Projections of climate change impacts on central America tropical rainforest   总被引：1，自引：0，他引：1  

André Lyra  Pablo Imbach  Daniel Rodriguez  Sin Chan Chou  Selena Georgiou  Lucas Garofolo 《Climatic change》2017,141(1):93-105

Tropical rainforest plays an important role in the global carbon cycle, accounting for a large part of global net primary productivity and contributing to CO₂ sequestration. The objective of this work is to simulate potential changes in the rainforest biome in Central America subject to anthropogenic climate change under two emissions scenarios, RCP4.5 and RCP8.5. The use of a dynamic vegetation model and climate change scenarios is an approach to investigate, assess or anticipate how biomes respond to climate change. In this work, the Inland dynamic vegetation model was driven by the Eta regional climate model simulations. These simulations accept boundary conditions from HadGEM2-ES runs in the two emissions scenarios. The possible consequences of regional climate change on vegetation properties, such as biomass, net primary production and changes in forest extent and distribution, were investigated. The Inland model projections show reductions in tropical forest cover in both scenarios. The reduction of tropical forest cover is greater in RCP8.5. The Inland model projects biomass increases where tropical forest remains due to the CO₂ fertilization effect. The future distribution of predominant vegetation shows that some areas of tropical rainforest in Central America are replaced by savannah and grassland in RCP4.5. Inland projections under both RCP4.5 and RCP8.5 show a net primary productivity reduction trend due to significant tropical forest reduction, temperature increase, precipitation reduction and dry spell increments, despite the biomass increases in some areas of Costa Rica and Panama. This study may provide guidance to adaptation studies of climate change impacts on the tropical rainforests in Central America.  相似文献   

A semi‐distributed parallel‐type linear reservoir rainfall‐runoff model and its application in Taiwan     

Lung‐Sheng Hsieh  Ru‐Yih Wang 《水文研究》1999,13(8):1247-1268

The main purpose of this paper is to introduce a semi‐distributed parallel surface rainfall‐runoff conceptual model. In this paper, a general solution of the instantaneous unit hydrograph (IUH) has been derived successfully for N linearly connected reservoirs, each having a different storage constant. The solution is a function of geomorphologic parameters, meteorologic factors and roughness coefficients. The model also takes into account the hydrologic response which is influenced by outflow downstream of a reservoir. For calibration, the shuffled complex evolution (SCE) algorithm is used to search for the global optimal parameters of the model. Because of the parallel structure, the mean roughness parameter of the channel becomes a “conceptual” parameter without a real physical meaning. To evaluate the adaptability of the model adopted, three watersheds around the city of Taipei in Taiwan were chosen to test the effectiveness of the model. The study provides an appropriate rainfall‐runoff model for planning flood mitigation in Taiwan. Copyright © 1999 John Wiley & Sons, Ltd.  相似文献   

Efficient Bayesian sensor placement algorithm for structural identification: a general approach for multi‐type sensory systems          下载免费PDF全文

Ka‐Veng Yuen  Sin‐Chi Kuok 《地震工程与结构动力学》2015,44(5):757-774

In this paper, a Bayesian sequential sensor placement algorithm, based on the robust information entropy, is proposed for multi‐type of sensors. The presented methodology has two salient features. It is a holistic approach such that the overall performance of various types of sensors at different locations is assessed. Therefore, it provides a rational and effective strategy to design the sensor configuration, which optimizes the use of various available resources. This sequential algorithm is very efficient due to its Bayesian nature, in which prior distribution can be incorporated. Therefore, it avoids the possible unidentifiability problem encountered in a sequential process, which starts with small number of sensors. The proposed algorithm is demonstrated using a shear building and a lattice tower with consideration of up to four types of sensors. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

Projections of severe droughts in future climate in Southeast Brazil: a case study in Southern Minas Gerais State,Brazil     

Silva  Vinicius Oliveira  de Mello  Carlos Rogério  Chou  Sin Chan 《Theoretical and Applied Climatology》2022,148(3-4):1289-1302

Theoretical and Applied Climatology - South of Minas Gerais state, in Southeast Brazil, is known for the coffee crop production (more than 30% of country’s production) and hydroelectricity...  相似文献   

Complex study of characteristics of a Cb cloud developing over the Arabian Peninsula under high dew point deficit in the atmosphere. Part 1. Field observations and numerical modeling     

T. W. Krauss  A. A. Sin’kevich  N. E. Veremei  Yu. A. Dovgalyuk  V. S. Makitov  V. D. Stepanenko 《Russian Meteorology and Hydrology》2011,36(2):102-111

Basing on airmass motion trajectory calculations over the Arabian Peninsula on April 10, 2008, it can be assumed that in the lower and middle troposphere, zones with increased air moisture exist due to air inflow from the Red Sea. As a result, mesoscale volumes of dry and moist air are neighboring, though large-scale field is comparatively homogeneous with low humidity. In the mesoscale zones, intense thunderstorm and hailstorm Cb clouds developed, whose characteristics and evolution are studied in the paper. Continuous radar observations of the clouds are carried out during 5 hours. Numerical simulation of the cloud evolution is performed with nonstationary 1.5-dimensional model. It is noted that under the mentioned atmospheric conditions, in the area under consideration, heavy rain and hail from the Cb clouds are observed. The main factors of their origination are high thermal instability of the atmosphere and moist air inflow from outside.  相似文献   

Laboratory Validation of Ultra-Soft Soil Deformation Model     

Myint Win Bo  Victor Choa  Kai Sin Wong  Arul Arulrajah 《Geotechnical and Geological Engineering》2011,29(1):65-74

Ultra-soft soil with high moisture content will experience large strain deformation under one-dimensional compression with little or no gain in effective stress. Such deformation behaviour does not comply with Terzaghi’s effective stress gain theory. The e-log s_v^￠ \sigma_{v}^{\prime } relationship of ultra-soft soil is non-linear with large compression index in the first order of log cycle. This paper proposes three compression indices (C_c1^* C_{c1}^{*} , C_c2^* C_{c2}^{*} and C_c3^* C_{c3}^{*} ) for stresses covering three log cycles. Good prediction of settlement magnitude is possible with these newly proposed compression parameters for ultra-soft soil. In addition, implicit finite difference model applying the large strain theory is also proposed and validated with results from laboratory measurements. The time factor curves for ultra-soft soil with large strain compression are also proposed and validated.  相似文献   

Formula of incipient velocity for flooded vehicles   总被引：3，自引：3，他引：0  

Junqiang Xia  Fang Yenn Teo  Binliang Lin  Roger A. Falconer 《Natural Hazards》2011,58(1):1-14

With the climate change caused by global warming, the occurrence probability of urban flooding due to flash floods has increased gradually. Flush floods propagate rapidly, which can lead to significant hazard to human life and property. Flood hazard to vehicles has become more noticeable and frequent in recent years. Therefore, it is important to investigate the behaviour of vehicles on flooded streets or roads. In the current study, a formula has been derived to predict the incipient velocity of flooded vehicles according to the mechanical condition of sliding equilibrium. A series of flume experiments were conducted using three types of scaled die-cast model vehicles, with two scales being tested for each type of vehicle. The experimental data obtained for the small-scale model vehicles were used to determine the two parameters in the derived formula, and the prediction accuracy of this formula was validated using the experimental data obtained for the large-scale model vehicles. Finally, the corresponding incipient velocities under various incoming depths were computed using this formula for these three prototype vehicles. It is found that for a specified vehicle, the value of incipient velocity reaches its minimum as the incoming flow depth approaches the height of the vehicle, and the smaller and lighter vehicle like Mini Cooper is the easiest to start sliding in floodwaters. The results can be used as a preliminary assessment to define the hazard to vehicles parking on flooded streets or roads.  相似文献   

SINGAPORE LANDSCAPE: A HISTORICAL OVERVIEW OF HOUSING CHANGE     

Teo Siew Eng  B.A.  M.A.  Ph.D.  Victor R. Savage  B.A.  M.A.  Ph.D. 《Singapore journal of tropical geography》1985,6(1):48-63

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Quantification of the breakage of lump materials during handling operations     

C. S. Teo  A. G. Waters  S. K. Nicol 《International Journal of Mineral Processing》1990,30(3-4)

The strength of raw ironmaking materials is usually determined by tumble and shatter tests. Although an average result for a bulk sample is determined, the strength index is empirical and its numerical value cannot be used to predict the extent of breakage for a particular material handling circuit. A new experimental procedure has been developed to measure the strength based on the extent of breakage of agglomerates repeatedly dropped from a predetermined height. The drop procedure combined with impact and breakage theories has been used to quantify the effect of particle size and drop height on the extent of breakage of lump materials such as iron ore sinter, coke, coal and iron ore. Results from a plant trial indicated that the drop procedure could also be used to examine the stabilization effect of brittle material due to repeated dropping during handling.  相似文献   

Investigations of the development of thunderstorm with hail. Part 1. Cloud development and formation of electric discharges     

A. A. Sin’kevich  Yu. P. Mikhailovskii  Yu. A. Dovgalyuk  N. E. Veremei  E. V. Bogdanov  A. Kh. Adzhiev  A. M. Malkarova  A. M. Abshaev 《Russian Meteorology and Hydrology》2016,41(9):610-619

The results of synchronous radar, radiometric, and lightning-detection measurements are analyzed to reveal interrelations between the parameters of electric discharges and the parameters of cumulonimbus clouds developing in the North Caucasus. The dependences of electric activity of the cloud on radar parameiers as well as on the parameiers reirieved from Meteosat SEVIRI radiometer measurements are considered. Electric discharges (intracloud discharges and lightnings) were registered for 1 hour 40 minutes (the maximum frequency was equal to 448 discharges per minute). The relation ships are identified that connect the parameters of electric discharges with the precipitation rate and with the field of cloud top temperaiure. It was found that the frequency of eleciric discharges increases as the precipitation rate increases. The maximum frequency is reached at the precipitation rate equal to 70 mm/hour. Normalized autocorrelation functions ofthe field ofcloud top temperature retrieved from the satellite data are constructed. The high correlation is revealed between the scale of inhomogeneity of the field of cloud top temperature and the frequency of electrical discharges.  相似文献