Skopje Thermal Map — the warmest hotspots in the city and measures to tackle the problem
Designing a Thermal Map of Skopje
To detect the heat islands in Skopje, it was necessary to create a detailed thermal map of the city. A goal that was rather challenging, though. However, the possibility to test several techniques and approaches in the previous years within Skopje Lab, as space for experimentation, enabled us to find the easiest and most effective and at the same time the cheapest way for the realization of this interesting project. Skopje Lab is an excellent platform for cooperation, and this project was completed as a trilateral partnership among the City of Skopje, UNDP and the Faculty of Computer Science and Engineering. Once it was agreed with Skopje Aero Club to perform a flight over the urban area of the city, the team from the Faculty of Computer Science and Engineering comprised of prof. Dimitar Trajanov, associate prof. Igor Mishkovski and assistants Aleksandar Stojmenski and Kostadin Mishev, the preparations for the flight began. The goal we set out was to make a recording with a thermal and RGB camera in the urban part of Skopje. Since the FlirVue Pro thermal camera resolution was lower, we determined the parameters of the flight according to it. In cooperation with Skopje Aero Club, we devised a plan for the flight of the aircraft and determined the flight altitude of 1100 meters to get 50–60% coverage of the thermal images. Skopje Aero Club created a route for the planned movement of the aircraft given in Figure 1 and according to this plan, the overall useful route for the aircraft to cover was more than 375 km and the flight would last approximately from 2 to 3 hours.
The next problem to tackle was the lack of a GPS in the thermal camera, which made it difficult to merge the thermal images. The only GPS camera we had to create the visual RGB map, was the one mounted on the DJI Phantom 3 drone, where the GPS device itself was placed in the drone rather than the camera. Accordingly, we came up with the idea of mounting the whole drone on the aircraft and thus executing the visual recording of the city with a camera that would tag each image with GPS coordinates.
In order to mount the recording equipment on the aircraft, it was necessary to design and then construct an appropriate platform on the aircraft to accommodate the equipment. In cooperation with the engineers from Skopje Aero Club, a suitable aluminum platform was constructed on which the thermal camera and the drone (RGB camera) were installed.
With these do-it-yourself projects, we got the necessary equipment, the flight plan and we were only waiting for a nice and hot sunny day. After several delays, August 24, 2018 was determined as the day of the flight. Following the methodology for the development of a thermal map, the flight was executed around noon to reduce the effect of the shadows and record the maximum warming of the surfaces.
During the three-hour flight, 3951 RGB images and 10596 thermal images were collected, covering an area of about 213 km2. These individual images were processed by a team from Anadolu University to produce a geo-located thermal map and a geo-located RGB map of Skopje.
Additional sources for the development of an Action Plan
Besides the designed thermal map by aircraft, additional information obtained by microanalysis conducted in the summer of 2016 on the move from Vodno to the center of Skopje was also used. Furthermore, a global study of heat islands conducted by the Center for Earth Observation at Yale University was used for analysis of the heat islands.
Measures for tackling thermal islands in Skopje
For analysis of the measures for tackling the heat islands, the recommendations from the US Environmental Protection Agency have been primarily used as well as the recommendations of the relevant European agencies.
Based on the conducted analyses, a number of measures have been proposed. The aforementioned are divided into five groups, namely:
- General strategies for tackling heat islands (6 measures proposed)
- Actions/measures for the municipalities and the City of Skopje (14 measures proposed)
- Actions/measures for the citizens of Skopje (4 measures proposed)
- Innovative measures (5 measures proposed)
- Measures for certain characteristic areas in Skopje (43 measures proposed)
Accordingly, more than 70 actions and measures have been proposed by the Action Plan that could be undertaken in direction of mitigating the effects of urban heat islands in Skopje.
General strategies for tackling heat islands
According to the US Environmental Protection Agency, there are five main strategies on how communities can undertake measures to mitigate urban heat islands:
- Increasing the number of trees and the vegetative cover
- Installing green roofs
- Installing cold roofs
- Using cold sidewalks and surfaces that reflect heat or are water-permeable
- Using practices for green urban development.
In addition to these five measures, in this context, the strategy for creating Green Parking Lots has been added.
Actions/measures at the level of municipalities and the City of Skopje
Based on analyses of a large number of measures that are being implemented in different cities in the world, 14 measures have been selected that are adapted for Skopje and can be applied by the municipalities or the City of Skopje.
- A million trees for Skopje: this should be a cooperative action among the city, local communities, businesses and individuals, which would ensure a long-term partnership in order to plant 1.000.000 new trees throughout Skopje. The action should encompass all vacant areas that are currently bare or have bushes and non-quality trees, as well as the space along the streets.
- Tree Planting Contest: the contest would be designed to help people educate themselves on appropriate ways to plant trees, as well as the benefits of urban green areas for the community. Free trees for your garden.
- Adopt-a-lawn programme: this programme should enable the groups of citizens to take responsibility for planting and maintaining the trees.
- Decree on Green Factor: Setting higher minimum conditions for landscaping which would require all new buildings to be obliged to provide a certain minimum percentage of vegetative coverage of the construction parcel.
- Roadside afforestation: Adoption of a rulebook specifying that trees must be planted along both sides of the street at an appropriate minimum distance.
- Introducing regulations for green parking lots: A rulebook envisaging that when designing and implementing new or renovated parking lots it would be necessary to anticipate and plant an appropriate number of trees that would achieve a certain minimum percentage of shading of the parking lot.
- Project for conversion of parking lots into green parking lots: A project that would enable the transformation of existing parking lots into green parking lots.
- Programme for encouraging green roofs and vertical gardens: In order to encourage the creation of green roofs and vertical gardens, one should adopt a decree by which the owners of buildings on which green roofs or vertical gardens would be implemented and which would be maintained accordingly shall be reduced or completely exempt from property tax.
- Green roofs programme for public buildings: This project would help raise visibility and increase public understanding of green roofs.
- Initiative for grants for raising vertical gardens: provide grants to citizens who want to erect vertical gardens on their walls. Apart from dealing with heat islands, the purpose of this programme is to improve overall aesthetics, pedestrian comfort and air quality.
- Green alleys: A project that would promote the use of porous materials for paving the alleys that are being reconstructed or are being built.
- Introducing regulations for cold roofs installation: Traditionally in Macedonia, the roofs are made of dark red shingles. This material and colour contribute to the large warming of the roofs throughout the city. In this direction, the city will have to adopt regulations with recommendations for the roofs of residential and commercial buildings to use materials that have a high albedo, that is, reflect the heat.
- Increasing the number of trees in the parks: The main target of this measure should be the central city park, in which there are parts with not enough trees, so with this measure, additional trees should be planted in those places. Certainly, this measure should be implemented to other existing parks where the density of trees is not sufficient.
In addition to the standard measures, several interesting and unorthodox measures have been proposed that could be used to mitigate the heat islands effect.
- Portable green gardens
- Green camping in city
- Portable vertical gardens
- Urban agriculture
- Green roof with restaurant
Action plan for certain characteristic areas
Using statistical GIS tools, areas where there is a higher concentration of very hot or very cold spots have been singled out. The spots in such areas are being connected in a cluster and an area has been formed which is analyzed separately. The results of this analysis are shown in Figure 4.
Based on the results acquired, analyses of several characteristic areas of the city have been made. So, from the central city area, two additional areas close to the city center have been selected, that is Debar Maalo settlement and the New Railway Station with Madjir Maalo settlement, and then the area around the Plastic street has been analyzed. As part of the industrial areas in Skopje show greater warming, an industrial zone has been analyzed. We chose the industrial zone around the MZT factory.
Further details are given of the proposed micro measures for the location around the New Railway Station.
An Example of micro-measures for New Railway Station and Madjir Maalo settlement
The New Railway Station is a massive concrete structure with a huge concrete surface that is directly exposed to the sun and as such is susceptible to heating and results in a considerable increase in the temperature in its surroundings. In the vicinity of the railway station, there are several parking lots which are almost without any vegetation and additionally contribute to the heating of this area.
Madjir Maalo settlement is a very densely urbanized area with private houses and buildings that do not have or have a very small yard area. The streets are very narrow and are mostly without trees and other greenery. All this results in increasing the temperature in this part of the city.
Based on the conducted analyses and the possibilities for implementation, the following measures have been proposed for this location schematically shown in the following figure.
According to the conducted analyses, Skopje has the urban heat islands effect, although this is not strongly emphasized as in other larger cities. However, in order to tackle this phenomenon, it is necessary to implement a number of measures to make the city a pleasant place to live in.
Within the frameworks of this study, more than 70 measures and actions have been proposed that would enable tackling the heat islands effects in Skopje. Several areas of Skopje have been processed as specific locations, but this does not mean that this effect is not present in the rest of the city. Accordingly, the same or similar measures should be implemented in all areas that are detected as locations with increased temperature.
Additionally, since most of the measures preventing the urban heat islands effect also affect the reduction of pollution, an effort should be made to implement some of the proposed measures.
Prof. D-r. Dimitar Trajanov
Skopje, January 2019