Scholarly article on topic 'The Detection of Urban Open Space at Jakarta, Bogor, Depok, and Tangerang – Indonesia by Using Remote Sensing Technique for Urban Ecology Analysis'

The Detection of Urban Open Space at Jakarta, Bogor, Depok, and Tangerang – Indonesia by Using Remote Sensing Technique for Urban Ecology Analysis Academic research paper on "Agriculture, forestry, and fisheries"

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{"urban green space" / "vegetation structure" / landuse / microclimate}

Abstract of research paper on Agriculture, forestry, and fisheries, author of scientific article — Alinda F.M. Zain, Prita Ayu Permatasari, Cherish Nurul Ainy, Nefalianti Destriana, Desti Firza Mulyati, et al.

Abstract Trend of decreasing urban green space within the last few decades either in metropolitan area, towns and cities are detected by using remote sensing techniques. The selection of the appropriate urban green space to restore the stability of urban ecosystem is determined by several factors, such as site uniqueness, land-form, or microclimates. However, until now, there were no scientific data which could describe how much ecological effect differences of trees, shrubs and grass for affecting microclimate in urban areas. This research was conducted to measure urban air temperature at different vegetation structure and landuse in Jakarta, Bogor, Depok, and Tangerang.. The site from different landuses (urban park, residential, central business district and industrial area) for urban temperature measurement was selected by using remote sensing techniques. The results of spatial and statistical microclimate analysis indicated that the trees are more effective to reduce the temperature in comparison with the structure of other vegetation. The results also proved that there were differences in temperature at the same vegetation structure (tree, shrub, grass) on the different types of landuse, as well as at different cities.

Academic research paper on topic "The Detection of Urban Open Space at Jakarta, Bogor, Depok, and Tangerang – Indonesia by Using Remote Sensing Technique for Urban Ecology Analysis"

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Environmental Sciences

Procedia Environmental Sciences 24 (2015) 87 - 94

The 1st International Symposium on LAPAN-IPB Satellite for Food Security and Environmental

Monitoring

The detection of urban open space at Jakarta, Bogor, Depok, and Tangerang - Indonesia by using remote sensing technique for urban

ecology analysis

Alinda FM Zaina*, Prita Ayu Permatasarib, Cherish Nurul Ainya, Nefalianti Destrianaa,

Desti Firza Mulyatia, Salwa Edia

aDepartment of Landscape Architecture, Faculty of Agriculture, Bogor Agricultural University (IPB), Jl Meranti Dramaga, Bogor 16680,

Indonesia

bCenter for Environmental Research, PPLH Building 2nd-4th Floor, Jl Lingkar Akademik Dramaga, Bogor 16680, Indonesia

Abstract

Trend of decreasing urban green space within the last few decades either in metropolitan area, towns and cities are detected by using remote sensing techniques. The selection of the appropriate urban green space to restore the stability of urban ecosystem is determined by several factors, such as site uniqueness, land-form, or microclimates. However, until now, there were no scientific data which could describe how much ecological effect differences of trees, shrubs and grass for affecting microclimate in urban areas. This research was conducted to measure urban air temperature at different vegetation structure and landuse in Jakarta, Bogor, Depok, and Tangerang.. The site from different landuses (urban park, residential, central business district and industrial area) for urban temperature measurement was selected by using remote sensing techniques. The results of spatial and statistical microclimate analysis indicated that the trees are more effective to reduce the temperature in comparison with the structure of other vegetation. The results also proved that there were differences in temperature at the same vegetation structure (tree, shrub, grass) on the different types of landuse, as well as at different cities.

© 2015The Authors.Published by ElsevierB.V Thisis an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Selection and peer-review under responsibility of the LISAT-FSEM Symposium Committee Keywords:urban green space; vegetation structure; landuse; microclimate

CrossMark

* Corresponding author. Tel.: +62-81316052022; E-mail address:lindamedrial@gmail. com

1878-0296 © 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Selection and peer-review under responsibility of the LISAT-FSEM Symposium Committee doi:10.1016/j.proenv.2015.03.012

1. Introduction

Indonesia is experiencing rapid development in terms of economic, social, and infrastructure. The development was centered on the capital city, Jakarta and surrounding cities such as Bogor, Depok, and Tangerang. One significant development is the growth of population where the number of residents in Jabodetabek has reached 14 million. This raises a wide range of urban problems that bring environmental degradation. Increased air temperature can be expected to be particularly problematic in urban areas, where the temperature tends to be a few degrees warmer than the surrounding countryside. This difference in temperature between urban and rural areas is called the 'urban heat island effect' [1]. One of the solutions to minimize this problem is performed by increasing the green open space (GOS) in the city.

GOS will balance the urban ecosystem such as hydrology system, climatology, biodiversity, and other ecological system, aimed at improving the environment, city aesthetics, health, and well-being (eg. quality of life, human well-being) [2]. Vegetation and urban materials differ in moisture, aerodynamic and thermal properties; hence urban greening could affect temperatures through different processes [3]. Landuse is "the human activity associated with a specific piece of land" [4]. Currently the city has plenty of green space that has been converted into a variety of landuse such as residential, industrial areas, and Central the Business District (CBD) so that the effect of green space on microclimates is different.

This study will measure the temperature at different vegetation structure, namely trees, shrubs, and grasses. Measurements were taken at different landuse such as residential, CBD, industry, and urban park. This study will use Geographic Information System (GIS) to identify landuse and HeavyWeather Station Mini microclimate as gauges, so the measurement data will obtained microclimate on vegetation structure in different landuse so that, comparison of microclimate for each GOS at different vegetation structure in each landuse can be performed.

The purposes of this study are to identify land cover in Jakarta, Bogor, Depok, and Tangerang using remote sensing data; to determine the differences in microclimate on different vegetation structure (trees, shrubs, and grasses) for each landuse (park, CBD, residential, and industrial area).

2. Materials and Methods

The study was conducted in four types of landuse (urban park, CBD, residential, and industrial area) in Jakarta, Bogor, Depok, and Tangerang in the period of June-September 2012. Data used in the study were LANDSAT 7 ETM+ and air temperature. Before collecting the air temperature data, image data processing were conducted such as image restoration, image enhancement, and image classification. After the image processing steps, the landuse in every city was able to be identified. In the next stage, field data collection later on was conducted in four types of landuse. Selection of the location in this study was done by taking the three largest area of each landuse in Jakarta, Bogor, Depok, and Tangerang (Figure 1.). Each of the city district boundaries were digitized based on spatial plans maps and then overlaid with land cover maps so the width of GOS in each cities can be derived. Furthermore, the three largest GOS area on each landuse were averaged and the green space area that are close to the average were selected for data retrieval (Table 1.). In each location, microclimate measurement was conducted on 3 observation plots (trees, shrubs, and grass) at 00.30-01.00 pm at daylight. Three replication for similar plots were performed at the same observation plot on different day. Then, later on, the data on the same observation plot were averaged.

Fig 1. Research site

Table 1. Location of microclimate measurement

Jakarta Bogor Depok Tangerang

Urban Park Taman Suropati Bogor Botanical Garden Taman Hutan Rakyat Selapang Jaya

CBD Cempaka Putih Bantar Jati Margonda Raya PanunggangTimur

Residential Cakung Bukit Cimanggu City Bella Casa Poris Plawad Utara

Industrial Area Cakung PT Unitex BWK IV Sukatani Alam Jaya

3. Results and Discussion

3.1. Jakarta

Based on the results of image classification (Figure 2), it is known that the land cover in Jakarta is dominated by built space (88.6%). It can be seen from the existing condition of Jakarta land cover is mostly consists of office, residential, industrial area, and trade area. On the contrary, GOS width in Jakarta only reached 10% of total area in Jakarta. While blue open space (BOS) reaches 1.3%. The high percentage of developed land was occurred due to the high construction activity in this city. Jakarta is the capital city of Indonesia and the largest metropolitan area in Southeast Asia with tremendous population growth [5]. With 10 million people of population and located at the center of the surrounding city, development in the city is higher than the other land use where the number of GOS decreases.

Based on the results of the temperature measurements that has been carried out on four different landuses, it showed that the lowest temperature at various vegetation structure was located in urban park which ranged between 30-35°C. Air temperature measurement on trees and shrubs showed that residential had the highest air temperature while Air temperature measurement on the grass showed that industrial area had the highest temperatures. Furthermore, air temperature in residential and industrial areas reached 37°C during the day.

Air Temperature on Shrub (°C) 34.7

Urban Park CBD Residential Industrial

Air Temperature on Grass (°C) 37.7 37.9

Urban Park CBD Residential Industrial

Fig 2. Average air temperature on tree, shrub, and grass in urban park, CBD, residential, and industrial area in Jakarta

Air temperature differences for each landuse were caused due to the differences in the condition of each landuse. Many industrial areas generates heat from a variety of production activities, smoke from factories, and vehicles that produce hot air temperature.The residential area has a relatively high temperature due to residential location that are located close to the industrial area. This condition makes the air temperature in this region tends to be not much different from the industrial area. Moreover, residential has a small amount of GOS. Unlike the residential and industrial area, urban park has a small percentage of developed land and dominated by GOS which makes air

Air Temperature on Tree (°C)

34 33.9

Urban Park CBD Residential Industrial

temperature in this area was the lowest. 3.2. Bogor

Based on the results of image classification (Figure 3), it was known that the area of GOS in Bogor had the largest value than the other two categories of land cover with the amount of 54.76% of the Bogor total area. According to Government Regulation No. 26 of 2007, the proportion of GOS in urban areas was set to be at least 30% of the area of the city. So, it means that Bogor has already had a good proportion of GOS. The high contribution of GOS width in Bogor was caused by the design of a garden city with large main city park in the center of the city (Bogor Botanic Gardens) and around the main city park, where several satellite parks are located (Taman Kencana, Taman Topi, Lapangan Sempur, etc.) [6].

From the results of air temperature measurements taken at four different types of landuse, it was known that the air temperature in urban park was the lowest ranged between 30-34°C. On the contrary, Air temperature measurement taken from tree in residential area obtained the highest temperatures. While on shrubs and grasses, CBD area has the highest air temperature than other landuse. Residential had the air temperature in the range of 33-36°C, while the air temperature in the CBD ranged between 32-37°C. If we compared this city with the three other cities, Bogor has the lowest air temperature. However, during the daytime, temperature in this town was above 30°C. This showed that during the day, air temperature in Jabodetabek area was quite high and did not meet the standard of thermal comfort.

Air Temperature on Tree (°C) 33.5

32.5 32.3

Urban Park CBD Residential Industrial

Air Temperature on Shrub (°C) 35.7

I 34-6 34.4

Urban Park CBD Residential Industrial

Air Temperature on Grass (°C) 37.6

Urban Park CBD Residential Industrial

Fig 3. Average air temperature on tree, shrub, and grass in urban park, CBD, residential, and industrial area in Bogor

The high temperatures in the CBD and residential occured because of the small amount of GOS and located on the edge of the busy traffic. Asphalt heating during the day has cause the air temperature around the highway to be high. Studies were consistent in finding lower surface temperatures for grass than for concrete or asphalt [7]. The second highest temperature is residential area where it consists of many physical buildings that create more heat to

the surrounding air [8]. Industrial area has the third highest temperature where it has industrial activities that generate heat. However, because of the existing GOS in this area is large enough, the temperature was lower than the CBD and residential. The lowest temperature found in the city was urban park which is dominated by vegetation so that the temperature at the top of the grass can have a lower temperature than the other three landuses.

3.3. Depok

Land cover in Depok is dominated by the GOS (50%). Furthermore, the built space in Depok reached 44%, while the BOS reach 6% from the total area in Depok (Figure 4). GOS size in Depok still meets the minimum standards of GOS area in the city. Total amount of GOS area in Depok is smaller compared to GOS in the previous years. The large number of Jakarta workers who choose to live in Depok has caused the property development in this city become quite high. When compared with Jakarta, Bogor, and Tangerang, the BOS percentage in Depok has the greatest value which due to larger amount of lake as a water catchment area. At first, Depok has 31 lakes but today the number has decreased to 24 [9].

Based on the results of air temperature measurements, it is known that urban park had the lowest air temperature than the other three types of landuse which ranged between 31 -34°C. Air temperature measurement taken from trees and shrubs indicate that residential has the highest air temperature. While air temperature measurement on grass showed that industrial areas had the highest temperatures. During the day, the air temperature in residential can reach 39°C while in the area of industrial air temperature can reach 40°C.

Air Temperature on Tree (°C) 35.18

134.47

Urban Park CBD Residential Industrial

Air Temperature on Shrub (°C)

38.96 ^j.- -.r 32.37 34.54 35.76

Urban Park CBD Residential Industrial

Air Temperature on Grass (°C)

39.84 4036

■ III

Urban Park CBD Residential Industrial

Fig 4. Average air temperature on tree, shrub, and grass in urban park, CBD, residential, and industrial area in Depok

Most of residential area in this city has high building density and were using lots of asphalt pavement, so that the resulting temperature becomes higher. In the residential area taken from the field data, it can be identified that this area has a smaller amount of GOS than the other landuses which means that it has the highest air temperature. While industrial area are dominated by industrial activities that emit more heat which makes the air temperatures higher.

In contrast, urban park is dominated by vegetation that can reduce the air temperature during the daytime. In addition, there is an urban park that was located away from industrial activities. There was some evidence that the cooling effect of a green area increases with its size, even though it is not clear if there is a minimum size threshold or if there is a simple linear relationship. However, a small number of studies reported that the cooling effect of a park could extend into the surrounding area [10].

3.4. Tangerang

Tangerang City consists of 17% GOS, 81% built space, and2% BOS (Figure 5). GOS width in Tangerang city is far below the government regulation standard. Tangerang City is famous as 'the city of a thousand industries'. However, in fact, Tangerang not only became an industry center, but also a city of business, trade and services [11]. This is what triggered the high level of development in Tangerang. The high level of development in this city is not complemented by the availability of GOS in the city which was reflected on the amount of GOS in Tangerang that are well below the standard.

Based on the results of air temperature measurements at various vegetation structures, it is known that the urban park was a landuse with the lowest air temperature which ranged between 32-33°C. Air temperature measurements taken from on trees and grass showed that industrial areas have the highest temperature. While the measurement of air temperature in the shrubs showed that residential area has the highest air temperature. Temperatures in the industrial area in Tangerang reached 39°C while in the the residential area, it can reached 35°C.

Air Temperature on Shrub (°C) 35.27

34.63 34.87

■ III

Urban Park CBD Residential Industrial

Air Temperature on Grass (°C)

35.43 35.56

Urban Park CBD Residential Industrial

Fig 5. Average air temperature on tree, shrub, and grass in urban park, CBD, residential, and industrial area in Tangerang

The industrial area has the highest temperature caused by various production activities in it which generates heat and pollution. Activities in residential were not as high as industrial area, but the presence of asphalt pavement in this region has caused higher air temperature during the day. CBD still has more GOS than residential and industrial so that the air temperature is lower.

Air Temperature on Tree (°C)

33.51 33.57

11 I I

Urban Park CBD Residential Industrial

Conclusion

From air temperature measurement, urban park is a landuse can provide the lowest air temperature. This is caused by the largest amount of GOS in urban park compared to the other three landuses. Meanwhile, the highest temperature in each city was resulted from different land uses such as CBD, residential, and industrial areas. This difference was caused by the differences in the condition of each location of air temperature data retrieval. Some of the factors that lead into high temperature is the lack of GOS amount on the landuse composition, high levels of industrial activity that can generate heat, and the amount of pavement (asphalt) which undergo heating during the day. The results of analysis also indicated that the trees are more effective to reduce the temperature compared to the structure of other vegetations (shrubs and grasses).

One way to minimize the high temperature in the air in the CBD area, residential, and industrial is by expanding GOS area. However, the lack of land becomes a limiting factor to increase the area of GOS. Solution that can be done is by creating a vertical garden or roof garden on the building in the region. One study showed that the surface temperature of green roofs can be cooler than non-green roofs [12]. Moreover, the choice of plants can also affect the air temperature. Tree species have been shown to have different ability to reduce air temperature, due to a number of factors, such as tree size and tree canopy characteristics that affect the penetration of solar radiation [13]. Plants with thick and spread canopy can shade wider areas and absorb solar radiation better so it can reduce the air temperature. Shade from trees has been shown to be important for lowering temperature; however, temperature have also been shown to be lower in un-shaded green sites or short vegetation, which suggests evaporative cooling may also play a role [1].

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