Journal of Applied Science and Agriculture, 10(3) Special 2015, Pages: 9-16 AENSI Journals Journal of Applied Science and Agriculture ISSN 1816-9112 Journal home page: www.aensiweb.com/JASA In situ measurement of temperatures in Kuala Lumpur area 1 Illyani Ibrahim, 2Azizan Abu Samah, 3Rosmadi Fauzi, 4Samsuddin Jaafar 1,4 International Islamic University Malaysia, Department of Urban and Regional Planning, Kuliyyah of Architecture and Environmental Design, 68100 Kuala Lumpur, Malaysia. 2,3 University of Malaya, Department of Geography, Faculty Arts and Social Sciences, 50603, Kuala Lumpur. ARTICLE INFO Article history: Received 25 November 2014 Received in revised form 26 December 2014 Accepted 1 January 2015 Available online 10 January 2015 Keywords: Urban Heat Island Geographical Information System (GIS) In situ measurement ABSTRACT The current situation of environmental condition becomes an importance niche that is crucial to be understand by many researchers. This research attempts carried out an investigation on the temperature daytime measurement across different land cover areas. These land cover types were selected for interrogating the temperature varies in different measurement that was conducted. The method used in this study by utilizing vehicle equipped with a surface and air temperature sensor and a global positioning system (GPS) receiver, and measuring temperature to the same location in a different day period. The finding of this study is the playing field shows a hot pocket of temperature compared to the other areas, including residential, roads and commercial. Another finding is a consistency of the heat island areas was found; Sungei Wang Plaza and Dataran Merdeka of POI (Point of Interest) as the main attraction area of people and tourists. This study leads to the propose for the land use map in the urban planning department not to include playing fields and golf course under green areas, as it does not cool down the temperatures. © 2015 AENSI Publisher All rights reserved. To Cite This Article: Illyani Ibrahim, Azizan Abu Samah, Rosmadi Fauzi, Samsuddin Jaafar, In situ measurement of temperatures in Kuala Lumpur area. J. Appl. Sci. & Agric., 10(3): 9-16, 2015 INTRODUCTION Numerous studies have concluded that urbanization has altered the urban micro climate by looking at the aspect of temperature, precipitation and cloudiness (Quattrochi and Lo 2003, Nonomura, Kitahara et al. 2009). The extensive modification of non-vegetated of impervious surface and huge construction buildings has stored amount of solar radiation and reradiated to the urban areas. As a result, solar energy is absorbed into roads and rooftops, causing the surface temperature of urban structures to become 50 - 70 °F higher than the ambient air temperatures (Taha, Sailor et al. 1992). This is impaired with the reflection of solar radiation by glass buildings and windows that made the temperature in those areas are higher. As surfaces throughout an entire community or city become hotter, overall ambient air temperature increases (Gorsevski, Taha et al. n. y.)whereby with the heat keep continuously increasing, this scenario lead to the urban heat island phenomenon. In these decades, the heat pollution was rigorously affected the environmental quality and the human health. According to Weng and Yang (2006), with the alteration of energy balance in the Earth’s surface, the partitioning of incoming solar radiation into fluxes of sensible and latent heat is skewed in favor of increased sensible heat flux as evapotranspirative surfaces are reduced. The thermal increased with severed by released heat from the commercial, residential, transportation and deforestation; all these have impacted people in term of environmental pollution and healthy life. Weng and Yang (2006) has using the assistance of Landsat TM to retrieved the land surface temperature to examining the relationships among spatial variables such as urban land use, pollution, and thermal variation within an urban context. However, accurate of LST measurement with the correction of atmospheric correction and emissivity values is crucial for a scientific assessment of the relationship between LSTs and air quality measurements. In situ measurement is the earliest type of measurement that was applied in UHI studies. Most of the researchers applied this type of measurement in their research work. Earlier researchers such as (Kopec 1970, Sani 1980, Sani 1990) had undertaken the in situ measurement to identify thermal behaviour according to their own study area. In addition, another conventional method was to manually measure the temperature by having a person use a bicycle to visit numerous locations around the city as was reported by Melhuish and Pedder (n.y.). Corresponding Author: Illyani Ibrahim, International Islamic University Malaysia, Kulliyyah of Architecture and Environmental Design, P.O Box 10, Kuala Lumpur, Malaysia. Tel: 03-61964000, E-mail: illyani_i@iium.edu.my 10 Illyani Ibrahim et al, 2015 Journal of Applied Science and Agriculture, 10(3) Special 2015, Pages: 9-16 Different studies have their own methods for data collection, depending on the personnel available and budget of the research. Some studies have distributed several personnel to a different land use areas. Kolokotsa, Psomas et al (2009) had carried out mobile in situ measurement according to a grid that was planned before the measurement was conducted. Saaroni, Ben-Dor et al.(2000) and Kubota and Ossen (n.y.) performed a mobile temperature traverse with different routes and using fixed stations to retrieve the measurements. In the tropical area, Wong and Yu (2005) performed mobile temperature measurement in Singapore and found that the maximum UHI is 4.01° Celsius. Analysis in the subtropical area, Fung, Lam et al.(2009) also took several sets of mobile measurement in Hong Kong and found the maximum UHI is 5.5° Celsius during summer. Another subtropical area study which was conducted in Nanjing, China found that the average UHI intensity was 2° Celsius which was influenced by local climatic conditions Huang, Zhao et al. (2008). However, Alonso, Labajo et al.(2003) found a negative UHI during daytime, which amounts to the lowest temperature in the urban areas. Researchers such as (Deosthali 2000, Alonso, Labajo et al. 2003) had applied in situ measurement to study the thermal dynamics of their respective study areas. In the temperate areas of TelAviv, Israel, Saaroni, Ben-Dor et al. (2000) found the UHI between 3-5° Celsius. However another temperate area, Hania, Crete had UHI about 8° Celsius (Kolokotsa, Psomas et al. 2009). Methodology: Urban heat island in a humid tropical as the study area is not as extreme as in the European country until it would bring into heat wave (Vandentorren, Bretin et al. 2006, Foroni, Salvioli et al. 2007), however this study is needed to investigate on how the climate variable interact within the land covers areas. In addition, this type of study was been done in the same area about three decades ago by Sani (2007). The study area covers 5 x 5 km of Kuala Lumpur area which covers Manjalara (North west) to Bukit Bintang (South east). The POIs are selected based on its location; easily accessible from mobile and away from the shaded buildings or trees. At least 100 POIs were repeatedly visited in the same place at different period. Fig. 1 shows the mobile traverses around part of Kuala Lumpur done by the researcher. Fig. 1: Location for POIs in 5 x 5 km of Kuala Lumpur area. In situ measurement: There are three sets of in situ measurement that was done in the study area with various of land cover types. The condition under weak wind will be considered in this study. The other measurements were not taken into account due to sudden rain and heavy wind. Due to the limitations of the budget to perform in situ measurement in the whole Klang Valley area, only one vehicle was used to cover the Kuala Lumpur area; including the City Centre, Sentul and Bangsar. The vehicle was equipped with a surface and air temperature sensor and a global positioning system (GPS) receiver. The handheld temperature sensor was positioned at the appropriate location; whereas for the surface temperature it was located on the ground surface; while for the other, it was positioned at 1 meter from the ground. The 11 Illyani Ibrahim et al, 2015 Journal of Applied Science and Agriculture, 10(3) Special 2015, Pages: 9-16 measurement was also performed in one hour gaps to avoid the separation time variation of temperature range. Time range of each of the measurement is set from 12 pm to 1 pm. The temperature measurements are done by using the Protimeter tool that was manufactured in the United States. This tool is able to collect four variables simultaneously; the air temperature, surface temperature, relative humidity and the dew point. The raw datasets collected by the tool are then transferred to the computer to be paired with the GPS coordinates according to the unique id. These technical parts were done by using GIS software. Fig. 2: Three sets of in situ measurements done in the study area. Kriging interpolation: Kriging interpolation is one of the spatial models used to derive the temperature distribution by estimating unknown temperatures in a particular location. Kriging solves this problem by using a mapping of the statistical difference between data points for distance separation to a set of weights, which is known as semi-variogram. Several studies have used the spatial interpolation method of spline, inverse distance weighting (IDW) and Kriging for continuous data of air temperature (Holdaway 1996, Anderson n. y.)with the air temperature. As a result, these articles recommended that Kriging performance is better in estimating the air temperature. In order to assess the temperature variation, the data collection of the in situ measurement is 100 points in 25 km2 in the study area. The points are distributed within the study area with difference of an hour data collection between each point. According to (Bilonick 1985), at least 50 stations are needed as a minimum to estimate the weighting fairly well. In this case, the sample size collected in the study area is appropriate to estimating temperature as the point has covered major locations. Quality Control of the Sensors: It was assumed that the data was collected at the same time (12 pm), although it was done over one hour to cover all location points in the study area. In order to minimize bias, only those measurements with no wind or light wind are acceptable for the regression. From all of the sets of measurements, only six out of eight daytime and night time measurements were accepted and will be analysed, due to the other measurements being affected adversely by high winds and sudden heavy rain in the middle of the day. However, the limitations of the sensor are that it has no covered tools (such as Stevenson screen) as used by the Meteorological stations to prevent solar heating and wind chill. The samplings of temperature are taken according to the appropriate locations; avoid taking temperature under trees and between buildings to avoid bias of measurement. The precision of the temperature sensor was 0.1° Celsius. The temperature measurements in each location are assigned as the unique id for the integration with the GPS reading that will be combined later after the site visit. Results: The kriging datasets was prepared for the analysis in each set of in situ measurement. There are three (3) sets of measurements that were managed to be done in this study. The analysis is as follows; Site visit: 19th January 2011: At 1200 hour 19th January 2011 during a weak wind, mobile temperature sampling was carried out in the Kuala Lumpur (KL) main city area. A difference of built up and green sites has been found (ΔTa builtup-green = 8.9° i) 12 Illyani Ibrahim et al, 2015 Journal of Applied Science and Agriculture, 10(3) Special 2015, Pages: 9-16 Celsius). The range of temperature show a distinction as the vehicle changes position for the measurements that were carried out. A cool pocket (28° Celsius) seems to be the result of a cool breeze from greenery areas around Mahameru Highway and Parliament. The cooler pocket was also found in the Lake Garden (Taman Tasik Perdana), greenery areas around Mahameru and Parliament at the northwestern part of the study area where it can be identified as most of the land cover has green features. A small cool pocket was also found in Jalan Masjid India which might be due to the shade of the buildings and trees. A slightly higher temperature was found in Putra World Trade Centre (PWTC) area where the mean temperature found was 30º Celsius. One extraordinary finding was that Kg. Baru area showed a wide heat island (mean temperature 35º Celsius over a heat coverage approximated 1.5 km x 1 km wide), which is an unexpected result, and indicated that this area contained high thermal energy, in an area which is supposed to be a town cool area. However, Kuala Lumpur Convention Centre (KLCC) is located at the heat island fringe and had a lower mean temperature than Kg. Baru area. KLCC and KL Tower are two tourist hotspots that attract visitors to visit these places, the results show that the temperature is not obviously high by examination of these three measurements, and the air temperatures between different dates are all around 32° Celsius. This might be related to a wide range of greenery areas with water bodies outside of these buildings that avoids excessive heat from being trapped in those areas. In addition, the shaded areas from the tall buildings prevent higher temperatures at the ground surface. Lebuh Ampang is a highway area and has different fluctuating temperatures which depend on the prevailing sun radiation and wind at a particular time. A steep gradient of concentric isotherms was shown between LebuhAmpang and Jalan Masjid India (distance approximately 300 metres, with mean temperature difference 6° Celsius) which is due to the existence of shop lot blocks in between these areas that has formed a thermal fringe in this area. Sungai Wang Plaza areas have a small heat pocket (250 meters x 150 meters) and it was found that the mean temperature was 34º Celsius. As a tourist attraction, the presumption that the heat pocket due to human factor was occurred in this place is true. The denser and higher buildings, less trees and high levels of vehicle congestion on the roads were the factors that contribute to the heat island in this area. Dataran Merdeka (playing field) however has the highest temperatures among the other land cover types; around 36-38º Celsius. A small heat island (37° Celsius) also occurred in this area. It was noted that during the time that the measurement was taken there was less transportation on the roads and that the measurement was done during holiday. However, the temperature is still higher compared to the surrounding areas. In addition, due to the fact that the measurement was taken during a holiday; a lot of people were doing recreational activities in this area. Also, the location is situated next to the federal roads and surrounded by high buildings, which might obstruct the wind from any direction from moving to this area. Fig. 3 represents Kriging temperature map for 19th January 2011. Fig. 3: Kriging temperature map during observation: 19th January 2011. 13 Illyani Ibrahim et al, 2015 Journal of Applied Science and Agriculture, 10(3) Special 2015, Pages: 9-16 ii) Site visit: 24th January 2011: Horizontal distribution of temperature at 1200 hours on 24 th January 2011 indicates a wide coverage of cool pockets in Mahameru up to Parliament area until Perdana Lake Garden (1.5 km x 1 km) with a mean average temperature of 28º Celsius. The moderate temperature has a linear pattern along Masjid India to PWTC creating a temperature boundary between warm (built up areas) and cool (greenery areas) about 400 meters wide. An intensity between built up and green sites has been found (ΔTa builtup-green = 9.5° Celsius). An intense and increasing size of heat island was found in the Dataran Merdeka area, compared to the previous one. In this case, this measurement was carried out during a working day, with a highway located just beside Dataran Merdeka and consequently this had affected the temperature at this site. Referring to the image, another hot spot of temperature was found around China Town near to Pasar Seni areas and the Stadium Merdeka. This pattern shows that the even though the river is in those areas it could not moderate the temperature. The ground surface is covered by concrete roads and cement that has increased absorption of solar radiation to the ground which has made the temperature in those areas become more intense. In this analysis, a wide coverage of high temperatures were centred around the study area, including KampungBaru, KLCC, Jalan Ampang and KL Tower areas; it was speculated that the high temperature was due to the time of measurement was performed. This measurement was undertaken during a working day; therefore heavy transportation would be a factor of higher temperature. A cool island pattern was found in the greenery areas (Perdana Lake Garden). A sharp gradient was found between Perdana Lake Garden and Dataran Merdeka area of at least 350 metres in width. The continuity of the temperature gradient (Masjid India to Jalan Raja Laut) heads up to the north part of the map and the temperature range becomes wider at the north measurement area. It is due to the higher temperature at the north east and cooler temperature at the north west. Fig. 4 shows the Kriging temperature map during 24th January 2011. Fig. 4: Kriging temperature map during observation: 24th January 2011. iii) Site visit: 27th February 2011: A broad perspective of temperature variation shows that a visit during 27 th February 2011 at 1200 to 1300 (local time) is the highest temperature compared to the other measurements taken (Fig. 4.20). The difference between built up and green sites reaches its greatest intensity (ΔTabuiltup-green = 7.5° Celsius). Thus two distinct heat islands, southwest and southeast are defined. These two heat islands are located in Dataran Merdeka and Sungai Wang Plaza. Sungei Wang areas showed a higher temperature range as high as Dataran Merdeka. Several reasons were identified; most locals and foreigners visits this place as it was one of the attraction places in Kuala Lumpur. In addition, it was holiday during the time that the measurement was taken thus it made these areas highly populated with people and vehicular traffic. In addition, hundreds of people attended a community programme that was conducted at Dataran Merdeka during the measurement was done. The influence of open area, surrounded by high buildings, concrete roads and high population densities, resulting of the high thermal gradient in the study area. 14 Illyani Ibrahim et al, 2015 Journal of Applied Science and Agriculture, 10(3) Special 2015, Pages: 9-16 A lower temperature in Mahameru Highway area at 1200 hrs., indicates the continuous cool pocket (31º Celsius) temperature variation in the area, however, the coverage of the cool pocket seems smaller compared to the other measurement days. Another smaller oval shape cooler pocket with was found in Jalan P. Ramlee. In addition, this analysis shows that the temperature of Masjid India and Lebuh Ampang was lower and had created a thermal block to Sg. Wang Plaza area; between lower and higher temperatures with a ‘V’ linear pattern. The temperature contour of Masjid India that goes to PWTC area had defined a thermal boundary between the cooler and higher temperatures where the mean temperature is about 32º Celsius. In addition, Kampung Baru (mean temperature about 33º Celsius), which is a bit lower compared to the previous measurement days. A similar range of temperature has formed a curved linear pattern from Jalan Tun Razak and KLCC to the Swiss Garden area. Fig. 5 shows the Kriging temperature map during 27th January 2011. Fig. 5: Kriging temperature map during observation: 27 February 2011. Discussion: Comparison of the temperature boundaries between measurement dates at the same hour has been investigated throughout the analysis. Firstly, plots show that the southeast of the region is warmer than the southwest, whereby greenery areas are located in the southwest region and it is expected that greenery will moderate temperature. Here, the presence of greenery areas creates a gradient between the sensible and latent heat. Secondly, this analysis has showed that the playing field shows a hot pocket of temperature compared to the other areas, including residential, roads and commercial areas which are due to several reasons; it is located near to a highway, surrounded with high buildings and human activities. The measurement was done at 1200 hrs, at a high sun angle, the solar radiation has penetrated straight to the grassland and it is not reflected resulting the heat trap in this area. In addition, the playing field is surrounded by small shrubs and grasses and these features are not able to mitigate the UHI problem. Furthermore, Masjid India area up to The Mall area plays a role as an intermediate boundary between the cooler and hotter pocket. Kampung Baru, which plays a role as a village in Kuala Lumpur area does not shows its ability to cool down temperature due to several reasons. Firstly, the majority of areas here are covered with grass and concrete, and fewer matured trees were found in this area. Secondly, fewer trees in the area has resulted in less sun shading and the solar radiation easily penetrates the ground creating an uncomfortable heat impact to the residents. A consistency of the heat island areas are Sungei Wang Plaza area and Dataran Merdeka. One main similarity was found between these areas; these areas are the attraction area of people and tourists. The obvious difference of these areas is the Sungai Wang is the commercial area with compact and tall buildings, but Dataran Merdeka is the 7.22 acre playing field surrounded by buildings and highways. Conclusion: The in situ measurement shows that playing fields can have the highest temperature compared to the other land use types (commercial and residential). As the playing field that was analysed in the study area was 15 Illyani Ibrahim et al, 2015 Journal of Applied Science and Agriculture, 10(3) Special 2015, Pages: 9-16 surrounded with higher buildings and concrete highways. Therefore, in term of land use types, playing field and the golf course should be not be categorized under green areas, as green areas should be able to moderating temperature. In addition, the main feature of the playing field is the grassland, whereas 90 degrees of solar radiation is easily absorbed and penetrates deep down in to the ground surface. It re-radiates back to the surface which made the air temperature become more intense. Benchmark describing of ‘green areas’, is not solely due to any of the greenery features on the ground, and the definition of green area needs to be scrutinized as each is unique in terms of its ground characteristics and location relative to other land use types and they can produce different effects towards the environment. 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