The efficiency of the shade index in activating public spaces (Al-Umma park as a case study)

1. Introduction

Shade plays a vital role in regulating local climate and enhancing pedestrian comfort, particularly in hot areas where insufficient coverage reduces space usability [1, p. 12]. Green roofs and shaded surfaces can lower urban temperatures by 3-4°C in hot climates, with surface materials and color influencing thermal performance [2, p. 366-378]. Shaded outdoor spaces foster recreation, social interaction, and walkability, making cities more livable and environmentally resilient [3, p. 118-125; 4]. Economically, thermally comfortable open spaces attract longer visitor stays, supporting local events and economic activities [5]. Sunlight and shade significantly shape how people use public spaces throughout the day and year, affecting urban space perception [6]. Fred Kent (2021) emphasized shade as a key factor distinguishing usable spaces from uninhabitable ones during peak heat, linking it to climate adaptation [7, p. 29]. Thermal conditions in open spaces directly influence public well-being and mental health, making shaded environments essential for livable cities [8, p. 1-32]. Trees have been shown to outperform other shading strategies in reducing urban heat stress, especially in small-scale settings [9, p. 241-255]. This study raises the following question: To what extent does the proportion of shade contribute to the activation of public spaces within urban contexts? The core issue lies in the existence of inactive public spaces in the hot climate areas of Baghdad. Therefore, the aim of this study is to clarify the role of the shade index in activating public spaces by analyzing its impact on user behavior and their willingness to remain in these spaces during daytime hours. This objective is based on the hypothesis that an increase in the duration of individuals' stay in public spaces during the day indicates the effectiveness of shading and, consequently, the functionality of the space. Moreover, users of these spaces are capable of identifying indicators that contribute to their activation, suggesting that shading has a direct impact on the usability and increased use of such spaces. The case study of "al-umma park" was conducted to shed light on this aspect within the local urban context.

2. Literature Review

This paragraph summarizes key studies that highlight the crucial role of the shade index and its essential variables in activating public spaces. A study in Pecs, Hungary, investigated the effectiveness of different shading methods, particularly sun sails and trees, in improving thermal comfort during summer. Using field biometric measurements and a six-directional radiation technique, the research assessed heat stress levels through Physiologically Equivalent Temperature (PET). The results revealed that dense trees significantly enhanced thermal comfort compared to sun sails, making them a superior strategy for creating inclusive, pedestrian-friendly urban environments [10, p. 241-255]. Similarly, research conducted in Taman Segarah Park, Bandung, Indonesia, examined the influence of shading on the “urban interior design” of public spaces in tropical climates. The findings showed that shading not only improved thermal comfort but also increased spatial utilization, shaped user distribution, and positively influenced behavioral patterns. The study emphasized the need to integrate shading within spatial design and encouraged multidisciplinary approaches to improve public space efficiency in hot and humid regions [11]. In the hot climate of Ahvaz, another study analyzed the role of shading and urban engineering solutions in enhancing pedestrian thermal comfort. The results indicated that reducing the Sky View Factor (SVF) and applying shading strategies considerably decreased mean radiant temperature, particularly in east–west oriented canyons. However, the effect on air temperature itself was limited, underlining the need for integrated climatic design approaches [12, p. 102]. Beyond these case-specific analyses, a systematic review of 116 quantitative behavioral studies on public urban spaces emphasized the impact of environmental factors on human behavior. The findings identified shade as a critical variable that encourages physical and social activities, prolongs dwell time, and enhances spatial interaction. Shaded areas were found to significantly improve both user experience and the overall effectiveness of public spaces as thermally comfortable environments [13, p. 109-118]. More recently, innovative methods have been proposed to refine shade measurement. The Transmissive Canopy Method (TCM), for example, introduced an improved approach to evaluating Sky View Factor and solar radiation by incorporating tree canopy transmissivity. This advancement enhances the accuracy of thermal comfort assessments and provides urban planners with reliable tools to optimize shading strategies and mitigate heat impacts [14, p. 12-18]. Taken together, these studies emphasize the vital role of natural and artificial shading in improving comfort, usability, and safety in public spaces. Building on this knowledge, the present analysis identifies key indicators for assessing shade effectiveness (summarized in table), which contribute to bridging the research gap and establishing climate-responsive design standards. Accordingly, shading can be operationally defined as the percentage of utilized areas particularly seating and movement zones covered by shade (whether natural or artificial) during the critical peak solar period. This definition is further refined by accounting for the actual shading duration of each specific area, ensuring that both spatial and temporal dimensions of shading are systematically integrated into the evaluation process.

Table

Indicators for Assessing Shade Efficiency in Public Spaces

3. Methodology

The study employs a mixed-methods approach that integrates quantitative digital simulation with qualitative fieldwork, utilizing observation and interviews. Al-Ummah Park in Baghdad was chosen as a representative case study. Rhinoceros7 software was employed to analyze shade distribution and ratios across different times of the day. The climatic data for simulations were obtained from the EPW weather file for Baghdad, ensuring accurate representation of local temperature, solar radiation, and sunlight hours. Simulation parameters included material properties for ground surfaces and shading elements, canopy geometry and porosity, and the spatial and temporal resolution of the model, with a spatial resolution of [0.5 m × 0.5 m] and temporal resolution capturing hourly variations during the critical solar peak period (10:00 am – 2:00 pm). All inputs are fully documented to ensure reproducibility and transparency of the results. Qualitative data were collected through direct observation, open-ended questions, and user interviews. The research focused on how shading influences user behavior and perception, based on indicators from previous literature. To evaluate the spatial dynamics, the park was divided into three zones around key landmarks: Zone A (Freedom Monument), Zone B (Mother Monument), and Zone C (Jawad Salim Monument). Participants were asked to identify their preferred shaded zones and assess the impact of added shading elements on park usage. Comparisons were made between pre- and post-renovation plans to understand behavioral shifts. Data collection took place over three days in July, with interviews held during the morning, noon, and afternoon. Roughly 20 participants were interviewed per day. The questions explored shaded area preferences, comfort, and duration of stay, reinforcing the role of shade in enhancing the usability of public spaces.

4. Case Study Description

Al- Al-Ummah Park, located in Bab Al-Sharqi in central Baghdad, was established in 1937 during the royal era and inaugurated by King Ghazi. Following the 1958 revolution, it underwent major renovations, including the addition of lakes, fountains, statues, and the Freedom Monument, and was renamed accordingly. Thepark lies between the Al-Rasheed Street commercial hub and the heritage-rich Al-Bataween area. Its area ranges between 18,475 m² and 21,060 m², with a length of 348.5–351 m and a width of 53–60 m. After years of neglect, it was redeveloped in 2021 and divided into three main zones. The first section (A) on the eastern side includes the Freedom Monument, designed by sculptor Jawad Salim. Its façade faces Tahrir Square and contains seating areas. The second section (B) features a small lake with a fountain and the Mother Monument, accompanied by a pedestrian walkway. The third section (C) contains the Revolution Mural by the artist Faiq Hassan, as shown in figure 1, which illustrates Al-Ummah Park before and after development. Various buildings with different functions surround the park, including educational, cultural, public, and mainly commercial uses, with limited residential units located on the upper floors behind the commercial streets. Notable surrounding buildings include Al-Aqeedah Girls’ High School and the Al-Marjan building on the left, and the former Turkish Restaurant building on the right, as shown in figure 2, which shows the most prominent buildings around Al-Ummah Park.

Fig. 1. It shows Al-Ummah Park Before and After Development

Fig. 2. It shows most prominent buildings around Al-Ummah Park

4.1. Analysis and Simulation of the Role of Shade in Thermal Comfort: A Field Study in Al-Ummah Park

The role of shade in enhancing thermal comfort within public spaces is examined through a mixed-methods approach combining quantitative digital simulations with qualitative observations and interviews. Using Rhinoceros and Ladybug software, climate data specific to Al-Ummah Park in Baghdad were analyzed. Qualitative methods explored users’ perceptions of comfort and climatic effectiveness. The study highlights Al-Ummah Park’s significance due to its central location and environmental impact. Findings reveal significant thermal challenges in summer, emphasizing the need for effective shading strategies to improve space usability and visitor comfort.

4.1.1. Quantitative Analysis: Simulation of the Role of Shade in Enhancing Thermal Comfort

The quantitative analysis examines climate data and thermal comfort indices (UTCI, PET, HI), assesses solar radiation and shade distribution, and uses digital simulations to evaluate shading effects and propose strategies for enhancing thermal comfort in public spaces.

A. Analysis of Site Climatic Data

A.1. Analysis of Solar Movement and Annual Thermal Variations and Their Impact on Human Climatic Needs:

A comprehensive analysis of solar movement in Al-Ummah Park showed that the sun travels from east to west, affecting shadow length, which increases in winter due to a lower solar angle and decreases in summer with a higher solar altitude. Figure 3 shows the movement of the sun throughout the months of the year. The maximum annual temperature in the park exceeds 48°C, with seasonal variations from 18.5°C in January to 48°C and above in July, decreasing to 39.5°C in September, figure 4 shows annual temperature changes. Studies highlight the impact of climate change on thermal sensation throughout the year. The optimal temperatures for human comfort were 19.53°C in January and 21.7°C in August, with cumulative daily temperature variations totaling 829.3°C.

Fig. 3. It shows the movement of the sun throughout the months of the year

Fig. 4. It shows annual temperature changes

A.2. Wind Direction and Speed

An analysis from January 6 to December 21 showed that winds predominantly come from the northwest, with wind speed reducing 5.74% of the time (482 hours) and an average speed of 3.75 m/s. Seasonal examination revealed prevailing winds throughout the year except in autumn (September), when patterns become irregular.

A.3. Relative Humidity:

An annual study of outdoor relative humidity in Al-Umma Park revealed levels ranging from 20% to 40%, increasing in winter due to lower temperatures and decreasing in summer as temperatures rise. Figure 5 shows these variations, highlighting the need for shading and improved ventilation to enhance thermal comfort and microclimatic conditions.

Fig. 5. The graph shows the humidity level throughout the months of the year

B. Standard Criteria for Measuring Thermal Comfort and Comparing It to the Effect of Shade:

B.1. Thermal Comfort Evaluation Criteria:

Thermal comfort indicators refer to internationally recognized standards used to assess the extent to which individuals feel thermally comfortable within public spaces. These indicators rely on climatic analysis data and include the following

Analysis of Thermal Comfort Level According to the Universal Thermal Climate Index (UTCI)

The Universal Thermal Climate Index (UTCI) evaluates thermal comfort based on air temperature, solar radiation, wind speed, and humidity. In Al-Umma Park, UTCI analysis showed that perceived temperatures exceed 45°C during July and August, highlighting the need for shading. In contrast, winter conditions are moderate, allowing better use of solar exposure to enhance thermal comfort.

Analysis of Thermal Comfort Level According to the Physiological Equivalent Temperature (PET) Index

Al-Umma Park experiences intense heat stress in July and August, as indicated by the PET index, highlighting the need for shading and cooling strategies. In winter, although temperatures are moderate, design solutions remain important to further enhance thermal comfort.

Analysis of Thermal Comfort Level According to the Heat Index

The Heat Index in Al-Umma Park exceeds 48°C during summer, indicating severe heat stress and reduced thermal comfort, while winter conditions remain moderate. Figure 6 shows the Heat Index analysis, emphasizing the need for year-round design interventions to enhance public space usability and thermal balance.

Fig. 6. It shows Heat index (Hi) analysis

B.2. Solar Radiation Assessment Criteria:

Al-Umma Park experiences intense solar radiation year-round, peaking along the east-west axis near the Freedom Monument (over 1204.8 kWh/m²), highlighting the need for dense shading, while lower radiation levels near the Peace Mural in Al-Tayaran Square (around 401.6 kWh/m²) reduce the shading requirement, as shown in figure 7, which presents the percentage of solar radiation.

Fig. 7. It shows the percentage of solar radiation

Analysis of Mean Radiant Temperature (MRT) Related to (UTCI – Heat Index)

The analysis of Mean Radiant Temperature (MRT) in Al-Umma Park showed high values in open areas, reaching up to 20.07°C, indicating thermal discomfort. Cooler zones, ranging between 16.59°C and 17.64°C, were found near partially shaded areas. This variation in MRT highlights differing comfort levels across the park. Figure 8 shows the effect of solar radiation on comfort levels. All thermal values were reported in degrees Celsius and calculated consistently for the same critical period (10:00 am – 2:00 pm) during the study days to ensure comparability across zones.

Fig. 8. It shows the effect of solar radiation and comfort levels

Analysis of Sunlight Exposure Duration Related to (UTCI)

Direct exposure to sunlight increases temperatures and reduces visitor comfort, highlighting the need for trees and shading elements. The analysis showed that most of the site experiences extended sunlight, with yellow and orange areas indicating high exposure. Annually, the site receives over 4,000 hours of solar radiation, averaging around 2,069 hours, contributing to higher surface temperatures and heat perception. Figure 9 shows the hours the yard is exposed to direct sunlight and determines the percentage of beneficial and unbeneficial shade. All solar radiation and sunshine duration values were calculated using consistent units (hours) and standardized for the same critical period to ensure comparability across the site.

Fig. 9. It shows sunlight exposure hours and the percentage of beneficial versus unbeneficial shade

Analysis of Incident Solar Radiation on Surfaces and Thermal Comfort Levels

Incident solar radiation significantly affects surface temperatures and thermal comfort in urban areas. Measurements in Al-Umma Park showed annual radiation levels ranging from 1,700 to 1,900 kWh/m², averaging around 1,300 kWh/m². The dominance of red and orange hues indicates high heat absorption. Figure 10 shows the analysis of solar radiation falling on surfaces in Al-Umma Park. All solar radiation values are reported in kWh/m² and were calculated consistently over the same reference period to ensure comparability across different areas of the park.

Fig. 10. It shows the analysis of solar radiation falling on surfaces in Al-Umma Park

Analysis of Sky View Factor (SVF)

The Sky View Factor (SVF) measures the openness of outdoor spaces to the sky, influencing solar exposure and nighttime cooling. Values range from 0 (shaded/enclosed) to 1 (fully open). Analysis of Al-Umma Park showed significant variation in SVF, reflecting diverse shading and sky openness, categorized into three main classes. High sky openness areas (SVF 0.8–1.0), shown in blue, are found in open spaces and pathways with high sun exposure, increasing temperatures and reducing comfort. Moderate openness areas (SVF 0.5–0.7), shown in green, occur where trees and buildings provide partial shade, balancing shade and ventilation for a better microclimate. Relatively enclosed areas (SVF < 0.3), shown in red and pink, have dense shade from trees or buildings, reducing sunlight but potentially limiting ventilation and nighttime cooling. According to the SVF Rose model, low SVF values (0.0–0.3, pink) are concentrated in the park’s shaded central area, moderate values (0.4–0.7, turquoise green) occur near the southern entrance and northern mural, and high values (0.8–1.0, blue) appear in the northern plaza and open walkways, as shown in figure 11, which presents the sky analysis and celestial radiation dome of Al-Umma Park.

Fig. 11. It shows the sky analysis and the celestial radiation dome of Al-Umma Park

C. Analysis of the Amount of Shade Received by the Site

Shading elements are crucial for thermal comfort in open spaces by reducing direct solar radiation and lowering ambient temperatures. In Al-Umma Park, shading is limited, with palm trees used mainly as vegetative fences but providing sparse shade due to their structure. Most shade-providing trees are ornamental, limiting their effectiveness in creating comfortable shaded areas. Southern seating areas lack adequate shading and are exposed to intense solar radiation, making them uncomfortable. Overall, only about 33.11% of the park is shaded, with the majority exposed to direct sunlight, increasing temperatures, and reducing comfort, as shown in figure 12, which presents the amount of shade a location receives in Al-Umma Park.

Fig. 12. It shows the amount of shade a location receives in Al-Umma Park

4.1.2. Results of the Survey on the Preferred Area for Shading Intervention

User interviews at Al-Umma Park revealed Zone A as the most suitable for added shading due to its high foot traffic, dense seating, and proximity to the "Monument of Freedom." However, it lacks adequate shading, causing uneven comfort. Zone B, near circulation points and the "Mother" monument, offers calmness but is underused due to limited seating and sparse shade, with only 10% of visitors preferring it. Zone C, although spacious and quiet with a mural by Faiq Hassan, suffers from insufficient shading and security, making it the least favored (5%). Overall, Zone A stands out as the priority for shading interventions to improve thermal comfort and visitor experience.

4.1.3. Digital Simulation of the Shading Intervention in Section (A) Based on Users' Prevailing Preferences

A numerical simulation is proposed to evaluate the impact of shading on reducing ambient temperatures and enhancing thermal comfort in Al-Umma Park. The proposal calls for adding approximately 10% more shading, focusing on the southern part of the site, which is most exposed to sunlight. Celtis occidentalis trees and retractable or dynamic shade structures will be placed over seating areas to reduce surface exposure to solar radiation. A 3D model will be developed using Rhino software, and simulation tools such as Ladybug and Honeybee within Grasshopper will analyze thermal parameters and shade distribution.

A. Quantitative Analysis: Testing the Role of Shading in Reducing Temperature Increases

Solar radiation levels in Al-Ummah Park are assessed to determine the amount of radiation the site receives after the addition of shading elements, as shown in figure 13, which presents the analysis of solar radiation and its impact on thermal comfort. This analysis also includes evaluating user thermal comfort based on the following assessment criteria:

Fig. 13. It shows the amount of solar radiation and temperature received by Al-Umma Park

A.1. Adopted Evaluation Criteria – Solar Radiation:

Mean Radiant Temperature (MRT) Analysis

A noticeable decrease in temperatures was observed in the area where shading elements were added. Many zones that previously appeared in red shifted to cooler shades of blue or yellow, indicating an improvement in thermal comfort levels. A clear variation in temperature is evident, particularly during the summer season. This addition contributed to reducing the average temperatures, which ranged between 16.59°C and 18.33°C across most parts of the area, as illustrated in Figure 14, which illustrates the effect of solar radiation on Al-Umma Park. All temperature values are reported in °C and correspond to the same critical solar period (10:00 am – 2:00 pm) used throughout the study to ensure consistency and comparability with pre-intervention measurements.

Fig. 14. It illustrates the effect of solar radiation on Al-Umma Park

Analysis of Direct Sunlight Exposure Hours

A noticeable reduction in sun exposure hours was observed, with the spread of darker color zones (reds and blues), reflecting a decrease in direct solar radiation. This improvement led to a more balanced distribution of shade, contributing to a reduction in exposure hours to between 2,500 and 3,000 hours annually in the areas where shading elements were added. In contrast, the average exposure value dropped to approximately 1,206 hours per year. A clear reduction in bright yellow-colored areas can also be seen, indicating a significant improvement in the local microclimate and a reduction in negative thermal impacts on users, as shown in figure 15, which shows sunlight exposure hours and the percentage of beneficial versus unbeneficial shade. All sun exposure hours are reported in hours per year and were calculated consistently using the same reference period and methodology applied throughout the study to ensure comparability across zones.

Fig. 15. It shows sunlight exposure hours and the percentage of beneficial versus unbeneficial shade

Analysis of Solar Radiation on Surfaces and Thermal Comfort Levels

A significant decrease was observed in annual incident solar radiation levels, ranging between 760 and 870 kWh/m², with average values stabilizing at 631 kWh/m². This reflects a significant improvement in mitigating solar radiation impact. Additionally, the prevalence of low-irradiance areas, represented by blue and light yellow colors, has increased, indicating improved thermal distribution. However, some areas are still exposed to high levels of radiation, necessitating further interventions to improve thermal comfort and reduce heat impact, as shown in figure 16, which illustrates solar radiation distribution across the park. All solar radiation values are reported in kWh/m² per year and were calculated consistently using the same reference period and methodology applied throughout the study to ensure comparability across different areas.

Fig. 16. It shows solar radiation falling on roofs and open spaces

Sky View Factor (SVF) Analysis

The analysis of shading impact in Al-Ummah Park showed a clear reduction in areas with high SVF values above 0.8 (blue), indicating less direct solar radiation exposure. Meanwhile, areas with SVF values between 0.5 and 0.7 (green) increased, reflecting improved balance between shade and sky openness. In previously exposed areas, SVF dropped from 0.8–1 to 0.5–0.7, enhancing microclimate conditions, as illustrated in figure 17, which illustrates the analysis of the sky view factor (SVF) and its impact on thermal comfort in Al-Umma Park. However, in heavily shaded zones, SVF values fell below 0.3, which may reduce solar gain but also limit ventilation and nighttime cooling. This highlights the importance of strategic shading distribution to balance thermal comfort and environmental efficiency.

Fig. 17. It illustrates the analysis of the sky view factor (SVF) thermal comfort in Al Umma park

A.2. Analysis of the Amount of Shade Received by the Site:

Anoticeable increase in shading was observed, reaching 49.85%, reflecting a significant improvement in reducing sun exposure. This increase of 16.74% contributed to lowering heat absorption on exposed surfaces, which in turn enhanced thermal comfort levels in the park. The average values reached 1,206 hours annually. As a result, the environment has become more suitable for public use.

5. Results and Discussion

Through interviews, observations, and open-ended questions, it was found that Section (A) is the preferred area for intervention to increase shading, according to users' opinions. The reasons for this preference are as follows: First: This section experiences the highest visitor density due to its proximity to the Freedom Monument, a major attraction. However, it lacks effective shading, resulting in uneven thermal comfort. The area includes existing seating and open spaces, allowing for easy integration of artificial or green shading solutions. Its location near main entrances enhances accessibility, while nearby greenery supports the use of plant-based shading. Given its popularity, especially among families and youth, enhancing thermal and functional comfort in this area is essential to improve space efficiency and extend visitor stay. Second: Sections (B) and (C) were not selected for shading interventions due to their lack of necessary functional and spatial requirements. Section (B) serves as a main movement corridor, especially in the curved area towards the "Mother Monument," and does not contain seating areas or rest zones, despite its relative proximity to park entrances. It also suffers from a complete absence of shading elements, reducing the potential for improving thermal comfort and rendering any shading intervention ineffective within its current function as a passageway, particularly with its low visitation rates (10%). In contrast, Section (C) is the most isolated within the park, located far from entrances and movement corridors, and is fully exposed to the sky, making it susceptible to the highest levels of solar radiation according to the Sky View Factor (SVF) analysis. Additionally, the absence of basic infrastructure such as seating and shading, along with low visitation rates (5%) and its distance from services and surveillance points, diminishes the priority for intervention in this section at the present stage.

6. Conclusions:

• The results of this study can contribute to more efficient improvements of outdoor environments by increasing shading levels in open spaces, thereby enhancing thermal comfort for pedestrians and reducing discomfort.
• Users demonstrate a clear ability to suggest activation tools for their public spaces based on their daily experiences and actual needs, making their participation an effective tool for improving design quality and responding to local requirements.
• Shade in hot climates serves as a key determinant influencing individual behavior within open spaces, directly affecting decisions related to space use, duration of stay, and movement patterns.
• Shade generated by vegetation is among the preferred solutions for users in public spaces, and its effective implementation depends on selecting appropriate plant species with suitable density, height, and spatial distribution.
• The duration of stay in a public space is an important indicator of its suitability; longer stays reflect higher space quality and user satisfaction, whereas shorter stays suggest the opposite.
• Shading changes in public spaces directly affect thermal comfort, influencing users’ movement, seating, and interaction behavior.

Declaration of Competing Interest

The authors declare that there are no conflicts of interest regarding the publication of this manuscript.

Funding Information

No funding was received from any financial organization to conduct this research.

Author Contributions

Professor Haitham A. H. Alshamari identified the research problem. In collaboration with researcher Ahmed Abd. N. Abboudi, recent studies were collected, organized, and analyzed. The researchers discussed the proposed solutions, the design, and the results, and jointly contributed to the final version of this research paper.

Acknowledgments

This research was supported by the College of Engineering and Department of Architecture, Al-Nahrain University, Iraq, and the authors express their sincere thanks.

Ethics Statement

This study was conducted in accordance with the ethical standards of the College of Engineering, Al-Nahrain University. Observations of public space users were carried out in open areas without recording any personally identifiable information. No intervention was applied, and all data were collected anonymously to ensure participants’ privacy. Therefore, formal informed consent was not required.