Temporal (and Spatial) Scales and Sampling Requirements in Environmental Flows (with Emphasis on Inland and Coastal Waters)

Water samples were collected within river mouths, at river plume sites and at well flushed ocean-influenced sites within Moreton Bay, a shallow subtropical embayment in south-eastern Queensland. Rates of inorganic nitrogen (NH+4 and NO-3) and carbon uptake were determined across temporal and spatial scales by use of 15N and 14C incorporation. Phytoplankton productivity, measured as CO2 uptake, was highest at the river mouths. Rates of NH+4 uptake exceeded rates of NO-3 uptake at all sites at all times. Relative preference indices demonstrated a consistent preference by phytoplankton for NH+4 uptake, and NH+4 uptake rates were higher at ocean-influenced sites than at river-mouth sites. Inorganic nutrient and chlorophyll a concentrations were highest at river mouths; however, the greatest NH+4 uptake occurred at the ocean-influenced sites, reflecting a greater dependence on ‘recycled’ N than on ‘new’ N. Biomass-independent NH+4 uptake increased with increasing water temperature; however, NO-3 uptake increased with decreasing water temperature, reflecting the lower temperature optimum for nitrate reductase. The range of NH+4 and NO-3 uptake rates was greater than ranges reported for other coastal waters, reflecting the strong temporal and spatial gradients within Moreton Bay. This trend of strong gradients in C and N dynamics from oligotrophic to river-influenced waters with seasonal flows is likely to exist in many tropical and subtropical coastal waters of Australia.

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WAVE CLIMATE OF THE BLACK SEA’S COASTAL WATERS DURING THE LAST THREE DECADES

Proceedings of International Conference "Managinag risks to coastal regions and communities in a changinag world" (EMECS'11 - SeaCoasts XXVI) ◽

10.31519/conferencearticle_5b1b943584ab71.87772537 ◽

2017 ◽

Author(s):

Fedor Gippius ◽

Stanislav Myslenkov ◽

Elena Stoliarova ◽

...

Keyword(s):

Wind Speed ◽

Cell Size ◽

Coastal Waters ◽

Wind Wave ◽

Spatial Scales ◽

Wave Model ◽

Wave Climate ◽

Computational Grid ◽

Coastal Areas ◽

Wave Parameters

This study is focused on the alterations and typical features of the wind wave climate of the Black Sea’s coastal waters since 1979 till nowadays. Wind wave parameters were calculated by means of the 3rd-generation numerical spectral wind wave model SWAN, which is widely used on various spatial scales – both coastal waters and open seas. Data on wind speed and direction from the NCEP CFSR reanalysis were used as forcing. The computations were performed on an unstructured computational grid with cell size depending on the distance from the shoreline. Modeling results were applied to evaluate the main characteristics of the wind wave in various coastal areas of the sea.

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THE SZ4D INITIATIVE: AN EMERGING OPPORTUNITY FOR COORDINATED RESEARCH IN SUBDUCTION ZONE DEFORMATION ACROSS TEMPORAL AND SPATIAL SCALES

10.1130/abs/2019am-338373 ◽

2019 ◽

Author(s):

Harold J. Tobin ◽

◽

Alison R. Duvall

Keyword(s):

Subduction Zone ◽

Spatial Scales ◽

Temporal And Spatial ◽

Zone Deformation

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Larval Feeding: Mechanisms, Rates, and Performance in Nature

10.1093/oso/9780198786962.003.0007 ◽

2018 ◽

Keyword(s):

Marine Invertebrates ◽

Spatial Scales ◽

Size Spectrum ◽

Larval Feeding ◽

Natural Habitats ◽

Feeding Mechanism ◽

Temporal And Spatial ◽

And Performance ◽

Bioenergetics Models ◽

Many Particles

Larvae of many marine invertebrates must capture and ingest particulate food in order to develop to metamorphosis. These larvae use only a few physical processes to capture particles, but implement these processes using diverse morphologies and behaviors. Detailed understanding of larval feeding mechanism permits investigators to make predictions about feeding performance, including the size spectrum of particles larvae can capture and the rates at which they can capture them. In nature, larvae are immersed in complex mixtures of edible particles of varying size, density, flavor, and nutritional quality, as well as many particles that are too large to ingest. Concentrations of all of these components vary on fine temporal and spatial scales. Mechanistic models linking larval feeding mechanism to performance can be combined with data on food availability in nature and integrated into broader bioenergetics models to yield increased understanding of the biology of larvae in complex natural habitats.

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Humans and the Environment

10.1093/oso/9780199590292.001.0001 ◽

2013 ◽

Keyword(s):

Spatial Scales ◽

Empirical Studies ◽

Human Action ◽

Cultural Practice ◽

Environmental Archaeology ◽

Archaeological Data ◽

Temporal And Spatial ◽

Global And Local ◽

The Relationship ◽

The Way

The environment has always been a central concept for archaeologists and, although it has been conceived in many ways, its role in archaeological explanation has fluctuated from a mere backdrop to human action, to a primary factor in the understanding of society and social change. Archaeology also has a unique position as its base of interest places it temporally between geological and ethnographic timescales, spatially between global and local dimensions, and epistemologically between empirical studies of environmental change and more heuristic studies of cultural practice. Drawing on data from across the globe at a variety of temporal and spatial scales, this volume resituates the way in which archaeologists use and apply the concept of the environment. Each chapter critically explores the potential for archaeological data and practice to contribute to modern environmental issues, including problems of climate change and environmental degradation. Overall the volume covers four basic themes: archaeological approaches to the way in which both scientists and locals conceive of the relationship between humans and their environment, applied environmental archaeology, the archaeology of disaster, and new interdisciplinary directions.The volume will be of interest to students and established archaeologists, as well as practitioners from a range of applied disciplines.

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On the generation of internal waves by river plumes in subcritical initial conditions

Scientific Reports ◽

10.1038/s41598-021-81464-5 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

R. Mendes ◽

J. C. B. da Silva ◽

J. M. Magalhaes ◽

B. St-Denis ◽

D. Bourgault ◽

...

Keyword(s):

Numerical Modeling ◽

Internal Waves ◽

Coastal Waters ◽

Initial Conditions ◽

Spatial Scales ◽

River Plumes ◽

Wide Range ◽

Near Shore ◽

Generation Mechanisms ◽

Douro River

AbstractInternal waves (IWs) in the ocean span across a wide range of time and spatial scales and are now acknowledged as important sources of turbulence and mixing, with the largest observations having 200 m in amplitude and vertical velocities close to 0.5 m s−1. Their origin is mostly tidal, but an increasing number of non-tidal generation mechanisms have also been observed. For instance, river plumes provide horizontally propagating density fronts, which were observed to generate IWs when transitioning from supercritical to subcritical flow. In this study, satellite imagery and autonomous underwater measurements are combined with numerical modeling to investigate IW generation from an initial subcritical density front originating at the Douro River plume (western Iberian coast). These unprecedented results may have important implications in near-shore dynamics since that suggest that rivers of moderate flow may play an important role in IW generation between fresh riverine and coastal waters.

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8-Day and Daily Maximum and Minimum Air Temperature Estimation via Machine Learning Method on a Climate Zone to Global Scale

Remote Sensing ◽

10.3390/rs13122355 ◽

2021 ◽

Vol 13 (12) ◽

pp. 2355

Author(s):

Linglin Zeng ◽

Yuchao Hu ◽

Rui Wang ◽

Xiang Zhang ◽

Guozhang Peng ◽

...

Keyword(s):

Spatial Scale ◽

Air Temperature ◽

Spatial Scales ◽

Model Performance ◽

Global Scale ◽

Scale Model ◽

Validation Dataset ◽

Daily Maximum ◽

Climate Zone ◽

Temporal And Spatial

Air temperature (Ta) is a required input in a wide range of applications, e.g., agriculture. Land Surface Temperature (LST) products from Moderate Resolution Imaging Spectroradiometer (MODIS) are widely used to estimate Ta. Previous studies of these products in Ta estimation, however, were generally applied in small areas and with a small number of meteorological stations. This study designed both temporal and spatial experiments to estimate 8-day and daily maximum and minimum Ta (Tmax and Tmin) on three spatial scales: climate zone, continental and global scales from 2009 to 2018, using the Random Forest (RF) method based on MODIS LST products and other auxiliary data. Factors contributing to the relation between LST and Ta were determined based on physical models and equations. Temporal and spatial experiments were defined by the rules of dividing the training and validation datasets for the RF method, in which the stations selected in the training dataset were all included or not in the validation dataset. The RF model was first trained and validated on each spatial scale, respectively. On a global scale, model accuracy with a determination coefficient (R2) > 0.96 and root mean square error (RMSE) < 1.96 °C and R2 > 0.95 and RMSE < 2.55 °C was achieved for 8-day and daily Ta estimations, respectively, in both temporal and spatial experiments. Then the model was trained and cross-validated on each spatial scale. The results showed that the data size and station distribution of the study area were the main factors influencing the model performance at different spatial scales. Finally, the spatial patterns of the model performance and variable importance were analyzed. Both daytime and nighttime LST had a significant contribution in the 8-day Tmax estimation on all the three spatial scales; while their contribution in daily Tmax estimation varied over different continents or climate zones. This study was expected to improve our understanding of Ta estimation in terms of accuracy variations and influencing variables on different spatial and temporal scales. The future work mainly includes identifying underlying mechanisms of estimation errors and the uncertainty sources of Ta estimation from a local to a global scale.

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Sequential modelling of the Earth’s core magnetic field

Earth Planets and Space ◽

10.1186/s40623-020-01230-1 ◽

2020 ◽

Vol 72 (1) ◽

Cited By ~ 3

Author(s):

Guillaume Ropp ◽

Vincent Lesur ◽

Julien Baerenzung ◽

Matthias Holschneider

Keyword(s):

Magnetic Field ◽

Prior Information ◽

Spatial Scales ◽

Model Parameters ◽

International Geomagnetic Reference Field ◽

The Earth ◽

Temporal And Spatial ◽

Different Sources ◽

Original Approach ◽

Modelling Approach

Abstract We describe a new, original approach to the modelling of the Earth’s magnetic field. The overall objective of this study is to reliably render fast variations of the core field and its secular variation. This method combines a sequential modelling approach, a Kalman filter, and a correlation-based modelling step. Sources that most significantly contribute to the field measured at the surface of the Earth are modelled. Their separation is based on strong prior information on their spatial and temporal behaviours. We obtain a time series of model distributions which display behaviours similar to those of recent models based on more classic approaches, particularly at large temporal and spatial scales. Interesting new features and periodicities are visible in our models at smaller time and spatial scales. An important aspect of our method is to yield reliable error bars for all model parameters. These errors, however, are only as reliable as the description of the different sources and the prior information used are realistic. Finally, we used a slightly different version of our method to produce candidate models for the thirteenth edition of the International Geomagnetic Reference Field.

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Dissecting the turbulent weather driven by mechanical AGN feedback

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa2747 ◽

2020 ◽

Vol 498 (4) ◽

pp. 4983-5002

Author(s):

D Wittor ◽

M Gaspari

Keyword(s):

Feedback Loop ◽

Spatial Scales ◽

Self Regulation ◽

Cosmic Time ◽

Massive Galaxies ◽

Temporal And Spatial ◽

Lagrangian Tracers ◽

Field Unit ◽

Integral Field ◽

Gaseous Halo

ABSTRACT Turbulence in the intracluster, intragroup, and circumgalactic medium plays a crucial role in the self-regulated feeding and feedback loop of central supermassive black holes. We dissect the 3D turbulent ‘weather’ in a high-resolution Eulerian simulation of active galactic nucleus (AGN) feedback, shown to be consistent with multiple multiwavelength observables of massive galaxies. We carry out post-processing simulations of Lagrangian tracers to track the evolution of enstrophy, a proxy of turbulence, and its related sinks and sources. This allows us to isolate in depth the physical processes that determine the evolution of turbulence during the recurring strong and weak AGN feedback events, which repeat self-similarly over the Gyr evolution. We find that the evolution of enstrophy/turbulence in the gaseous halo is highly dynamic and variable over small temporal and spatial scales, similar to the chaotic weather processes on Earth. We observe major correlations between the enstrophy amplification and recurrent AGN activity, especially via its kinetic power. While advective and baroclinc motions are always subdominant, stretching motions are the key sources of the amplification of enstrophy, in particular along the jet/cocoon, while rarefactions decrease it throughout the bulk of the volume. This natural self-regulation is able to preserve, as ensemble, the typically observed subsonic turbulence during cosmic time, superposed by recurrent spikes via impulsive anisotropic AGN features (wide outflows, bubbles, cocoon shocks). This study facilitates the preparation and interpretation of the thermo-kinematical observations enabled by new revolutionary X-ray integral field unit telescopes, such as XRISM and Athena.

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