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1.
Historical documentary sources, reflecting different port activities in Stockholm, are utilised to derive a 500-year winter/spring temperature reconstruction for the region. These documentary sources reflect sea ice conditions in the harbour inlet and those series that overlap with the instrumental data correlate well with winter/spring temperatures. By refining dendroclimatological methods, the time-series were composited to a mean series and calibrated (1756–1841; r 2?=?66%) against Stockholm January–April temperatures. Strong verification was confirmed (1842–1892; r 2?=?60%; RE/CE?=?0.55). By including the instrumental data, the quantified (QUAN) reconstruction indicates that recent two decades have been the warmest period for the last 500 years. Coldest conditions occurred during the 16th/17th and early 19th centuries. An independent qualitative (QUAL) historical index was also derived for the Stockholm region. Comparison between QUAN and QUAL shows good coherence at inter-annual time-scales, but QUAL distinctly appears to lack low frequency information. Comparison is also made to other winter temperature based annually resolved records for the Baltic region. Between proxy coherence is generally good although it decreases going back in time with the 1500–1550 period being the weakest period—possibly reflecting data quality issues in the different reconstructions.  相似文献   

2.
We use long instrumental temperature series together with available field reconstructions of sea-level pressure (SLP) and three-dimensional climate model simulations to analyze relations between temperature anomalies and atmospheric circulation patterns over much of Europe and the Mediterranean for the late winter/early spring (January–April, JFMA) season. A Canonical Correlation Analysis (CCA) investigates interannual to interdecadal covariability between a new gridded SLP field reconstruction and seven long instrumental temperature series covering the past 250 years. We then present and discuss prominent atmospheric circulation patterns related to anomalous warm and cold JFMA conditions within different European areas spanning the period 1760–2007. Next, using a data assimilation technique, we link gridded SLP data with a climate model (EC-Bilt-Clio) for a better dynamical understanding of the relationship between large scale circulation and European climate. We thus present an alternative approach to reconstruct climate for the pre-instrumental period based on the assimilated model simulations. Furthermore, we present an independent method to extend the dynamic circulation analysis for anomalously cold European JFMA conditions back to the sixteenth century. To this end, we use documentary records that are spatially representative for the long instrumental records and derive, through modern analogs, large-scale SLP, surface temperature and precipitation fields. The skill of the analog method is tested in the virtual world of two three-dimensional climate simulations (ECHO-G and HadCM3). This endeavor offers new possibilities to both constrain climate model into a reconstruction mode (through the assimilation approach) and to better asses documentary data in a quantitative way.  相似文献   

3.
Temperature reconstructions from Europe for the past 500 years based on documentary and instrumental data are analysed. First, the basic documentary data sources, including information about climate and weather-related extremes, are described. Then, the standard palaeoclimatological reconstruction method adopted here is discussed with a particular application to temperature reconstructions from documentary-based proxy data. The focus is on two new reconstructions; January–April mean temperatures for Stockholm (1502–2008), based on a combination of data for the sailing season in the Stockholm harbour and instrumental temperature measurements, and monthly Central European temperature (CEuT) series (1500–2007) based on documentary-derived temperature indices of the Czech Republic, Germany and Switzerland combined with instrumental records from the same countries. The two series, both of which are individually discussed in greater detail in subsequent papers in this special edition, are here compared and analysed using running correlations and wavelet analysis. While the Stockholm series shows a pronounced low-frequency component, the CEuT series indicates much weaker low-frequency variations. Both series are analysed with respect to three different long-period reconstructions of the North Atlantic Oscillation (NAO) and are compared with other European temperature reconstructions based on tree-rings, wine-harvest data and various climate multiproxies. Correlation coefficients between individual proxy-based series show weaker correlations compared to the instrumental data. There are also indications of temporally varying temperature cross-correlations between different areas of Europe. The two temperature reconstructions have also been compared to geographically corresponding temperature output from simulations with global and regional climate models for the past few centuries. The findings are twofold: on the one hand, the analysis reinforces the hypothesis that the index-data based CEuT reconstruction may not appropriately reflect the centennial scale variations. On the other hand, it is possible that climate models may underestimate regional decadal variability. By way of a conclusion, the results are discussed from a broader point of view and attention is drawn to some new challenges for future investigations in the historical climatology in Europe.  相似文献   

4.
A new reconstruction of winter and summer temperatures in the Low Countries(the present-day Netherlands and Belgian Flanders), based upon documentary evidence from AD 764 to 1705 and extended by observationsto 1998, is compared with relevant paleo series from the European network. The Low Countries Temperature (LCT) reconstruction is well supported by existing evidence in both seasons from about 1300 onwards,on timescales ranging from annual to centennial.The spectral analysis confirms that the dominant oscillations in the LCT have counterparts in the independent data and that most of theperiodicities characteristic for the instrumental segment of the LCT are preserved in the reconstruction. Throughout thisperiod of reliable reconstruction there was no detectable inhomogeneity of the variances in either seasons.Prior to about 1300, there are few sources that can be used to evaluate LCT. It was possible to add some support for the LCT on decadal andcentennial timescales for the 12th and 13th centuries. However, there is no independent data for the first three centuriesof the reconstruction.The LCT series exhibits significant season-dependent variability on bidecadal and centennial timescales. The seasonality is particularly remarkable in the 10th and 15th centuries which were – on average – warm in the summer and cold in the winter.The 20th century was by far (three standard errors) the warmest century of the last millenniumin terms of winter temperatures, while the 13th century was warmest in terms of summer temperatures (by the narrow margin of one standard error).In both seasons, the coldest centennial period was centered around 1600. The present results place the reconstructed LCT series withinthe existing paleoclimatic network, and provide an insight into temperature variability in the Low Countries through the centuries.  相似文献   

5.
Tree-ring records are a valuable source of information for understanding long-term, regional-scale drought changes. In this study, a tree ring width chronology spanning the last 330?years (A.D. 1681–2010) is developed for the northern fringe of the Asian summer monsoon in north central China based on tree ring widths of the Chinese pine (Pinus tabulaeformis) at three sites in the Hasi Mountain (HSM). An annual (running from the previous August to the present July) Palmer Drought Severity Index (PDSI) series is reconstructed for the period A.D. 1698 to 2010 using a linear regression model. This reconstruction accounts for 49?% of the actual PDSI variance during the calibration period (A.D.1951–2005). During the last past 330?years, the year 1759 drought was the most severe and the 1926–1932 drought was the most long-lasting. These drought episodes resulted in huge economic losses and severe famine. Similar periods of drought are also found in the Great Bend of the Yellow River region, northeastern Tibetan Plateau and northern China. Our drought reconstruction is consistent with the dry-wet index derived from historical documents for the Great Bend of the Yellow River region for the last three centuries, revealing that our annual PDSI reconstruction reflects broad-scale climate anomalies and represents drought variations in the northern fringe of the Asian summer monsoon. The PDSI reconstruction correlates significantly with sea surface temperature (SST) in the eastern equatorial Pacific Ocean and northern Indian Ocean at an annual timescale, implying that El Ni?o-Southern Oscillation and the Indian monsoon might be influencing drought variability in the study area. Some extremely dry years of 1707, 1764, 1837, 1854, 1878, 1884, 1926 and 1932 coincided with major El Ni?o events in historical times. The decadal-scale variability is linked to Pacific Decadal Oscillation (PDO) and SST variations in the Atlantic Ocean. The observed recent tree growth reduction is unusual when viewed from a long-term perspective.  相似文献   

6.
Two European temperature reconstructions for the past half-millennium, January-to-April air temperature for Stockholm (Sweden) and seasonal temperature for a Central European region, both derived from the analysis of documentary sources and long instrumental records, are compared with the output of climate simulations with the model ECHO-G. The analysis is complemented by comparisons with the long (early)-instrumental record of Central England Temperature (CET). Both approaches to study past climates (simulations and reconstructions) are burdened with uncertainties. The main objective of this comparative analysis is to identify robust features and weaknesses in each method which may help to improve models and reconstruction methods. The results indicate a general agreement between simulations obtained with temporally changing external forcings and the reconstructed Stockholm and CET records for the multi-centennial temperature trend over the recent centuries, which is not reproduced in a control simulation. This trend is likely due to the long-term change in external forcing. Additionally, the Stockholm reconstruction and the CET record also show a clear multi-decadal warm episode peaking around AD 1730, which is absent in the simulations. Neither the reconstruction uncertainties nor the model internal climate variability can easily explain this difference. Regarding the interannual variability, the Stockholm series displays, in some periods, higher amplitudes than the simulations but these differences are within the statistical uncertainty and further decrease if output from a regional model driven by the global model is used. The long-term trend of the CET series agrees less well with the simulations. The reconstructed temperature displays, for all seasons, a smaller difference between the present climate and past centuries than is seen in the simulations. Possible reasons for these differences may be related to a limitation of the traditional ‘indexing’ technique for converting documentary evidence to temperature values to capture long-term climate changes, because the documents often reflect temperatures relative to the contemporary authors’ own perception of what constituted ‘normal’ conditions. By contrast, the amplitude of the simulated and reconstructed inter-annual variability agrees rather well.  相似文献   

7.
We present the first winter (December to March) rainfall reconstruction based in a novel proxy, the thickness of annual calcite laminations preserved in Lake La Cruz (central–eastern Spain). A previous calibration analysis between laminae thickness and the instrumental data series (1950 to present) indicated a highly significant correlation with winter rainfall. Therefore this study attempts the winter rainfall reconstruction since the onset of laminations (1579 a.d.) by means of the calibration function previously developed. The verification analysis between inferred annual values and earlier instrumental data (1859–1949) confirms the suitability of this novel proxy and the reliability of the series reconstructed. The reconstructed series show the fluctuating character of winter rainfall in the western Mediterranean area; interdecadal dry periods alternated with wetter periods following, in a board sense, the pattern recorded by documentary sources in other regions of the Iberian Peninsula. At present times regional winter rainfall anomalies are highly correlated with the phase of the North Atlantic Oscillation (NAO). However the time series analysis showed the dominance of nonstationary components at high frequencies of the climate signal over the last four centuries suggesting that the connection between winter rainfall and the NAO has not been stable over time and also other modes of variability, not only NAO, may have conditioned winter rainfall variability.  相似文献   

8.
Temperature reconstructions for recent centuries provide a historical context for the warming over the twentieth century. We reconstruct annual averaged surface temperatures of the past 400?years on hemispherical and global scale from glacier length fluctuations. We use the glacier length records of 308 glaciers. The reconstruction is a temperature proxy with decadal resolution that is completely independent of other temperature records. Temperatures are derived from glacier length changes using a linear response equation and an analytical glacier model that is calibrated on numerical model results. The global and hemispherical temperatures reconstructed from glacier length fluctuations are in good agreement with the instrumental record of the last century. Furthermore our results agree with existing multi-proxy reconstructions of temperature in the pre-instrumental period. The temperature record obtained from glacier fluctuations confirms the pronounced warming of the twentieth century, giving a global cumulative warming of 0.94?±?0.31?K over the period 1830–2000 and a cumulative warming of 0.84?±?0.35?K over the period 1600–2000.  相似文献   

9.
We present two tree-ring chronologies for the southeastern Tibetan Plateau (TP), established by applying the signal-free regional curve standardization and standard dendrochronological methodologies to a set of ring-width series of Tibetan juniper. The relationship between tree growth and climate shows that temperature variability in the previous year is the primary factor controlling tree growth at the upper portion of the forest belt. Accordingly, we developed a mean annual temperature reconstruction covering the period A.D. 984–2009 and explaining 50 % of the instrumental variance. The spatial correlation patterns suggest that our temperature reconstruction is a reasonable proxy for temperature change over the TP. At long time scales, the temperature reconstruction shows similar warm-cold patterns to those in temperature records from other regions of the TP, indicating that decadal and multidecadal temperature variations were generally synchronous across the TP during the past millennium. The periods 1140–1350 and 1600–1800 were common warm and cold episodes over the TP, respectively. Comparison of our reconstruction with four Northern Hemisphere (NH) temperature series indicates that temperature changes on the southeastern TP have generally followed the NH temperature patterns during the past millennium. Our results also suggest that temperature variability over the TP is affected by the Atlantic Multidecadal Oscillation (AMO), with the warm (cool) phases of the AMO associated with above-average (below-average) temperatures over the TP.  相似文献   

10.
The paper reports the main results of the EU project Millennium in the Mediterranean area over the last 500 years. It analyses a long series of temperature from Portugal, Spain, France, Italy and Greece. The series are obtained by combining indices from documentary sources from AD 1500 to the onset of regular instrumental observations. There is an ongoing discussion regarding the proper way of combining documentary and instrumental data and how to translate accurately the conventional indices from ??3 to +?3 into modern units, i.e. degree Celsius. This paper produces for the first time a number of early instrumental observations, in some cases (i.e. Italy and France) covering 350 years, including thereby the earliest regular observations after the invention of the thermometer. These Mediterranean data show that anomalous temperatures usually had only a locally limited effect, while only few extreme events had a widespread impact over the whole region, such as the summer of 2003. During the period from 1850 to the present day, the Mediterranean temperature anomaly was close to the Northern Hemisphere in spring and summer, while it was warmer in autumn and winter. Compared with the long-term instrumental records (i.e. 1655 onwards), the recent warming has not exceeded the natural past variability characterized by heating–cooling cycles with no significant long-term trends.  相似文献   

11.
We present seasonal precipitation reconstructions for European land areas (30°W to 40°E/30–71°N; given on a 0.5°×0.5° resolved grid) covering the period 1500–1900 together with gridded reanalysis from 1901 to 2000 (Mitchell and Jones 2005). Principal component regression techniques were applied to develop this dataset. A large variety of long instrumental precipitation series, precipitation indices based on documentary evidence and natural proxies (tree-ring chronologies, ice cores, corals and a speleothem) that are sensitive to precipitation signals were used as predictors. Transfer functions were derived over the 1901–1983 calibration period and applied to 1500–1900 in order to reconstruct the large-scale precipitation fields over Europe. The performance (quality estimation based on unresolved variance within the calibration period) of the reconstructions varies over centuries, seasons and space. Highest reconstructive skill was found for winter over central Europe and the Iberian Peninsula. Precipitation variability over the last half millennium reveals both large interannual and decadal fluctuations. Applying running correlations, we found major non-stationarities in the relation between large-scale circulation and regional precipitation. For several periods during the last 500 years, we identified key atmospheric modes for southern Spain/northern Morocco and central Europe as representations of two precipitation regimes. Using scaled composite analysis, we show that precipitation extremes over central Europe and southern Spain are linked to distinct pressure patterns. Due to its high spatial and temporal resolution, this dataset allows detailed studies of regional precipitation variability for all seasons, impact studies on different time and space scales, comparisons with high-resolution climate models as well as analysis of connections with regional temperature reconstructions. Electronic Supplementary Material Supplementary material is available for this article at and is accessible for authorized users.  相似文献   

12.
A 520-year stable carbon isotope chronology from tree ring cellulose in high altitude larch trees (Larix decidua Mill.), from the eastern European Alps, correlates more strongly with summer temperature than with summer sunshine hours. However, when instrumental records of temperature and sunshine diverge after AD1980, the tree ring time series does not follow warming summer temperatures but more closely tracks summer sunshine trends. When the tree ring stable carbon isotope record is used to reconstruct summer temperature the reconstruction is not robust. Reconstructed temperatures prior to the twentieth century are higher than regional instrumental records, and the evolution of temperature conflicts with other regional temperature reconstructions. It is concluded that sunshine is the dominant control on carbon isotope fractionation in these trees, via the influence of photosynthetic rate on the internal partial pressure of CO2, and that high summer (July–August) sunshine hours is a suitable target for climate reconstruction. We thus present the first reconstruction of summer sunshine for the eastern Alps and compare it with the regional temperature evolution.  相似文献   

13.
Instrumental temperature recording in the Greater Alpine Region (GAR) began in the year 1760. Prior to the 1850–1870 period, after which screens of different types protected the instruments, thermometers were insufficiently sheltered from direct sunlight so were normally placed on north-facing walls or windows. It is likely that temperatures recorded in the summer half of the year were biased warm and those in the winter half biased cold, with the summer effect dominating. Because the changeover to screens often occurred at similar times, often coincident with the formation of National Meteorological Services (NMSs) in the GAR, it has been difficult to determine the scale of the problem, as all neighbour sites were likely to be similarly affected. This paper uses simultaneous measurements taken for eight recent years at the old and modern site at Kremsmünster, Austria to assess the issue. The temperature differences between the two locations (screened and unscreened) have caused a change in the diurnal cycle, which depends on the time of year. Starting from this specific empirical evidence from the only still existing and active early instrumental measuring site in the region, we developed three correction models for orientations NW through N to NE. Using the orientation angle of the buildings derived from metadata in the station histories of the other early instrumental sites in the region (sites across the GAR in the range from NE to NW) different adjustments to the diurnal cycle are developed for each location. The effect on the 32 sites across the GAR varies due to different formulae being used by NMSs to calculate monthly means from the two or more observations made at each site each day. These formulae also vary with time, so considerable amounts of additional metadata have had to be collected to apply the adjustments across the whole network. Overall, the results indicate that summer (April to September) average temperatures are cooled by about 0.4°C before 1850, with winters (October to March) staying much the same. The effects on monthly temperature averages are largest in June (a cooling from 0.21° to 0.93°C, depending on location) to a slight warming (up to 0.3°C) at some sites in February. In addition to revising the temperature evolution during the past centuries, the results have important implications for the calibration of proxy climatic data in the region (such as tree ring indices and documentary data such as grape harvest dates). A difference series across the 32 sites in the GAR indicates that summers since 1760 have warmed by about 1°C less than winters.  相似文献   

14.
One obstacle on the way to a comprehensive spatial reconstruction of regional temperature changes over the past centuries is the sparseness of long winter temperature records. This paper reconstructs a proxy record of April and November–December temperatures in south-central Finland for the interval from 1836 to 1872 from breakup and freeze-up dates and ice-cover duration of a lake. Emphasis is on detecting the suitable winter months and quantifying the calibrations with measured temperatures (1873–2002). The calibration slope for the breakup date (0.158°C/day) is larger than for freeze-up date (0.119°C/day) or duration (0.090°C/day). A comparison with results from other proxy records shows that the slope may depend also on the geographical site. Trend analyses of the full temperature records (1836–2002) indicate the existence of minor change-points at around 1867 (April temperature) and 1874 (November–December temperature), with warming rates thereafter of 1.67°C per century (April) and 1.16°C per century (November–December). Spectral analyses reveal peaks in the band between 2 and 5?year period, which may point to influences of the North Atlantic Oscillation, and less power in the decadal band (up to 42?year period).  相似文献   

15.
Eight tree-ring chronologies from coastal sites along the Gulf of Alaska (GOA) are used to develop a 227-year (1762–1988) reconstruction of spring/summer (March–September) coastal land temperatures for the region. This reconstruction explains 35% of the variance in the instrumental temperature data. The tree-ring records and reconstruction reflect the documented 1976 transition from cold to warm conditions in the North Pacific and are consistent with regional temperature compilations. Three of the eight ring-width series, from elevational timberline sites where trees are particularly stressed by temperature, extend back to A.D. 1600 and are used to identify additional occurrences of such transitions. The first principal component (PC) scores of these three longer records are positively correlated with spring (March–May) land and sea surface temperatures for the GOA region and are used to reconstruct land surface temperatures. Decadal-scale fluctuations in the reconstructions show agreement with decade-long changes in the intensity of the Aleutian Low pressure cell over the past century, suggesting that the tree-ring data may provide an index of past circulation changes for the northeast Pacific. Blackman-Tukey spectral analyses of both reconstructions indicate significant power at 7–11 years, with additional peaks at 3 years for the spring/summer reconstruction and 19 years for the longer spring temperature series. The modes of variation at about 3 and 7 years may correspond to those associated with the El Niño-Southern Oscillation bandwidth, whereas the 19-year term may relate to a proposed 20-year cycle of North Pacific circulation. The spring temperature series shows generally increased growth over the past century, coinciding with warmer spring temperatures in south coastal Alaska over this interval. Comparison with the entire spring series suggests that the recent warming exceeds temperature levels of prior centuries, extending back to A.D. 1600.  相似文献   

16.
The reconstruction of a temperature record for eighteenth century eastern Massachusetts is discussed. In addition to instrumental records diaries were analyzed in order to produce temperature indices. Reliability tests demonstrate that the methodology used is capable of replicating results regardless of changes in coders or intraregional variability in language. Validity tests, comparing diary reconstructions with instrumental records for the same period, produced positive results. A compilation of all climate related data shows the decades of the 1720's, 1750's, and 1760's were cool, while the 1770's and 1790's were warm.  相似文献   

17.
The introductory paper to this special issue of Climatic Change summarizes the results of an array of studies dealing with the reconstruction of climatic trends and anomalies in sixteenth-century Europe and their impact on the natural and the social world. Areas discussed include glacier expansion in the Alps, the frequency of natural hazards (floods in central and southern Europe and storms on the Dutch North Sea coast), the impact of climate deterioration on grain prices and wine production, and finally, witch-hunts.The documentary data used for the reconstruction of seasonal and annual precipitation and temperatures in central Europe (Germany, Switzerland and the Czech Republic) include narrative sources, several types of proxy data and 32 weather diaries. Results were compared with long-term composite tree ring series and tested statistically by cross-correlating series of indices based on documentary data from the sixteenth century with those of simulated indices based on instrumental series (1901-1960). It was shown that series of indices can be taken as good substitutes for instrumental measurements.A corresponding set of weighted seasonal and annual series of temperature and precipitation indices for central Europe was computed from series of temperature and precipitation indices for Germany, Switzerland and the Czech Republic, the weights being in proportion to the area of each country. The series of central European indices were then used to assess temperature and precipitation anomalies for the 1901-1960 period using transfer functions obtained from instrumental records. The statistical analysis of these series of estimated temperature and precipitation anomalies yielded features which are similar to those obtained from instrumental series.Results show that winter temperatures remained below the 1901-1960 average except in the 1520s and 1550s. Springs fluctuated from 0.3°C to 0.8°C below this average. Summer climate was divided into three periods of almost equal length. The first was characterized by an alternation of cool and warmer seasons. The second interval was 0.3°C warmer and between 5 and 6% drier than in the 1901–1960 period. It is emphasized that this warm period included several cold extremes in contrast to the recent period of warming. Summers from 1560 were 0.4°C colder and 4% more humid. Autumns were 0.7°C colder in the 1510s and 20% wetter in the 1570s. The deterioration of summer climate in the late sixteenth century initiated a second period of enlarged glaciers in this millennium (the first having been in the fourteenth century) which did not end until the late nineteenth century.An analysis of forcing factors (solar, volcanic, ENSO, greenhouse) points only to some volcanic forcing. In order to understand circulation patterns in the sixteenth century in terms of synoptic climatology, proxy information was mapped for a number of anomalous months. Attempts to compare circulation patterns in the sixteenth century with twentieth-century analogues revealed that despite broad agreements in pressure patterns, winters with distinct northeasterly patterns were more frequent in the sixteenth century, whereas the declining summer temperatures from the mid-1560s seem to be associated with a decreasing frequency of anticyclonic ridging from the Azores' center of action towards continental Europe. The number of severe storms on the Dutch North Sea coast was four times greater in the second half of the century than in the first. A more or less continuous increase in the number of floods over the entire century occurred in Germany and the Czech lands. The Iberian peninsula and the Garonne basin (France) had the greatest number of severe floods in the 1590s.The analysis of the effects of climate on rye prices in four German towns involved a model that included monthly temperatures and precipitation values known to affect grain production. The correlation with rye prices was found significant for the entire century and reached its highest values between 1565 and 1600. From the 1580s to the turn of the century wine production slumped almost simultaneously in four regions over a distance of 800 kilometers (Lake Zurich to western Hungary). This had far-reaching consequences for the Habsburg treasury and promoted a temporary shift in drinking habits from wine to beer. Peasant communities which were suffering large collective damage from the effects of climatic change pressed authorities for the organization of witch-hunts. Seemingly most witches were burnt as scapegoats of climatic change.  相似文献   

18.
Monthly (1659–1995) and seasonal (1500–1658) North Atlantic Oscillation (NAO) indices were estimated using instrumental and documentary proxy predictors from Eurasia. Uncertainty estimates were calculated for the reconstructions, and the variability of the 500-year winter NAO has been assessed. The late twentieth century NAO extremes are within the range of variability during earlier centuries.  相似文献   

19.
The ten-year mean anomalies of seasonal and annual temperatures were reconstructed on the basis ofhistorical documents of cold events such as severe snowing and freezing of lakes and rivers.The assorted eventswere calibrated with instrumental observations of temperature and transformed into ten-year mean anomalies.The reconstructed temperature series show predominance of cold climate in the first four hundred years of theperiod examined.The centenary seasonal temperature anomalies for the 16th to the 19th century vary between-0.1 and -0.7K.The coldest decades concentrated in the middle of 17th and 19th centuries.It provided theirrefutable evidence of the occurrence of the Little Ice Age in China.The minima of ten-year mean temperatureanomalies ranged about -1.5 to 2.0K in spring and winter.Meanwhile,the variance of ten-year mean tempera-ture was increased by more than 20％ in comparison to the 20th century.  相似文献   

20.
The paper presents a qualitative and quantitative analysis of flood variability and forcing of major European rivers since AD 1500. We compile and investigate flood reconstructions which are based on documentary evidence for twelve Central European rivers and for eight Mediterranean rivers. Flood variability and underlying climatological causes are reconstructed by using hermeneutic approaches including critical source analysis and by applying a semi-quantitative classification scheme. The paper describes the driving climatic causes, seasonality and variability of observed flood events within the different river catchments covering the European mainland. Historical flood data are presented and recent research in the field of historical flood reconstructions is highlighted. Additionally, the character of the different flood series is discussed. A comparison of the historical flood seasonality in relation to modern distribution is given and aspects of the spatial coherence are presented. The comparative analysis points to the fact that the number of flood events is predominately triggered by regional climatic forcing, with at most only minor influence on neighbouring catchments. The only exceptions are extreme, supra-regional climatic events and conditions such as anomalous cold winters, similar to that of 1784, which affected large parts of Europe and triggered flood events in several catchments as a result of ice-break at the beginning of the annual thaw. Four periods of increased occurrence of flooding, mostly affecting Central European Rivers, have been identified; 1540–1600, 1640–1700, 1730–1790, 1790–1840. The reconstruction, compilation and analysis of European-wide flood data over the last five centuries reveal the complexity of the underlying climatological causes and the high variability of flood events in temporal and spatial dimension.  相似文献   

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