Anggaran hasilan air tadahan Sungai Kelantan dengan menggunakan teknik penderiaan jauh

Pengurusan sumber air yang berkesan sangat penting kerana dapat memastikan ketersediaan sumber air yang boleh menyokong keperluan air yang berubah-ubah sepanjang tempoh perancangan yang dipilih dengan cara yang boleh dipercayai dan kos efektif. Cabaran utama yang dihadapi oleh pengurusan sumber air pada hari ini adalah peningkatan permintaan air bersih di Malaysia. Di Kelantan, anggaran permintaan untuk penggunaan air bersih dijangka meningkat sebanyak 450 juta liter kepada 1,000 juta liter menjelang tahun 2050 berbanding 2019. Beberapa kajian telah dijalankan menggunakan teknik pengesan jarak jauh untuk menganggar hasilan air di Malaysia. Kajian ini menganggarkan hasilan air dengan menggunakan model Alat Penilaian Tanah & Air (SWAT) dan teknik penderiaan jauh di lembah Sungai Kelantan. Anggaran hasilan air menggunakan teknik penderiaan jarak jauh telah disahkan terhadap model SWAT bagi tahun 2000 hingga 2014. Analisis spatial dan masa dijalankan untuk mengkaji kesan perubahan penggunaan tanah terhadap anggaran hasil air bagi 13 tadahan air di Lembangan Sungai Kelantan pada tahun 2000, 2008, dan 2013. Scenario bagi Laluan Konsentrasi Perwakilan (RCP) 2.6 dan RCP 8.5 daripada model Model Peredaran Am (GCM) Projeck Perbandingan Model Gabungan Fasa 5(CMIP5) telah ditentukur menggunakan dari Model SWAT untuk meramalkan hasilan air masa hadapan bagi tahun 2015 -2044 dan tahun 2045-2074 berdasarkan tahun asas dari tahun 1975-2004. Keputusan menunjukkan bahawa anggaran hasilan air berasaskan penderiaan jauh telah memperolehi pekali korelasi yang boleh diterima dan memuaskan bagi skala tahunan dan bulanan. Anggaran hasilan air tahunan dari tahun 2000 hingga 2014 adalah 1,280 ± 207.7 mm/tahun untuk model SWAT dan 1,687 ± 373.9 mm/tahun untuk teknik penderiaan jauh. Perubahan guna tanah untuk tahun 2000, 2008, dan 2013 tidak memberi kesan yang ketara ke atas jumlah air yang dihasilkan. Faktor utama yang mempengaruhi model hasilan air berasaskan penderiaan jauh adalah jumlah hujan dan penyejatpeluhan RCP 2.6 menunjukkan peningkatan hasil air pada tahun 2015-2044 sebanyak 16.6% dan, untuk tahun 2045-274, sebanyak 14.22%, sementara RCP 8.5 menunjukkan peningkatan 26.46% untuk tahun 2015-2044 dan 24.36% untuk tahun 2045-2074. RCP 8.5 menunjukkan peningkatan yang lebih tinggi dalam hasil air berbanding dengan RCP 2.6 untuk tahun 2015-2044 dan 2045-2074. Berdasarkan hasil penemuan kajian ini, pengemasan model hasilan air berasaskan penderiaan jauh diperlukan dan perlu mempertimbangkan lebih banyak parameter hidrologi dan data guna tanah untuk meningkatkan kecekapannya

Penggunaan Data Satelit NOAA-AVHRR Dalam Mengukur Ketinggian Suhu Bandar-bandar Utama Di Malaysia

The development and urbanization process in Malaysia has changed the face the earth. Land fill with tress and vegetation was replaced with concrete buildings and paved roads, which have an impact on the rate of heat production and retention. This research was conducted to study the increasing temperature in major cities such as Kuala Lumpur, Penang, Kelantan and Johor Bahru. This study used the NOAA -AVlHRR satellite data because it covers wide areas such as the whole of Peninsular Malaysia. The split window technique was used to extract the temperature from the NOAA·AVHRH data. This method saved money, time and transportation costs, and it is suitable for wide area study. A comparison between the NOAA-AVHRR temperature data with the actual data collected by the weather stations in the above mentioned cities, showed no significant differences at< 1"C. This means the accuracy of the NOAA-AVHRR can be trusted and accepted

Assessment of three GPM IMERG products for GIS-based tropical flood hazard mapping using analytical hierarchy process

The use of satellite precipitation products can overcome the limitations of rain gauges in flood hazard mapping for mitigation purposes. Hence, this study aims to evaluate the capabilities of three global precipitation measurement (GPM) integrated multisatellite retrievals for GPM (IMERG) products in tropical flood hazard mapping in the Kelantan River Basin (KRB), Malaysia, using the GIS-based analytic hierarchy process (AHP) method. In addition to the precipitation factor, another eleven factors that contribute to flooding in the KRB were included in the AHP method. The findings demonstrated that the spatial pattern and percentage area affected by floods simulated under the IMERG-Early (IMERG-E), IMERG-Late (IMERG-L), and IMERG-Final (IMERG-F) products did not differ significantly. The receiver operating characteristics curve analysis showed that all three IMERG products performed well in generating flood hazard maps, with area under the curve values greater than 0.8. Almost all the recorded historical floods were placed in the moderate-to-very-high flood hazard areas, with only 1“2 found in the low flood hazard areas. The middle and lower parts of the KRB were identified as regions of very high" and "high" hazard levels that require particular attention from local stakeholders

Spatiotemporal characteristics of hydro-meteorological droughts and their connections to large-scale atmospheric circulations in the Kelantan River Basin, Malaysia

Climate change exacerbates dry seasons in Southeast Asia, leading to water supply shortage. However, the link between hydro-meteorological droughts and large-scale atmospheric circulations, such as the El Nino Southern Oscillation (ENSO), Indian Ocean Dipole (IOD), and Madden–Julian oscillation (MJO), has received very little attention. Therefore, this study aims to analyse the hydro-meteorological droughts that occurred in the Kelantan River Basin (KRB) between 1985 and 2020 using the Standardized Precipitation Index (SPI) and Standardized Streamflow Index (SSI) as well as their connections to ENSO, IOD, and MJO. Sen's slope and Mann–Kendall test were employed to evaluate the trends and magnitude changes of the historical droughts, respectively. In addition, the response rate of SSI to SPI was considered to understand how precipitation affects streamflow. The results show that extremely dry events occurred in 1986, 1987, 1989, 1990, 1992, 1997–1998, 2015–2016, and 2020. Based on the SSI results, more than 70% of extremely dry periods last 6 months or longer. Interestingly, from January to May, when there was low precipitation, SSI had a higher response rate to SPI. The ENSO, as opposed to the IOD and MJO, had a stronger impact on the dry conditions over the KRB. HIGHLIGHTS An in-depth analysis of hydro-meteorological droughts in a tropical basin.; Moderate response rate of SSI to SPI due to the high withdrawal of groundwater.; About half of the stations experienced more than 10 extremely dry events.; ENSO has a larger impact on tropical droughts than IOD and MJO.; Major drought events have occurred during the strong El Nino years.