Search results for "FEA"
showing 10 items of 4862 documents
Bunker Cave stalagmites: an archive for central European Holocene climate variability
2012
Holocene climate was characterised by variability on multi-centennial to multi-decadal time scales. In central Europe, these fluctuations were most pronounced during winter. Here we present a record of past winter climate variability for the last 10.8 ka based on four speleothems from Bunker Cave, western Germany. Due to its central European location, the cave site is particularly well suited to record changes in precipitation and temperature in response to changes in the North Atlantic realm. We present high-resolution records of &delta;<sup>18</sup>O, &delta;<sup>13</sup>C values and Mg/Ca ratios. Changes in the Mg/Ca ratio are attributed to past meteoric p…
Effectiveness of a New Drainage System for Decreasing Erosion in Road Hillslopes
2021
© The Author(s) 2021.
Decadal oscillations of the aquatic chemistry of river waters in Latvia
2018
Abstract. Water quality changes of surface waters can be used to assess human impact intensity, but of importance is to consider also impacts of climate change/variability and naturally occurring changes of environmental quality. In Latvia, during the recent decades a major reduction of anthropogenic pressure has happened due to restructuring of economy and industrial production, resulting in major decrease of loading of many groups of pollutants. However, trends and driving factors for other groups of substances have not been much studied. Long term (1980–2012) results of hydrochemical monitoring, performed in rivers of Latvia, are analysed during this study in connection with long-term se…
WATER MANAGEMENT PROBLEMS AT THE BUKÓWKA DRINKING WATER RESERVOIR’S CROSS-BORDER BASIN AREA IN TERMS OF ITS ESTABLISHED FUNCTIONS
2015
The paper covers the analysis of water management problems in the cross-border reservoir basin of Bukówka, located at the Bóbr river, at 271+540 km of its course, below the Czech-Polish border, in Dolnośląskie Voivodeship. The problems of water management in the context of the reservoir’s functions have been analyzed; these are: flood control, the provision of water during low water level periods for the Water Treatment Plant in Marciszów, the provision of drinking water for the city of Wałbrzych as well as the provision of proper flow in the Bóbr river bed downstream from the reservoir. Due to its localization right below the border with the Czech Republic, the reservoir is exposed to a nu…
Sensitivity of a mesoscale model to different convective parameterization schemes in a heavy rain event
2011
Abstract. The Valencia region, on the Mediterranean coast of the Iberian Peninsula, is propitious to heavy precipitation, especially the area encompassing the South of Valencia province and the North of the Alicante province. In October 2007 a torrential rain affected the aforementioned area, producing accumulated rainfall values greater than 400 mm in less than 24 h and flash-floods that caused extensive economic losses and human casualties. This rain event has been studied in numerical experiments using the Regional Atmospheric Modeling System. The present paper deals with the effect of using the different convective parameterizations (CP) currently implemented in the Regional Atmospheric…
Numerical study of the October 2007 flash flood in the Valencia region (Eastern Spain): the role of orography
2010
Abstract. A torrential rain event took place in the Valencia region in October 2007, mainly affecting coastal areas and nearby mountains in the center-south of the region, in northern Alicante province. More than 400 mm in 24 h were recorded at some stations in these areas, with lower accumulations in the rest of the region where rainfall was less intense. In the first part of this work a description of the meteorological situation is given. The synoptic frame of the event is characterised by an advection of easterly maritime winds across the Western Mediterranean, lasting for at least 48 h, driving moist air towards the Iberian Peninsula eastern coast and the presence of an upper level iso…
Shoreline Extraction and Change Detection using 1:5000 Scale Orthophoto Maps: A Case Study of Latvia-Riga
2015
Coastal management requires rapid, up-to-date, and
 correct information. Thus, the determination of coastal movements and its
 directions has primary importance for coastal managers. For monitoring the
 change of shorelines, remote sensing data, very high resolution aerial images
 and orthophoto maps are utilized for detections of change on shorelines. It is
 possible to monitor coastal changes by extracting the coastline from orthophoto
 maps. Along the Baltic Sea and Riga Gulf, Latvian coastline length is 496 km.
 It is rich of coastal resources and natural biodiversity.&nbsp; Around 120 km of coastline are affected by
 significant coastal chang…
River-bed erosion due to changing boundary conditions: performance of a protective measure
2018
Abstract. Due to the introduction of man-made sediment barriers along a river, the amount of sediment load entering the downstream river reach is different to that leaving the reach, and erosion processes occur downstream of the barrier itself. Designers are often required to take into account the scouring process and to include adequate protective measures against the local scour. This paper addresses the performance of bio-engineering protective measures against the erosion process. In particular, a green carpet, realized with real flexible vegetation, has been used as the protective measure against erosion processes downstream of a rigid bed. Analyses are based on experimental work carri…
Evaluation of plankton communities in small highly humic bog lakes in Latvia
1998
This paper reports the results of a study performed at the Teici State Reserve in Latvia The results indicated that algal communities in brown water lakes were formed by species that were tolerant to a low pH and high humic substance concentration. The composition of the species of phytoplankton and zooplankton was comparatively simple. A significant correlation was found between the number of species of phytoplankton, zooplankton, and the pH value. Similarly there was a clear relationship between the taxonomic composition of phytoplankton, zooplankton, and the trophic state of the lakes. Dyseutrophic lakes were characterized by comparatively higher biodiversity of planktonic communities th…
Modelling the shrub encroachment in a grassland with a Cellular Automata Model
2018
Abstract. Arid and semi-arid grasslands of southwestern North America have changed dramatically over the last 150 years as a result of shrub encroachment, i.e. the increase in density, cover and biomass of indigenous shrubby plants in grasslands. Numerous studies have documented the expansion of shrublands in the southwestern American grasslands; in particular shrub encroachment has occurred strongly in part of the northern Chihuahuan desert since 1860. This encroachment has been simulated using an ecohydrological Cellular Automata model, CATGraSS. It is a spatially distributed model driven by spatially explicit irradiance and runs on a fine-resolution gridded domain. Plant competition is m…