Top PDF Daytime Variation of Urban Heat Islands: The Case Study of Doha, Qatar

Daytime Variation of Urban Heat Islands: The Case Study of Doha, Qatar

Daytime Variation of Urban Heat Islands: The Case Study of Doha, Qatar

One approach to developing a temporal-based assessment of urban heat is to use ground-based empirical measures of temperature. One advantage to using ground-based measurements is the capacity to describe differences that individuals and communities directly experience. Oke [ 17 ] measured air temperature from car traverses in Vancouver, B.C. and claimed that heat island intensity is more directly related the physical structure of an urban area than its size. More recently, Hart and Sailor [ 18 ] employed tree-structured regression models to investigate the spatial variability of urban heat intensity using vehicle temperature traverse and GIS resources in Portland (Oregon, USA). Tree-structured regression models enable the determination of the most important land-use and surface variables affecting the UHI intensity of metropolitan areas. Later, Heusinkveld et al. [ 19 ] conducted bicycle traverse measurements to assess the spatial variation of temperature during a summer day in Rotterdam. They found that spatial variations in temperature were strongly affected by local vegetation cover. Using a ground-based approach and regression analysis, Yan et al. [ 20 ] found that localized land cover composition and site geometry were two of the most important variables affecting local air temperatures in Beijing. Further, Ho et al. [ 21 ] examined three statistical models by calibrating satellite-derived predictors such as LST and weather station data to map the daily maximum air temperature distribution in greater Vancouver. They found that the random forest model was the best among three statistical models used to map temperature distributions in the area. Finally, Yokobori and Ohta [ 22 ] used mobile traverses to conduct air temperature observations that would clarify the effect of land cover on ambient air temperatures in Tokyo. They found that an intra-urban heat island existed throughout the year, and they observed that air temperatures varied significantly according to ambient land cover types.
Show more

15 Read more

Impact of urban heat islands on the thermal comfort and cooling energy demand of artificial islands-A case study of AMWAJ Islands in Bahrain

Impact of urban heat islands on the thermal comfort and cooling energy demand of artificial islands-A case study of AMWAJ Islands in Bahrain

Elevated temperatures within the centre or at the boundaries of AMWAJ Islands will have a substantial impact upon the urban cooling, particularly the CDD. For appropriate assessment Figure 10 shows the impact of changes in air temperature on the number of CDD of AMWAJ Islands and compares it with that of two other islands, Sitra and Umm al-Nasan. Um al-Nasan is an uninhabited island with a considerable area of greenery and some concrete blocks, while Sitra is a mixed use district with few green areas. It can be noted that the highest values of the CDD are found to correspond to the highest values of temperatures on Sitra Island, while the lowest values are found to be corresponding with the lowest values of temperature on Umm al-Nasan Island. Within each island, a variation of average CDD appears, especially in July and August. For the purpose of comparison, Umm al-Nasan is taken as a reference. The maximum increase in CDD was found to be 26% in Sitra, while the minimum was found to be 14% in AMWAJ Islands. The increase in CDD due to urbanisation implies that to reach comfortable internal conditions in the hot summer a considerable quantity of electricity will be consumed by air-conditioning systems. Equation (9), introduced and validated by Radhi and Sharples (2013), enabled the estimate of urban electricity consumption based on CDD.
Show more

31 Read more

Land-Use/Land-Cover Changes and Their Impact on Surface Urban Heat Islands: Case Study of Kandy City, Sri Lanka

Land-Use/Land-Cover Changes and Their Impact on Surface Urban Heat Islands: Case Study of Kandy City, Sri Lanka

temperature in Kelvin (K), and the multispectral bands of Landsat-8 Operational Land Imager (OLI) and Landsat-5 Thematic Mapper ™ were provided as surface reflectance [3,31]. In the data selection stage, the following attributes were collected for generating quality and reliable outputs: (i) daytime dry-season data, (ii) cloud-free images, and (iii) pre-georectification by using Universal Transverse Mercator (UTM) zone 44 north projection. We note that the temporal resolution of the data was maintained as much as possible for temporal uniformity over the study period (Table 1). Nevertheless, it was difficult to find the same spatial-resolution data from the available sources due to the cloud cover, which is common in tropical-region Landsat data [4]. However, this matter did not have a considerable effect on the findings because the research focused on LST variations and SUHI formation over the changed land rather than the absolute value of LST. A comprehensive outline of the necessary metadata and the air-temperature information are outlined in Table 1.
Show more

21 Read more

Identification of Urban Heat Islands &Its Relationship withVegetation Cover: A Case Study of Colombo & Gampaha Districts in Sri Lanka

Identification of Urban Heat Islands &Its Relationship withVegetation Cover: A Case Study of Colombo & Gampaha Districts in Sri Lanka

Identification of the relationship between UHIs and vegetation was basically done by using satellite data. Two major steps were followed to archive the objectives. In the first step UHI areas and vegetated areas in Colombo and Gampaha districts were identified and inthe second step relationship wereanalysed between these two. Identification of Urban Heat Islands can be done in two ways. One is measuring air temperature using data of weather station network. Second is the measuring surface temperature using airborne satellite data. First method has high temporal resolution, but spatial resolution is very low. As daily measurements of air temperature are recorded in weather stations, this data represents high temporal resolution. But this temperature is recorded from only one place and it assumes as area temperature. But temperature is varying from one place to another based on different land use and land cover types.Thus, spatial resolution of the weather station data is very low. As an example, Colombo temperature is observed by the weather station located in Department of Meteorology, BauddhalokaMawatha,Colombo 7 and it assumes as air temperature of Colombo districts. But people can feel the variation of air temperature in different land use within the district as well. But remotely sensed temperature measurement from satellites has higher spatial coverage and can be carried on simultaneously. Landsat thermal data can be used effectively to derive the surface temperature of the urban environment. In recent years with the advance of the study on algorithm and the improvement of sensor, remotely sensed data began to be used in the field of urban climate and urban heat island. Thus, this study used Landsat data (L8 OLI/TIRS (Operational Land Imager (OLI) and Thermal Infrared Sensor (TIRS)) to identify the UHIs in Colombo and Gampaha districts.
Show more

19 Read more

An Evaluation of Surface Urban Heat Islands in Two Contrasting Cities

An Evaluation of Surface Urban Heat Islands in Two Contrasting Cities

A number of possible reasons, mostly associated with the circumstances of field measurements, are expected to have an effect on the LST values. The field measurements of water bodies in this study were taken from several different locations, which were twenty meters away from the edge of the rivers. These locations may not accurately represent the values for the middle of the river due to the depth of water, as well as the conditions of water in terms of purity. Hence some disparity between datasets may be expected. The analysis revealed that the extracted value from Landsat 8 was 27.1 °C whereas the field value was 30.4 °C for water bodies. This result was expected also because the thermal pixels of Landsat 8 cover a large area of water surface with differing depths. In contrast, field values of water were measured from shallow locations at 11 am (and were not adjusted for diurnal variation), and this delay may have allowed absorption of extra heat by those water bodies. According to Webb and Zhang (1997), the surface albedo and temperature of river water varies from one place to another depending on flow rates and the level of suspended materials. The average values of bare-soil were significantly different in surface temperature between datasets (48.3 °C from field work, compared to 40.5 °C estimated from Landsat). The surface temperature values of bare-soil categories were observed from vacant land within the study area, which included homogeneous area of mulch, sandy soil, and bare-land. While, the categories represented by several heterogeneous areas included sandy soil, cultivated land, land covered by mulch and woody weeds for Landsat derived surface temperatures. As a result, in-situ value was higher than the estimated Landsat based surface temperature.
Show more

203 Read more

Event website Tuesday, April 28th 2015 Research Complex, Qatar University, Doha, Qatar

Event website Tuesday, April 28th 2015 Research Complex, Qatar University, Doha, Qatar

Youssif Saleh has been in the oil and gas industry for 15 years in technical, research and management positions. He started his career in 1997 in the Qatar Petrochemical Company (Qapco), an ethylene cracker and low density polyethylene plant, as a Quality Control and Laboratory Supervisor; he progressed rapidly through the organization to leadership positions. In 2007, Youssif joined the Qatar Shell Research & Technology Centre (QSRTC), which is the anchor tenant in the Qatar Science & Technology Park, home for technology based companies. QSRTC’s mandate is to provide a hub for research development and implementation of technologies that support Qatar’s specific needs. He became QRSTC’s General Manager in 2011, where he now manages the $100 million investment commitment to research, focusing on ‘unlocking the subsurface’, ‘breakthrough products’ and ‘water solutions’. Youssif also manages Qatar Shell’s collaborations with various universities in Qatar and academic institutions abroad. Youssif is a long standing member of the Qatar University Technical Advisory Committee for the science and engineering disciplines. He is a permanent jury member of the ‘Stars of Science’, the first Pan-Arab reality-TV programme dedicated to innovation by young innovators. He is also a published author of an Arabic management book (translated title “The Path to Personal Success”.)
Show more

13 Read more

Reducing Urban Heat Islands: Compendium of Strategies. Cool Roofs

Reducing Urban Heat Islands: Compendium of Strategies. Cool Roofs

Solar reflectance, or albedo, is the percent­ age of solar energy reflected by a surface. Researchers have developed methods to determine solar reflectance by measuring how well a material reflects energy at each solar energy wavelength, then calculating the weighted average of these values (see Section 4.1). Traditional roofing materi­ als have low solar reflectance of 5 to 15 percent, which means they absorb 85 to 95 percent of the energy reaching them instead of reflecting the energy back out to the atmosphere. The coolest roof materi­ als have a high solar reflectance of more than 65 percent, absorbing and transferring to the building 35 percent or less of the energy that reaches them. These materi­ als reflect radiation across the entire solar spectrum, especially in the visible and infrared (heat) wavelengths.
Show more

31 Read more

Employee satisfaction from indoor work environments in Doha, Qatar

Employee satisfaction from indoor work environments in Doha, Qatar

The response of office workers to these changes in terms of satisfaction from their work environment has been the topic of a host of studies by environmental psychologists particularly in the western world. These studies have researched into the varying space configurations of office spaces, design and indoor environment parameters and the corresponding worker satisfaction while attempting to link them to worker productivity and resultant corporate profit. However, the method and objectives of the study have varied with the discipline of the researcher, and the socio- cultural-economic-politico setting of the study. The differences in these characteristics have resulted in totally different results which are therefore difficult to generalise. Further, while western studies have limited applicability in the context of the Gulf, regional studies in the Arabic cultural context are severely limited. This research seeks to shed light on these aspects as well as to contribute to the database of limited studies in the region.
Show more

14 Read more

Urbanizationeffect on urban heat island, a case study sakarya

Urbanizationeffect on urban heat island, a case study sakarya

In order to prevent the formation of heat islands and their negative effects, it is obligatory to increase green fields within cities and to prevent harmful emissions and the destruction of forests. Moreover, measures such as roof gardens and white roofs, have begun to be implemented in many cities in the world, with the support of local authoritiesPreference of light colors for the urban surfaces (pavements, building surfaces, asphalt roads, roofs, etc.) to be built is a correct one for reduction of the heat island effect. Development of structures to drain pollution caused by sources of emission as well as expansion and especially preservation of green areas are important for draining are among the important measures to be taken (Behfar et al., 20139.It is clear that the negativities arising in cities in respect of the quality of life and natural values can be decreased by climate science based and planned approaches, which will not decrease the wind speed thus making urbanization coherent with nature. Moreover, it is necessary to determine the effect of cities on global warming - one of the most significant problems of today - and to make assessments accordingly.
Show more

7 Read more

DNI, GHI and DHI Ground Measurements in Doha, Qatar

DNI, GHI and DHI Ground Measurements in Doha, Qatar

2. Methodology The Qatar Environment and Energy Research Institute has been operating a high precision Kipp & Zonen solar radiation monitoring station since the end of November 2012 in Education City, Doha (25.33ºN, 51.43ºE). The station is equipped with a Solys2 sun tracker with sun sensor kit for improved tracking accuracy and shading ball assembly for diffuse measurements. Mounted on the sun tracker are one CHP1 pyrheliometer [9] for measuring DNI and two CMP11 pyranometers [10] (one of them shaded) for GHI and DHI measurements; both pyranometers are fitted with CVF 3 ventilation units. Data from the monitoring station are collected as minute by minute averages in W/m 2 . The sensors and sun tracker are new and were calibrated just before the installation. Maintenance and checks
Show more

7 Read more

Museum and Art Education as a Response to Place in Doha, Qatar

Museum and Art Education as a Response to Place in Doha, Qatar

Doha is a rapidly growing, busy metropolis in which a multitude of cultures intermingle. Situated on the Arabian Gulf (also known as the Persian Gulf), the city has prominent ocean views along an area known as the Corniche, significant skyscrapers and embassies in the West Bay, human-made islands in a new shopping and housing development known as the Pearl, large housing complexes for construction workers in the industrial area, a multitude of shopping malls, a new airport that saw almost 3,000,000 passengers in January of 2014 (Khatri, 2014), several major museums under construction, and frequently has new traffic patterns. Because it is a city in the desert, much of the landscape is the beige color of the sand and most houses are a similar color. However, in some areas, various plants and trees are cultivated and these spots of green punctuate the local area. Because urban development began in the 1950s (Eakin, 2011) and the population is growing rapidly, much of the built environment is new construction. Several times in recent years, the government has significantly revised population growth estimates, with 15% growth in country expected between the end of 2013 and 2015 (Khatri, 2013). The current estimate includes many immigrant construction workers to build the infrastructure for the burgeoning population and the World Cup 2022 stadiums to be built in Doha (Khatri, 2014). Approximately 90% of Doha’s 1.3 million residents are expatriates, with the majority coming from Southeast Asia. As the population of the country has quadrupled since 2000, changes in the physical environment seemingly happen overnight, with cranes and construction sites omnipresent elements in Doha.
Show more

9 Read more

Abdullah M. Seko Doha, Qatar Sub: Intention Letter

Abdullah M. Seko Doha, Qatar Sub: Intention Letter

International Organization Officer at Qatar Innovative Solution Company 1- Linking different organizations based in Croatia with potential distributor or business partners in Qatar like JGL Pharmaceutical Corporation and Spacva wood industry. 2- Implementing marketing research either proactive or preliminary one.

5 Read more

Impact Assessment of Land Use Planning on Travel Behavior in Doha, Qatar

Impact Assessment of Land Use Planning on Travel Behavior in Doha, Qatar

Smart growth is a planned economic and community development that challenges to restrain urban sprawl and deterioration of environmental conditions. It concentrates employment within existing urban areas to increase transport efficiency” (Zaina, 2016).The occurrence of increased congestion, sprawl, air pollution, loss of spaces, and carbon dioxide emission call upon the implementation of smart growth policies. The policies encourage provision for walking, transport option and mixed use developments. Another element that leads to smart growth is the increased rise in housing pricing in central cities leading to inadequate residential choices and homeownership opportunities for most of the population (Litman, 2016b). As such the introduction of smart growth creates communities that are productive, hospitable and environmentally responsible. It also supports multiple discipline including developers, environmentalists, public officials, residents, citizens etc. to house growth (Lai, 2014). Smart growth and sustainable developments aim to meet the demand of the present with compromising the ability of future generations. “Despite the general thought that land use management communities evolve to become highly urbanized, these strategies have flexibility and can be manipulated” (Zaina, 2016).
Show more

120 Read more

Urban Heat Islands as Viewed by Microwave Radiometers and Thermal Time Indices

Urban Heat Islands as Viewed by Microwave Radiometers and Thermal Time Indices

largely to control the day-night (or diel) thermal range. High latitude lands (above 50° N and 50° S), including tundra and polar regions, receive many hours of insolation over the growing season, but the total heat is still much lower than regions at lower latitudes (Figure 2a); thus, the shades are darker green, indicating that the diel variation is larger as a proportion of the total heat (Figure 1). In contrast, warm and dry ecoregions have the highest day-night thermal difference (Figure 2a). Note, for example, the bright green shades of Basin and Range province in the western United States or the Atacama Desert in western South America (Figure 1). Rainforest and savanna (Cerrado) regions of South America are the warmer and more humid regions in the Western Hemisphere and, thus, day- night differences are low, despite the high heat available, resulting in the shades of magenta in Figure 1. High and dry mountains appear darker relative to the neighboring lowlands, whether in the high Andes or the Canadian Rockies. A comparison between mountain areas and the lower elevations in similar ecoregions shows higher diel ranges at higher elevation as all data points in the Figure 2b are located above the 1:1 line.
Show more

13 Read more

Environmental and Spatial Assessment of Urban Heat Islands in Qalyubia Governorate, Egypt

Environmental and Spatial Assessment of Urban Heat Islands in Qalyubia Governorate, Egypt

T he p resent study is the first attempt to map Urban Heat Islands (UHIs) and assess the associated environmental characteristics in Qalyubia Governorate using remote sensing and GIS integrated with a field survey. A calibrated Landsat Operational Land Imager (OLI) acquired on July 22, 2018 was processed to calculate Land Surface Temperature (LST) and UHIs as well as to evaluate the environmental conditions through calculating the Land Use Land Cover (LULC) and the spectral retrieved indices. The investigated indices include Normalized Difference Built-Up Index (NDBI), Normalized Difference Vegetation Index (NDVI), Modified Normalized Difference Water Index (MNDWI), Normalized Difference Salinity Index (NDSI) and Normalized Difference Moisture Index (NDMI). Likewise, multispectral algorithm model was applied on the landsat calibrated image for mapping Particulate Matter of diameters lower than 10 micrometer (PM 10 ) and characterizing its levels in the UHIs. The results demonstrated that the mean LST of each LULC class in Qalyubia Governorate followed this order; bare lands > urban > vegetation > water bodies. Most of bare land and built-up areas exist as heat island regions. The total area of UHI s was 397.5 km 2 ; 119.8 km 2 as bare land (30.2%), 201.2 km 2 as
Show more

18 Read more

COMPANY PROFILE. PO Box: 31534, Doha Qatar. Tel: , Fax:

COMPANY PROFILE. PO Box: 31534, Doha Qatar. Tel: , Fax:

JAS Business Systems experts in providing well-designed, carefully implemented structured cabling systems that meet your data and communications needs. We specialized in the installation of copper network cabling to ensure long term performance, system integrity, and investment protection. JAS Business Systems’ specialists are experienced in carrying out major Fiber Optic network installations with all the detailed planning and resource utilization required for such projects. Having successfully designed and implemented many structured cabling projects in Qatar, you can be assured that you would have a very reliable network infrastructure for years to come.
Show more

13 Read more

Mouhanad Hammami, MD. DIFI International Seminar Doha, Qatar, 2013

Mouhanad Hammami, MD. DIFI International Seminar Doha, Qatar, 2013

 (Chaaban, J. et al. 2012) assessed the impact of remittances on education in Jordan, Syria and Lebanon. The results of the study indicated that migrant remittances are encouraging both females and males aged [18-24] to reach further levels in their education. The effect appears to be larger in magnitude for males in cases of Jordan and Syria while for Lebanon the reverse trend is observed.

60 Read more

KHALID ABDULLA ALALI, PhD Foundation Program Qatar University P O Box 2713 Doha-Qatar

KHALID ABDULLA ALALI, PhD Foundation Program Qatar University P O Box 2713 Doha-Qatar

Afifi, N, Alali,K, (2007) Scanning and Transmission Electron Microscopic Study of the Human Spermatozoa from Male Smokers and Nonsmokers. EMMJ 60 49-57 Hunter-Zinck H, Musharoff S, Salit J, Alali K, Chouchane L, Gohar A, Mathews R, Butler MW, Fuller J, Hackett N, Crystal R, Clark AG, (July-2010) Population Genetic Structure of the People of Qatar. Am. J. Human Genetic. 87 (1), 17-25.

8 Read more

A comparative, epidemiological study of acute renal colic presentations to emergency departments in Doha, Qatar, and Melbourne, Australia

A comparative, epidemiological study of acute renal colic presentations to emergency departments in Doha, Qatar, and Melbourne, Australia

identified using ICD-9/10-CM codes for renal colic from ED attendance registries. The ED at Hamad General Hospital (HGH-ED) in Doha, Qatar, has an annual cen- sus of approximately 470,000 that serves as the only tertiary-care ED in a country with a population of 2,700,000. The HGH is the major academic center and teaching hospital in Doha Qatar, and the ED presenta- tions reflect the population of Qatar. The Alfred ED is a major adult quaternary referral center and has an annual census of approximately 60,000 patients per year. Urology consultation and services were present at both centers at all hours. Computed tomography (CT) im- aging was available at both the centers round the clock. The practice at The Alfred ED was similar to most developed countries and included a CT non-contrast study for most of the patients presenting with renal colic [9]. There were pre-defined protocols for the imaging in renal colic at the HGH-ED during the study period, dic- tating selective imaging among patients at a high risk of complications. A CT scan was requested in the ED only for higher risk patients such as those with a single kid- ney, renal transplant, known renal impairment, having multiple comorbid conditions, frequent visits to the ED for similar pain within the last 2 weeks, signs of renal in- jury or sepsis, or patients with persistent pain not responding to parenteral analgesia. For females in repro- ductive age group, ultrasound was the initial imaging test at the HGH-ED. The limited CT and ED resources, a high volume of ED renal colic presentations in an otherwise healthy young population, were the main con- tributors to selective imaging approach at the HGH-ED.
Show more

6 Read more

Contrasting responses of urban and rural surface energy budgets to heat waves explain synergies between urban heat islands and heat waves

Contrasting responses of urban and rural surface energy budgets to heat waves explain synergies between urban heat islands and heat waves

The results presented here have important impli- cations. First of all, urban residents, especially the elderly and those who do not have access to air cities, such as the use of green roofs and planting trees (e.g., Gaffin et al 2010 , Georgescu et al 2014 , Stone et al 2014 ), are strongly needed in order to reduce these synergistic interactions. These strategies also have other environmental and socio-economic bene- fits such as improving air quality (e.g., Yang et al 2008 ), managing storm-water (e.g., Berndts- son 2010 , Yang et al 2014 ), and reducing energy use (e.g., Jim and Peng 2012 ). White roofs that increase the reflection of incoming shortwave radiation (Akbari et al 2001 , Synnefa et al 2008 , Akbari et al 2009 , Krayenhoff and Voogt 2010 , Oleson et al 2010 , Akbari et al 2012 , Jacobson and Ten Hoeve 2012 ) can also be helpful given that the incom- ing shortwave radiation is found to be increased under HW conditions. Examining the impacts of these miti- gation and adaptation strategies (particularly the use of green and white roofs) using regional and global cli- mate models has been the subject of research recently (Oleson et al 2010 , Jacobson and Ten Hoeve 2012 , Georgescu et al 2014 , Li et al 2014 , Stone et al 2014 ), which is partly attributed to advances in urban model- ing (Taha 2008a , 2008b , 2008c , Grimmond et al 2010 , Chen et al 2011 , Grimmond et al 2011 , Best and Grim- mond 2014 ) and development of more sophisticated green roofs (Sailor 2008 , Sun et al 2013 , Yang and Wang 2014 ) and irrigation modules (Vahmani and Hogue 2014 ). However, studies focusing on the impact of these strategies under HW conditions (see e.g., Li et al 2014 ) are still limited and are thus recom- mended. In particular, the soil moisture needs to be maintained (for example by irrigation) at a high level in order for green roofs to be effective under HW con- ditions (Sun et al 2014 ). Hence, the potential cost of irrigation needs to be taken into account when con- sidering the effectiveness of green roofs under HW conditions.
Show more

12 Read more

Show all 10000 documents...