bluuebunny/crossref_metadata_2025_split huggingface dataset:
Seasonal mean pressure reconstruction for the North Atlantic (1750–1850) based on early marine data
Authors: Gallego D. , Garcia-Herrera R. , Ribera P. , Jones P. D. 
Published: April 2010

Abstract. Measurements of wind strength and direction abstracted from European ships' logbooks during the recently finished CLIWOC project have been used to produce the first gridded Sea Level Pressure (SLP) reconstruction for the 1750–1850 period over the North Atlantic based solely on marine data. The reconstruction is based on a spatial regression analysis calibrated by using data taken from the ICOADS database. An objective methodology has been developed to select the optimal calibration period and spatial domain of the reconstruction by testing several thousands of possible models. The finally selected area, limited by the performance of the regression equations and by the availability of data, covers the region between 28° N and 52° N close to the European coast and between 28° N and 44° N in the open Ocean. The results provide a direct measure of the strength and extension of the Azores High during the 101 years of the study period. The comparison with the recent land-based SLP reconstruction by Luterbacher et al. (2002) indicates the presence of a common signal. The interannual variability of the CLIWOC reconstructions is rather high due to the current scarcity of abstracted wind data in the areas with best response in the regression. Guidelines are proposed to optimize the efficiency of future abstraction work.
Inter-hemispheric linkages in climate change: paleo-perspectives for future climate change
Authors: Shulmeister J. , Rodbell D. T. , Gagan M. K. , Seltzer G. O. 
Published: April 2010

Abstract. The Pole-Equator-Pole (PEP) projects of the PANASH (Paleoclimates of the Northern and Southern Hemisphere) programme have significantly advanced our understanding of past climate change on a global basis and helped to integrate paleo-science across regions and research disciplines. PANASH science allows us to constrain predictions for future climate change and to contribute to the management of consequent environmental changes. We identify three broad areas where PEP science makes key contributions. 1. The pattern of global changes. Knowing the exact timing of glacial advances (synchronous or otherwise) during the last glaciation is critical to understanding inter-hemispheric links in climate. Work in PEPI demonstrated that the tropical Andes in South America were deglaciated earlier than the Northern Hemisphere (NH) and that an extended warming began there ca. 21 000 cal years BP. The general pattern is consistent with Antarctica and has now been replicated from studies in Southern Hemisphere (SH) regions of the PEPII transect. That significant deglaciation of SH alpine systems and Antarctica led deglaciation of NH ice sheets may reflect either i) faster response times in alpine systems and Antarctica, ii) regional moisture patterns that influenced glacier mass balance, or iii) a SH temperature forcing that led changes in the NH. This highlights the limitations of current understanding and the need for further fundamental paleoclimate research. 2. Changes in modes of operation of oscillatory climate systems. Work across all the PEP transects has led to the recognition that the El Niño Southern Oscillation (ENSO) phenomenon has changed markedly through time. It now appears that ENSO operated during the last glacial termination and during the early Holocene, but that precipitation teleconnections even within the Pacific Basin were turned down, or off. In the modern ENSO phenomenon both inter-annual and seven year periodicities are present, with the inter-annual signal dominant. Paleo-data demonstrate that the relative importance of the two periodicities changes through time, with longer periodicities dominant in the early Holocene. 3. The recognition of climate modulation of oscillatory systems by climate events. We examine the relationship of ENSO to a SH climate event, the Antarctic cold reversal (ACR), in the New Zealand region. We demonstrate that the onset of the ACR was associated with the apparent switching on of an ENSO signal in New Zealand. We infer that this related to enhanced zonal SW winds with the amplification of the pressure fields allowing an existing but weak ENSO signal to manifest itself. Teleconnections of this nature would be difficult to predict for future abrupt change as boundary conditions cannot readily be specified. Paleo-data are critical to predicting the teleconnections of future changes.
Mid-Holocene climate change in Europe: a data-model comparison
Authors: Brewer S. , Guiot J. , Torre F. 
Published: April 2010

Abstract. We present here a comparison between the outputs of a set of 25 climate models run for the mid-Holocene period (6 ka BP) with a set of palaeo-climate reconstructions from over 400 fossil pollen sequences distributed across the European continent. Three climate parameters were available (moisture availability, temperature of the coldest month and growing degree days), which were then grouped together using cluster analysis to provide regions of homogenous climate change. Each model was then investigated to see if it reproduced 1) the same directions of change and 2) the correct location of these regions. A fuzzy logic distance was used to compare the output of the model with the data, which allowed uncertainties from both the model and data to be taken into account. The initial comparison showed that the models were only capable of reproducing regions of little climate change, as the data-based reconstructions have a much larger range of changes due to their local nature. A correction for the model standard deviation was then applied to allow the comparison to proceed, and this second test shows that the majority of models simulate all the observed patterns of climatic change, although most do not simulate the observed magnitude of change. The models were then compared by distance to data, and by the amount of correction required. The majority of the models are grouped together both in distance and correction, suggesting that they are becoming more consistent. A test against a set of zero anomalies (no climate change) shows that, whilst the models are unable to reproduce the exact patterns of change, they all produce the correct direction of change for the mid-Holocene.
Quasi-100 ky glacial-interglacial cycles triggered by subglacial burial carbon release
Authors: Zeng N. 
Published: April 2010

Abstract. A new mechanism is proposed in which climate, carbon cycle and icesheets interact with each other to produce a feedback that can produce quasi-100 ky glacial-interglacial cycles. A key process is the burial and preservation of organic carbon by icesheets. The switch from glacial maximum to deglaciation is triggered by the ejection of glacial burial carbon when icesheets grow to sufficiently large size and subglacial transport becomes significant. Glacial inception is initiated by CO2 drawdown due to a ''rebound'' from a high but transient interglacial CO2 value as the land-originated CO2 invades into deep ocean via thermohaline circulation and CaCO3 compensation. Also important for glacial inception is the CO2 uptake by vegetation regrowth in the previously ice-covered boreal regions. When tested using a fully coupled Earth system model with comprehensive carbon cycle components and semi-empirical physical climate components, it produced self-sustaining glacial-interglacial cycles of duration about 93 ky, CO2 change of 90 ppmv, temperature change of 6°C under certain parameter regimes. Since the 100 ky cycles can not be easily explained by the weak Milankovitch astronomical forcing alone, this carbon-climate mechanism provides a strong feedback that could interact with external forcings to produce the major observed Quaternary climatic variations.
Impact of spatial data resolution on simulated catchment water balances and model performance of the multi-scale TOPLATS model
Authors: Bormann H. 
Published: April 2010

Abstract. This paper analyses the effect of spatial input data resolution on the simulated water balances and flow components using the multi-scale hydrological model TOPLATS. A data set of 25m resolution of the central German Dill catchment (693 km2) is used for investigation. After an aggregation of digital elevation model, soil map and land use classification to 50 m, 75 m, 100 m, 150 m, 200 m, 300 m, 500 m, 1000 m and 2000 m, water balances and water flow components are calculated for the entire Dill catchment as well as for 3 subcatchments without any recalibration. The study shows that model performance measures and simulated water balances almost remain constant for most of the aggregation steps for all investigated catchments. Slight differences in the simulated water balances and statistical quality measures occur for single catchments at the resolution of 50 m to 500 m (e.g. 0–3% for annual stream flow), significant differences at the resolution of 1000 m and 2000 m (e.g. 2–12% for annual stream flow). These differences can be explained by the fact that the statistics of certain input data (land use data in particular as well as soil physical characteristics) changes significantly at these spatial resolutions. The impact of smoothing the relief by aggregation occurs continuously but is barely reflected by the simulation results. To study the effect of aggregation of land use data in detail, in addition to current land use the effect of aggregation on the water balance calculations based on three different land use scenarios is investigated. Land use scenarios were available aiming on economic optimisation of agricultural and forestry practices at different field sizes (0.5 ha, 1.5 ha and 5.0 ha). The changes in water balance terms, induced by aggregation of the land use scenarios, are comparable with respect to catchment water balances compared to the current land use. A correlation analysis between statistics of input data and simulated annual water fluxes only in some cases reveals systematically high correlation coefficients for all investigated catchments and data sets (e.g. actual evapotranspiration is correlated to land use, surface runoff generation is correlated to soil properties). Predominantly the correlation between catchment properties (e.g. topographic index, transmissivity, land use) and simulated water flows varies from catchment to catchment. Catchment specific properties determine correlations between properties and fluxes, but do not influence the effect of data aggregation. This study indicates that an aggregation of input data for the calculation of regional water balances using TOPLATS type models leads to significant errors from a resolution exceeding 500 m. Correlating statistics of input data and simulation results indicates that a meaningful aggregation of data should in the first instance aim on preserving the areal fractions of land use classes.
Validation of MODIS snow cover images over Austria
Authors: Parajka J. , Blöschl G. 
Published: April 2010

Abstract. This study evaluates the Moderate Resolution Imaging Spectroradiometer (MODIS) snow cover product over the territory of Austria. The aims are (a) to analyse the spatial and temporal variability of the MODIS snow product classes, (b) to examine the accuracy of the MODIS snow product against in situ snow depth data, and (c) to identify the main factors that may influence the MODIS classification accuracy. We use daily MODIS grid maps (version 4) and daily snow depth measurements at 754 climate stations in the period from February 2000 to December 2005. The results indicate that, on average, clouds obscured 63% of Austria, which may significantly restrict the applicability of the MODIS snow cover images to hydrological modelling. On cloud-free days, however, the classification accuracy is very good with an average of 95%. There is no consistent relationship between the classification errors and dominant land cover type and local topographical variability but there are clear seasonal patterns to the errors. In December and January the errors are around 15% while in summer they are less than 1%. This seasonal pattern is related to the overall percentage of snow cover in Austria, although in spring, when there is a well developed snow pack, errors tend to be smaller than they are in early winter for the same overall percent snow cover. Overestimation and underestimation errors balance during most of the year which indicates little bias. In November and December, however, there appears to exist a tendency for overestimation. Part of the errors may be related to the temporal shift between the in situ snow depth measurements (07:00 a.m.) and the MODIS acquisition time (early afternoon). The comparison of daily air temperature maps with MODIS snow cover images indicates that almost all MODIS overestimation errors are caused by the misclassification of cirrus clouds as snow.
Threshold effects in catchment storm response and the occurrence and magnitude of flood events: implications for flood frequency
Authors: Kusumastuti D. I. , Struthers I. , Sivapalan M. , Reynolds D. A. 
Published: April 2010

Abstract. The aim of this paper is to illustrate the effects of selected catchment storage thresholds upon runoff behaviour, and specifically their impact upon flood frequency. The analysis is carried out with the use of a stochastic rainfall model, incorporating rainfall variability at intra-event, inter-event and seasonal timescales, as well as infrequent summer tropical cyclones, coupled with deterministic rainfall-runoff models that incorporate runoff generation by both saturation excess and subsurface stormflow mechanisms. Changing runoff generation mechanisms (i.e. from subsurface flow to surface runoff) associated with a given threshold (i.e. saturation storage capacity) are shown to be manifested in the flood frequency curve as a break in slope. It is observed that the inclusion of infrequent summer storm events increases the temporal frequency occurrence and magnitude of surface runoff events, in this way contributing to steeper flood frequency curves, and an additional break in the slope of the flood frequency curve. The results of this study highlight the importance of thresholds on flood frequency, and provide insights into the complex interactions between rainfall variability and threshold nonlinearities in the rainfall-runoff process, which are shown to have a significant impact on the resulting flood frequency curves.
Snow fences on slopes at high wind speed: physical modelling in the CSTB cold wind tunnel
Authors: Naaim-Bouvet F. , Naaim M. , Michaux J.-L. 
Published: April 2010

Abstract. In order to determine the effect of steep slopes on snowdrift generated by snow fences, we have conducted physical modeling experiments in the CSTB (Centre Scientifique et Technique du Bâtiment) cold wind tunnel as part of the European project "Access to Large Facilities". After an overview of previous studies and an accurate description of the drifting snow process inside the experimental chamber, we present the main results obtained. (1) On flat areas, even for high wind speed, the acknowledged results for moderate wind are still valid: the porous snow fence (50%) is the most efficacious and the bottom gap increases the efficacy of the dense snow fence. (2) The steeper the slope is, the less effective all tested snow fences are. Their effectiveness decreases considerably: the snow catch is approximately divided by two for a slope of 10°. (3) Contrary to flat areas, on steep slopes, the "efficacy" is greater for a dense snow fence.
Tsunami generation in Stromboli island and impact on the south-east Tyrrhenian coasts
Authors: Tinti S. , Pagnoni G. , Zaniboni F. , Bortolucci E. 
Published: April 2010

Abstract. Stromboli is one of the most active volcanoes in the Aeolian island arc in south Tyrrhenian sea, Italy. In the last 100 years the most relevant volcanic eruptions have beenaccompanied by local tsunamis, that have caused damage and casualties. In some cases the direct mechanism of local tsunami generation is clear, i.e. pyroclastic flows entering the sea. In some others it is uncertain and some speculation concerning the collapse of the eruptive column on the sea surface or the failure of some underwater mass can be made. But the ordinary activity is unlikely to generate large regional tsunamis. These can be produced by the lateral collapse of the volcanic cone that geomorphological and volcanological investigations have proven to have occurred repeatedly in the recent history of the volcano, with return period in the order of some thousands of years. The last episode is dated to less than 5 ka BP, and left the Sciara del Fuoco scar on the north-west flank of Stromboli. Based on previous studies, the possible collapse of the nortwestern sector of Stromboli and the consequent generation and propagation of a tsunami are explored. The impact on Stromboli and on the other islands of the Aeolian archipelago is estimated, as well as the impact on the coast of Sicily and the Tyrrhenian coasts of Calabria. The simulation is carried out by means of a double model: a Lagrangian block model to compute the motion of the collapsing mass, and a finite-element hydrodynamic model to compute the evolution of the tsunami. Two distinct tsunami simulations are carried out, one on a very fine grid around the source region to evaluate the tsunami near Stromboli, and one utilising a coarser grid covering the whole south-east Tyrrhenian sea to compute the tsunami propagation toward Sicily and Calabria. It is found that a huge-volume collapse of the north-western flank of the Stromboli cone is capable of producing a regional tsunami which is catastrophic at the source and devastating on long stretches of Tyrrhenian coasts, but particularly in the neighbouring islands of Panarea and Salina, and along the Calabria coasts around Capo Vaticano.
Relations between rainfall and triggering of debris-flow: case study of Cancia (Dolomites, Northeastern Italy)
Authors: Bacchini M. , Zannoni A. 
Published: April 2010

Abstract. Debris-flows occurring in the area of Cancia (Dolomites, Northeastern Italy) in recent years have exposed the population to serious risk. In response to the recurring hazard, an alarm and monitoring system was installed to provide a sufficient level of safeguard for inhabitants and infrastructures. The data recorded at three rain gauges during debris-flow events has been analysed, taking into consideration the different elevation of the gauges to delineate the storm rainfall distributions. Rainfall data is compared with the occurrence of debris-flows to examine relations between debris-flow initiation and rainfall. In addition, the data is compared with that recorded during debris-flows which occurred under similar or different geological settings in the Eastern Italian Alps, in order to define triggering thresholds. A threshold for debris-flow activity in terms of mean intensity, duration and mean annual precipitation (M.A.P.) is defined for the study area The normalised rainfall and the normalised intensity are expressed as a per cent with respect to M.A.P. This threshold is compared with thresholds proposed by other authors, and the comparison shows that a lower value is obtained, indicating the debris-flow susceptibility of the area. The threshold equations are: R/M.A.P. = - 1.36 · ln(I) + 3.93 where I > 2 mm/h I /M.A.P. = 0.74 · D-0.56. The determination of a debris-flow threshold is linked to the necessity of a fast decisional phase in a warning system for debris-flow protection. This threshold cannot be used as a predictive tool, but rather as a warning signal for technicians who manage the monitoring/warning system.
Atmospheric tide disturbances as Earthquake precursory phenomena
Authors: Arabelos D. N. , Asteriadis G. , Bloutsos A. , Contadakis M. E. , Spatalas S. D. 
Published: April 2010

Abstract. The tidal changes of the barometric pressure in the area of Thessaloniki were studied by analysing a sample of 21 years of hourly measurements. The resulted tidal parameters (amplitude and phase difference) were considered as "mean values" of the corresponding parameters for this long time period. Using these parameters, barometric changes were computed and subtracted from the observations. Assuming that the residuals might include local (in terms of time) information,the residual time series was split in 21 blocks and a new analysis was performed for each block separately. The 21 amplitude values computed for each tidal wave were considered as the amplitude variation with respect to the correspondingmean value. An observable correlation of the amplitude exalting of the most of the tidal waves was found to Earthquakes of magnitude >4, occurred close to Thessaloniki in the test period.
Estimation uncertainty of direct monetary flood damage to buildings
Authors: Merz B. , Kreibich H. , Thieken A. , Schmidtke R. 
Published: April 2010

Abstract. Traditional flood design methods are increasingly supplemented or replaced by risk-oriented methods which are based on comprehensive risk analyses. Besides meteorological, hydrological and hydraulic investigations such analyses require the estimation of flood impacts. Flood impact assessments mainly focus on direct economic losses using damage functions which relate property damage to damage-causing factors. Although the flood damage of a building is influenced by many factors, usually only inundation depth and building use are considered as damage-causing factors. In this paper a data set of approximately 4000 damage records is analysed. Each record represents the direct monetary damage to an inundated building. The data set covers nine flood events in Germany from 1978 to 1994. It is shown that the damage data follow a Lognormal distribution with a large variability, even when stratified according to the building use and to water depth categories. Absolute depth-damage functions which relate the total damage to the water depth are not very helpful in explaining the variability of the damage data, because damage is determined by various parameters besides the water depth. Because of this limitation it has to be expected that flood damage assessments are associated with large uncertainties. It is shown that the uncertainty of damage estimates depends on the number of flooded buildings and on the distribution of building use within the flooded area. The results are exemplified by a damage assessment for a rural area in southwest Germany, for which damage estimates and uncertainty bounds are quantified for a 100-year flood event. The estimates are compared to reported flood damages of a severe flood in 1993. Given the enormous uncertainty of flood damage estimates the refinement of flood damage data collection and modelling are major issues for further empirical and methodological improvements.