• 已选条件:
  • × Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
 全选  【符合条件的数据共:162条】

来源:Atmospheric Measurement Techniques

作者:Andrew D. Aubrey;Riley M. Duren;Simon J. Hook;等

使用许可:署名(BY)

预览  |  原文链接  |  全文  [ 浏览:0 下载:0  ]     分享

来源:Atmospheric Measurement Techniques

作者:Xiuji Zhou;Holger Vömel;Nathaniel J. Livesey;等

使用许可:署名(BY)

预览  |  原文链接  |  全文  [ 浏览:0 下载:0  ]     分享

来源:Biogeosciences

作者:A. Kleidon;B. Reu;K. Bohn;等

预览  |  原文链接  |  全文  [ 浏览:0 下载:0  ]     分享

Terrestrial biosphere modelstypically abstract theimmense diversity of vegetation forms and functioning intoa relatively small set of predefined semi-empirical plant functionaltypes (PFTs). There is growing evidence, however, from the fieldecology community as well as from modelling studies that current PFTschemes may not adequately represent the observed variations inplant functional traits and their effect on ecosystemfunctioning. In this paper, we introduce the Jena Diversity-Dynamic Global Vegetation Model(JeDi-DGVM) as a new approach to terrestrial biosphere modelling witha richer representation of functional diversity than traditionalmodelling approaches based on a small number of fixed PFTs.JeDi-DGVM simulates the performance of a large number ofrandomly generated plant growth strategies, each defined bya set of 15 trait parameters which characterize various aspects ofplant functioning including carbon allocation, ecophysiology andphenology. Each trait parameter is involved in one or morefunctional trade-offs. These trade-offs ultimately determine whethera strategy is able to survive under the climatic conditions in a givenmodel grid cell and its performance relative to the other strategies. Thebiogeochemical fluxes and land surface properties of the individualstrategies are aggregated to the grid-cell scale using a mass-basedweighting scheme.We evaluate the simulated global biogeochemical patternsagainst a variety of field and satellite-based observations following aprotocol established by the Carbon-Land Model Intercomparison Project. Theland surface fluxes and vegetation structural properties are reasonably wellsimulated by JeDi-DGVM, and compare favourably with other state-of-the-artglobal vegetation models. We also evaluate the simulated patterns offunctional diversity and the sensitivity of the JeDi-DGVM modelling approachto the number of sampled strategies. Altogether, the results demonstrate theparsimonious and flexible nature of a functional trade-off approach to globalvegetation modelling, i.e. it can provide more types of testable outputs thanstandard PFT-based approaches and with fewer inputs.The approach implemented here in JeDi-DGVM sets the foundation for futureapplications that will explore the impacts of explicitly resolving diverseplant communities, allowing for a more flexible temporal and spatialrepresentation of the structure and function of the terrestrial biosphere.

    来源:Biogeosciences

    作者:A. Kleidon;B. Reu;K. Bohn;等

    预览  |  原文链接  |  全文  [ 浏览:0 下载:0  ]     分享

    Terrestrial biosphere modelstypically abstract theimmense diversity of vegetation forms and functioning intoa relatively small set of predefined semi-empirical plant functionaltypes (PFTs). There is growing evidence, however, from the fieldecology community as well as from modelling studies that current PFTschemes may not adequately represent the observed variations inplant functional traits and their effect on ecosystemfunctioning. In this paper, we introduce the Jena Diversity-Dynamic Global Vegetation Model(JeDi-DGVM) as a new approach to terrestrial biosphere modelling witha richer representation of functional diversity than traditionalmodelling approaches based on a small number of fixed PFTs.JeDi-DGVM simulates the performance of a large number ofrandomly generated plant growth strategies, each defined bya set of 15 trait parameters which characterize various aspects ofplant functioning including carbon allocation, ecophysiology andphenology. Each trait parameter is involved in one or morefunctional trade-offs. These trade-offs ultimately determine whethera strategy is able to survive under the climatic conditions in a givenmodel grid cell and its performance relative to the other strategies. Thebiogeochemical fluxes and land surface properties of the individualstrategies are aggregated to the grid-cell scale using a mass-basedweighting scheme.We evaluate the simulated global biogeochemical patternsagainst a variety of field and satellite-based observations following aprotocol established by the Carbon-Land Model Intercomparison Project. Theland surface fluxes and vegetation structural properties are reasonably wellsimulated by JeDi-DGVM, and compare favourably with other state-of-the-artglobal vegetation models. We also evaluate the simulated patterns offunctional diversity and the sensitivity of the JeDi-DGVM modelling approachto the number of sampled strategies. Altogether, the results demonstrate theparsimonious and flexible nature of a functional trade-off approach to globalvegetation modelling, i.e. it can provide more types of testable outputs thanstandard PFT-based approaches and with fewer inputs.The approach implemented here in JeDi-DGVM sets the foundation for futureapplications that will explore the impacts of explicitly resolving diverseplant communities, allowing for a more flexible temporal and spatialrepresentation of the structure and function of the terrestrial biosphere.

      来源:Atmospheric Chemistry and Physics

      作者:K. N. Liou;Y. Liu;Z. Ye;等

      预览  |  原文链接  |  全文  [ 浏览:0 下载:0  ]     分享

      来源:Atmospheric Chemistry and Physics

      作者:J. H. Jiang;L. Froidevaux;W. G. Read;等

      预览  |  原文链接  |  全文  [ 浏览:0 下载:1  ]     分享

      The interrelated geographic and temporal variability seen in morethan seven years of tropical and subtropical upper tropospheric(215 hPa) ozone, carbon monoxide and cloud ice water content (IWC)observations by the Aura Microwave Limb Sounder (MLS) are presented.Observed ozone abundances and their variability (geographic andtemporal) agree to within 10–15 ppbv with records from sondeobservations.MLS complements these (and other) observations withglobal coverage and simultaneous measurements of related parameters.Previously-reported phenomena such as the ozone "wave one" featureare clearly seen in the MLS observations, as is a double peak inozone abundance over tropical East Africa, with enhanced abundancesin both May to June and September to November.While repeatableseasonal cycles are seen in many regions, they are often accompaniedby significant interannual variability.Ozone seasonal cycles inthe southern tropics and subtropics tend to be more distinct (i.e.,annually repeatable) than in the northern.By contrast, carbonmonoxide shows distinct seasonal cycles in many northern subtropicalregions, notably from India to the Eastern Pacific.Deep convection(as indicated by large values of IWC) is typically associated withreductions in upper tropospheric ozone.Convection over pollutedregions is seen to significantly enhance upper tropospheric carbonmonoxide.While some regions show statistically significantcorrelations among ozone, carbon monoxide and IWC, simplecorrelations fall well short of accounting for the observedvariability.The observed interrelated variations and metrics ofannual and interannual variability described here represent a newresource for validation of atmospheric chemistry models.