NDVI With Artificial Neural Networks For SRTM Elevation Model Improvement – Hydrological Model Application

Digital elevation model (DEM) plays a substantial role in hydrological study, from understanding the catchment characteristics, setting up a hydrological model to mapping the flood risk in the region. Depending on the nature of study and its objectives, high resolution and reliable DEM is often desired to set up a sound hydrological model. However, such source of good DEM is not always available and it is generally high-priced. Obtained through radar based remote sensing, Shuttle Radar Topography Mission (SRTM) is a publicly available DEM with resolution of 92m outside US. It is a great source of DEM where no surveyed DEM is available. However, apart from the coarse resolution, SRTM suffers from inaccuracy especially on area with dense vegetation coverage due to the limitation of radar signals not penetrating through canopy. This will lead to the improper setup of the model as well as the erroneous mapping of flood risk. This paper attempts on improving SRTM dataset, using Normalised Difference Vegetation Index (NDVI), derived from Visible Red and Near Infra-Red band obtained from Landsat with resolution of 30m, and Artificial Neural Networks (ANN). The assessment of the improvement and the applicability of this method in hydrology would be highlighted and discussed

Combining Satellite And Gauge Precipitation Data With Co-Kriging Method For Jakarta Region

Jakarta is vulnerable to flooding mainly caused by prolonged and heavy rainfall and thus a robust hydrological modeling is called for. A good quality of spatial precipitation data is therefore desired so that a good hydrological model could be achieved. Two types of rainfall sources are available: satellite and gauge station observations. At-site rainfall is considered to be a reliable and accurate source of rainfall. However, the limited number of stations makes the spatial interpolation not very much appealing. On the other hand, the gridded rainfall nowadays has high spatial resolution and improved accuracy, but still, relatively less accurate than its counterpart. To achieve a better precipitation data set, the study proposes cokriging method, a blending algorithm, to yield the blended satellite-gauge gridded rainfall at approximately 10-km resolution. The Global Satellite Mapping of Precipitation (GSMaP, 0.1⁰×0.1⁰) and daily rainfall observations from gauge stations are used. The blended product is compared with satellite data by cross-validation method. The newly-yield blended product is then utilized to re-calibrate the hydrological model. Several scenarios are simulated by the hydrological models calibrated by gauge observations alone and blended product. The performance of two calibrated hydrological models is then assessed and compared based on simulated and observed runoff

Effects of water scarcity awareness and climate change belief on recycled water usage willingness: Evidence from New Mexico, United States

The global water crisis is being exacerbated by climate change, even in the United States. Recycled water is a feasible alternative to alleviate the water shortage, but it is constrained by humans’ perceptions. The current study examines how residents’ water scarcity awareness and climate change belief influence their willingness to use recycled water directly and indirectly. Bayesian Mindsponge Framework (BMF) analytics was employed on a dataset of 1831 residents in Albuquerque, New Mexico, an arid inland region in the US. We discovered that residents’ willingness to use direct recycled potable water is positively affected by their awareness of water scarcity, but the effect is conditional on their belief in the impacts of climate change on the water cycle. Meanwhile, the willingness to use indirect recycled potable water is influenced by water scarcity awareness, and the belief in climate change further enhances this effect. These findings implicate that fighting climate change denialism and informing the public of the water scarcity situation in the region can contribute to the effectiveness and sustainability of long-term water conservation and climate change alleviation efforts

Safety and efficacy of fluoxetine on functional outcome after acute stroke (AFFINITY): a randomised, double-blind, placebo-controlled trial

Background Trials of fluoxetine for recovery after stroke report conflicting results. The Assessment oF FluoxetINe In sTroke recoverY (AFFINITY) trial aimed to show if daily oral fluoxetine for 6 months after stroke improves functional outcome in an ethnically diverse population. Methods AFFINITY was a randomised, parallel-group, double-blind, placebo-controlled trial done in 43 hospital stroke units in Australia (n=29), New Zealand (four), and Vietnam (ten). Eligible patients were adults (aged ≥18 years) with a clinical diagnosis of acute stroke in the previous 2–15 days, brain imaging consistent with ischaemic or haemorrhagic stroke, and a persisting neurological deficit that produced a modified Rankin Scale (mRS) score of 1 or more. Patients were randomly assigned 1:1 via a web-based system using a minimisation algorithm to once daily, oral fluoxetine 20 mg capsules or matching placebo for 6 months. Patients, carers, investigators, and outcome assessors were masked to the treatment allocation. The primary outcome was functional status, measured by the mRS, at 6 months. The primary analysis was an ordinal logistic regression of the mRS at 6 months, adjusted for minimisation variables. Primary and safety analyses were done according to the patient's treatment allocation. The trial is registered with the Australian New Zealand Clinical Trials Registry, ACTRN12611000774921. Findings Between Jan 11, 2013, and June 30, 2019, 1280 patients were recruited in Australia (n=532), New Zealand (n=42), and Vietnam (n=706), of whom 642 were randomly assigned to fluoxetine and 638 were randomly assigned to placebo. Mean duration of trial treatment was 167 days (SD 48·1). At 6 months, mRS data were available in 624 (97%) patients in the fluoxetine group and 632 (99%) in the placebo group. The distribution of mRS categories was similar in the fluoxetine and placebo groups (adjusted common odds ratio 0·94, 95% CI 0·76–1·15; p=0·53). Compared with patients in the placebo group, patients in the fluoxetine group had more falls (20 [3%] vs seven [1%]; p=0·018), bone fractures (19 [3%] vs six [1%]; p=0·014), and epileptic seizures (ten [2%] vs two [<1%]; p=0·038) at 6 months. Interpretation Oral fluoxetine 20 mg daily for 6 months after acute stroke did not improve functional outcome and increased the risk of falls, bone fractures, and epileptic seizures. These results do not support the use of fluoxetine to improve functional outcome after stroke

Performance enhancement of data-driven models with derived quality data and data assimilation in water resources

Ph.DDOCTOR OF PHILOSOPH

Climate change, energy depletion, and the greenhouse effect

Biến đổi khí hậu, cạn kiệt năng lượng và hiệu ứng nhà kính là những vấn đề về môi trường đang được quan tâm ngày nay

GIẢI PHÁP CHO VẤN ĐỀ BIẾN ĐỔI KHÍ HẬU VÀ NĂNG LƯỢNG TRONG THẾ KỶ 21

Bảo vệ môi trường sống xanh – sạch – đẹp là vấn đề đang được cả thế giới quan tâm. Có rất nhiều hội nghị tầm cỡ toàn cầu hoặc khu vực đã được tổ chức để bàn bạc và tìm ra hướng giải quyết vấn đề đó. Trong đó, sự biến đổi khí hậu, cạn kiệt nguồn năng lượng và hiệu ứng nhà kính là những vấn đề nóng hổi, đây là một trong những thách thức lớn đối với toàn nhân loại vì chúng đang ảnh hưởng trực tiếp đến sinh thái, môi trường và cuộc sống của con người

Precipitation response to Heinrich Event-3 in the northern Indochina as revealed in a high-resolution speleothem record

Heinrich Event-3 (HE-3) differs from other Heinrich Events (HEs) in terms of the strength of its expression in climatic records from different global localities. Here, we present new high resolution δ18O records from a composite speleothem record spanning from 31.5 to 28.4 ka within the HE-3 time interval. The record is obtained from two stalagmites collected from the Thuong Thien cave (TT), northern Vietnam, which exhibit growth rates of 0.12 to 0.68 mm/yr. The TT record shows a pronounced positive excursion of δ18O values of stalagmite in the time interval from 30.8 ka and lasted about one thousand years. Specifically, the δ18O reached maximum between ∼30.3–30.2 ka and returned to low values at 29.5 ka. Both the onset and termination phases of the excursion show gradual changes in δ18O values that form a relatively symmetric ‘V’ shape. The excursion suggests that the Indian Summer Monsoon (ISM), which modulates the climate and hydrology in the region, has endured dramatic weakening in response to HE-3. The timing and duration of the monsoonal decline are consistent with a significant slowdown of the Atlantic Meridional Ocean Circulation (AMOC), which probably drove the southward migration of the intertropical convergence zone (ITCZ) and consequently a decrease in precipitation over the Asian monsoonal region including northern Vietnam. To test the proposed mechanism, we further performed modeling simulations via an atmosphere general circulation model with a coupled slab ocean. Simulated results confirm both the scale and mechanistic connections between cooling in the North Atlantic and changes in precipitation at the Thuong Thien cave locality.Ministry of Education (MOE)Nanyang Technological UniversityPublished versionThis study is financially supported by the Ministry of Science and Technology (MOST), Taiwan, under grant number 107-2116-M-002-015-MY3 and MOST 103-2116-M-002-027-MY3 to Y.-G.C. XW acknowledges the funding support from Singapore Ministry of Education (MOE2019-T2-1-174) and Earth Observatory of Singapore. 230Th dating was supported by grants from the Science Vanguard Research Program of the Ministry of Science and Technology (MOST), Taiwan, ROC (109-2123-M-002-001 to C.-C.S.), the Higher Education Sprout Project of the Ministry of Education, Taiwan, ROC (109L901001 to C.-C.S.), the National Taiwan University (110L8907 to C.-C.S.)

Optical characterization of thin films by means of transmission data

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