期刊文献+
共找到465篇文章
< 1 2 24 >
每页显示 20 50 100
Water Vapor,Cloud,and Surface Rainfall Budgets Associated with the Landfall of Typhoon Krosa(2007):A Two-Dimensional Cloud-Resolving Modeling Study 被引量:3
1
作者 岳彩军 寿绍文 Xiaofan LI 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2009年第6期1198-1208,共11页
Water vapor, cloud, and surface rainfall budgets associated with the landfall of Typhoon Krosa on 6-8 October 2007 are analyzed based on a two-dimensional cloud-resolving model simulation. The model is integrated with... Water vapor, cloud, and surface rainfall budgets associated with the landfall of Typhoon Krosa on 6-8 October 2007 are analyzed based on a two-dimensional cloud-resolving model simulation. The model is integrated with imposed zonally-uniform vertical velocity, zonal wind, horizontal temperature, and vapor advection from NCEP/Global Data Assimilation System (GDAS) data. The simulation data that are validated with observations are examined to study physical causes associated with surface rainfall processes during the landfall. The time- and domain-mean analysis shows that when Krosa approached the eastern coast of China on 6 October, the water vapor convergence over land caused a local atmospheric moistening and a net condensation that further produced surface rainfall and an increase of cloud hydrometeor concentration. Meanwhile, latent heating was balanced by advective cooling and a local atmospheric warming. One day later, the enhancement of net condensation led to an increase of surface rainfall and a local atmospheric drying, while the water vapor convergence weakened as a result of the landfall-induced deprivation of water vapor flux. At the same time, the latent heating is mainly compensated the advective cooling. Further weakening of vapor convergence on 8 October enhanced the local atmospheric drying while the net condensation and associated surface rainfall was maintained. The latent heating is balanced by advective cooling and a local atmospheric cooling. 展开更多
关键词 budget cloud-resolving modeling Typhoon Krosa
下载PDF
Case Analyses and Numerical Simulation of Soil ThermalImpacts on Land Surface Energy Budget Based on anOff-Line Land Surface Model 被引量:3
2
作者 郭维栋 孙菽芬 钱永甫 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2002年第3期500-512,共13页
The statistical relationship between soil thermal anomaly and short-term climate change is presented based on a typical case study. Furthermore, possible physical mechanisms behind the relationship are re-vealed throu... The statistical relationship between soil thermal anomaly and short-term climate change is presented based on a typical case study. Furthermore, possible physical mechanisms behind the relationship are re-vealed through using an off-line land surface model with a reasonable soil thermal forcing at the bottom of the soil layer. In the first experiment, the given heat flux is 5 W m<SUP>2</SUP> at the bottom of the soil layer (in depth of 6.3 m) for 3 months, while only a positive ground temperature anomaly of 0.06°C can be found compared to the control run. The anomaly, however, could reach 0.65°C if the soil thermal conductivity was one order of magnitude larger. It could be even as large as 0.81°C assuming the heat flux at bottom is 10 W m<SUP>-2</SUP>. Mean-while, an increase of about 10 W m<SUP>&#8722;2</SUP> was detected both for heat flux in soil and sensible heat on land sur-face, which is not neglectable to the short-term climate change. The results show that considerable response in land surface energy budget could be expected when the soil thermal forcing reaches a certain spatial-tem-poral scale. Therefore, land surface models should not ignore the upward heat flux from the bottom of the soil layer. Moreover, integration for a longer period of time and coupled land-atmosphere model are also necessary for the better understanding of this issue. 展开更多
关键词 Soil thermal anomaly Land surface model Land surface energy budget
下载PDF
Modeling the Impact of Land-Use Change on Water Budget of Gaza Strip 被引量:1
3
作者 Jehad T. Hamad Tamer A. Eshtawi +1 位作者 Almotasembellah M. Abushaban Mohammed O. Habboub 《Journal of Water Resource and Protection》 2012年第6期325-333,共9页
Gaza has a water crisis and faces serious challenges for the future sustainability of its water resources. Land-use change has an expected effect on water budget of the Gaza Strip. Three different land cover scenarios... Gaza has a water crisis and faces serious challenges for the future sustainability of its water resources. Land-use change has an expected effect on water budget of the Gaza Strip. Three different land cover scenarios;the and cover of 2007, land cover of 2020, and full urbanization land cover were simulated independently using The Automated Geospatial Watershed Assessment (AGWA) tool which work under the umbrella of GIS. In general, the simulation results indicate that land-cover changes will significantly alter the hydrologic response of Gaza region. Percolation is expected to decrease in all options as urban areas are expanded where as the simulated surface runoff reflected a relative departure from the first scenario comparing with other scenarios. In the baseline scenario (2007), the simulated surface runoff and percolation represent 12% and 41% respectively from the water budget components of the Gaza Strip. In year 2020, these values were expected by the simulation results to be 20% and 27% respectively. A unique linear relationship between the relative change in urban area and the corresponding relative change in surface water has been investigated from the simulation results. The analysis of the three urbanization scenarios can give decision makers better understand for the future situation and assist them to advance towards achieving sustainable development planning for water resources system in the Gaza Strip. 展开更多
关键词 Land-Use Change Automated GEOSPATIAL Watershed Assessment WATEr budget Hydrologic modelING GAZA Strip WATEr CrISIS
下载PDF
Sensitivity analysis of the De Nitrification and De Composition model for simulating regional carbon budget at the wetlandgrassland area on the Zoige Plateau,China 被引量:3
4
作者 WANG Ji-yan LI Ai-nong JIN Hua-an 《Journal of Mountain Science》 SCIE CSCD 2016年第7期1200-1216,共17页
Although mathematical models(e.g., De Nitrification and De Composition(DNDC) provide a powerful tool to study regional carbon budget, it is still difficult to obtain accurate simulation results because there exists la... Although mathematical models(e.g., De Nitrification and De Composition(DNDC) provide a powerful tool to study regional carbon budget, it is still difficult to obtain accurate simulation results because there exists large uncertainties in modeling regional carbon budget. Through the investigation on the sensitivity of model output parameters to the input parameters, sensitivity analysis(SA) has been proved to be able to identify the key sources of uncertainties and be helpful to reduce the model uncertainties. However, some input parameters with discrete values(e.g., land use type and soil type) and the regional effect of the sensitive parameters were rarely examined in SA. In this paper, taking the Zoige Plateau as a case area, we combined the one-factor-ata-time(OAT) with Extended Fourier Amplitude Sensitivity Test(EFAST) to conduct a SA of DNDC for simulating the regional carbon budget, including Gross Primary Productivity(GPP), Net Primary Productivity(NPP), Net Ecosystem Productivity(NEP), autotrophic respiration(Ra), soil microbial heterotrophic respiration(Rh) and ecosystem respiration(Re). The result showed that the combination of OAT and EFAST could test the contribution of the input parameters with discrete values to the output parameters. In DNDC model, land use type and soil type had a significant impact on the regional carbon budget of the Zoige Plateau, and daily temperature was also confirmed to be one of the most important parameters for carbon budget. For the other input parameters, with the change of land use type or soil type at regional scale, the sensitive parameters of carbon budget would vary accordingly. The SA results would provide scientific evidence to optimize DNDC model and they suggested that we should pay attention to the spatial/temporal effect of SA and try to use the appropriate data in simulation of the regional carbon budget. 展开更多
关键词 Sensitivity analysis OAT EFAST dNdC model Carbon budget Zoige Plateau
下载PDF
Effects of Vertical Wind Shear on the Pre-Summer Heavy Rainfall Budget:A Cloud-Resolving Modeling Study
5
作者 SHEN Xin-Yong QING Tao +1 位作者 HUANG Wen-Yan LI Xiao-Fan 《Atmospheric and Oceanic Science Letters》 CSCD 2013年第1期44-51,共8页
This study investigates the effects of vertical wind shear on the torrential rainfall response to the large-scale forcing using a rainfall separation analysis of a pair of two-dimensional cloud-resolving model sensiti... This study investigates the effects of vertical wind shear on the torrential rainfall response to the large-scale forcing using a rainfall separation analysis of a pair of two-dimensional cloud-resolving model sensitivity experiments for a pre-summer heavy rainfall event over southern China from 3-8 June 2008 coupled with National Centers for Environmental Prediction(NCEP)/Global Data Assimilation System(GDAS) data.The rainfall partitioning analysis based on the surface rainfall budget indicates that the exclusion of vertical wind shear decreases the contribution to total rainfall from the largest contributor,which is the rainfall associated with local atmospheric drying,water vapor divergence,and hydrometeor loss/convergence,through the reduction of the rainfall area and reduced rainfall during the rainfall event.The removal of vertical wind shear increases the contribution to total rainfall from the rainfall associated with local atmospheric drying,water vapor convergence,and hydrometeor loss/convergence through the expansion of the rainfall area and enhanced rainfall.The elimination of vertical wind shear enhances heavy rainfall and expands its area,whereas it reduces moderate rainfall and its area. 展开更多
关键词 cloud-resolving model simulation vertical wind shear rainfall partitioning surface rainfall budget
下载PDF
Controllability, Budget Flexibility and New Model of Budgeting System
6
作者 Fu Chenxi 《Journal of Modern Accounting and Auditing》 2011年第9期974-985,共12页
How to extend the flexibility of the budget control to adapt for need of strategy management and management control is a difficult and very important problem. The purpose of this paper is to study tentatively this pro... How to extend the flexibility of the budget control to adapt for need of strategy management and management control is a difficult and very important problem. The purpose of this paper is to study tentatively this problem based on the extant results of controllability principle and budgeting in management control system of organization. In this paper, three main results are as follows: (1) To disclose that the controllability of an organization is one characteristic of the budgeting systems and the controllability is not impartial and not single personal action. (2) To discuss tentatively an improved budgeting system to improve the several weaknesses of traditional budgeting control that Otley (1999) summarized from the academic and practitioner literatures in order to improve the controllability of strategy management with budget flexibility. (3) To build the new model of flexible budget with three new features: it makes strategy objectives easily achievable and controllable; it makes controllers have a more strategic role; it can balance these multiple goals when they cannot be achieved simultaneously and external conditions are more demanding. 展开更多
关键词 CONTrOLLABILITY budget flexibility new model budgeting system
下载PDF
How R&D investment promotes green technology innovation in the context of digitalization?-An empirical analysis based on provincial panel data
7
作者 LIU Jie LI Zhi-hui WEI Fang-xin 《Ecological Economy》 2024年第1期39-52,共14页
Green technology innovation is an important driving force and source to promote my country’s high-quality development,and it is the core path to achieve sustainable development.This paper uses my country’s provincia... Green technology innovation is an important driving force and source to promote my country’s high-quality development,and it is the core path to achieve sustainable development.This paper uses my country’s provincial panel data from 2016 to 2019 to study the impact mechanism of R&D investment on green technology innovation,and introduces the level of digitization,using the panel threshold model to discuss its role in the impact mechanism of R&D investment on green technology innovation.The study found that when the level of digitalization in a region is low,increasing R&D investment does not necessarily improve the ability of green technology innovation;when the level of digitalization is relatively high,R&D investment has a positive role in promoting green technology innovation.Therefore,it is necessary to improve policies to encourage enterprises to increase investment in research and development;at the same time,it is necessary to promote the coordinated development of digital foundation,digital investment,digital literacy,digital economy and digital application,and promote the deep integration of digitalization and green technology innovation. 展开更多
关键词 green technology innovation r&d investment digital level panel model
下载PDF
Seasonal variability of salinity budget and water exchange in the northern Indian Ocean from HYCOM assimilation 被引量:10
8
作者 张玉红 杜岩 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2012年第6期1082-1092,共11页
Based on HYbrid Coordinate Ocean Model (HYCOM) assimilation and observations, we analyzed seasonal variability of the salinity budget in the southeastern Arabian Sea (AS) and the southern part of the Bay of Bengal (BO... Based on HYbrid Coordinate Ocean Model (HYCOM) assimilation and observations, we analyzed seasonal variability of the salinity budget in the southeastern Arabian Sea (AS) and the southern part of the Bay of Bengal (BOB), as well as water exchange between the two basins. Results show that fresh water flux cannot explain salinity changes in salinity budget of both regions. Oceanic advection decreases salinity in the southeastern AS during the winter monsoon season and increases salinity in the southern BOB during the summer monsoon season. In winter, the Northeast Monsoon Current (NMC) carries fresher water from the BOB westward into the southern AS; this westward advection is confined to 4°-6°N and the upper 180 m south of the Indian peninsula. Part of the less saline water then turns northward, decreasing salinity in the southeastern AS. In summer, the Southwest Monsoon Current (SMC) advects high-salinity water from the AS eastward into the BOB, increasing salinity along its path. This eastward advection of high-salinity water south of the India Peninsula extends southward to 2°N, and the layer becomes shallower than in winter. In addition to the monsoon current, the salinity difference between the two basins is important for salinity advection. 展开更多
关键词 seasonal variability salinity budget Arabian Sea Bay of Bengal zonal water exchange HYbridCoordinate Ocean model (HYCOM) assimilation
下载PDF
Nitrogen and phosphorus budgets of the Changjiang River estuary 被引量:2
9
作者 李祥安 俞志明 +2 位作者 宋秀贤 曹西华 袁涌铨 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2011年第4期762-774,共13页
Eutrophication has emerged as a key environmental problem in Chinese coastal waters, especially in the Changjiang (Yangtze) River estuary. In this area, large nutrient inputs result in frequent harmful algal blooms an... Eutrophication has emerged as a key environmental problem in Chinese coastal waters, especially in the Changjiang (Yangtze) River estuary. In this area, large nutrient inputs result in frequent harmful algal blooms and serious hypoxia in bottom waters. Four cruises were made in the estuary in 2006 to assess the concentration and distribution of dissolved inorganic nitrogen (DIN) and phosphorus (DIP). The concentration of DIN decreased gradually in a linear relationship with salinity from the river mouth to outer waters, while DIP was relatively more dispersed. A modified box budget method was used to estimate nutrient fluxes in the estuary and its adjacent waters. Water and nutrient budgets as well as primary production and denitrification rates were estimated from the box budget model. Estimated water residence time in the estuary was about 11 d. The turbid mixing zone released 33% of DIN and 49% of DIP, while in the adjacent outer sea 17.9 mmol DIN/m2·d and 0.36 mmol DIP/m2·d were fixed. Dissolved inorganic phosphorus was imported from the deep open sea waters, supporting primary production and population growth in this zone. Net ecosystem production (NEP) was calculated at 38.2 mmol/m2·d in the outer estuary and the estimated rate (N-fixation minus denitrification) was negative (1.92 mmol/m2·d), implying that a large amount of input nitrogen was taken up by algae and recycled through denitrification in bottom water and sediment. 展开更多
关键词 NITrOGEN PHOSPHOrUS NUTrIENTS TrANSPOrT budget model Changjiang (Yangtze) river estuary
下载PDF
Annual Cycle and Budgets of Nutrients in the Bohai Sea 被引量:3
10
作者 ZHAOLiang WEIHao FENGShizuo 《Journal of Ocean University of Qingdao》 2002年第1期29-37,共9页
The environmental problems in the Bohai Sea have become more serious in the last decade. High nutrient concentration contributes much to it. A Sino-German cooperation program has been carried out to improve the unders... The environmental problems in the Bohai Sea have become more serious in the last decade. High nutrient concentration contributes much to it. A Sino-German cooperation program has been carried out to improve the understanding of the ecosystem by observations and modelling. A three-dimensional ecosystem model, coupled with a physical transport model, is adopted in this study. The simulation for the year 1982 is validated by the data collected in 1982/1983. The simulated annual mean nutrient concentrations are in good agreement with observations. The nutrient concentrations in the Bohai Sea, which are crucial to the algal growth, are high in winter and low in summer. There are depletion from spring to summer and elevation from autumn to winter for nutrients. The nutrients’ depletion is a response to the consumption of the phytoplankton bloom in spring. Internal recycle and external compensation affect the nutrient cycle. Their contributions to the nutrient budgets are discussed based on the simulated results. Production and respiration are the most important sink and source of nutrients. The process of photosynthesis consumes 152 kilotons-P and 831.1 kilotons-N while respiration releases 94.5 kilotons-P and 516.6 kilotons-N in the same period. The remineralization of the detritus pool is an important source of nutrient regene- ration. It can compensate 23 percent of the nutrient consumed by the production process. The inputs of phosphates and nitrogen from rivers are 0.55 and 52.7 kilotons respectively. The net nutrient budget is -3.05 kilotons-P and 31.6 kilotons-N. 展开更多
关键词 Bohai Sea modelLING annual cycle nutrients cycle nutrient budget
下载PDF
Analysis of the spatial and temporal distributions of ecological variables and the nutrient budget in the Beibu Gulf 被引量:1
11
作者 Huanglei Pan Dishi Liu +2 位作者 Dalin Shi Shengyun Yang Weiran Pan 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2021年第8期14-31,共18页
Based on a hydrodynamic-ecological model, the temperature, salinity, current, phytoplankton(Chl a),zooplankton, and nutrient(dissolved inorganic nitrogen, DIN, and dissolved inorganic phosphorous, DIP)distributions in... Based on a hydrodynamic-ecological model, the temperature, salinity, current, phytoplankton(Chl a),zooplankton, and nutrient(dissolved inorganic nitrogen, DIN, and dissolved inorganic phosphorous, DIP)distributions in the Beibu Gulf were simulated and the nutrient budget of 2015 was quantitatively analyzed. The simulated results show that interface processes and monsoons significantly influence the ecological processes in the gulf. The concentrations of DIN, DIP, phytoplankton and zooplankton are generally higher in the eastern and northern gulf than that in the western and southern gulf. The key regions affected by ecological processes are the Qiongzhou Strait in winter and autumn and the estuaries along the Guangxi coast and the Red River in summer.In most of the studied domains, biochemical processes contribute more to the nutrient budget than do physical processes, and the DIN and DIP increase over the year. Phytoplankton plays an important role in the nutrient budget;phytoplankton photosynthetic uptake is the nutrient sink, phytoplankton dead cellular release is the largest source of DIN, and phytoplankton respiration is the largest source of DIP. The nutrient flux in the connected sections of the Beibu Gulf and open South China Sea(SCS) inflows from the east and outflows to the south. There are 113 709 t of DIN and 5 277 t of DIP imported from the open SCS to the gulf year-around. 展开更多
关键词 Beibu Gulf hydrodynamic-ecological model marine ecosystem nutrient budget
下载PDF
Borehole Heat Budget Calculator: A New Tool for the Quick Exploitation of High-Resolution Temperature Profiles by Hydrogeologists
12
作者 Guillaume Meyzonnat Florent Barbecot +5 位作者 José Antonio Corcho Alvarado Jean-Marc Lauzon Renald McCormack Antoine Tognelli Hermann Zeyen Marina Alazard 《Journal of Water Resource and Protection》 2019年第2期122-147,共26页
Distributed temperature sensing is known to provide sharp signals which are very efficient for mapping hydraulically active fractures in wellbores. High-resolution temperature sensing has specifically demonstrated its... Distributed temperature sensing is known to provide sharp signals which are very efficient for mapping hydraulically active fractures in wellbores. High-resolution temperature sensing has specifically demonstrated its capacity to characterize very low flows in wellbores. But as sharp as they can be, temperature profiles are often difficult to decipher. The aim of the present work is to provide and to test the “Borehole Heat Budget Calculator” (BHB Calculator), which is implemented as a fast and easy to use tool for the quantitative analysis of depth-temperature profiles. The Calculator is suitable for most pumping and draining configurations, as the heat budget is generalized for modelling multidirectional flow systems within the same wellbore. The formatted worksheet allows the quick exploitation of temperature logs, and is applicable for the characterization of distributed fractures in long screened wellbores. Objectives of the heat modelling are to enhance the readability of complex depth-temperature data, as well as to quantify distribution of inflow intensities and temperatures with depth. The use of heat budget helps to clearly visualize how heat conduction and heat advection contributions are distributed along wellbores profiles. Calculations of inflow temperatures and their evolution through pumping duration is a prerequisite to infer about the nature of aquifer properties (i.e. conduits, distributed or discrete fractures, porous media), as well as to give insight information about the mapping of effective flow paths draining the aquifer. The efficiency and limitations of the BHB Calculator are being tested through high-resolution temperature logging, along with complementary flowmetering and televiewing logging in fractured aquifers located in the St-Lawrence Lowlands, Quebec, Canada. 展开更多
关键词 Fractured BEdrOCK Aquifer HIGH-rESOLUTION Temperature LOGGING Heat budget modelling Long Screened Wellbores
下载PDF
Nutrient Budget for Optimal Oil Palm (<i>Elaeis guineensis</i>Jacq) Yield on Coastal Plain Sands Soils of Akwa Ibom State Nigeria
13
作者 Jude Chukwuma Obi Bassey Thomas Udoh 《Open Journal of Soil Science》 2012年第3期289-298,共10页
The objective of the study was to establish approximate relationships between yield and soil nutrients in oil palm production. The study was conducted in Nigerian Institute for Oil Palm Research (NIFOR) substation Ibe... The objective of the study was to establish approximate relationships between yield and soil nutrients in oil palm production. The study was conducted in Nigerian Institute for Oil Palm Research (NIFOR) substation Ibesit ekoi in Oruk Anam Local Government Area of Akwa Ibom State Nigeria. Soil, rainfall and yield data were collected from oil palm plantation established 49, 29, 9 and 0 (control) years ago in an area underlain by coastal plain sands. Descriptive statistics, analysis of variance and multiple stepwise regression analysis were used to study variations, effect of land use on soil properties at different depths and contributions of various soil nutrients at different depths to the yield (fresh fruit bunch ‘FFB’ and palm oil) of oil palm. Results of coefficient of variability revealed that approx. 45.5% of the variables were highly variable including available phosphorus, extractable zinc, FFB and palm oil, while others were either least or moderately variable. Oil palm trees influenced soil development with its effect on silt content at 30 - 60 cm depth. Uptake of phosphorus in oil palm land use system decreases with depth. This was further confirmed by the relative contribution of available phosphorus to FFB yield that decreased from the surface of the soil downwards. Extractable zinc contents of oil palm land use were not significantly different from each other (ranging between 9.65 and 7.84 mg·kg–1) but significantly different from the control (23.99 mg·kg–1). In the modeling process, it was observed that the absolute contribution of texture was minimal while exchangeable sodium was highest (i.e. 66.5 percent) in the quantity of oil palm production. Also extractable copper and zinc were found to have made large contributions to FFB and oil palm. Oil palm (Elaeis guineensis) is a high-yielding source of edible and technical oils but requires proper knowledge and precise administration of nutrient demands for management of a major production constraint which is soil fertility. 展开更多
关键词 SOIL Nutrient budget Oil Palm MICrONUTrIENTS modeling SOIL development
下载PDF
A Study on Assessment Model of Colleges' R&D Institution of Hebei Province
14
作者 Hu Baomin Yang Lankun Wang Lin(Dept.of Business Adiministration,Hebei University of Technology,Tianjin 300130,P.R.China) 《河北工业大学学报》 CAS 1997年第A01期35-40,共6页
This paper,in view of colleges’ R&D institUtion assessment of Hebeiprovince,builds DEA assessment model,and compares this model with the general evaluation method.
关键词 colleges’ r&d INSTITUTION ASSESSMENT dEA model
下载PDF
Bridging mapping and simulation modelling in the ecosystem service assessments of boreal forests:effects of bioenergy production on carbon dynamics
15
作者 Anu Akujärvi Anna Repo +1 位作者 Altti M.Akujärvi Jari Liski 《Forest Ecosystems》 SCIE CSCD 2021年第1期35-49,共15页
Background:Increasing the use of forest harvest residues for bioenergy production reduces greenhouse emissions from the use of fossil fuels.However,it may also reduce carbon stocks and habitats for deadwood dependent ... Background:Increasing the use of forest harvest residues for bioenergy production reduces greenhouse emissions from the use of fossil fuels.However,it may also reduce carbon stocks and habitats for deadwood dependent species.Consequently,simple tools for assessing the trade-offs of alternative management practices on forest dynamics and their services to people are needed.The objectives of this study were to combine mapping and simulation modelling to investigate the effects of forest management on ecosystem services related to carbon cycle in the case of bioenergy production;and to evaluate the suitability of this approach for assessing ecosystem services at the landscape level.Stand level simulations of forest growth and carbon budget were combined with extensive multi-source forest inventory data across a southern boreal landscape in Finland.Stochastic changes in the stand age class distribution over the study region were simulated to mimic variation in management regimes.Results:The mapping framework produced reasonable estimates of the effects of forest management on a set of key ecosystem service indicators:the annual carbon stocks and fluxes of forest biomass and soil,timber and energy-wood production and the coarse woody litter production over a simulation period 2012–2100.Regular harvesting,affecting the stand age class distribution,was a key driver of the carbon stock changes at a landscape level.Extracting forest harvest residues in the final felling caused carbon loss from litter and soil,particularly with combined aboveground residue and stump harvesting.It also reduced the annual coarse woody litter production,demonstrating negative impacts on deadwood abundance and,consequently,forest biodiversity.Conclusions:The refined mapping framework was suitable for assessing ecosystem services at the landscape level.The procedure contributes to bridging the gap between ecosystem service mapping and detailed simulation modelling in boreal forests.It allows for visualizing ecosystem services as fine resolution maps to support sustainable land use planning.In the future,more detailed models and a wider variety of ecosystem service indicators could be added to develop the method. 展开更多
关键词 Carbon budget Ecosystem services Forest management Forest bioenergy Landscape level MAPPING modelLING
下载PDF
Application of Model-Based Data Transmission Techniques to Gravitational Model Data
16
作者 Jeremy Straub 《Journal of Data Analysis and Information Processing》 2013年第3期46-57,共12页
The transmission of scientific data over long distances is required to enable interplanetary science expeditions. Current approaches include transmitting all collected data or transmitting low resolution data to enabl... The transmission of scientific data over long distances is required to enable interplanetary science expeditions. Current approaches include transmitting all collected data or transmitting low resolution data to enable ground controller review and selection of data for transmission. Model-based data transmission (MBDT) seeks to increase the amount of knowledge conveyed per unit of data transmitted by comparing high-resolution data collected in situ to a pre-existing (or potentially co-transmitted) model. This paper describes the application of MBDT to gravitational data and characterizes its utility and performance. This is performed by applying the MBDT technique to a selection of gravitational data previously collected for the Earth and comparing the transmission requirements to the level required for raw data transmis-sion and non-application-aware compression. Levels of transmission reduction up to 31.8% (without the use maximum-error-thresholding) and up to 97.17% (with the use of maximum-error-thresholding) resulted. These levels significantly exceed what is possible with non-application-aware compression. 展开更多
关键词 SPACECrAFT Communications Link budget reduction GrAVITATIONAL model dATA GrAVITATIONAL model dATA Processing High-Value Transmission deep Space Enabling Technologies
下载PDF
Numerical study of the seasonal salinity budget of the upper ocean in the Bay of Bengal in 2014
17
作者 Qingyue WANG Changming DONG +2 位作者 Junde LI Jingsong YANG Qing TIAN 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2021年第4期1169-1187,共19页
Impact factors on the salinity budget, especially the eddy salt fluxes and smaller-scale diffusive salt fluxes for the upper 50 m of the Bay of Bengal(BoB) in 2014 are investigated using a box model based on the Regio... Impact factors on the salinity budget, especially the eddy salt fluxes and smaller-scale diffusive salt fluxes for the upper 50 m of the Bay of Bengal(BoB) in 2014 are investigated using a box model based on the Regional Ocean Modeling System(ROMS) daily outputs. The model results reproduce that the precipitation and river runoff s are the dominant factors modulating the sharp salinity decrease during the summer monsoon season. The analysis shows that the salinity increase after the summer monsoon is mostly due to the meridional advective and diffusive salt fluxes. The vertical advective salt flux, which is sensitive to the different signals of the wind stress curl, plays an important role in balancing the salinity change induced by the meridional advective salt flux during both the summer and winter monsoon seasons. Distinctive spatial mesoscale structures are presented in the eddy salt flux throughout the year, and their contributions are sizeable(over 30% in the meridional direction and about 10%–30% in the vertical direction). The meridional eddy salt flux is larger in the monsoon seasons than that in the inter-monsoon seasons, and in a positive pattern near the western boundary during the winter monsoon and autumn inter-monsoon. The vertical eddy salt flux makes an important contribution to the salinity budget, especially along the coastal area and around the Andaman and Nicobar Islands. The vertical eddy salt flux becomes large when a tropical cyclone passes the area. 展开更多
关键词 salinity budget Bay of Bengal regional Ocean modeling System(rOMS) MONSOON eddy flux
下载PDF
An evaluation of the Arctic clouds and surface radiative fluxes in CMIP6 models
18
作者 Jianfen Wei Zhaomin Wang +2 位作者 Mingyi Gu Jing-Jia Luo Yunhe Wang 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2021年第1期85-102,共18页
To assess the performances of state-of-the-art global climate models on simulating the Arctic clouds and surface radiation balance,the 2001–2014 Arctic Basin surface radiation budget,clouds,and the cloud radiative ef... To assess the performances of state-of-the-art global climate models on simulating the Arctic clouds and surface radiation balance,the 2001–2014 Arctic Basin surface radiation budget,clouds,and the cloud radiative effects(CREs)in 22 coupled model intercomparison project 6(CMIP6)models are evaluated against satellite observations.For the results from CMIP6 multi-model mean,cloud fraction(CF)peaks in autumn and is lowest in winter and spring,consistent with that from three satellite observation products(Cloud Sat-CALIPSO,CERESMODIS,and APP-x).Simulated CF also shows consistent spatial patterns with those in observations.However,almost all models overestimate the CF amount throughout the year when compared to CERES-MODIS and APP-x.On average,clouds warm the surface of the Arctic Basin mainly via the longwave(LW)radiation cloud warming effect in winter.Simulated surface energy loss of LW is less than that in CERES-EBAF observation,while the net surface shortwave(SW)flux is underestimated.The biases may result from the stronger cloud LW warming effect and SW cooling effect from the overestimated CF by the models.These two biases compensate each other,yielding similar net surface radiation flux between model output(3.0 W/m2)and CERES-EBAF observation(6.1 W/m2).During 2001–2014,significant increasing trend of spring CF is found in the multi-model mean,consistent with previous studies based on surface and satellite observations.Although most of the 22 CMIP6 models show common seasonal cycles of CF and liquid water path/ice water path(LWP/IWP),large inter-model spreads exist in the amounts of CF and LWP/IWP throughout the year,indicating the influences of different cloud parameterization schemes used in different models.Cloud Feedback Model Intercomparison Project(CFMIP)observation simulator package(COSP)is a great tool to accurately assess the performance of climate models on simulating clouds.More intuitive and credible evaluation results can be obtained based on the COSP model output.In the future,with the release of more COSP output of CMIP6 models,it is expected that those inter-model spreads and the model-observation biases can be substantially reduced.Longer term active satellite observations are also necessary to evaluate models’cloud simulations and to further explore the role of clouds in the rapid Arctic climate changes. 展开更多
关键词 Arctic Basin surface radiation budget cloud radiative effect(CrE) CMIP6 models CErES Cloud Sat-CALIPSO APP-x
下载PDF
Primary Reasoning behind the Double ITCZ Phenomenon in a Coupled Ocean-Atmosphere General Circulation Model 被引量:6
19
作者 李江龙 张学洪 +1 位作者 俞永强 戴福山 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2004年第6期857-867,共11页
This paper investigates the processes behind the double ITCZ phenomenon, a common problem in Coupled ocean-atmosphere General Circulation Models (CGCMs), using a CGCM—FGCM-0 (Flexible General Circulat... This paper investigates the processes behind the double ITCZ phenomenon, a common problem in Coupled ocean-atmosphere General Circulation Models (CGCMs), using a CGCM—FGCM-0 (Flexible General Circulation Model, version 0). The double ITCZ mode develops rapidly during the ?rst two years of the integration and becomes a perennial phenomenon afterwards in the model. By way of Singular Value Decomposition (SVD) for SST, sea surface pressure, and sea surface wind, some air-sea interactions are analyzed. These interactions prompt the anomalous signals that appear at the beginning of the coupling to develop rapidly. There are two possible reasons, proved by sensitivity experiments: (1) the overestimated east-west gradient of SST in the equatorial Paci?c in the ocean spin-up process, and (2) the underestimated amount of low-level stratus over the Peruvian coast in CCM3 (the Community Climate Model, Version Three). The overestimated east-west gradient of SST brings the anomalous equatorial easterly. The anomalous easterly, a?ected by the Coriolis force in the Southern Hemisphere, turns into an anomalous westerly in a broad area south of the equator and is enhanced by atmospheric anomalous circulation due to the underestimated amount of low-level stratus over the Peruvian coast simulated by CCM3. The anomalous westerly leads to anomalous warm advection that makes the SST warm in the southeast Paci?c. The double ITCZ phenomenon in the CGCM is a result of a series of nonlocal and nonlinear adjustment processes in the coupled system, which can be traced to the uncoupled models, oceanic component, and atmospheric component. The zonal gradient of the equatorial SST is too large in the ocean component and the amount of low-level stratus over the Peruvian coast is too low in the atmosphere component. 展开更多
关键词 coupled ocean-atmosphere general circulation model double intertropical convergence zone heat budget sensitivity experiment
下载PDF
Sulfur Distribution and Transport Studies in East Asia Using Eulerian Model 被引量:3
20
作者 王自发 黄美元 +2 位作者 何东阳 徐华英 周玲 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 1996年第3期399-409,共11页
A three-dimensional regional Eulenan model of sulfur deposition and transport is developed.Processes treated in the model include emission,transport,diffusion,gas-phase and aqueous-phase chemical process,dry depositio... A three-dimensional regional Eulenan model of sulfur deposition and transport is developed.Processes treated in the model include emission,transport,diffusion,gas-phase and aqueous-phase chemical process,dry deposition,ramout and washout of sulfur.A 'looking up table' method is provided to deal with the gas-phase chemical process including sulfur transfer Dry-depositon velocity considers the influence of underlying surface,wind,degree of stability by parameterization Model calculated values reasonably agrees with observation.Distribution of sulfur deposition and transport in East Asia are also analyzed in this paper Some amount of sulfur emission of different countries transport across boundaries,but the main origin of sulfur deposition in each country in East Asia is from itself.Furthermore.some transport paths on different layers and outlet or inlet zones are found.According to sulfur balance and budget we concluded that sulfur outlets are bigger than inlets across boundary and emissions are more than deposition in most places of East Asia 展开更多
关键词 Sulfur distribution Transport budget Eulerian model East Asia
下载PDF
上一页 1 2 24 下一页 到第
使用帮助 返回顶部