In Situ Evaluation of Seasonal Variability of Subgrade Modulus Using DCP and FWD Tests

In recent years, the change of marine environment due to climate change and declining primary productivity have been big concerns in the East/Japan Sea, Korea. However, the main causes for the recent changes are still not revealed clearly. The particulate organic carbon (POC) to chlorophyll-a (chl-a) ratio (POC:chl-a) could be a useful indicator for ecological and physiological conditions of phytoplankton communities and thus help us to understand the recent reduction of primary productivity in the East/Japan Sea. To derive the POC in the East/Japan Sea from a satellite dataset, the new regional POC algorithm was empirically derived with in-situ measured POC concentrations. A strong positive linear relationship (R2 = 0.6579) was observed between the estimated and in-situ measured POC concentrations. Our new POC algorithm proved a better performance in the East/Japan Sea compared to the previous one for the global ocean. Based on the new algorithm, long-term POC:chl-a ratios were obtained in the entire East/Japan Sea from 2003 to 2018. The POC:chl-a showed a strong seasonal variability in the East/Japan Sea. The spring and fall blooms of phytoplankton mainly driven by the growth of large diatoms seem to be a major factor for the seasonal variability in the POC:chl-a. Our new regional POC algorithm modified for the East/Japan Sea could potentially contribute to long-term monitoring for the climate-associated ecosystem changes in the East/Japan Sea. Although the new regional POC algorithm shows a good correspondence with in-situ observed POC concentrations, the algorithm should be further improved with continuous field surveys.

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Seasonal variability of the Equatorial Undercurrent at 10°W as inferred from recent in situ observations

Journal of Geophysical Research Atmospheres ◽

10.1029/2008jc004976 ◽

2009 ◽

Vol 114 (C6) ◽

Cited By ~ 27

Author(s):

N. Kolodziejczyk ◽

B. Bourlès ◽

F. Marin ◽

J. Grelet ◽

R. Chuchla

Keyword(s):

Seasonal Variability ◽

Equatorial Undercurrent ◽

In Situ Observations

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Low melt rates with seasonal variability at the base of Fimbul Ice Shelf, East Antarctica, revealed by in situ interferometric radar measurements

Geophysical Research Letters ◽

10.1002/2014gl061782 ◽

2014 ◽

Vol 41 (22) ◽

pp. 8138-8146 ◽

Cited By ~ 13

Author(s):

Kirsty Langley ◽

Jack Kohler ◽

Anna Sinisalo ◽

Mats Jørgen Øyan ◽

Svein Erik Hamran ◽

...

Keyword(s):

Seasonal Variability ◽

East Antarctica ◽

Ice Shelf ◽

Radar Measurements

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Supplementary material to "Seasonal Variability in In-situ Supraglacial Streamflow and Drivers in Southwest Greenland in 2016"

10.5194/tc-2020-314-supplement ◽

2020 ◽

Author(s):

Rohi Muthyala ◽

Asa K. Rennermalm ◽

Sasha Z. Leidman ◽

Matthew G. Cooper ◽

Sarah W. Cooley ◽

...

Keyword(s):

Seasonal Variability ◽

Supplementary Material ◽

Southwest Greenland

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Use of optical absorption indices to assess seasonal variability of dissolved organic matter in Amazon floodplain lakes

Biogeosciences ◽

10.5194/bg-17-5355-2020 ◽

2020 ◽

Vol 17 (21) ◽

pp. 5355-5364

Author(s):

Maria Paula da Silva ◽

Lino A. Sander de Carvalho ◽

Evlyn Novo ◽

Daniel S. F. Jorge ◽

Claudio C. F. Barbosa

Keyword(s):

Remote Sensing ◽

Organic Matter ◽

Optical Absorption ◽

Dissolved Organic Matter ◽

Seasonal Variability ◽

Large Scale ◽

Remote Sensing Data ◽

Floodplain Lakes ◽

Sentinel 2

Abstract. Given the importance of dissolved organic matter (DOM) in the carbon cycling of aquatic ecosystems, information on its seasonal variability is crucial. In this study we assess the use of optical absorption indices available in the literature based on in situ data to both characterize the seasonal variability of DOM in a highly complex environment and for application in large-scale studies using remote sensing data. The study area comprises four lakes located in the Mamirauá Sustainable Development Reserve (MSDR). Samples for the determination of colored dissolved organic matter (CDOM) and measurements of remote sensing reflectance (Rrs) were acquired in situ. The Rrs was used to simulate the response of the visible bands of the Sentinel-2 MultiSpectral Instrument (MSI), which was used in the proposed models. Differences between lakes were tested using the CDOM indices. The results highlight the role of the flood pulse in the DOM dynamics at the floodplain lakes. The validation results show that the use of the absorption coefficient of CDOM (aCDOM) as a proxy of the spectral slope between 275 and 295 nm (S275–295) during rising water is worthwhile, demonstrating its potential application to Sentinel-2 MSI imagery data for studying DOM dynamics on the large scale.

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Use of absorption optical indices to assess seasonal variability of dissolved organic matter in amazon floodplain lakes

10.5194/bg-2019-324 ◽

2019 ◽

Author(s):

Maria Paula da Silva ◽

Lino A. Sander de Carvalho ◽

Evlyn Novo ◽

Daniel S. F. Jorge ◽

Claudio C. F. Barbosa

Keyword(s):

Remote Sensing ◽

Organic Matter ◽

Dissolved Organic Matter ◽

Seasonal Variability ◽

Large Scale ◽

River Bank ◽

In Situ Data ◽

Amazon Floodplain ◽

Significant Difference

Abstract. Given the importance of DOM in the carbon cycling of aquatic ecosystems, information on its seasonal variability is crucial. This study assesses the use of available absorption optical indices based on in situ data to both characterize the seasonal variability of the DOM dynamics in a highly complex environment and their viability of being used for satellite remote sensing on large scale studies. The study area comprises four lakes located at the Mamirauá Sustainable Development Reserve (MSDR). Samples for the determination of coloured dissolved organic matter (CDOM) and remote sensing reflectance (Rrs) were acquired in situ. The Rrs was applied to simulate MSI visible bands and used in the proposed models. Differences between lakes were tested regarding CDOM indices. Significant difference in the average of aCDOM (440), aCDOM spectra and S275–295 were found between lakes located inside the flood forest and those near the river bank. The proposed model showed that aCDOM can be used as proxy of S275–295 during rising water with good validation results, demonstrating the potential of Sentinel/MSI imagery data in large scale studies on the dynamics of DOM.

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Seasonal differences in the vertical profiles of aerosol optical properties over rural Oklahoma

Atmospheric Chemistry and Physics ◽

10.5194/acp-11-10661-2011 ◽

2011 ◽

Vol 11 (20) ◽

pp. 10661-10676 ◽

Cited By ~ 34

Author(s):

E. Andrews ◽

P. J. Sheridan ◽

J. A. Ogren

Keyword(s):

Seasonal Variability ◽

Gulf Coast ◽

Single Scattering ◽

Single Scattering Albedo ◽

Ambient Conditions ◽

Seasonal Differences ◽

Aerosol Loading ◽

Aerosol Absorption ◽

Aerosol Scattering

Abstract. A small airplane made 597 aerosol optical property (light absorption and light scattering) vertical profile measurements over a rural Oklahoma site between March 2000 and December 2007. The aerosol profiles obtained during these 8 yr of measurements suggest significant seasonal differences in aerosol loading (scattering and absorption). The highest amounts of scattering and absorbing aerosol are observed during the summer and the lowest loading occurs during the winter. The relative contribution of aerosol absorption is highest in the winter (i.e., single scattering albedo is lowest in winter), particularly aloft. Aerosol absorption generally decreased with altitude below ~1.5 km and then was relatively constant or decreased more gradually above that. Aerosol scattering decreased sharply with altitude below ~1.5 km but, unlike absorption, also decreased at higher altitudes, albeit less sharply. Scattering Ångström exponents suggest that the aerosol was dominated by sub-micron aerosol during the summer at all altitudes, but that larger particles were present, especially in the spring and winter above 1 km. The seasonal variability observed for aerosol loading is consistent with AERONET aerosol optical depth (AOD) although the AOD values calculated from in situ adjusted to ambient conditions and matching wavelengths are up to a factor of two lower than AERONET AOD values depending on season. The column averaged single scattering albedo derived from in situ airplane measurements are similar in value to the AERONET single scattering albedo inversion product but the seasonal patterns are different – possibly a consequence of the strict constraints on obtaining single scattering albedo from AERONET data. A comparison of extinction Ångström exponent and asymmetry parameter from the airplane and AERONET platforms suggests similar seasonal variability with smaller particles observed in the summer and fall and larger particles observed in spring and winter. The observed seasonal cycle of aerosol loading corresponds with changes in air mass back trajectories: the aerosol scattering was higher when transport was from polluted areas (e.g., the Gulf Coast) and lower when the air came from cleaner regions and/or the upper atmosphere.

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