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1.
Total 26 modern soil samples were collected from various regions under different climate conditions from tropical to arid temperate in China and systematically analyzed for their organic matters by GC/MS in order to evaluate climatic impacts on soil organic components. Abundant lipids molecules were recognized, including n-alkanes, n-alkenones, and long-chain branched alkanes. We find the pre- dominance of main peaks of long-chain n-alkanes (nC29, nC31, nC33) and short-chain ones (nC16, nC17, nC18) records information of soil generation in warm-humid and cold-dry regions. The proportion of n-alkanes (nC16 nC17 nC18) to (nC29 nC31 nC33) varies in good agreement with moisture-heat conditions and thus probably can serve as a new index for climate change. The ratios of C21-/nC22 , nC17/nC31 and (nC15 nC17 nC19) / ( nC27 nC29 nC31) of n-alkanes, indicating respectively input ratios of lower bacterial alga, aquatic organisms, and higher plants and terraneous organisms, co-vary well in different climate regions from forest to grassland and desert, suggesting that they have also reflected the difference of climates between monsoon region and inland one. The C21-/C22 ratio of n-alkan-2-one records largely the discrepancy of temperature from north to south of China bordered by the Qinling Mountains, but less humidity. The C21-/C22 ratio of n-alkan-3-ones changes well with climatic factors, such as tem- perature and humidity. The biogenic source of series A-D long-chain branched alkanes may be derived from some kinds of special epiphyte that most likely live in weak oxic-anoxic and moisture-heat envi- ronments, suggesting their distribution record as well some information on climatic change. All these researches demonstrate that the distributions of lipids molecules in modern soils in China record well signals of climates from quite different climatic regions, and can serve as important climatic proxies to reveal climatic change over China.  相似文献   

2.
Total 26 modern soil samples were collected from various regions under different climate conditions from tropical to arid temperate in China and systematically analyzed for their organic matters by GC/MS in order to evaluate climatic impacts on soil organic components. Abundant lipids molecules were recognized, including n-alkanes, n-alkenones, and long-chain branched alkanes. We find the predominance of main peaks of long-chain n-alkanes (nC29,nC31,nC33) and short-chain ones(nC16,nC17,nC18) records information of soil generation in warm-humid and cold-dry regions. The proportion of n-alkanes(nC16 nC17 nC18)to(nC29 nC31 nC33)varies in good agreement with moisture-heat conditions and thus probably can serve as a new index for climate change. The ratios of C21-/nC22 ,nC17/nC31 and (nC15 nC17 nC19)/(nC27 nC29 nC31)of n-alkanes, indicating respectively input ratios of lower bacterial alga, aquatic organisms, and higher plants and terraneous organisms, co-vary well in different climate regions from forest to grassland and desert, suggesting that they have also reflected the difference of climates between monsoon region and inland one. The C21-/C22 ratio of n-alkan-2-one records largely the discrepancy of temperature from north to south of China bordered by the Qinling Mountains, but less humidity. The C21-/C22 ratio of n-alkan-3-ones changes well with climatic factors, such as temperature and humidity. The biogenic source of series A-D long-chain branched alkanes may be derived from some kinds of special epiphyte that most likely live in weak oxic-anoxic and moisture-heat environments, suggesting their distribution record as well some information on climatic change. All these researches demonstrate that the distributions of lipids molecules in modern soils in China record well signals of climates from quite different climatic regions, and can serve as important climatic proxies to reveal climatic change over China.  相似文献   

3.
Total 26 modern soil samples were collected from various regions under different climate conditions from tropical to arid temperate in China and systematically analyzed for their organic matters by GC/MS in order to evaluate climatic impacts on soil organic components. Abundant lipids molecules were recognized, including n-alkanes, n-alkenones, and long-chain branched alkanes. We find the predominance of main peaks of long-chain n-alkanes (nC29,nC31,nC33) and short-chain ones(nC16,nC17,nC18) records information of soil generation in warm-humid and cold-dry regions. The proportion of n-alkanes(nC16+nC17+nC18)to(nC29+nC31+nC33)varies in good agreement with moisture-heat conditions and thus probably can serve as a new index for climate change. The ratios of C21-/nC22+,nC17/nC31 and (nC15+nC17+nC19)/(nC27+nC29+nC31)of n-alkanes, indicating respectively input ratios of lower bacterial alga, aquatic organisms, and higher plants and terraneous organisms, co-vary well in different climate regions from forest to grassland and desert, suggesting that they have also reflected the difference of climates between monsoon region and inland one. The C21-/C22+ ratio of n-alkan-2-one records largely the discrepancy of temperature from north to south of China bordered by the Qinling Mountains, but less humidity. The C21-/C22+ ratio of n-alkan-3-ones changes well with climatic factors, such as temperature and humidity. The biogenic source of series A-D long-chain branched alkanes may be derived from some kinds of special epiphyte that most likely live in weak oxic-anoxic and moisture-heat environments, suggesting their distribution record as well some information on climatic change. All these researches demonstrate that the distributions of lipids molecules in modern soils in China record well signals of climates from quite different climatic regions, and can serve as important climatic proxies to reveal climatic change over China.  相似文献   

4.
The loess record in southern Tajikistan and correlation with Chinese loess   总被引：12，自引：0，他引：12  
In the present study, the Chashmanigar loess–soil sequence in southern Tajikistan is studied; this loess section has a paleomagnetic basal age of about 1.77 Myr. Magnetic susceptibility, color reflectance and grain size were systematically measured for closely spaced samples from the section. Paleosols consistently have a finer grain size distribution, higher magnetic susceptibility, redder color reflectance and lower dust sedimentation rate than loess horizons, suggesting a colder, drier and dustier environment during glacial periods than in interglacial periods. The grain size record was tuned to variations in obliquity and precession of the Earth’s orbit. The resulting magnetic susceptibility, grain size and color reflectance time series all show well-expressed astronomical periodicities during the Pleistocene. The mid-Pleistocene climate transition, characterized by a shift of dominant climatic periods from 41 kyr to 100 kyr at about 1.0–0.8 Myr, is clearly documented in these proxy records. Comparison of the Chashmanigar loess record with the Lingtai loess section in China and the ODP site 677 δ18O record shows that during the entire Pleistocene, the climate cycles recorded by the Central Asian loess can be well correlated to the Chinese loess and deep-sea oxygen isotope records. It is suggested that alternations of loess and soil horizons both in Central Asia and China could be basically forced by global ice volume variations, although different wind systems have controlled the Pleistocene loess transport and sedimentation in the two areas.  相似文献   

5.
Abstract

An HBV rainfall–runoff model was applied to test the influence of climatic characteristics on model parameter values. The methodology consisted of the calibration and cross-validation of the HBV model on a series of 5-year periods for four selected catchments (Axe, Kamp, Wieprz and Wimmera). The model parameters were optimized using the SCEM-UA method which allowed for their uncertainty also to be assessed. Nine climatic indices were selected for the analysis of their influence on model parameters, and divided into water-related and temperature-related indices. This allowed the dependence of HBV model parameters on climate characteristics to be explored following their response to climate change conditioned on the catchment’s physical characteristics. The Pearson correlation coefficient and weighted Pearson correlation coefficient were used to test the dependence. Most parameters showed a statistically significant dependence on several climatic indices in all catchments. The study shows that the results of the correlation analysis with and without parametric uncertainty taken into account differ significantly.  相似文献   

6.
D. Raje  P. Priya  R. Krishnan 《水文研究》2014,28(4):1874-1889
In climate‐change studies, a macroscale hydrologic model (MHM) operating over large scales can be an important tool in developing consistent hydrological variability estimates over large basins. MHMs, which can operate at coarse grid resolutions of about 1° latitude by longitude, have been used previously to study climate change impacts on the hydrology of continental scale or global river basins. They can provide a connection between global atmospheric models and water resource systems on large spatial scales and long timescales. In this study, the variable infiltration capacity (VIC) MHM is used to study large scale hydrologic impacts of climate change for Indian river basins. Large‐scale changes in runoff, evapotranspiration and soil moisture for India, as well as station‐scale changes in discharges for three major river basins with distinct climatic and geographic characteristics are examined in this study. Climate model projections for meteorological variables (precipitation, temperature and wind speed) from three general circulation models (GCMs) and three emissions scenarios are used to drive the VIC MHM. GCM projections are first interpolated to a 1° by 1° hydrologic model grid and then bias‐corrected using a quantile–quantile mapping. The VIC model is able to reproduce observed statistics for discharges in the Ganga, Narmada and Krishna basins reasonably well, even at the coarse grid resolution employed using a calibration period for years 1965–1970 and testing period from 1971–1973/1974. An increasing trend is projected for summer monsoon surface runoff, evapotranspiration and soil moisture in most central Indian river basins, whereas a decrease in runoff and soil moisture is projected for some regions in southern India, with important differences arising from GCM and scenario variability. Discharge statistics show increases in mid‐flow and low flow at Farakka station on Ganga River, increased high flows at Jamtara station upstream of Narmada, and increased high, mid‐flow and low flow for Vijayawada station on Krishna River in the future. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

7.
ABSTRACT

Sir Charles Cotton (1964) has pointed out that in an earlier paper (Carlston, 1963) which related drainage density to hydrology, there was insufficient emphasis on the role of climate in its effect on drainage density. Re-examination of the relation of drainage density to base flow in the 15 basins originally described has revealed additional evidence that base flow is affected by precipitation or recharge (a climatic variable), while varying inversely with drainage density.

Within the climatic region studied in the earlier paper (the Humid Subtropical Climate of the eastern U. S.), no evidence could be found that amount or intensity of rainfall affected the intensity of flood runoff or the scale of drainage density. In comparison with other climates, however, such as the Marine West Coast Climate, it is possible that the less intense precipitation of a marine climate may result in lower runoff intensities and lower drainage densities, however the lower mean temperatures of such climates may develop soils of generally higher infiltration capacity which would produce lower drainage densities.

A progressive increase in aridity results in a decrease in soil and vegetal cover which greatly magnifies the range of drainage densities characteristic of semi-arid regions. In such regions, where the land sur-face has a good infiltration capacity rainfall sinks readily into the dry soil (although recharge to ground water may be negligible), and runoff is virtually zero, as is drainage density, Impermeable terranes devoid of vegetal and soil cover reject the rain, runoff is briefly total and drainage density may be greatly magnified, as in the South Dakota Badlands, where drainage density runs into the hundreds. Arid or Desert Climates should produce erosional landforms with generally high drainage densities, though not reaching the magnitudes of drainage density found in the semi-arid badlands where rainfall intensities are much higher.  相似文献   

8.
Vegetation and soil carbon storage in China   总被引：18，自引：2，他引：18  
This study estimated the current vegetation and soil carbon storage in China using a biogeochemical model driven with climate, soil and vegetation data at 0.5° latitude-longitude grid spatial resolution. The results indicate that the total carbon storage in China's vegetation and soils was 13.33 Gt C and 82.65 Gt C respectively, about 3% and 4% of the global total. The nationally mean vegetation and soil carbon densities were 1.47 kg C/m2 and 9.17 kg C/m2, respectively, differing greatly in various regions affected by climate, vegetation, and soil types. They were generally higher in the warm and wet Southeast China and Southwest China than in the arid Northwest China; whereas vegetation carbon density was the highest in the warm Southeast China and Southwest China, soil carbon density was the highest in the cold Northeast China and southeastern fringe of the Qinghai-Tibetan Plateau. These spatial patterns are clearly correlated with variations in the climate that regulates plant growth and soil organi  相似文献   

9.
Long term synthetic precipitation data are useful for water resources planning and management. Commonly stochastic weather generator (SWG) models are useful to produce synthetic time series of unlimited length of weather data based on the statistical characteristics of observed weather at a given location. However, it is difficult to find a single model which works best for all weather (climate) patterns. The objective of this study is to evaluate five different SWG models namely CLIGEN, ClimGen, LARS-WG, RainSim and WeatherMan to generate precipitation at three diverse climatic regions: a Mediterranean climate of western USA, temperate climate of eastern Australia and tropical monsoon region in northern Vietnam. The performance of SWG models to generate precipitation characteristics (i.e., precipitation occurrence; wet and dry spell; and precipitation intensity on wet days) varies between three selected climatic regimes. It was observed that the second order Markov chain (ClimGen and WeatherMan) performed well for all three selected regions in generating precipitation occurrence statistics. All models are able to simulate the ratio of wet/dry spell lengths with respect to observed precipitation. The RainSim performed well in reproducing wet/dry spell lengths in comparison to other models for wetter regions in Australia and Vietnam. ClimGen and WeatherMan are the two best models in simulating precipitation in the western USA, followed by CLIGEN and LARS. Similarly, ClimGen and WMAN are the two best models for synthetic precipitation generation for eastern Australian and northern Vietnam stations, but CLIGEN performs poorly over these regions. All SWG model performed differently with respect to climatic regimes, therefore careful validation is required depending on the weather pattern as well as its application in different water resources sectors. Although our findings are preliminary in nature, however, in order to generalize the performance of SWG’s in a given climate type, it is recommended that more number of stations needs to be evaluated in future studies.  相似文献   

10.
The northeastern Tibetan Plateau began to grow during the Eocene and it is important to understand the climatic history of Asia during this period of so-called ‘doubthouse' conditions. However, despite major advances in the last few decades,the evolutionary history and possible mechanisms of Eocene climate change in the northeastern Tibetan Plateau remain unclear.The Xining Basin in the northeastern Tibetan Plateau contains a continuous sequence of Early to Late Eocene non-marine sediments which provides the opportunity to resolve long-term climate changes during this period. In this study, we report the results of analyses of lithofacies, sediment color and geochemistry of bulk samples collected from the Xijigou section of the Xining Basin. An abrupt lithofacies change between the Early(~52–40 Ma) and Late Eocene(~40–34 Ma) indicates a change in the depositional environment from a shallow lake to a playa lake in response to a significant climatic shift. During ~52–40 Ma,higher values of sediment redness(a*), redness/lightness(a*/L*) and higher modified Chemical Index of Weathering(CIW′)indicate a relatively warm and humid climate, while from ~40–34 Ma the lower values of a*, a*/L*and lower CIW′ imply subhumid to semi-arid climatic conditions. The paleoclimatic records indicate a long-term(~52–34 Ma) trend of decreasing chemical weathering, consistent with global climate change. An abrupt sharp excursion of the proxy records during ~42–40 Ma suggests a relatively brief warm interval, corresponding to the Middle Eocene Climatic Optimum(MECO). We suggest that global cooling substantially reduced humidity in inner Asia, resulting in sub-humid to semi-arid climatic conditions after 40 Ma in the Xining Basin, which may have been responsible for the long-term trend of decreasing chemical weathering during the Eocene.  相似文献   

11.
Y. Wang  X. Zhang  M. Mu  C. Zhang  A. Lv 《水文科学杂志》2019,64(16):2006-2014
ABSTRACT

Flood-risk is affected by both climatic and anthropogenic factors. In this study, we assess changes in flood risk induced by a combination of climate change and flood prevention sets in the Baiyangdian (BYD) Lake area of China. Extreme storm events are analysed by the bias-corrected climate data from global climate models. A hydrological model is implemented and integrated with a hydrodynamic model to assess flood risk under three scenarios. The streamflow into the BYD was validated against historical flash-flood events. The results indicate that the changing climate increased extreme precipitation, upstream total inflow and the flood risk at the core region of Xiong’an New Area (XNA), the newly announced special economic zone in the BYD area. However, flood prevention measures can effectively mitigate the climatic effect. The research highlights the severe flash-flood risk at BYD and demonstrates the urgent need for a climate-resilient plan for XNA.  相似文献   

12.
Abstract

River runoff and the resulting water resources which provide the needs of mankind for fresh water are subject to variations in space and time mainly depending on the space and time variability of climate characteristics. Thus there are close interrelations between the problems of the provision of fresh water and the problems of both natural and anthropogenic changes in climate. Moreover, these interrelations are characterized by specific features both under natural conditions and during a period of man's intensive impact on water resources. The problem of these interrelations has acquired a particular scientific and practical importance during recent years in which climatologists have attempted to predict global anthropogenic changes in climate for the near future, changes unknown on our plant for millennia. The present paper has been prepared mainly on the basis of research results obtained at the State Hydrological Institute in Leningrad. It describes the global interrelations between climatic characteristics and water resources under natural conditions and in the case of intensive water resources development; up-to-date ideas on the anthropogenic changes of the global climate are given; the possible consequent effects on future water resources are analysed.  相似文献   

13.
我国小冰期盛期的气候环境   总被引：22，自引：3，他引：19  
王苏民  刘健  周静 《湖泊科学》2003,15(4):369-376
小冰期是距今最近的全球性冷气候事件,是至今研究历史时期气候与人类活动关系的重点时期,它曾对世界和我国的社会经济产生了重要影响. 本文根据我国近年来历史文献、冰芯、树轮、湖芯和石笋的高分辨率研究成果,结合部分国外的结果,对小冰期从高纬、高山地区向中纬、低海拔地区的发展过程,17世纪小冰期盛期大范围普遍的降温、降水变化和空间分布与季风的关系进行了讨论. 该成果和气候模拟的结果可进行检验,为全球增温背景上可能出现的冷波动提供历史相似型.  相似文献   

14.
Abstract

This study quantifies global changes in irrigation requirements for areas presently equipped for irrigation of major crop types, using climate projections from 19 GCMs up to the 2080s. Analysis is based on results from the global eco-hydrological model LPJmL that simulates the complex and dynamic interplay of direct and indirect climate change effects upon irrigation requirements. We find a decrease in global irrigation demand by ～17% in the ensemble median, due to a combination of beneficial CO2 effects on plants, shorter growing periods and regional precipitation increases. In contrast, increases of >20% are projected with a high likelihood (i.e. in more than two thirds of the climate change scenarios) for some regions, including southern Europe, and, with a lower likelihood, for parts of Asia and North America as well. If CO2 effects were not accounted for, however, global irrigation demand would hardly change, and increases would prevail in most regions except for southern Asia (where higher precipitation is projected). We stress that the CO2 effects may not be realized everywhere, that irrigation requirements will probably increase further due to growing global food demand (not considered here), and that a significant amount of water to meet future irrigation requirements will have to be taken from fossil groundwater, environmental flow reserves or diverted rivers.

Editor D. Koutsoyiannis; Associate editor A. Montanari

Citation Konzmann, M., Gerten, D., and Heinke, J., 2013. Climate impacts on global irrigation requirements under 19 GCMs, simulated with a vegetation and hydrology model. Hydrological Sciences Journal, 58 (1), 1–18.  相似文献   

15.
This study analyzed the influence of large-scale climate pattern on precipitation in the Colorado River Basin. Large-scale climatic oscillations, like ENSO, PDO, NAO, and the global warming trend are associated with regional hydrologic variation. Ten types of climate indices were gathered and analyzed to investigate their influence on seasonal precipitation variation in the basin based on a linear correlation analysis and an influence index analysis. The influence index was developed in this study to measure the effect of climate variation on the seasonal precipitation in the basin. The statistical evidence achieved in this study confirms that the Colorado River Basin is subjected to the phase of climate variation. The strength of the seasonal response of precipitation to the climate variation varies in different localities in the basin. The methods of analysis used in this study were proposed in the hope that progress in understanding and modeling dynamic climatic systems can result in developing a valuable long-term forecasting model for water resources management.  相似文献   

16.
Predicting global climate change is a great challenge and must be based on a thorough understanding of how the climate system components behave. Precipitable water vapor (PWV) is one of the key components in determining and predicting the global climate system. It is well known that the local surface temperature and pressure have a direct influence on the production of PWV. However, the influence of solar activity on atmospheric dynamics and their physical mechanisms is still an open debate, where past studies are focused at mid-latitude regions. A new method of determining and quantifying the solar influence on PWV based on GPS observations to correlate the GPS PWV and total electron content (TEC) variations is proposed. Observed data from Scott Base (SBA) and McMurdo (MCM) stations from 2003 to 2005 have been used to study the response of PWV to solar activity. In the analysis, the effects of local conditions (wind speed and relative humidity) on the distribution of PWV are investigated. Results show significant correlation between PWV and solar activity for four geomagnetic storms, with correlation coefficients of 0.74, 0.77, 0.64 and 0.69, which are all significant at the 95% confidence level. There was no significant correlation between TEC and PWV changes during the absence of storms. On a monthly analysis, a strong relationship exists between PWV and TEC during storm-affected days, with correlation coefficients of 0.83 and 0.89 (99% confidence level) for SBA and MCM respectively. These indicate a statistically significant seasonal signal in the Antarctic region, which is very active (higher) during the summer and inactive (lower) for the winter periods.  相似文献   

17.
Climatological drivers of changes in flood hazard in Germany   总被引：1，自引：0，他引：1  
Since several destructive floods have occurred in Germany in the last decades, it is of considerable interest and relevance (e.g., when undertaking flood defense design) to take a closer look at the climatic factors driving the changes in flood hazard in Germany. Even if there also exist non-climatic factors controlling the flood hazard, the present paper demonstrates that climate change is one main driver responsible for the increasing number of floods. Increasing trends in temperature have been found to be ubiquitous in Germany, with impact on air humidity and changes in (intense) precipitation. Growing trends in flood prone circulation pattern and heavy precipitation are significant in many regions of Germany over a multi-decade interval and this can be translated into the rise of flood hazard and flood risk.  相似文献   

18.

The basic climatic characteristics about the Tibetan Plateau surface heating field intensity (TPSHFI)and its anomalous change trend are analyzed by using Lhasa,Yushu and Wudaoliang as the representatves of north-part,east-part and mid-north part of the Tibetan Plateau, respectively.The impact of heating intensity anomalism on NH general circulation and the climate of China is diagnosed.

  相似文献   

19.
根据青藏高原东部若尔盖盆地ＲＭ孔,北部柴达木盆地ＺＫ－３３６及ＣＫ－６孔和滇池盆地参１井等长孔的湖泊深钻记录,探讨了中更新世以来我国环境的区域分异特点,结合黄土－古土壤序列的研究成果,初步分析了导致区域环境分异的原因与亚洲季风的关系,结果表明青藏高原在其中扮演很重要的角色。  相似文献   

20.
The Tagus River basin is an ultimately important water source for hydropower production, urban and agricultural water supply in Spain and Portugal. Growing electricity and water supply demands, over‐regulation of the river and construction of new dams, as well as large inter‐basin and intra‐basin water transfers aggravated by strong natural variability of climate in the catchment, have already imposed significant pressures on the river. The substantial reduction of discharge is observed already now, and projected climatic change is expected to alter the water budget of the catchment further.In this study, we address the effects of projected climate change on the water resources availability in the Tagus River basin and influence of potential changes on hydropower generation of the three important reservoirs in the basin. The catchment‐scale, process‐based eco‐hydrological model soil and water integrated model was set up, calibrated and validated for the entire Tagus River basin, taking into account 15 large reservoirs in the catchment. The future climate projections were selected from those generated within the Inter‐Sectoral Impact Model Intercomparison Project. They include five bias‐corrected climatic datasets for the region, obtained from global circulation model runs under two emissions scenario – moderate and extreme ones – and covered the whole century. The results show a strong agreement among model runs in projecting substantial decrease of discharge of the Tagus River discharge and, consequently, a strong decrease in hydropower production under both future climate scenarios. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

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