16 research outputs found

    Rivers : our heritage our future

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    "Inaugural lecture University of Malaya, 9 December 2003"

    Factors Controlling Gully Erosion Development in Toroud Basin – Iran

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    AbstractGully erosion, is often associated as one of the most severe forms of soil erosion processes. And often results in much displacement of the soil mass, culminating in sedimentation, and degradation of the land. Gully erosion has tremendous impacts on human activities which includes decreasing soil nutrients and agriculture productivity, river channel sedimentation and increasing floods and impact on water resources development within a river basin. Considering the challenges faced in semiarid regions, this research tries to evaluate all the factors controlling gully erosion in Toroud basin that there is no comprehensive study on this gully and basin. In order to achieve this goal and providing greater assistance for obtaining all the elements to stop gully erosion expansion, the research examines two major objectives, which focuses on the formation of gully erosion and the short term or long term approach in the extension of gully erosion in Toroud basin- Iran. This research is using software of Ilwis in GIS for preparing the maps and Excel for preparing the graphs. By considering the importance of the subjects and with regard to the fact that studied region contains large and extensive gully which introduces potential hazards for croplands and habitats, and also make it difficult to pass through them, it is required to perform all possible actions which lead to bring an end to the development and expansion of gullies

    Spatial Temporal Analysis of Urban Heat Hazard on Education Area (University of Indonesia)

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    As education area, campus or university is full with various activities which have an impact on the existence of land-use or land-cover. The variation of activities dynamically change the shape of land-use or land-cover within the campus area, thus also create variations in Land Surface Temperature (LST). The LST are impacting the coziness of human activity especially when reaches more than 30 oC. This study used the term Urban Heat Signature (UHS) to explain LST in different land-use or land-cover types. The objective of this study is to examine UHS as an Urban Heat Hazard (UHH) based on Universal Temperature Climate Index (UTCI) and Effective Temperature Index (ETI) in University of Indonesia. Thermal bands of Landsat 8 images (the acquisition year 2013-2015) were used to create LST model. A ground data known as Air Surface Temperature (AST) were used to validate the model. The result showed an increased level of maximum temperature during September-October since 2013 until 2014. The maximum temperature was reduced in October 2014, however it increased again in August 2015. The UTCI showed “moderate” and “strong heat stress”, while EFI showed “uncomfortable” and “very uncomfortable” categories during that period. This research concluded that build up area in UI Campus highest temperature on UI campus based on UHS. Range UHS in Campus UI on 2013 (21.8-31.1oC), 2014 (25.0-36.2oC) and 2015 (24.9-38.2oC). This maximum UHS on September (2014 and 2015) put on levelling UTCI included range temperature 32-35oC, with an explanation of sensation temperature is warm and sensation of comfort is Uncomfortable, Psychology with  Increasing Stress Case by Sweating and Blood Flow and Health category is Cardiovascular Embarrassment. This UHS occurs in September will give impact on psychology and health, that’s become the UHH of the living on education area

    Penilaian indeks keterancaman komuniti orang asli di Lembangan Sungai Telom, Bertam dan Lemoi, Cameron Highlands

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    Istilah keterancaman bertujuan untuk menjelaskan perhubungan yang wujud di antara keterdedahan ancaman fizikal dengan kesejahteraan manusia dan keupayaan mereka untuk menghadapi ancaman. Penilaian keterancaman menggabungkan tiga komponen utama iaitu ancaman, sistem yang mengalami risiko dan daya tahan diri sedia ada. Keterancaman bagi kajian ini merujuk kepada komuniti orang asli yang tinggal di zon tanah tinggi Cameron Highlands. Tujuan kajian ini dijalankan untuk mengenal pasti jenis ancaman perubahan alam sekitar tempatan di tiga lembangan utama Cameron Highlands iaitu Telom, Bertam dan Lemoi. Ancaman ini dilihat daripada hasil proses pembangunan guna tanah di kawasan tanah tinggi yang mendatangkan kesan keterancaman ke atas komuniti orang asli sebagai golongan yang memiliki daya tahan yang rendah. Hasil soal selidik iaitu ciri-ciri yang dinilai dan penghasilan peta indeks keterancaman ini akan menggambarkan keadaan sebenar komuniti orang asli Semai Cameron Highlands yang telah lama menjadikan sistem alam sekitar tanah tinggi sebagai satu bentuk perhubungan. Jumlah ketua isi rumah yang terlibat dalam sesi soal selidik ialah 153 orang iaitu 30% daripada jumlah keseluruhan ketua isi rumah bagi kampung terpilih. Hasil daripada penilaian indeks secara keseluruhan menunjukkan tahap keterancaman komuniti orang asli adalah terancam dan mereka memerlukan peningkatan daya tahan diri sedia ada. Kesimpulannya, penilaian indeks keterancaman komuniti orang asli di zon tanah tinggi bukan sahaja menggambarkan tahap keterancaman komuniti tersebut, malah boleh dijadikan petunjuk dan panduan kepada mereka dan pihak yang terlibat dalam aspek pengurusan komuniti orang asli di zon tanah tinggi

    Land Cover Types and Their Effect on the Urban Heat Signature of University Campuses using Remote Sensing

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    The campus, as an educational area, has a variety of land cover with varying surface temperatures. Knowledge of land use in a localized urban environment and its effect on the Urban Heat Signature (UHS) of a university campus is insufficient, so it is essential to assess UHS-related localized urban environments. The objective of this study is to assess land cover and its effect on the UHS of two university campuses. The research used spatial-temporal analysis employing satellite images during the period 2013-2014. The areas studied were the University Malaya (UM) and University Indonesia (UI) campuses. The results show that the land cover of both university campuses has the same localized urban environment pattern. Based on Landsat 8 TIRS (100 m ground resolution) both university campuses had UHS profiles related to vegetation cover of 25-33°C, with mean temperature 28°C is the lowest temperature, and building cover of 33-39°C, with a mean temperature 35°C, is the highest temperature, caused effect from Land cover types. Google Earth visual interpretation and digitalization provided the land cover based on 10m × 10m vector square grids with their attributes validated by field survey. The research shows a trend of UHS change between 2013 and 2014, with the maximum temperature of > 30°C on the UM and UI Campuses with increased of temperature 1°C. The study concludes that the UHS behavior is an effect of its temporal relation with land cover, which is new knowledge on university campuses about localized urban environments

    Landscape features and potential heat hazard threat: a spatial–temporal analysis of two urban universities

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    Urban universities are a microcosm of urban built-up areas, such as cities, but with a much smaller scale of spatial resolution. Within universities, there are many types of landscape features exhibiting different heat absorption and transmission capacities. These landscape features generate spatial–temporal heat signatures, and the knowledge about landscape features and urban heat hazard on university campuses is limited. The objective of this research is an assessment of landscape features and the potential heat hazard threats of two urban universities in ASEAN, located in the centre of the equatorial region. The focus of this research is on urban heat hazards in two urban universities in ASEAN, the University of Malaysia in Kuala Lumpur and the University of Indonesia in Jakarta, within the context of the spatial–temporal behaviour of urban heat and the urban heat effects on the environment and human well-being on campuses. The spatial and temporal analysis used to answer the objective of this research via data-gathering methods from image satellite, ground trough, and human perception study. The UM campus and UI campus, both urban campuses, had similar landscape features but had different total percentage areas of these features. The UM campus was 59.1% covered by the densely vegetated surface landscape feature, a percentage lower than that of the UI campus, which was 65.3% vegetation covered. The temporal results for the UHS of the UM campus in 2013–2016 show a maximum temperature of 39 °C. Therefore, the UHS of the UI campus demonstrated temporal behaviour in 2013–2016, with a maximum temperature of 38 °C. The UHS behaviour of the UM campus and UI campus had an air surface temperature with a maximum average temperature of 33 °C. The air surface temperatures exceeding 32 °C at the UM campus (12 pm until 6 pm = 5 h) lasted for a longer time than those at the UI campus (12 pm until 3 pm = 3 h). This study showed that, based on the perceptions on both campuses, if temperatures exceeded 30 °C, respondents were very hot and very uncomfortable, which will impact health and decrease work or academic achievements, as perceptions of heat intensity impact human well-being. Students perceived that heat intensity impacted their health and they reported becoming tired and lethargic under maximum temperatures and were very hot and very uncomfortable, and this condition impacted their work activity. These results indicated that, at both the UM and UI campuses, heat intensity impacts human well-being, with risks associated with hot temperatures. These two urban campuses are significant for ASEAN university awareness of the urban heat hazard of the equatorial area

    Kesan aktiviti pembangunan tanah terhadap kawasan punca pengambilan air di Cameron Highlands

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    Pembangunan guna tanah merupakan aspek penting dalam pertumbuhan ekonomi dan peningkatan tahap sosial masyarakat. Bagaimanapun, pembangunan guna tanah sering kali dikaitkan dengan kemerosotan sumber alam khususnya sumber air. Hal ini kerana aktiviti guna tanah yang dijalankan di kawasan tadahan air telah menyebabkan kesan negatif kepada kawasan punca pengambilan air. Sehubungan dengan itu, artikel ini akan menghujah bahawa aktiviti pembangunan guna tanah yang dijalankan dalam lingkungan kawasan punca pengambilan air memberi kesan negatif kepada kawasan dan kualiti air di Cameron Highlands. Kaedah kajian yang digunakan dalam kajian ini adalah analisis Sistem Maklumat Geografi (SMG) versi 10.1 yang melibatkan analisis pertindihan (overlay analysis) dan analisis tadahan air (watershed analysis) berdasarkan point based watershed analysis. Di samping itu, temu bual semi struktur, penggunaan data sekunder dan google earth turut digunakan. Dapatan kajian menunjukkan aktiviti guna tanah di kawasan tadahan air telah menyebabkan kesan negatif terhadap kualiti air yang kemudiannya menyumbang kepada masalah pengeluaran dan pengagihan sumber bekalan air di kawasan tersebut
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