scholarly journals Approaches to evaluate spatial and temporal variability of deep marine sediment characteristics under the impact of dense water formation events

2020 ◽  
Author(s):  
XAVIER DURRIEU de MADRON ◽  
MARION STABHOLZ ◽  
LARS-ERIC HEIMBÜRGER-BOAVIDA ◽  
DOMINIQUE AUBERT ◽  
PHILIPPE KERHERVÉ ◽  
...  
Keyword(s):  
Spatial Variability ◽  
Temporal Variability ◽  
Small Scale ◽  
Spatial And Temporal Variability ◽  
Geochemical Composition ◽  
Dense Water ◽  
Water Formation ◽  
Dense Water Formation ◽  
Northwestern Mediterranean Sea ◽  
The Impact

Dense shelf water cascading and open-ocean convection frequently occurs in the Gulf of Lions, northwestern Mediterranean Sea. These intense dense water formation events are capable of supplying large amounts of particulate matter as well as remobilizing and dispersing local sediments and, therefore, are thought to leave an imprint on superficial deposits. Here, we compared the spatial variability of the superficial sediment composition (grain size, organic parameters, and metals) at different scales (from decimetric to kilometric) on the continental slope and rise with the temporal variability linked to the occurrence of intense dense water formation events. The spatial and temporal variability of the geochemical composition of deep sediments was assessed using multivariate and geostatistical analysis. The results indicate that, on the outer reach of the Cap de Creus Canyon, where both processes interact, no clear relation was found between the temporal variability of the superficial sediment and the deep-water formation events, and that the small-scale spatial variability of the sediment is masking the temporal variability. Measurements across the southern slope indicate the presence of a somehow distinct geochemical signature that likely results from the influence of recurrent intense, dense water formation events as well as an unabating bottom trawling activity.

scholarly journals The influence of riparian woodland on the spatial and temporal variability of stream water temperatures in an upland salmon stream

2004 ◽  
Vol 8 (3) ◽  
pp. 449-459 ◽  
Author(s):  
I. A. Malcolm ◽  
D. M. Hannah ◽  
M. J. Donaghy ◽  
C. Soulsby ◽  
A. F. Youngson
Keyword(s):  
Thermal Regime ◽  
Temporal Variability ◽  
Heat Budget ◽  
Riparian Forest ◽  
Stream Water ◽  
Spatial And Temporal Variability ◽  
Substantial Impact ◽  
Site Specific ◽  
The Impact ◽  
Riparian Woodland

Abstract. The spatio-temporal variability of stream water temperatures was investigated at six locations on the Girnock Burn (30km2 catchment), Cairngorms, Scotland over three hydrological years between 1998 and 2002. The key site-specific factors affecting the hydrology and climatology of the sampling points were investigated as a basis for physical process inference. Particular emphasis was placed on assessing the effects of riparian forest in the lower catchment versus the heather moorland riparian zones that are spatially dominant in the upper catchment. The findings were related to river heat budget studies that provided process detail. Gross changes in stream temperature were affected by the annual cycle of incoming solar radiation and seasonal changes in hydrological and climatological conditions. Inter-annual variation in these controlling variables resulted in inter-annual variability in thermal regime. However, more subtle inter-site differences reflected the impact of site-specific characteristics on various components of the river energy budget. Inter-site variability was most apparent at shorter time scales, during the summer months and for higher stream temperatures. Riparian woodland in the lower catchment had a substantial impact on thermal regime, reducing diel variability (over a period of 24 hours) and temperature extremes. Observed inter-site differences are likely to have a substantial effect on freshwater ecology in general and salmonid fish in particular. Keywords: temperature, thermal regime, forest, salmon, hydrology, Girnock Burn, Cairngorm

Dense water formation on the Icelandic shelf and its contribution to the North Icelandic Jet

2021 ◽  
Author(s):  
Yarisbel Garcia‐Quintana ◽  
Nathan Grivault ◽  
Xianmin Hu ◽  
Paul G. Myers
Keyword(s):  
Dense Water ◽  
The North ◽  
Water Formation ◽  
Dense Water Formation

scholarly journals Spatial and temporal variability of rainfall and their effects on hydrological response in urban areas – a review

2017 ◽  
Vol 21 (7) ◽  
pp. 3859-3878 ◽  
Author(s):  
Elena Cristiano ◽  
Marie-Claire ten Veldhuis ◽  
Nick van de Giesen
Keyword(s):  
Temporal Variability ◽  
Urban Areas ◽  
Rainfall Variability ◽  
Urban Environments ◽  
Hydrological Processes ◽  
Small Scale ◽  
Spatial And Temporal Variability ◽  
Hydrological Response ◽  
Weather Radars ◽  
New Instruments

Abstract. In urban areas, hydrological processes are characterized by high variability in space and time, making them sensitive to small-scale temporal and spatial rainfall variability. In the last decades new instruments, techniques, and methods have been developed to capture rainfall and hydrological processes at high resolution. Weather radars have been introduced to estimate high spatial and temporal rainfall variability. At the same time, new models have been proposed to reproduce hydrological response, based on small-scale representation of urban catchment spatial variability. Despite these efforts, interactions between rainfall variability, catchment heterogeneity, and hydrological response remain poorly understood. This paper presents a review of our current understanding of hydrological processes in urban environments as reported in the literature, focusing on their spatial and temporal variability aspects. We review recent findings on the effects of rainfall variability on hydrological response and identify gaps where knowledge needs to be further developed to improve our understanding of and capability to predict urban hydrological response.

scholarly journals The influence of a new water infrastructure development on the relative abundance of two Australian freshwater turtle species

2018 ◽  
Vol 66 (1) ◽  
pp. 57 ◽  
Author(s):  
Natalie J. Clark ◽  
Courtenay E. Mills ◽  
Nicolette A. Osborne ◽  
Kerry M. Neil
Keyword(s):  
Relative Abundance ◽  
Temporal Variability ◽  
Monitoring Program ◽  
Freshwater Turtle ◽  
Spatial And Temporal Variability ◽  
Main Body ◽  
Water Infrastructure ◽  
Turtle Species ◽  
Australian Freshwater ◽  
The Impact

Development of water infrastructure benefits water security and agriculture but poses risks to habitat and aquatic fauna. Wyaralong Dam was constructed on Teviot Brook in 2010 to provide future urban water supplies for South East Queensland, Australia. Construction of the dam created a large impoundment area and environmental impact assessment predicted significant impacts upon resident freshwater turtle species and their habitats. Differences in habitat requirements, life-history characteristics and sensitivity to change between the Macquarie River turtle (Emydura macquarii macquarii) and the common saw-shelled turtle (Myuchelys latisternum) were expected to influence the impact of the dam on the spatial and temporal abundance of these species. The relative abundance of each species was monitored at sites located within, upstream and downstream of the impoundment across wet and dry seasons during the dam’s first five years of operation. The results of this monitoring program indicate that spatial and temporal variability in the relative abundance of E. macquarii macquarii and M. latisternum occurred during the study but not all expected impacts were realised. Contrary to expectation, the relative abundance of E. macquarii macquarii did not increase over time within, upstream or downstream of the dam. M. latisternum showed greater temporal variability at some sites; however, no clear relationship between relative abundance and operational years was observed during the monitoring program. Spatial variability in relative abundance between sites was dependent upon season, with trends generally consistent across both turtle species. Where differences between species were observed, these are suspected to have resulted from the influence of environmental conditions on species-specific movement behaviours. The monitoring program confirmed the use of the upper limits of the impoundment and the plunge pool below the dam wall by both turtle species but relative abundance within the main body of the impoundment remained low throughout monitoring. The results of the study allow for consideration of the suitability of predefined management measures and the development of recommendations for future monitoring programs prescribed for water infrastructure developments.

scholarly journals A hydrochemical modelling framework for combined assessment of spatial and temporal variability in stream chemistry: application to Plynlimon, Wales

2001 ◽  
Vol 5 (1) ◽  
pp. 49-58 ◽  
Author(s):  
H.J. Foster ◽  
M.J. Lees ◽  
H.S. Wheater ◽  
C. Neal ◽  
B. Reynolds
Keyword(s):  
Land Use ◽  
Land Use Change ◽  
Spatial Variability ◽  
Temporal Variability ◽  
Biological Diversity ◽  
Spatial And Temporal Variability ◽  
Stream Chemistry ◽  
Two Component ◽  
End Members

Abstract. Recent concern about the risk to biota from acidification in upland areas, due to air pollution and land-use change (such as the planting of coniferous forests), has generated a need to model catchment hydro-chemistry to assess environmental risk and define protection strategies. Previous approaches have tended to concentrate on quantifying either spatial variability at a regional scale or temporal variability at a given location. However, to protect biota from ‘acid episodes’, an assessment of both temporal and spatial variability of stream chemistry is required at a catchment scale. In addition, quantification of temporal variability needs to represent both episodic event response and long term variability caused by deposition and/or land-use change. Both spatial and temporal variability in streamwater chemistry are considered in a new modelling methodology based on application to the Plynlimon catchments, central Wales. A two-component End-Member Mixing Analysis (EMMA) is used whereby low and high flow chemistry are taken to represent ‘groundwater’ and ‘soil water’ end-members. The conventional EMMA method is extended to incorporate spatial variability in the two end-members across the catchments by quantifying the Acid Neutralisation Capacity (ANC) of each in terms of a statistical distribution. These are then input as stochastic variables to a two-component mixing model, thereby accounting for variability of ANC both spatially and temporally. The model is coupled to a long-term acidification model (MAGIC) to predict the evolution of the end members and, hence, the response to future scenarios. The results can be plotted as a function of time and space, which enables better assessment of the likely effects of pollution deposition or land-use changes in the future on the stream chemistry than current methods which use catchment average values. The model is also a useful basis for further research into linkage between hydrochemistry and intra-catchment biological diversity. Keywords: hydrochemistry, End-Member Mixing Analysis (EMMA), uplands, acidification

scholarly journals The improvements of the ships of opportunity program in MFS-TEP

Ocean Science ◽  
2007 ◽  
Vol 3 (2) ◽  
pp. 245-258 ◽  
Author(s):  
G. M. R. Manzella ◽  
F. Reseghetti ◽  
G. Coppini ◽  
M. Borghini ◽  
A. Cruzado ◽  
...  
Keyword(s):  
Mediterranean Sea ◽  
Pilot Project ◽  
Quality Data ◽  
Dense Water ◽  
Short Period ◽  
Water Formation ◽  
Dense Water Formation ◽  
Forecasting System ◽  
Opportunity Program ◽  
The Mediterranean

Abstract. The Ships Of Opportunity Program in the Mediterranean Sea was established at the end of 1999, in the framework of the Mediterranean Forecasting System – Pilot Project (MFS-PP). Many improvements have been made in data collection, transmission and management. Calibration of selected XBTs and a comparison of XBTs vs. CTDs during some research cruises have assured the quality of the data. Transmission now allows receiving data in full resolution by using GSM or satellite telecommunication services; management is offering access to high quality data and view services. The effects of technological and methodological improvements in the observing system are assessed in terms of capability to represent the most important circulation features. The improved methodologies have been tested during the Mediterranean Forecasting System – Toward Environmental Prediction (MFS-TEP) – Targeted Operational Period (MFS-TOP), lasting from September 2004 to February 2005. In spite of the short period of measurements, several important aspects of the Mediterranean Sea circulation have been verified, such as eddies and gyres in the various sub-basins, and dense water formation processes in some of them (vertical homogeneous profiles of about 13°C down to ~800 m in the Provençal, and of about 14.9°C down to ~300 m in the Levantine have allowed defining an index of dense water formation).

scholarly journals Circulation, dense water formation, and outflow on the northeast Chukchi Shelf

1998 ◽  
Vol 103 (C4) ◽  
pp. 7647-7661 ◽  
Author(s):  
Thomas J. Weingartner ◽  
Donald J. Cavalieri ◽  
Knut Aagaard ◽  
Yasunori Sasaki
Keyword(s):  
Dense Water ◽  
Water Formation ◽  
Dense Water Formation ◽  
Chukchi Shelf

Anthropogenic CO2 in a dense water formation area of the Mediterranean Sea

2017 ◽  
Vol 123 ◽  
pp. 118-128 ◽  
Author(s):  
Gianmarco Ingrosso ◽  
Manuel Bensi ◽  
Vanessa Cardin ◽  
Michele Giani
Keyword(s):  
Mediterranean Sea ◽  
Dense Water ◽  
Anthropogenic Co2 ◽  
Water Formation ◽  
Dense Water Formation ◽  
The Mediterranean
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