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[en] This article explores the challenges associated with governing the competing objectives of energy security and environmental sustainability. It examines this challenge in the context of Hong Kong and the city's recent fuel mix consultation. Based on the results of ten interviews with public and private stakeholders in the Hong Kong power sector, the findings analyze the perceptions of stakeholders with respect to the tension between sustainability and core pillars of energy security — accessibility, affordability and reliability. It concludes with four policy recommendations for managing and potentially moving beyond the energy dilemma, including suggestions for locally feasible sustainable energy, long-term pathways to decarbonization, policy changes on tariffs, incentives and pricing, and collaboratively co-governing clean energy. - Highlights: • Contests between energy security and environmental sustainability are a key challenge for energy governance. • Hong Kong fuel mix consultation shows tension between energy security and environmental sustainability. • Clearest pathway to low-carbon power sector is via unpopular cooperation with mainland China. • Recommended that city make new efforts to realize new pathways to low carbon power sector reform.
[en] Meteorological observations in Tibet are poor in quality with a severe amount of missing data; this is mostly caused by extreme climatological conditions and higher maintenance costs. This paper focuses on the imputation of missing data and the reconstruction of the regional temperature field. Due to insufficient observation stations and complicated topography, we employ the weather research and forecasting (WRF) model to produce the proper orthogonal decomposition (POD) basis for the study region. We then develop the gappy POD method for the imputation of missing data. Both methods are compared and tested for various missing data cases, and the results show that the gappy POD method dramatically outperforms the regularized EM algorithm when the amount of missing spatial data is not severe. Furthermore, between the two methods, only the gappy POD method is capable of reconstructing the temperature field at locations where the data are absent. The gappy POD method can also be generalized for data assimilation with the assumption that the data across all model grids have missing values.
[en] Geometric correction without ground control points (GCPs) is a very important topic. Conventional airborne photogrammetry is difficult to implement in areas where the installation of GCPs is not available. The technical of integrated GPS/INS systems providing the positioning and attitude of airborne systems is a potential solution in such areas. This paper first states the principle of geometric correction based on a combination of GPS and INS then the error of the geometric correction of Pushbroom Hyperspectral Imager (PHI) without GCP was analysed, then a flight test was carried out in an area of Damxung, Tibet. The experiment result showed that the error at straight track was small, generally less than 1 pixel, while the maximum error at cross track direction, was close to 2 pixels. The results show that geometric correction of PHI without GCP enables a variety of mapping products to be generated from airborne navigation and imagery data
[en] Civic Exchange added climate change to their research agenda some time ago, recognising that it is a cross-cutting issue that will have substantial impact, not only on Hong Kong but on the entire Pearl River Delta. The Hong Kong region is the wealthiest part of China. Along with growing material wealth, Hong Kong's ecological footprint and particularly it's greenhouse gas emissions - have increased exponentially. Therefore, there exists a special responsibility to contribute to finding effective mitigation measures that can help to slow the process; as well as a pressing need to find ways to adapt to those effects of climate change that cannot be forestalled. This paper represents a first attempt to pull together the relevant materials, with the aim of providing a broad-brush view of how climate change may affect Hong Kong, Macao and the Pearl River Delta. The key recommendation is that more region-specific research must be carried out. Civic Exchange has also taken note of the recently published Stern Review, which was commissioned by the United Kingdom government, to assess the economics of climate change. The report calls for urgent action. In this respect, this report therefore doubles as a funding proposal
[en] Highlights: •Three typical air-conditioning system options are comparatively analyzed. •The “partially decoupled option” is proposed for retrofit projects. •Simulation and on-site test results show the proposed method performed properly. •The annual cost saving is about 4.6 million HKD in the reported retrofit project. -- Abstract: Compared with spaces air-conditioned for thermal comfort, cleanrooms often have special requirements on dry bulb temperature, relative humidity and particle concentrations. It is a challenging task to achieve those requirements with minimum energy consumption, especially when different parameters interfere with each other. A significant amount of energy would be wasted if the system is not properly designed and controlled. This paper firstly provides an overview and a discussion on the essentials for design and control of cleanroom air-conditioning systems. The existing systems and controls are categorized into three typical options and their performances are then analyzed based on different weather and load conditions. For new design, the “fully decoupled option” is the preferred option for humid sub-tropical regions. The analysis results are applied in a retrofit project for a pharmaceutical factory located in Hong Kong, a humid sub-tropical city, which employed the “interactive option”. This system is proposed to operate as a “partially decoupled option” in this project since such retrofit requires no modification on the existing hardware. The retrofitted system option has been on-site tested in mild weather condition, which provided 69.6% and 87.8% reductions of cooling and heating consumptions respectively. More comprehensive comparison tests are also conducted on a dynamic platform built on Matlab/Simulink.
[en] Devastating typhoons that induce enormous losses to various sectors of the economy underline the importance of an improved understanding of the regional hazard-to-loss relationship. This study utilizes the up-to-date loss data of typhoons in Taiwan from 2006 to 2015 to analyze the interannual variations in the annual aggregate losses (AALs) and develop a loss prediction model for the major administrative divisions. Return period analysis applied to the AALs identifies western-to-southwestern Taiwan as the high-risk region, among which Chiayi and Pingtung exhibit the highest 10-year AALs over 100 million. The gamma hurdle model (GHM) is adopted for loss prediction for its ability to stepwise model the loss occurrence and amount, leading to straightforward discussion regarding the explanatory power and statistical significance of meteorological predictors in their marginal and joint space. In the first part of the GHM, maximum daily rainfall and maximum gust wind are selected as the two most significant meteorological predictors for the logistic regression model of the loss occurrence, showing a remarkable model accuracy of . In the second part of the GHM, maximum sustained wind is added to the gamma generalized linear model of the loss amount, generating the cross-validated Nash–Sutcliffe efficiency (mean absolute error) values higher (lower) than 0.6 (3 million) for several southwestern cities. Event assessment for Typhoons Soudelor (2015) and Morakot (2009) further demonstrates the utility of the GHM and illustrates the essential for accounting for the combination effect of rainfall and wind on loss estimation.
[en] The eighth Asia and Oceania congress of nuclear medicine and biology was held in Beijing, China, October 9-13 2004. The congress also held satellite meeting in Hong Kong SAR, China October 16-17 2004 and in Shanghai, China October 15 2005 respectively. The congress was sponsored by Chinese Society of Nuclear Medicine and organized by Asia and Oceania Federation of Nuclear Medicine and Biology. The final program includes 379 pieces abstracts, whose contents contain nuclear medicine diagnosis and therapy and biology
[en] The Tibetan Plateau (TP) has experienced significant climate changes in recent decades. Wind stilling is one of the most evident changes based on observations. This study assesses near-surface wind speed simulations from three WRF dynamical downscalings over the TP. The assessment is conducted by comparing with observations at 83 stations over the TP and ERA-Interim in 1980–2005. Results show that the three dynamical downscalings and ERA-Interim all overestimated the annual and seasonal wind speeds over the TP, especially in winter. Overestimation of the U component is the main contributor to the overestimation of near-surface wind speeds. The difference between grid and station elevations partly contributes to the larger overestimation, particularly in 3000–4000 m. Impacts of the land surface scheme on the simulations of wind speed are also noticed. Observations show significant decreasing wind speed trend and the variability is larger at higher elevations above 4000 m, which are not represented in the ERA-Interim. Affected by forcing, the dynamical downscalings do not capture the observed significantly decreasing trend, but they outperform the forcing in winter. The better performance in winter but summer is mainly because the dynamical downscalings are unable to reproduce the observed direction of the U component in summer. The ability of dynamical downscalings to simulate the near-surface wind speed may be improved by choosing forcing with better linear trends, enhancing the momentum transports in the planetary boundary parameterization scheme, and considering the unresolved topographic features sufficiently.
[en] The frequency of extreme weather events, which cause severe crop losses, is increasing. This study investigates the relationship between crop losses and extreme weather events in central Taiwan from 2003 to 2015 and determines the main factors influencing crop losses. Data regarding the crop loss area and meteorological information were obtained from government agencies. The crops were categorised into the following five groups: ‘grains’, ‘vegetables’, ‘fruits’, ‘flowers’ and ‘other crops’. The extreme weather events and their synoptic weather patterns were categorised into six and five groups, respectively. The data were analysed using the z score, correlation coefficient and stepwise regression model. The results show that typhoons had the highest frequency of all extreme weather events (58.3%). The largest crop loss area (4.09%) was caused by two typhoons and foehn wind in succession. Extreme wind speed coupled with heavy rainfall is an important factor affecting the losses in the grain and vegetable groups. Extreme wind speed is a common variable that affects the loss of ‘grains’, ‘vegetables’, ‘fruits’ and ‘flowers’. Consecutive extreme weather events caused greater crop losses than individual events. Crops with long production times suffered greater losses than those with short production times. This suggests that crops with physical structures that can be easily damaged and long production times would benefit from protected cultivation to maintain food security.
[en] This paper employs a stochastic frontier analysis (SFA) to examine cost efficiency and scale economies in Taiwan Power Company (TPC) by using the panel data covering the period of 1995-2006. In most previous studies, the efficiency estimated by the Panel Data without testing the endogeneity may bring about a biased estimator resulting from the correlation between input and individual effect. A Hausman test is conducted in this paper to examine the endogeneity of input variables and thus an appropriate model is selected based on the test result. This study finds that the power generation executes an increasing return to scale across all the power plants based on the pooled data. We also use installed capacity, service years of the power plant, and type of fuel as explanatory variable for accounting for the estimated cost efficiency of each plant by a logistic regression model to examine the factor affecting the individual efficiency estimates. The results demonstrate that the variable of installed capacity keeps a positive relationship with cost efficiency while the factor of working years has a negative relationship.