Past and Future Changes in the Climate of Hong Kong          下载免费PDF全文

GINN Wing-lui  LEE Tsz-cheung  CHAN Kin-yu 《Acta Meteorologica Sinica》2010,24(2):163-175

Over the years, the Hong Kong Observatory has carried out scientific studies to evaluate the observed climate trends and project the future climate in Hong Kong. Analysis of the meteorological observations at the observatory's headquarters in Tsim Sha Tsui since 1885 reveals that the temperature rise in Hong Kong during the past 124 years is in accord with the global rising trend. The accelerated rising trend in the mean temperature in last few decades may be attributed to the anthropogenic influences, especially urbanization. A similar increasing trend is also observed for rainfall. Other observations such as increasing cloud amount and decreasing total global solar radiation are all consistent with the global trend. Studies of past occurrences of extreme temperature and rainfall have also been carried out. The results indicate that cold episodes have become rarer while very hot days and heavy rain events are becoming more frequent. The observatory also makes use of the data from the Fourth Assessment Report (AR4) of the Intergovernmental Panel on Climate Change (IPCC) and employs statistical downscaling techniques to carry out projections of temperature and precipitation in the 21st century. It is found that the rise in temperature in Hong Kong will be slightly higher than the global mean in the 21st century. The annual rainfall in Hong Kong is also expected to rise by the end of the 21st century, so is its year-to-year variability.  相似文献   

Tropical cyclone genesis frequency over the western North Pacific simulated in medium-resolution coupled general circulation models   总被引：4，自引：0，他引：4  

Satoru Yokoi  Yukari N. Takayabu  Johnny C. L. Chan 《Climate Dynamics》2009,33(5):665-683

This study examines the tropical cyclone (TC) genesis frequency over the western North Pacific simulated in atmosphere–ocean coupled general circulation models from the World Climate Research Programme’s Coupled Model Intercomparison Project phase 3. We first evaluate performances of eight models with atmospheric horizontal resolution of T63 or T106 by analyzing their daily-mean atmospheric outputs of twentieth-century climate simulations available from the Program for Climate Model Diagnosis and Intercomparison database. The genesis frequency is validated against the best-track data issued by the Japan Meteorological Agency. Five of the eight models reproduce realistic horizontal distribution of the TC genesis with a large fraction over the 10°–20°N, 120°–150°E area. These five high-performance models also realistically simulate the summer–winter contrast of the frequency. However, detailed seasonal march is slightly unrealistic; four of the models overestimate the frequency in the early season (May–June) while all of them underestimate the frequency in the mature season (July–September). Reasons for these biases in the seasonal march for the five high-performance models are discussed using the TC genesis potential (GP) index proposed by Emanuel and Nolan (in Am Meteor Soc, pp 240–241, 2004). The simulated GP has seasonal biases consistent with those of the TC genesis frequency. For all five models, the seasonal biases in GP are consistent with those in environmental lower-tropospheric vorticity, vertical wind shear, and relative humidity, which can be attributed to the simulated behavior of monsoon trough. The observed trough migrates northward from the equatorial region to reach the 10°–20°N latitudinal band during the mature season and contributes to the TC frequency maximum, whereas the simulated trough migrates northward too rapidly and reaches this latitude band in the early season, leading to the overestimation of the TC genesis frequency. In the mature season, the simulated trough reaches as far as 15°–25°N, accompanied by a strong vertical shear south of the trough, providing an unfavorable condition for TC genesis. It is concluded that an adequate simulation of the monsoon trough behavior is essential for a better reproduction of the TC frequency seasonal march.  相似文献   

Short‐term stream water temperature observations permit rapid assessment of potential climate change impacts          下载免费PDF全文

Peter Caldwell  Catalina Segura  Shelby Gull Laird  Ge Sun  Steven G. McNulty  Maria Sandercock  Johnny Boggs  James M. Vose 《水文研究》2015,29(9):2196-2211

Assessment of potential climate change impacts on stream water temperature (T_s) across large scales remains challenging for resource managers because energy exchange processes between the atmosphere and the stream environment are complex and uncertain, and few long‐term datasets are available to evaluate changes over time. In this study, we demonstrate how simple monthly linear regression models based on short‐term historical T_s observations and readily available interpolated air temperature (T_a) estimates can be used for rapid assessment of historical and future changes in T_s. Models were developed for 61 sites in the southeastern USA using ≥18 months of observations and were validated at sites with longer periods of record. The T_s models were then used to estimate temporal changes in T_s at each site using both historical estimates and future T_a projections. Results suggested that the linear regression models adequately explained the variability in T_s across sites, and the relationships between T_s and T_a remained consistent over 37 years. We estimated that most sites had increases in historical annual mean T_s between 1961 and 2010 (mean of +0.11 °C decade^?1). All 61 sites were projected to experience increases in T_s from 2011 to 2060 under the three climate projections evaluated (mean of +0.41 °C decade^?1). Several of the sites with the largest historical and future T_s changes were located in ecoregions home to temperature‐sensitive fish species. This methodology can be used by resource managers for rapid assessment of potential climate change impacts on stream water temperature. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

A last peak in diversity: the stalked echinoderms of the Permian of Timor          下载免费PDF全文

Stephen K. Donovan  Gary D. Webster  Johnny A. Waters 《Geology Today》2016,32(5):179-185

In north‐west Europe, the Permian is limited to the New Red Sandstone and the restricted marine facies of the Zechstein, yet elsewhere it is constituted of thick marine deposits with an abundant shelly fauna. One of the most notable sites for the marine Permian is the island of Timor in south‐east Asia, where thick, olistostromic blocks of limestone have yielded 1000+ shelly species. Over a third of these are stalked echinoderms, both crinoids and blastoids, two diverse Palaeozoic groups that would be devastated by the end‐Permian mass extinction.  相似文献   

辽河口沉积物反硝化细菌数量及多样性的研究   总被引：5，自引：0，他引：5  

樊景凤  陈佳莹  陈立广  关道明 《海洋学报》2011,33(3):94-102

对辽河口沉积物中反硝化细菌的数量、多样性以及群落结构进行了研究.采用MPN-Griess分析了春夏秋三季的反硝化细菌数量,结果表明其数量春季最多,秋季次之,夏季最低,且从辽河下游及河口向远海区域逐渐降低.采用PCR-RFLP对反硝化细菌的亚硝酸盐还原酶基因(nirS)进行分析,发现沉积物中的反硝化细菌类型较新,大多数细...  相似文献   

Metallogenic series and regularity of skarn-type deposits in Huaibei area of Anhui Province     

CHAN Siwei  YANG Zhi 《中国地质调查》2014,7(3):38-44

Huaibei area is an important iron-copper metallogenic area in northern Anhui Province. In order to summarize the metallogenic series and regularity of skarn-type deposits systematically in this area, based on recent prospecting results and the diagenesis and metallogenic chronology, the authors systematically investigated the geological characteristics and metallogenic conditions of the known deposits and divided thern into three metallogenic series. They are skarn-type iron-copper-gold metallogenic series related to high-K calc-alkali intrusive rocks, skarn-type iron-gypsum metallogenic series related to high-K calc-alkaline intrusive rocks and skarn-type iron-light rare earth metallogenic series related to monzogranite. Then the geological characteristics and metallogenic regularity of four typical deposits were discussed respectively. The results show that the deposit formation can be divided into two stages in this area, and the metallogenic space is controlled by deep faults, arc structures and magmatic belts. Finally, the regional metallogenic models of Qianchang type, Yangqiaozi type and Wangchang type iron polymetallic deposits in the early stage of Early Cretaceous and Qiganlou type iron-light rare earth deposits in the late stage of Early Cretaceous were established.  相似文献   

Regional climate simulations of summer diurnal rainfall variations over East Asia and Southeast China   总被引：1，自引：0，他引：1  

Wan-Ru Huang  Johnny C. L. Chan  Andie Y. M. Au-Yeung 《Climate Dynamics》2013,40(7-8):1625-1642

This study evaluates the performance of RegCM3 (Regional Climate Model Version 3) in simulating the East Asian rainfall, with emphasis on the diurnal variations of rainfall over Southeast China during the 1998–2002 summer (June–August) seasons. The evaluation focuses on the sensitivity of the choice of cumulus parameterizations and model domain. With the right setup, the spatial and temporal evolution of diurnal rainfall over Southeast China, which has not been well simulated by past studies, can be accurately simulated by RegCM3. Results show that the Emanuel cumulus scheme has a more realistic simulation of summer mean rainfall in East Asia, while the GFC (Grell scheme with the Frisch-Chappell convective closure assumption) scheme is better in simulating the diurnal variations of rainfall over Southeast China. The better performance of these two schemes [relative to the other two schemes in RegCM3: the Kuo scheme and the GAS (Grell scheme with the Arakawa–Schubert closure assumption) scheme] can be attributed to the reasonable reproduction of the major formation mechanism of rainfall—the moisture flux convergence—over Southeast China. Furthermore, when the simulation domain covers the entire Tibetan Plateau, the diurnal variations of rainfall over Southeast China are found to exhibit a noticeable improvement without changes in the physics schemes.  相似文献   

Rectifier effect in an atmospheric model with daily biospheric fluxes: impact on inversion calculation     

MISA ISHIZAWA  DOUGLAS CHAN  KAZ HIGUCHI  SHAMIL MAKSYUTOV  CHIU-WAI YUEN  JING CHEN  DOUGLAS WORTHY 《Tellus. Series B, Chemical and physical meteorology》2006,58(5):447-462

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Forest floor versus ecosystem CO₂ exchange along boreal ecotone between upland forest and lowland mire     

BORIS &#;UPEK  KARI MINKKINEN  PASI KOLARI  MIKE STARR  TOMMY CHAN  JUKKA ALM  TIMO VESALA  JUKKA LAINE  EERO NIKINMAA 《Tellus. Series B, Chemical and physical meteorology》2008,60(2):153-166

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New Zealand: Environmentally Determined?     

ADRIAN CHAN 《New Zealand geographer》1971,27(1):65-68

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