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1.
基于全球土地利用类型和覆盖度,利用生长季多年平均（1982～2015年）归一化植被指数（Normalized Difference Vegetation Index,NDVI）和气候平均态（气温、降水量）数据,讨论了全球植被格局与气候因子之间的关系,建立了两者之间的多元回归模型,并分析了植被对气温和降水气候态敏感性的特征。植被与气候因子在气候梯度上存在明显的对应关系,回归模型可较好拟合气候态NDVI的全球分布格局,拟合与观测NDVI的相关系数达0.90。其中,常绿阔叶林、混交林、常绿针叶林、落叶阔叶林、农田和木本稀树草原空间分布的拟合能力较好（r>0.8）。不同土地覆盖类型的NDVI对气温、降水气候态的空间敏感性特征不同。整体而言,植被对气温和降水的敏感性呈现反相关关系（r=-0.6）。不同土地覆盖类型对气温表现出正/负敏感性,寒带灌木对气温的敏感性最强,而农作物、草原、裸地对气温负敏感性较大;植被对降水的敏感性均表现出正敏感性,其中落叶针叶林、草原和稀树草原对降水的空间敏感性较强。 相似文献
2.
开展北京松柏植被的高分辨率空间信息提取及其花粉致敏风险评估对花粉浓度监测及预报具有重要意义。本文利用2019—2020年冬季304景高分辨率哨兵2A号（Sentinel 2A）卫星影像，引入新型增强型归一化植被指数（Enhanced normalized Vegetation Index,EVI）和地表水分指数（Land Surface Water Index,LSWI），开展了10 m空间分辨率的北京松柏植被分布制图研究；同时依据风险评估原理，结合2020年北京松柏花粉浓度观测数据，建立了基于松柏植被分布的花粉致敏风险空间评估方法，并初步开展了影响松柏花粉浓度范围与花粉致敏风险空间评估研究。结果表明：①基于冬季合成晴空Sentinel 2A卫星影像，利用EVI和LSWI可有效提取北京10 m空间分辨率的松柏植被分布，用户精度可达80%以上；②松柏花粉观测站14 km范围内松柏植被对该站花粉浓度具有正贡献，其中6 km范围内的松柏植被贡献最大；③松柏花粉致敏相对高风险区主要分布在西北部山区、昌平北部以及门头沟东部、石景山西北和海淀西南等地区。 相似文献
3.
Lawrence R. Heaney 《Climatic change》1991,19(1-2):53-61
Tropical rain forest in Southeast Asia has developed within an extensive archipelago during the past 65 million years or more. During the Miocene (beginning 25 million years BP), rain forest extended much further north (to southern China and Japan); since that time it has contracted. During the Pleistocene (beginning 2.0 million years BP), development of continental glaciers at high latitudes was associated in Southeast Asia with lowered sea level, cooler temperatures, and modified rainfall patterns. Fossil pollen records demonstrate that Southeast Asian vegetation during the last glacial maximum (ca. 18 000 BP) differed substantially from that of today, with an increase in the extent of montane vegetation and savannah and a decline in rain forest. These data show that the distribution and extent of rain forest in Southeast Asia has historically been quite sensitive to climatic change. 相似文献
4.
Hui Hao David K. Ferguson Guang-Ping Feng Albert Ablaev Yu-Fei Wang Cheng-Sen Li 《Climatic change》2010,99(3-4):547-566
The pollen and spores of the Wuyun Formation (Danian, Early Paleocene) from Jiayin County, Heilongjiang Province, Northeast China, are studied in this paper. The Danian vegetation at Wuyun was composed of mixed temperate and subtropical broad-leaved forest, with an admixture of conifers. The climatic parameters, obtained by the Coexistence Approach based on the palynological and megafossil data, are Mean Annual Temperature of 14.8–16.8°C, Mean Annual Precipitation of 815.8–1,571.8 mm. Combining other climatic parameters in the Tertiary, we obtained the latitudinal temperature gradients: 0.24 in Paleocene, 0.1 in Eocene, 0.45 in Miocene and 0.55 in Pliocene, in the area of East Asia. All these values and modern latitudinal gradient of 0.7 suggest a climatic transition from Paleocene to today: the temperature at higher latitudes first increased then decreased gradually during last 65 Ma, while it changed slightly in lower latitudes. 相似文献
5.
Martin Schmidt Doris Klein Christopher Conrad Stefan Dech Heiko Paeth 《Theoretical and Applied Climatology》2014,115(1-2):341-353
Vegetation cover is a crucial component of the Earth’s climate system but, still, our understanding of the mechanisms governing the reciprocal influence between atmosphere and vegetation is limited. In this study, we investigate the unilateral atmospheric impact on vegetation cover in tropical and northern Africa, differentiated into regions with different circulation regimes and into detailed land-cover classes. In contrast to former studies, climate predictors from a regional climate model are used as input for a multiple regression model. Climate models provide consistent data without gaps at high spatial resolution, a considerably larger set of available climate variables and the perspective to transfer the statistical relationships to future projections, e.g., in the context of anthropogenic climate change. Indeed, robust climate predictors which drive up to 70 % of observed interannual vegetation variability could be extracted from the climate model. Besides precipitation and temperature, global radiation, and relative humidity play an important role. The statistical transfer functions are plausible in terms of the affected regions and land-cover classes and draw a rather complex picture of the atmosphere–vegetation relation in Africa. 相似文献
6.
K. Gajewski André E. Viau Michael Sawada David E. Atkinson Philippe Fines 《Climatic change》2006,78(2-4):341-361
Interpreting the postglacial climate history of the European continent using pollen data has proven difficult due in part to human modification of the landscape. Separating climate from human-caused changes in the vegetation requires a strategy for determining times of change across the entire region. We quantified transitions in the vegetation across Europe during the past 12,000 years using a mixture model approach on two datasets: radiocarbon dates from pollen diagrams and zone boundaries from selected reference sites. Major transitions in the vegetation, as recorded in pollen diagrams, appear synchronous across the continent. These transitions were also synchronous with those identified in North America pollen diagrams and major environmental changes recorded in North Atlantic marine records and Greenland ice cores. This synchronicity suggests that the major vegetation transitions in Europe during the Holocene and late glacial were primarily caused by large-scale atmospheric circulation change. These climate changes may have caused some of the cultural, political and migration changes in European societies during the Holocene. 相似文献
7.
To interpret past vegetation and climate changes from pollen data, we need to reveal the degree of similarity between modern analogues and fossil pollen spectra, which would help us predict the future climate and vegetation. Ninety surface pollen samples across six vegetation zones along an altitudinal gradient from 460 to 3510 m and 44 fossil samples at Caotan Lake were collected in the central Tianshan Mountains, northern Xinjiang, China. Discriminant analyses results, fossil pollen and phytolith assemblages were then used to reconstruct palaeovegetation and palaeoclimate in the area. The 90 surface samples were divided into six pollen zones (alpine cushion, alpine and subalpine meadow, montane Tianshan spruce forest, forest-steppe ecotone, Artemisia desert, typical desert), corresponding to the major vegetation types in the area. These zones follow a climatic gradient of increasing precipitation with increasing elevation. Paleovegetation reconstructed from 44 fossil pollen assemblages through discriminant analysis reflects the regional vegetation shifted from typical desert to Artemisia desert since 4640 cal. year BP in the Caotan Lake wetland. The fossil pollen and phytolith record also reveal the arid climate has not fundamentally changed in the period. But a dry-wet-dry local climate oscillation since 2700 cal. year BP has a fundamental influence on local wetland vegetation dynamics and peat accumulation of the Caotan wetland. Modern wetland landscape and surface pollen assemblages from the Ebinur Lake Wetland Nature Reserve provide further evidence for ferns and Betula growing in the Caotan Lake wetland during the historical period. 相似文献
8.
9.
D. Greenland 《Theoretical and Applied Climatology》1993,46(4):229-239
Summary Modelling and Geographic Information System (GIS) technology are employed in order to extend spatially, estimated and observed growing season values of the components of the surface heat energy budget for an area of alpine tundra in the Colorado Front Range. A surface equilibrium temperature model is calibrated for one sub-class of vegetation surface and is used to model surface heat energy budget component values for other sub-classes of vegetation. The model values compare favorably with values independently estimated or observed. The data are spatially displayed using the Idrisi GIS. At the microclimatic scale the presence of different sub-classes of vegetation plays a large role in controlling the actual values of the surface heat budget components. This is in contrast to the larger scale at which climatic variables such as air temperature control the overall vegetation type found in the area.With 6 Figures 相似文献
10.
Spatial information on climatic characteristics is beneficial in e.g. regional planning, building construction and urban ecology. The possibility to spatially predict urban?Crural temperatures with statistical techniques and small sample sizes was investigated in Turku, SW Finland. Temperature observations from 36 stationary weather stations over a period of 6?years were used in the analyses. Geographical information system (GIS) data on urban land use, hydrology and topography served as explanatory variables. The utilized statistical techniques were generalized linear model and boosted regression tree method. The results demonstrate that temperature variables can be robustly predicted with relatively small sample sizes (n????20?C40). The variability in the temperature data was explained satisfactorily with few accessible GIS variables. Statistically based spatial modelling provides a cost-efficient approach to predict temperature variables on a regional scale. Spatial modelling may aid also in gaining novel insights into the causes and impacts of temperature variability in extensive urbanized areas. 相似文献
11.
利用GIS和遥感技术方法分析了2000—2014年那曲地区植被归一化指数(NDVI)的时空分布特征和变化趋势,探讨了NDVI与几种气象因子的关系。结果表明:空间上,研究区植被NDVI在空间上呈自西向东、自南向北逐步增大,高海拔地区小于低海拔地区的分布特点;时间上,近15a的NDVI总体上呈不显著性下降趋势,NDVI变化可以分为3个阶段,分别为2000—2005年较好,2006—2008年略差,2009—2014年好转。植被面积变化趋势表现为西北部植被处于稳定状态的面积居多,变化较明显的区域集中在中部和东南部地区的人口密集区,改善和退化区域呈现交错出现的特点。那曲地区植被变化的主要影响因素为降水量和热量因素引起的,人类活动在较短时间尺度上对植被也有较大影响。 相似文献
12.
A Bayesian statistical model for deriving the predictive distribution of hydroclimatic variables 总被引：1，自引：0，他引：1
Recent publications have provided evidence that hydrological processes exhibit a scaling behaviour, also known as the Hurst phenomenon. An appropriate way to model this behaviour is to use the Hurst-Kolmogorov stochastic process. The Hurst-Kolmogorov process entails high autocorrelations even for large lags, as well as high variability even at climatic scales. A problem that, thus, arises is how to incorporate the observed past hydroclimatic data in deriving the predictive distribution of hydroclimatic processes at climatic time scales. Here with the use of Bayesian techniques we create a framework to solve the aforementioned problem. We assume that there is no prior information for the parameters of the process and use a non-informative prior distribution. We apply this method with real-world data to derive the posterior distribution of the parameters and the posterior predictive distribution of various 30-year moving average climatic variables. The marginal distributions we examine are the normal and the truncated normal (for nonnegative variables). We also compare the results with two alternative models, one that assumes independence in time and one with Markovian dependence, and the results are dramatically different. The conclusion is that this framework is appropriate for the prediction of future hydroclimatic variables conditional on the observations. 相似文献
13.
14.
This study examines the impact of historical land-cover change on North American surface climate, focusing on the robustness of the climate signal with respect to representation of sub-grid heterogeneity and land biogeophysics within a climate model. We performed four paired climate simulations with the Community Atmosphere Model using two contrasting land models and two different representations of land-cover change. One representation used a biome classification without subgrid-scale heterogeneity while the other used high-resolution satellite data to prescribe multiple vegetation types within a grid cell. Present-day and natural vegetation datasets were created for both representations. All four sets of climate simulations showed that present-day vegetation has cooled the summer climate in regions of North America compared to natural vegetation. The simulated magnitude and spatial extent of summer cooling due to land-cover change was reduced when the biome-derived land-cover change datasets were replaced by the satellite-derived datasets. The diminished cooling is partly due to reduced intensity of agriculture in the satellite-derived datasets. Comparison of the two land-surface models showed that the use of a comparatively warmer and drier land model in conjunction with satellite-derived datasets further reduced the simulated magnitude of summer cooling. These results suggest that the cooling signal associated with North American land-cover change is robust but the magnitude and therefore detection of the signal depends on the realism of the datasets used to represent land-cover change and the parametrisation of land biogeophysics. 相似文献
15.
Summary In this study, spatial interpolation techniques have been applied to develop an objective climatic cartography of precipitation
in the Iberian Peninsula (583,551 km2). The resulting maps have a 200 m spatial resolution and a monthly temporal resolution. Multiple regression, combined with
a residual correction method, has been used to interpolate the observed data collected from the meteorological stations. This
method is attractive as it takes into account geographic information (independent variables) to interpolate the climatic data
(dependent variable). Several models have been developed using different independent variables, applying several interpolation
techniques and grouping the observed data into different subsets (drainage basin models) or into a single set (global model).
Each map is provided with its associated accuracy, which is obtained through a simple regression between independent observed
data and predicted values. This validation has shown that the most accurate results are obtained when using the global model
with multiple regression mixed with the splines interpolation of the residuals. In this optimum case, the average R
2 (mean of all the months) is 0.85. The entire process has been implemented in a GIS (Geographic Information System) which
has greatly facilitated the filtering, querying, mapping and distributing of the final cartography. 相似文献
16.
Interpolation of climate variables and temperature modeling 总被引：1，自引：0，他引：1
Sailesh Samanta Dilip Kumar Pal Debasish Lohar Babita Pal 《Theoretical and Applied Climatology》2012,107(1-2):35-45
Geographic Information Systems (GIS) and modeling are becoming powerful tools in agricultural research and natural resource management. This study proposes an empirical methodology for modeling and mapping of the monthly and annual air temperature using remote sensing and GIS techniques. The study area is Gangetic West Bengal and its neighborhood in the eastern India, where a number of weather systems occur throughout the year. Gangetic West Bengal is a region of strong heterogeneous surface with several weather disturbances. This paper also examines statistical approaches for interpolating climatic data over large regions, providing different interpolation techniques for climate variables' use in agricultural research. Three interpolation approaches, like inverse distance weighted averaging, thin-plate smoothing splines, and co-kriging are evaluated for 4°?×?4° area, covering the eastern part of India. The land use/land cover, soil texture, and digital elevation model are used as the independent variables for temperature modeling. Multiple regression analysis with standard method is used to add dependent variables into regression equation. Prediction of mean temperature for monsoon season is better than winter season. Finally standard deviation errors are evaluated after comparing the predicted temperature and observed temperature of the area. For better improvement, distance from the coastline and seasonal wind pattern are stressed to be included as independent variables. 相似文献
17.
Investigations of the ecological, atmospheric chemical, and climatic impacts of contemporary fires in tropical vegetation have received increasing attention during the last 10 years. Little is known, however, about the impacts of climate changes on tropical vegetation and wildland fires. This paper summarizes the main known interactions of fire, vegetation, and atmosphere. Examples of predictive models on the impacts of climate change on the boreal and temperate zones are given in order to highlight the possible impacts on the tropical forest and savanna biomes and to demonstrate parameters that need to be involved in this process. Response of tropical vegetation to fire is characterized by degradation towards xerophytic and pyrophytic plant communities dominated by grasses and fire-tolerant tree and bush invaders. The potential impacts of climate change on tropical fire regimes are investigated using a GISS GCM-based lightning and fire model and the Model for the Assessment of Greenhouse Gas-Induced Climate Change (MAGICC). 相似文献
18.
Influences of Climate Change and Its Interannual Variability on Surface Energy Fluxes from 1948 to 2000 总被引：1，自引：0，他引：1
Understanding changes in land surface processes over the past several
decades requires knowledge of trends and interannual variability in surface
energy fluxes in response to climate change. In our study, the Community
Land Model version 3.5 (CLM3.5), driven by the latest updated hybrid
reanalysis-observational surface climate data from Princeton University, is
used to obtain global distributions of surface energy fluxes during 1948 to
2000. Based on the climate data and simulation results, long-term trends and
interannual variability (IAV) of both climatic variables and surface energy
fluxes for this span of 50+ years are derived and analyzed. Regions with
strong long-term trends and large IAV for both climatic variables and
surface energy fluxes are identified. These analyses reveal seasonal
variations in the spatial patterns of climate and surface fluxes; however,
spatial patterns in trends and IAV for surface energy fluxes over the past
～50 years do not fully correspond to those for climatic variables,
indicating complex responses of land surfaces to changes in the climatic
forcings. 相似文献
19.
Climatic fluctuations on the century time scale: A review of high-resolution proxy data and possible mechanisms 总被引：2，自引：0，他引：2
We review the century time scale climatic variability that is observed in high-resolution proxy data records covering the past 10 000 yr. Cyclic variations with time scales ranging from 50 to 400 yr occur in oxygen isotope ratios derived from ice cores, tree-ring index series, pollen records and sea-ice extents. Century time scale cycles can also be identified in some biological and historical records and in long-term instrumental observations. In order to appreciate the century scale cycles in the context of climatic variability in general, a brief survey of all climatic time scales is presented.The traditional interpretation that decadal-to-century scale fluctuations in the climate system are externally forced, e.g. by variations in solar properties, is questioned. A different mechanism for these fluctuations is proposed on the basis of recent findings of numerical models of the ocean's thermohaline circulation. The results indicate that this oceanic circulation exhibits natural variability on the century time scale which produces oscillations in the ocean-to-atmosphere heat flux. Although global in extent, these fluctuations are largest in the Atlantic Ocean. 相似文献
20.
历史时期青藏高原气候变化特征的初步分析 总被引：18，自引：2，他引：18
本文利用树木年轮资料、气象观测记录、历史文献记载和孢粉分析等,推断了青藏高原数千年来气候变化的基本概况,并划出气候适宜期、新冰川期、温暖期、现代小冰期和最近的升温期等五个时期。 分析表明,历史时期内高原上气候变化的趋势、大的冷暖期演变,大体上与我国其它地区一致,这是气侯变迁的相关性所致。同时,它又有与平原地区不同的特征,主要表现在气候变化的振幅较大,对气侯变化的敏感性也较强。由此还推论高原在同纬度带地区中,应属气候变化敏感区,主要表现对升温过程反映强烈。 此外,还对高原气候变化的周期性等规律予以分析。 相似文献