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1.
In Part I, the authors succeeded in coupling the spectral atmospheric model （SAMIL_R42L9） developed at the State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, Chinese Academy of Sciences （LASG/IAP/CAS） with the land surface model, Atmosphere-Vegetation-Interaction-Model （AVIM） and analyzed the climate basic state and land surface physical fluxes simulated by R42_AVIM. In this Part Ⅱ, we further evaluate the simulated results of the biological processes, including leaf area index （LAI）, biomass and net primary productivity （NPP） etc. Results indicate that R42_AVIM can simulate the global distribution of LAI and has good consistency with the monthly mean LAI provided by Max Planck Institute for Meteorology. The simulated biomass corresponds reasonably to the vegetation classifications. In addition, the simulated annual mean NPP has a consistent distribution with the data provided by IGBP and MODIS, and compares well with the work in literature. This land-atmosphere coupled model will offer a new experiment tool for the research on the two-way interaction between climate and biosphere, and the global terrestrial ecosystem carbon cycle. 相似文献
2.
In Part Ⅰ, the authors succeeded in coupling the spectral atmospheric model (SAMIL_R42L9) developed at the State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, Chinese Academy of Sciences (LASG/IAP/CAS) with the land surface model, Atmosphere-Vegetation-Interaction-Model (AVIM) and analyzed the climate basic state and land surface physical fluxes simulated by R42_AVIM. In this Part Ⅱ, we further evaluate the simulated results of the biological processes, including leaf area index (LAI), biomass and net primary productivity (NPP) etc. Results indicate that R42_AVIM can simulate the global distribution of LAI and has good consistency with the monthly mean LAI provided by Max Planck Institute for Meteorology. The simulated biomass corresponds reasonably to the vegetation classifications. In addition, the simulated annual mean NPP has a consistent distribution with the data provided by IGBP and MODIS, and compares well with the work in literature. This land-atmosphere coupled model will offer a new experiment tool for the research on the two-way interaction between climate and biosphere, and the global terrestrial ecosystem carbon cycle. 相似文献
3.
Interannual Variability of the Normalized Difference Vegetation Index on the Tibetan Plateau and Its Relationship with Climate Change 总被引：7，自引：0，他引：7
The Qinghai-Xizang Plateau, or Tibetan Plateau, is a sensitive region for climate change, where the manifestation of global warming is particularly noticeable. The wide climate variability in this region significantly affects the local land ecosystem and could consequently lead to notable vegetation changes. In this paper, the interannual variations of the plateau vegetation are investigated using a 21-year normalized difference vegetation index （NDVI） dataset to quantify the consequences of climate warming for the regional ecosystem and its interactions. The results show that vegetation coverage is best in the eastern and southern plateau regions and deteriorates toward the west and north. On the whole, vegetation activity demonstrates a gradual enhancement in an oscillatory manner during 1982-2002. The temporal variation also exhibits striking regional differences： an increasing trend is most apparent in the west, south, north and southeast, whereas a decreasing trend is present along the southern plateau boundary and in the central-east region. Covariance analysis between the NDVI and surface temperature/precipitation suggests that vegetation change is closely related to climate change. However, the controlling physical processes vary geographically. In the west and east, vegetation variability is found to be driven predominantly by temperature, with the impact of precipitation being of secondary importance. In the central plateau, however, temperature and precipitation factors are equally important in modulating the interannual vegetation variability. 相似文献
4.
Sensitivity of the Terrestrial Ecosystem to Precipitation and Temperature Variability over China 
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下载免费PDF全文 SUN Guo-Dong 《大气和海洋科学快报》2014,(5):382-387
In this study, the sensitivities of net primary production （NPP）, soil carbon, and vegetation carbon to precipitation and temperature variability over China are discussed using the state-of-the-art Lund-Potsdam-Jena dynamic global vegetation model （LPJ DGVM）. The im- pacts of the sensitivities to precipitation variability and temperature variability on NPP, soil carbon, and vegeta- tion carbon are discussed. It is shown that increasing pre- cipitation variability, representing the frequency of ex- treme precipitation events, leads to losses in NPP, soil carbon, and vegetation carbon over most of China, espe- cially in North and Northeast China where the dominant plant functional types （i.e., those with the largest simu- lated areal cover） are grass and boreal needle-leaved for- est. The responses of NPP, soil carbon, and vegetation carbon to decreasing precipitation variability are opposite to the responses to increasing precipitation variability. The variations in NPP, soil carbon, and vegetation carbon in response to increasing and decreasing precipitation variability show a nonlinear asymmetry. Increasing pre- cipitation variability results in notable interannual variation of NPP. The sensitivities of NPP, soil carbon, and vegetation carbon to temperature variability, whether negative or positive, meaning frequent hot and cold days, are slight. The present study suggests, based on the LPJ model, that precipitation variability has a more severe impact than temperature variability on NPP, soil carbon, and vegetation carbon. 相似文献
5.
The coupled models of both the Global Ocean-Atmosphere-Land System (GOALS) and the Atmosphere-Vegetation
Interaction Model (GOALS-AVIM) are used to study the main characteristics of interannual variations. The simulated
results are also used to investigate some significant interannual variability and correlation analysis of the
atmospheric circulation and terrestrial ecosystem. By comparing the simulations of the climate model GOALS-AVIM
and GOALS, it is known that the simulated results of the interannual variations of the spatial and temporal
distributions of the surface air temperatures and precipitation are generally improved by using AVIM in GOALS-AVIM.
The interannual variation displays some distinct characteristics of the geographical distribution. Both the Net
Primary Production (NPP) and the Leap Area Index (LAI) have quasi 1-2-year cycles. Meanwhile, precipitation and
the surface temperatures have 2--4-year cycles. Conditions when the spectrum density values of GOALS are less
than those of GOALS-AVIM, tell us that the model coupled with AVIM enhances the simulative capability for
interannual variability and makes the annual cycle variability more apparent. Using Singular Value Decomposition
(SVD) analysis, the relationship between the ecosystem and the atmospheric circulation in East Asia is explored.
The result shows that the strengthening and weakening of the East Asian monsoon, characterized by the geopotential
heights at 500 hPa and the wind fields at 850 hPa, correspond to the spatiotemporal pattern of the NPP. The
correlation between NPP and the air temperature, precipitation and solar radiation are different in interannual
variability because of the variation in vegetation types. 相似文献
6.
Evaluation of CMIP5 Earth System Models in Reproducing Leaf Area Index and Vegetation Cover over the Tibetan Plateau 下载免费PDF全文
下载免费PDF全文 BAO Yan GAO Yanhong L&#; Shihu WANG Qingxi ZHANG Shaobo XU Jianwei LI Ruiqing LI Suosuo MA Di MENG Xianhong CHEN Hao CHANG Yan 《Acta Meteorologica Sinica》2014,28(6):1041-1060
The abilities of 12 earth system models (ESMs) from the Coupled Model Intercomparison Project Phase5 (CMIP5) to reproduce satellite-derived vegetation biological variables over the Tibetan Plateau (TP) were examined. The results show that most of the models tend to overestimate the observed leaf area index (LAI) and vegetation carbon above the ground, with the possible reasons being overestimation of photosynthesis and precipitation. The model simulations show a consistent increasing trend with observed LAI over most of the TP during the reference period of 1986-2005, while they fail to reproduce the downward trend around the headstream of the Yellow River shown in the observation due to their coarse resolutions. Three of the models: CCSM4, CESM1-BGC, and NorESM1-ME, which share the same vegetation model, show some common strengths and weaknesses in their simulations according to our analysis. The model ensemble indicates a reasonable spatial distribution but overestimated land coverage, with a significant decreasing trend (-1.48% per decade) for tree coverage and a slight increasing trend (0.58% per decade) for bare ground during the period 1950-2005. No significant sign of variation is found for grass. To quantify the relative performance of the models in representing the observed mean state, seasonal cycle, and interannual variability, a model ranking method was performed with respect to simulated LAI. INMCM4, bcc-csm-1.1m, MPI-ESM-LR, IPSL CM5A-LR, HadGEM2-ES, and CCSM4 were ranked as the best six models in reproducing vegetation dynamics among the 12 models. 相似文献
7.
利用耦合模式比较计划第5阶段（CMIP5）中5个全球气候模式3种典型浓度路径（RCPs）预估结果,基于植被净初级生产力模型,估算安徽省21世纪近期（2018—2030年)、中期（2031—2050年）和远期（2051—2099年）植被净初级生产力及其对气候变化的响应。结果表明：对不同模式在安徽省模拟能力的评估可知,气温以多模式集合模拟效果优于单个模式,MIROC-ESM-CHEM对降水的模拟能力较好。未来安徽省将持续变暖,北部变暖幅度高于南部,其中RCP8.5情景下变暖趋势更显著;全省降水量将增加,南部增加多于北部。随着气候趋于暖湿化,植被净初级生产力总体增加;与基准年相比,21世纪近期增加不明显,中后期显著增加,空间上南部增加总体高于北部。从气候变化响应来看,安徽省植被净初级生产力与降水量和平均气温均显著相关,并且对降水量的响应程度更高。 相似文献
8.
The approach of conditional nonlinear optimal perturbation related to parameter (CNOP-P) is employed to provide a possible climate scenario and to study the impact of climate change on the simulated net primary production (NPP) in China within a state-of-the-art Lund-Potsdam-Jena dynamic global vegetation model (LPJ DGVM). The CNOP-P, as a type of climate perturbation to bring variation in climatology and climate variability of the reference climate condition, causes the maximal impact on the simulated NPP in China. A linear climate perturbation that induces variation in climatology, as another possible climate scenario, is also applied to explore the role of variation in climate variability in the simulated NPP. It is shown that NPP decreases in northern China and increases in northeastern and southern China when the temperature changes as a result of a CNOP-P-type temperature change scenario. A similar magnitude of change in the spatial pattern variations of NPP is caused by the CNOP-P-type and the linear temperature change scenarios in northern and northeastern China, but not in southern China. The impact of the CNOP-P-type temperature change scenario on magnitude of change of NPP is more intense than that of the linear temperature change scenario. The numerical results also show that in southern China, the change in NPP caused by the CNOP-P-type temperature change scenario compared with the reference simulated NPP is sensitive. However, this sensitivity is not observed under the linear temperature change scenario. The seasonal simulations indicate that the differences between the variations in NPP due to the two types of temperature change scenarios principally stem from the variations in summer and autumn in southern China under the LPJ model. These numerical results imply that NPP is sensitive to the variation in temperature variability. The results influenced by the CNOP-P-type precipitation change scenario are similar to those under the linear precipitation change scenario, which cause the increasing NPP in arid and semi-arid regions of the northern China. The above findings indicate that the CNOP-P approach is a useful tool for exploring the nonlinear response of NPP to climate variability. 相似文献
9.
应用国家气候中心气候系统模式 (BCC_CSM1.0),在给定温室气体、太阳常数、硫酸盐气溶胶、火山灰等外强迫数据的条件下,对19世纪末到20世纪气候进行模拟。对降水模拟结果的检验表明:BCC_CSM1.0模式能够模拟出全球降水的基本气候状态、季节变化、季节内振荡、年际变化等特征。模拟结果显示:与CMAP及CRU观测分析资料相比基本一致,全球陆地降水在过去一个多世纪中存在上升趋势。同时,模式也存在不足和需要改进之处:模拟降水的时空分布与观测不一致;我国东部地区的雨带季节转变较观测偏快;主要雨带位置较观测偏西、偏北;夏季青藏高原东北侧有虚假的降水中心;热带季节内振荡较实际偏弱;降水年际变率较观测略大,主要发生在降水较明显的热带。BCC_CSM1.0模式模拟的全球陆地降水以及欧亚、亚洲、中国大陆 (中国东部、江南、华北等地区) 平均降水与近105年由观测所得的CRU资料基本一致,但多数地区比观测略偏低。模拟的全球陆地、中国东部、江南、华北等地区的降水趋势也与CRU资料一致;模拟的全球陆地降水在过去105年中有明显的上升趋势,与CRU资料相比,上升趋势更强,但在欧亚、亚洲、中国范围内模拟的降水趋势与观测有一定的差异。 相似文献
10.
Earth System Models （ESMs） are fundamental tools for understanding climate-carbon feedback. An ESM version of the Flexible Global Ocean-Atmosphere-Land System model （FGOALS） was recently developed within the IPCC AR5 Coupled Model Intercomparison Project Phase 5 （CMIP5） modeling framework, and we describe the development of this model through the coupling of a dynamic global vegetation and terrestrial carbon model with FGOALS-s2. The performance of the coupled model is evaluated as follows. The simulated global total terrestrial gross primary production （GPP） is 124.4 PgC yr-I and net pri- mary production （NPP） is 50.9 PgC yr-1. The entire terrestrial carbon pools contain about 2009.9 PgC, comprising 628.2 PgC and 1381.6 PgC in vegetation and soil pools, respectively. Spatially, in the tropics, the seasonal cycle of NPP and net ecosystem production （NEP） exhibits a dipole mode across the equator due to migration of the monsoon rainbelt, while the seasonal cycle is not so significant in Leaf Area Index （LAI）. In the subtropics, especially in the East Asian monsoon region, the seasonal cycle is obvious due to changes in temperature and precipitation from boreal winter to summer. Vegetation productivity in the northern mid-high latitudes is too low, possibly due to low soil moisture there. On the interannual timescale, the terrestrial ecosystem shows a strong response to ENSO. The model- simulated Nifio3.4 index and total terrestrial NEP are both characterized by a broad spectral peak in the range of 2-7 years. Further analysis indicates their correlation coefficient reaches -0.7 when NEP lags the Nifio3.4 index for about 1-2 months. 相似文献
11.
This is an investigation of exchanges of energy and water between the atmosphere and thevegetated continents,and the impact of and mechanisms for land surface-atmosphere interactionson hydrological cycle and general circulation by implementing the Simplified Simple Biosphere(SSiB)model in a modified version of IAP/LASG global spectral general model(L9R15 AGCM).This study reveals that the SSiB model produces a better partitioning of the land surface heat andmoisture fluxes and its diurnal variations,and also gives the transport of energy and water amongatmosphere,vegetation and soil explicitly and realistically.Thus the coupled SSiB-AGCM runslead to the more conspicuous improvement in the simulated circulation,precipitation,mean watervapor content and its transport.particularly in the Asian monsoon region in the real world thanCTL-AGCM runs.It is also pointed out that both the implementation of land surfaceparameterizations and the variations in land surface into the GOALS model have greatly improvedhydrological balance over continents and have a significant impact on the simulated climate.particularly over the massive continents.Improved precipitation recycling model was employed to verify the mechanisms for landsurface hydrology parameterizations on hydrological cycle and precipitation climatology in AGCM.It can be argued that the recycling precipitation rate is significantly reduced,particularly in the aridand semi-arid region of the boreal summer hemisphere,coincident with remarkable reduction inevapotranspiration over the continental area.Therefore the coupled SSiB-AGCM runs reduce thebias of too much precipitation over land surface in most AGCMs,thereby bringing the simulatedprecipitation closer to observations in many continental regions of the world than CTL-AGCMruns. 相似文献
12.
The ability of seven global coupled ocean-atmosphere models to reproduce East Asian monthly surface temperature and precipitation climatologies during 1961 1990 is evaluated. January and July climate differences during the 2050s and 2090s relative to 1961-1990 projected by the seven-model ensemble under the Special Report on Emission Scenarios （SRES） A2 and B2 scenarios are then briefly discussed. These projections, together with the corresponding atmospheric CO2 concentrations under the SRES A2 and B2 scenarios, are subsequently used to drive the biome model BIOME3 to simulate potential vegetation distribution in China during the 2050s and 2090s. It is revealed that potential vegetation belts during the 2050s shift northward greatly in central and eastern China compared to those during 1961-1990. In contrast, potential vegetation change is slight in western China on the whole. The spatial pattern of potential vegetation during the 2090s is generally similar to that during the 2050s, but the range of potential vegetation change against 1961 1990 is more extensive during the 2090s than the 2050s, particularly in western China. Additionally, there exists model-dependent uncertainty of potential vegetation change under the SRES A2 scenario during the 2090s, which is due to the scatter of projected climate change by the models. The projected change in potential vegetation under the SRES A2 scenario during the 2090s is attributable to surface temperature change south of 35°N and to the joint changes of surface temperature, precipitation, and atmospheric CO2 concentration north of 35°N. 相似文献
13.
Numerical simulation of the impact of vegetation index on the interannual variation of summer precipitation in the Yellow River Basin 总被引：1，自引：0，他引：1
Two sets of numerical experiments using the coupled National Center for Environmental Prediction General Circulation Model （NCEP/GCM T42L18） and the Simplified Simple Biosphere land surface scheme （SSiB） were carried out to investigate the climate impacts of fractional vegetation cover （FVC） and leaf area index （LAI） on East Asia summer precipitation, especially in the Yellow River Basin （YRB）. One set employed prescribed FVC and LAI which have no interannual variations based on the climatology of vegetation distribution; the other with FVC and LAI derived from satellite observations of the International Satellite Land Surface Climate Project （ISLSCP） for 1987 and 1988. The simulations of the two experiments were compared to study the influence of FVC, LAI on summer precipitation interannual variation in the YRB. Compared with observations and the NCEP reanalysis data, the experiment that included both the effects of satellite-derived vegetation indexes and sea surface temperature （SST） produced better seasonal and interannual precipitation variations than the experiment with SST but no interannual variations in FVC and LAI, indicating that better representations of the vegetation index and its interannual variation may be important for climate prediction. The difference between 1987 and 1988 indicated that with the increase of FVC and LAI, especially around the YRB, surface albedo decreased, net surface radiation increased, and consequently local evaporation and precipitation intensified. Further more, surface sensible heat flux, surface temperature and its diurnal variation decreased around the YRB in response to more vegetation. The decrease of surface-emitting longwave radiation due to the cooler surface outweighed the decrease of surface solar radiation income with more cloud coverage, thus maintaining the positive anomaly of net surface radiation. Further study indicated that moisture flux variations associated with changes in the general circulation also contributed to the precipitation interannual variation. 相似文献
14.
利用中国科学院大气物理研究所(IAP)一个海洋-大气-动态植被耦合模式(GOALS-AVIM),进行了100年模拟积分.基于模拟结果,对东亚地区的植被净初级生产力(NPP)、降水、地面气温和短波辐射的季节变化进行了标准化对比,分析了NPP的时空格局与气候因子(气温、短波辐射和降水)的关系;利用奇异值分解(SVD)对东亚夏季降水场和NPP的关系进行分解.结果表明,夏季东亚地区植被NPP及相关气候因子的时空变化规律明显,耦合模式可以很好地模拟出观测存在的降水及NPP、LAI(叶面积指数)大值区随季节北移南退的形态;由于耦合模式中AVIM的双向特点,模式模拟的NPP与其他物理场的季节变化有很强的对应关系,而且在不同时间和地区,NPP与降水、地面气温、短波辐射表现出不同的对应关系,其中植被NPP时间变化与气温和降水的相关性都较高;从NPP场和降水场夏季逐月标准化距平奇异值分解的空间分布模态来看.NPP与降水在时空场上表现出很强的耦合性,NPP的空间格局与降水存在较好的相关性,不同地理位置的相关性强弱不同,分解出的降水场异常相关模态也再现了东亚夏季降水移动的时空特征,同时东亚雨带随季节变化与NPP的气候变率表现出不同的对应模态. 相似文献
15.
NUMERICAL SIMULATIONS OF EFFECTS OF LAND SURFACE PROCESSES ON CLIMATE--IMPLEMENTING OF SSiB IN IAP/LASG AGCM AND ITS PERFORMANCE* 下载免费PDF全文
下载免费PDF全文 This is an investigation of exchanges of energy and water between the atmosphere and the vegetated continents,and the impact of and mechanisms for land surface-atmosphere interactions on hydrological cycle and general circulation by implementing the Simplified Simple Biosphere(SSiB) model in a modified version of IAP/LASG global spectral general model(L9R15 AGCM).This study reveals that the SSiB model produces a better partitioning of the land surface heat and moisture fluxes and its diurnal variations,and also gives the transport of energy and water among atmosphere,vegetation and soil explicitly and realistically.Thus the coupled SSiB-AGCM runs lead to the more conspicuous improvement in the simulated circulation,precipitation,mean water vapor content and its transport.particularly in the Asian monsoon region in the real world than CTL-AGCM runs.It is also pointed out that both the implementation of land surface parameterizations and the variations in land surface into the GOALS model have greatly improved hydrological balance over continents and have a significant impact on the simulated climate.particularly over the massive continents.Improved precipitation recycling model was employed to verify the mechanisms for land surface hydrology parameterizations on hydrological cycle and precipitation climatology in AGCM.It can be argued that the recycling precipitation rate is significantly reduced,particularly in the arid and semi-arid region of the boreal summer hemisphere,coincident with remarkable reduction in evapotranspiration over the continental area.Therefore the coupled SSiB-AGCM runs reduce the bias of too much precipitation over land surface in most AGCMs,thereby bringing the simulatedprecipitation closer to observations in many continental regions of the world than CTL-AGCMruns. 相似文献
16.
利用6个地球系统模式模拟的植被净初级生产力（NPP）对1901～2005年NPP时空变化进行了研究,并结合气候因子分析了NPP的变化与气温和降水的关系。结果表明:（1）近百年来全球NPP呈现上升趋势,模式集合平均的趋势系数为0.88,通过了99.9%的信度检验;北半球的趋势比南半球明显。（3）近百年来800 g(C) m-2 a-1以上的NPP高值区主要分布在南美洲赤道地区、非洲赤道地区、中南半岛和印度尼西亚一带的热带雨林区;低值区主要分布在北半球高纬度地区、非洲北部地区、亚洲大陆干旱半干旱区以及青藏高原西北部地区。（3）全球NPP与气温百年演变在大部分地区主要为正相关关系,仅在赤道附近的南美洲、非洲以及印度地区为负相关关系,主要由于这些地区辐射是NPP的限制因子。全球NPP与降水的百年变化在大部分地区也主要是正相关关系,在非洲北部到西亚中亚的干旱半干旱地区为负相关关系。（4）6个地球系统模式在全球21个区域的大部分地区的NPP和气温降水的变化关系较为一致,西非地区不同模式变化不一致,NPP模拟的不确定性较大,其次是地中海地区。（5）东亚地区NPP与气候的百年演变同步并且相关性高,反映了强烈的植被大气相互作用过程。 相似文献
17.
陆面过程对气候影响的数值模拟:SSiB与IAP/LASG L9R15 AGCM耦合及其模式性能 总被引：18，自引：2，他引：16
利用陆面过程模式 SSi B与 IAP/LASG发展的 L9R1 5AGCM的耦合 1 0 a积分试验 ,研究了全球尺度大气与地表的水分和能量交换以及陆地与大气环流和气候的相互作用。模拟表明 :SSi B模式可模拟出陆地上较为真实的表面通量及其日变化 ,较好地定量描述土壤 -植被 -大气连续体系 ( SPAC)中能量和水分的传输过程。因此 ,将其引入气候模式中能够模拟出比 CTL- AGCM更合理的气候平均状态、水汽分布以及水汽输送的气候特征 ,特别是亚洲夏季风水汽输送独特的地域性 ,再现了大气环流 ,尤其是陆面气候的基本特征。并指出 ,陆面过程参数化的引进及其陆面状况的变化显著地改善了全球陆地上的水分平衡状况。利用改进的再循环降水模式 ,进一步研究了陆面过程参数化明显改进降水模拟的物理机制。指出全球陆地 ,特别是盛夏北半球干旱、半干旱地区的再循环降水率明显减小 ,与陆面上表面潜热通量的显著减小区一致 ,从而克服了许多未耦合陆面过程的 AGCMs因对地表水过程非常简单地参数化导致的普遍存在着整个陆地降水偏高 ,改善了全球陆地上的水分平衡状况。因此 ,在充分耦合的陆气环流模式中模拟的降水分布与实况接近。 相似文献
18.
在验证CENTURY模型对中国陆地植被净初级生产力(Net Primary Productivity,NPP)模拟能力的基础上,利用该模型探讨了1981-2008年中国陆地植被NPP的年际变异和变化趋势对CO2浓度、温度和降水变化的响应。结果表明,中国陆地植被NPP对不同气候因子的响应程度存在明显不同。其中,CO2浓度变化对植被NPP年际变异的影响不显著,但能够引起中国大部分地区植被NPP趋势系数增大;温度对中国中高纬度地区植被NPP的年际变化影响显著,但就全国范围而言,植被NPP年际变异对温度变化的响应程度总体低于对降水变化的响应程度;降水变化是对中国植被NPP变化趋势起主导作用的气候因子。此外,综合考虑温度和降水变化的影响发现,植被NPP变化趋势的响应特征类似于降水单独变化时植被NPP变化趋势的响应特征。 相似文献
19.
Influence of dynamic vegetation on climate change arising from increasing CO<Subscript>2</Subscript>
A dynamic global vegetation model (DGVM) is coupled to an atmospheric general circulation model (AGCM) to investigate the
influence of vegetation dynamics on climate change under conditions of global warming. The model results are largely in agreement
with observations and the results of previous studies in terms of the present climate, present potential vegetation, present
net primary productivity (NPP), and pre-industrial carbon budgets. The equilibrium state of climate properties are compared
among pre-industrial, doubled, and quadrupled atmospheric CO2 values using DGVM–AGCM and current AGCM with fixed vegetation to evaluate the influence of dynamic vegetation change. We
also separated the contributions of temperature, precipitation and CO2 fertilization on vegetation change. The results reveal an amplification of global warming climate sensitivity by 10% due
to the inclusion of dynamic vegetation. The total effects of elevated CO2 and climate change also lead to an increase in NPP and vegetation coverage globally. The reduction of albedo associated with
this greening results in enhanced global warming. Our separation analysis indicates that temperature alters vegetation at
high latitudes such as Siberia or Alaska, where there is a switch from tundra to forest. On the other hand, CO2 fertilization provides the largest contribution to greening in arid/semi-arid region. Precipitation change did not cause
any drastic vegetation shift. 相似文献
20.
青藏高原冬、春植被归一化指数变化特征及其与高原夏季降水的联系 总被引：4，自引：0，他引：4
青藏高原气候独特,影响高原夏季降水的原因是十分复杂的和多方面的。文中利用1982—2001年的卫星遥感植被归一化指数(NDVI)资料和青藏高原55个实测台站降水资料,应用经验正交分解(EOF)、奇异值分解(SVD)等方法分析了青藏高原冬、春植被变化特征及其与高原夏季降水的联系,得到以下几点初步认识:青藏高原冬、春季植被分布基本呈现东南地区植被覆盖较好,逐渐向西北地区减少的特征。其中高原东南部地区和高原南侧边界地区NDVI值最大,而西北地区和北侧边界地区NDVI较小。EOF分析表明,20年来冬、春季高原植被的变化趋势是总体呈阶段性增加,其中尤以高原北部、西北部(昆仑山、阿尔金山和祁连山沿线)和南部的雅鲁藏布江流域植被增加明显。由SVD方法得到的高原前期NDVI与后期降水的相关性是较稳定的。青藏高原多数区域冬、春植被与夏季降水存在较好的正相关,且这种滞后相关存在明显的区域差异。高原南部和北部区域的NDVI在冬春两季都与夏季降水有明显的正相关,即冬春季植被对夏季降水的影响较显著。而冬季高原中东部玉树地区附近区域的NDVI与夏季降水也存在较明显的负相关,即冬季中东部区域的植被变化对夏季降水的影响也较显著。由此可见,高原前期NDVI的变化特征,可以作为高原降水长期预报综合考虑的一个重要参考因子。 相似文献