Bio-optical time series collected in coastal waters for SeaWiFS calibration and validation: large structure shadowing considerations

1997 ◽  
Author(s):  
Edward G. Kearns
Keyword(s):  
Time Series ◽  
Coastal Waters ◽  
Large Structure ◽  
Calibration And Validation ◽  
Optical Time

scholarly journals Technical note: A two-sided affine power scaling relationship to represent the concentration–discharge relationship

2020 ◽  
Vol 24 (4) ◽  
pp. 1823-1830 ◽  
Author(s):  
José Manuel Tunqui Neira ◽  
Vazken Andréassian ◽  
Gaëlle Tallec ◽  
Jean-Marie Mouchel
Keyword(s):  
Electrical Conductivity ◽  
Time Series ◽  
Power Law ◽  
High Frequency ◽  
Technical Note ◽  
Mathematical Representation ◽  
Power Scaling ◽  
Calibration And Validation ◽  
Numerical Criterion ◽  
Scaling Relationship

Abstract. This technical note deals with the mathematical representation of concentration–discharge relationships. We propose a two-sided affine power scaling relationship (2S-APS) as an alternative to the classic one-sided power scaling relationship (commonly known as “power law”). We also discuss the identification of the parameters of the proposed relationship, using an appropriate numerical criterion. The application of 2S-APS to the high-frequency chemical time series of the Orgeval-ORACLE observatory is presented here (in calibration and validation mode): it yields better results for several solutes and for electrical conductivity in comparison with the power law relationship.

Data augmentation of optical time series signals for small samples

2020 ◽  
Vol 59 (28) ◽  
pp. 8848
Author(s):  
Xuezhi Zhang ◽  
Zhaozhu Liu ◽  
Junfeng Jiang ◽  
Kun Liu ◽  
Xiaojun Fan ◽  
...  
Keyword(s):  
Time Series ◽  
Data Augmentation ◽  
Small Samples ◽  
Optical Time

scholarly journals Semi-automated open water iceberg detection from Landsat applied to Disko Bay, West Greenland

2019 ◽  
Vol 65 (251) ◽  
pp. 468-480 ◽  
Author(s):  
JESSICA SCHEICK ◽  
ELLYN M. ENDERLIN ◽  
GORDON HAMILTON
Keyword(s):  
Machine Learning ◽  
Time Series ◽  
Power Law ◽  
Coastal Waters ◽  
Landsat Imagery ◽  
Open Water ◽  
Size Distributions ◽  
Negative Power ◽  
West Greenland ◽  
Cloud Mask

ABSTRACTChanges in Greenland's marine-terminating outlet glaciers have led to changes in the flux of icebergs into Greenland's coastal waters, yet icebergs remain a relatively understudied component of the ice-ocean system. We developed a simple iceberg delineation algorithm for Landsat imagery. A machine learning-based cloud mask incorporated into the algorithm enables us to extract iceberg size distributions from open water even in partially cloudy scenes. We applied the algorithm to the Landsat archive covering Disko Bay, West Greenland, to derive a time series of iceberg size distributions from 2000–02 and 2013–15. The time series captures a change in iceberg size distributions, which we interpret as a result of changes in the calving regime of the parent glacier, Sermeq Kujalleq (Jakobshavn Isbræ). The change in calving style associated with the disintegration and disappearance of Sermeq Kujalleq's floating ice tongue resulted in the production of more small icebergs. The increased number of small icebergs resulted in increasingly negative power law slopes fit to iceberg size distributions in Disko Bay, suggesting that iceberg size distribution time series provide useful insights into changes in calving dynamics.

Variabilité interannuelle d'un indice d'intensité des remontées d'eau dans le secteur du cap Blanc (Mauritanie)

1985 ◽  
Vol 42 (12) ◽  
pp. 1969-1978 ◽  
Author(s):  
Robert Arfi
Keyword(s):  
Time Series ◽  
Deep Water ◽  
Coastal Waters ◽  
Water Mass ◽  
Initial Conditions ◽  
Trade Winds ◽  
Strong Activity ◽  
Northwest Africa ◽  
Progressive Return ◽  
Coastal Upwellings

The coastal waters along the Atlantic Sahara are characterized by intense hydrodynamic phenomena (upwellings, water mass alternations) throughout the year that deeply influence their productivity. Deep-water arrivals at surface levels are closely related to the local prevailing winds dominating all year long, the Northeast Trade winds. Working on a time series of 28 yr shows that far from being regular and constant during that period, the Trade winds were very variable. The coastal upwellings induced by these winds showed important intensity variations: after years of strong activity (1955–60) there was a period of minimal activity (1961–69), which was followed by a period of great irregularity (1970–82), showing a progressive return to the initial conditions. These important variations inducing deep hydrological consequences and modifications of water trophic potentialities can be related to the biological anomalies observed during the same time in the Northwest Africa fisheries.

Understanding jets in post-AGB close binaries

2018 ◽  
Vol 14 (S343) ◽  
pp. 355-356
Author(s):  
Dylan Bollen ◽  
Devika Kamath ◽  
Hans Van Winckel ◽  
Orsola De Marco
Keyword(s):  
Time Series ◽  
High Resolution ◽  
Orbital Motion ◽  
Young Stellar Objects ◽  
Close Binaries ◽  
Primary Star ◽  
Stellar Objects ◽  
Optical Time ◽  
The Impact ◽  
Stellar Mergers

AbstractWe have discovered jets in post-AGB binaries. The orbital motion allows us to carry out tomography of the jet as light from the primary star shines through the jet cone. Jets play a major role in many astrophysical environments, from young stellar objects to galaxies. They are also used to study the energetics of accretion phenomena in systems such as red transients and stellar mergers. We use high-resolution, optical, time-series spectra to constrain theories of jet launching, and the impact of jets on the evolution of these post-AGB binaries.

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