, 07, and 08 recorded islands of low intensity coolness. The UCIs of moderate intensity were found at locations 02, 05, 09, and 10. During the night period, Point 01 reported a UCI with a high intensity. When the magnitudes of the UCIs were compared during the day and at night, it was discovered that the intensity of the UCIs remained constant in three spots. During the night, five points reported a drop in the intensity of the UCI. Two places recorded an increase in the intensity of the coolness.

When monitoring UHIs and UCIs hourly, fluctuations in the incidence of phenomena can be observed throughout the day. Figure 6, Figure 7 and Figure 8 depict the hourly evolution (between 00:00 and 23:00) of the magnitudes of UHIs and UCIs recorded at the 10 places examined between 1–14 June 2022. For better visualization, the points were separated into three groups.

Except for Point 01, all sites in Figure 6 displayed UHIs of weak, moderate, or strong intensity. The UHIs were observed in a time span that began at 4 p.m. and ended around 6 a.m. At each place, UCIs appear at various periods. Point 01, for example, had negative magnitudes in practically all of the period’s recordings. Points 03, 05, 06, 07, 08, and 09 all displayed negative magnitudes between the early morning and early afternoon. Only at night and on specified days did Points 02 and 09 record negative magnitudes.

In the case of UHIs, heat bubbles display increased intensity at the end of the day (5/6 p.m.) and the early hours of the night (till 11 p.m.) at Points 01, 03, 04, 05, 06, 07, 08, and 10. The most significant UHI at Point 02 occurred between 1 p.m. and 3 p.m. The most extreme UHI was observed during the morning and early afternoon (between 8:30 a.m. and 2 p.m.) at Point 09, which had the highest UHI magnitude value of the time (8.4 °C). According to Figure 6, the heat at Point 09 was the most substantial over the time.

The UCIs observed during the analysis period did not follow an hourly trend. Points 01, 02, and 09 in Figure 8 recorded the lowest negative magnitudes at 8 p.m. They remained on the UCI until the early morning hours of the following day, but with less intensity. During the day, the other places reported the lowest magnitudes of UCIs. The most powerful of them occurred in the morning at Points 03 and 06. Points 04, 05, 07, 08, and 10 reported more substantial UCIs between 12 p.m. and 2 p.m. Figure 6, Figure 7 and Figure 8 further reveal that the maximum intensities of the UHI and UCI phenomena found in this investigation occurred between 11–14 June.

The synoptic analysis using SSC method at the time revealed that two distinct synoptic conditions occurred throughout the data collection period. These conditions were identified as the wet phase and the dry phase. The passage of polar frontal systems and frontal cyclones affected or influenced the city during the wet phase. Cloudy skies, air instability with rain, and minimum Ta above 15.0 °C defined this period. Clear skies and no cloud cover were observed during the dry phase, resulting in surface heating by direct solar radiation during the day and adiabatic cooling during the night. The minimum Ta was below 15.0 °C throughout the investigated interval. The classification of synoptic conditions found during the research period is presented in

Table 3. Synoptic conditions found for Balneário Camboriú region during the investigation period.

Day	Synoptic Classification	Weather Description
01/06	Moist polar	Dry moderate—The air conditions are calm, with low humidity, creating a dry and pleaseant atmosphere. Usually seen in certain regions where zonal airflow prevails. Occurs when a continental polar air mass moves far form its original location and undergoes significant changes.
02/06	Moist moderate
03/06	Dry moderate
04/06	Dry moderate	Dry polar—Is often linked with the classic continental polar air mass over the mid and upper latitudes, but it can develop in various atmospheric scenarios, usually when cold air moves in and there are chances for radiational cooling. It is commonly connected with the coldest temperatures recorded in a specific location for that time of the year, along with clear, dry weather.
05/06	Moist moderate
06/06	Moist moderate
07/06	Moist moderate	Moist moderate—The weather is significant warmer and more humid than de moist polar. It is commonly found in áreas with overruning air, where the front is closer. Can also occur in coastal regions near mild oceans. May occur when there is a disturbance causing heavy cloud cover, leading to lower daytime temperatures and precipitation.
08/06	Moist moderate
09/06	Moist moderate
10/06	Transition	Moist polar—Linked with maritime polar air masses, bring cool, cloudly, and humid conditions with minimal temperature fluctuations. Often lead to precipitation and are formed throught various processes like being transported from a cool ocean, formed due to frontal overruning or modified from a colder air mass near water bodies.
11/06	Dry polar
12/06	Transition
13/06	Moist moderate	Transition—Characterized by the change from one type of weather to another, tipically marked by significant shifts in pressure, dew point, and wind througout the day. In regions with mid- and high latitudes this transition is linked to the passage of a front. The weather conditions on transition days generally feature temperatures close to normal, increased winds and a higher chance of precipitation.
14/06	Moist moderate

.

The humid phase occurred between 1–2 June 2022 and 5–9 June 2022, with a preponderance of atmospheric instability, cloudiness, and low-intensity rain. The city was under the influence of the polar air mass during the 3–4 June as well as from the 10–14 June 2022. The thermal disparity between these two temporal slices of the dry phase is attributable to the loss of intensity of the Atlantic polar air mass as a result of rapid warming and thermal increase.

Otherwise, the polar air mass that reached Balneário Camboriú was vigorous between the June 10th and 11th. This meteorological condition lowers Ta and sustains atmospheric stability, promoting dry, cloudless days and contributing to the balance of daytime and nighttime energy. This stable atmospheric condition remained between June 12th and 14th, but with cloudiness and a gradual increase in temperatures.

3.4. Relation of LCZs, Average Ta and Day and Night Magnitudes of the UHI/UCI at Each Point

Table 4. Relationship between LCZs and average Ta (day and night) and the average magnitudes (daytime and nighttime) at each collection point.

			AVERAGE Ta (°C)
Point	LCZ	LCZ Influence	Daily Ta	Night Ta	Daily Magnitude	Night Magnitude
01	LCZ 9	LCZ A and 8	17.4	14.5	−0.3	−0.2
02	LCZ 3	-	18.4	15.1	0.7	0.4
03	LCZ 1	-	17.5	15.7	−0.1	1.0
04	LCZ 1	LCZ F	18.1	15.5	0.5	0.8
05	LCZ 3	LCZ 1	17.6	15.6	0.0	0.9
06	LCZ 1	LCZ A	17.7	15.4	0.1	0.7
07	LCZ 6	LCZ A	18.4	15.8	0.8	1.1
08	LCZ 8	-	17.7	15.4	0.1	0.7
09	LCZ 3	-	19.3	15.2	1.6	0.5
10	LCZ 3	-	17.9	15.1	0.3	0.4

shows how distinct metropolitan areas and their local climatic zones affect daytime and nighttime Ta. It also illustrates how Ta varies during the investigated period.

The highest average daily Ta recorded was 19.3 °C at Point 09 (LCZ 3), while the lowest was 17.4 °C at Point 01 (LCZ 9). Point 07 (LCZ 6) had the greatest average overnight Ta of 15.8 °C, while Point 01 (LCZ 9) had the lowest average nighttime Ta of 4.5 °C.

The maximum magnitude during the day was 1.6 °C at Point 09 (LCZ 3), while the lowest magnitude during the day was −0.3 °C at Point 01 (LCZ 9). The maximum magnitude during the night period was 1.1 °C at Point 07 (LCZ 6). Point 01 (LCZ 9) had the lowest nighttime magnitude of −0.2 °C.

Ta at LCZ 1 range from 17.5 °C to 18.1 °C during the day and from 15.4 °C to 15.7 °C at night. Magnitudes range from −0.1 °C and 1.0 °C during the day and 0.7 °C and 1.0 °C at night. Ta at LCZ 3 range from 17.6 °C to 19.3 °C during the day and 15.1 °C to 15.6 °C at night, with magnitudes ranging from 0.3 °C to 1.6 °C during the day and 0.4 °C to 0.9 °C at night.

The average Ta in LCZs 6 and 8 ranges from 17.6 °C to 19.3 °C during the day and from 15.1 °C to 15.6 °C at night. Variations in magnitude were found from 0.1 °C to 0.8 °C during the day and from 0.7 °C to 1.1 °C at night. LCZ 9 had the lowest Ta fluctuation, with −0.3 °C magnitude during the day and −0.2 °C magnitude at night.

Regarding the third column of Table 4, which concerns the LCZ influence, it was observed that the magnitudes presented at these points are related to the LCZ with the greatest vertical density, as Points 01, 04, 05, 06, and 07 are located in areas of contact between different LCZs (Figure 3), with the LCZ mentioned in the third column being the one that had the most impact on the values mentioned.

4. Discussion

The research findings clearly revealed that skyscraper building in Balneário Camboriú has a significant influence on local Ta conditions [23,24]. The presence of these high-rise structures in the metropolis has an impact on heat absorption, ventilation, and the creation of heat islands. These changes in the urban landscape are responsible for modifying the conventional thermal field dynamics reported in the literature. In addition, the size and direction of the metropolitan road network influence the intensity or attenuation of these Ta shifts. Narrow streets and street direction can have an impact on shade, air circulation, and heat accumulation in certain places, amplifying the effects of verticalization on the thermal field.

The materials utilized in urban buildings have a high thermal capacity and thermal emittance, resulting in delayed cooling late in the afternoon and at night [2]. Thus, heat island magnitudes rapidly grow after sunset, peaking at night and declining till daybreak [2,14]. Common urban materials such as asphalt and concrete, with their high thermal capacity ad emissivity, contribute to slower cooling at night, thereby exacerbating the UHI effect after sunset. This is particularly noticeable in densely populated areas with little vegetation [30].

The UHI and UCI magnitudes varied less across day and night periods at sites in LCZs with sparse building architectures (LCZs 6, 8, and 9). The same occurs with the Points influenced by LCZ A (Point 06, LCZ 1), with the dense vegetation typical of this LCZ contributing to climate control in nearby areas, even in densely urbanized LCZs such as LCZ 1, LCZ 3 and LCZ 6, attenuating the difference in the intensities of island heat and cold phenomena due to the strong presence of trees [19]. The opening and height of buildings and vegetation cover are characteristics that have a great impact on the intensity of UHIs and can contribute to mitigation both during the day and at night [13,18].

The LCZs 1 and 3 reported more substantial magnitudes of urban heat and coolness in well-defined temporal spaces. The nighttime UHI in LCZ 1 lasts from late afternoon till before daybreak. This LCZ’s UCI are likewise highly defined, occurring during the day. Unlike LCZ 1, LCZ 3 tracks the presence of high-intensity UHI during the day. The UCIs seen in this LCZ have a low to moderate intensity and are virtually usually documented at night [24].

The effect of LCZ F (exposed soil) on the Ta of LCZ 1 minimizes the incidence of an UCI, as seen at Point 03 vs. Point 04. Both are in a typical LCZ 1 zone, however at Point 03, the existence of the sand strip near to LCZ 1 and the higher incidence of solar radiation impact the heating of the local air. Point 03, on the other hand, is in a highly built-up region with towering structures that obstruct much of the sun radiation and local air movement. Sea wind does not necessarily have a favorable influence on Ta reduction, especially in metropolitan settings. As a result, urban morphology and land use become the primary factors affecting Ta in these places [31].

In metropolitan regions, the horizontal Ta gradient increases from the outskirts to the city center. This trend, however, can be disrupted depending on intra-urban land uses, which, as demonstrated by the data, alter temperature. Factors such as dense vegetation, closeness to water bodies, and the energy balance itself on a microscale can cause the local air to be colder than the metropolitan norm, resulting in “cold islands” [14]. Furthermore, the humidity in the urban atmosphere is higher than the natural/rural atmosphere during winter period [32], which may be a factor that contributes to the increase in the magnitude of urban heat islands.

Because urban morphology significantly influences warming patterns in these areas, it is believed that urban layout is a crucial factor that affects the distribution of Ta in this environment [33,34,35]. The spatial configuration of green areas plays a vital role in mitigating the UHI effect in temperate cities, emphasizing the importance of parks and vegetation in reducing surface temperatures [36]. Additionally, the analysis of hourly patterns and the intensity of heat islands can be enhanced by connecting the magnitude of these phenomena with the LCZ calculated to each position.

Furthermore, the synoptic factors associated with the magnitudes of UHIs found in this experiment are consistent with studies indicating the occurrence of the most intense UHIs and UCIs under very specific atmospheric conditions of clear skies, low wind speed, little or no cloudiness, and no precipitation [2,15]. Also, independent of the features of buildings and land use, temperatures inside urban areas tend to homogenize in situations of meteorological instability, such as increased wind speed and cloudiness [7,14].

5. Conclusions

This study sought to enhance the understanding of the climatic dynamics in urban areas with significant vertical development in coastal subtropical environments during a typical local winter climate period. The results and conclusions obtained offer valuable insights into the specific climatic challenges faced by these metropolitan regions.

The experiment results indicate that LCZs with a sparse building layout (LCZ 6, LCZ 8, and LCZ 9) and LCZs with a high presence of flora (LCZ A) have lower intensity magnitudes of heat and coolness. The period’s largest magnitudes of UHIs and UCIs were reported in LCZs 1 and 3. The observation showed that there is no correlation between the average magnitude of UHI and UCI and the defines LCZs. This study’s synoptic analysis confirms earlier research that points to atmospheric stability (Anticyclonic domain) as a favorable atmospheric setting for the emergence of UHIs and UCIs.

However, there is a restriction in the study of the influence of sea breeze in this research, which is the lack of a higher number of equipment to measure wind speed and direction at a greater number of data collecting stations. In this study, we were not able to conduct a more in-depth investigation of the impact of the marine wind. This is a major drawback since it limits a comprehensive knowledge of wind patterns and climatic fluctuations in Balneário Camboriú.

Finally, this experiment demonstrates the need for additional in-depth investigation into the thermal variation in the Balneário Camboriú urban area. A longer time of data collection is required, as well as the examination of additional atmospheric and environmental/urban factors at the surface level, such as relative air humidity, wind flow, and the sky view factor techniques. A comparison between summer and winter conditions will be of interest as will the comparison of atmospheric humidity. It is understood that local investigations into UHIs promote the understanding of their causes and collaborate in the planning of possible mitigating measures.