What can we learn about small-scale spatial variability of surface ocean dimethylsulfide (DMS) concentrations from high frequency novel measurements?

2021 ◽  
Author(s):  
George Manville ◽  
Paul Halloran ◽  
Tom Bell ◽  
Jane Mulcahy ◽  
Anoop Mahajan ◽  
...  
Keyword(s):  
Spatial Variability ◽  
High Frequency ◽  
Marine Ecosystem ◽  
Small Scale ◽  
Gas Transfer ◽  
Regional Variability ◽  
Anthropogenic Aerosol ◽  
Transfer Velocity ◽  
Latitudinal Dependence ◽  
The Impact

<p>Analysis of new high frequency dimethylsulfide (DMS) measurements indicates a latitudinal dependence to the patterns of small-scale variability; this points to previously unrecognised drivers of DMS spatial variability. DMS makes a significant contribution to natural marine aerosol. The amount and distribution of preindustrial DMS emissions is important for constraining the influence of anthropogenic aerosol on climate. The impact of variations in seawater DMS concentration on climatological (Lana et al. 2011) flux uncertainty is as large as the choice of gas transfer velocity parameterization. Improving understanding of the spatial variability of seawater DMS will help improve climatological flux estimates. High frequency data enables an assessment of the spatial variability lengthscale of DMS. We use 35 high frequency observational datasets, including measurements from the GSSDD (Global Surface Seawater DMS Database), NAAMES (North Atlantic Aerosol and Marine Ecosystem Study), and SCALE (Southern oCean SeAsonaL Experiment), to assess the variability lengthscale of DMS globally, and in all ocean basins at different stages of the seasonal cycle. We interpret our results within the context of ancillary physical and biogeochemical measurements, which may be potential drivers of the regional variability patterns of DMS concentrations.</p>

scholarly journals High spatial variability of gas transfer velocity in streams revealed by turbulence measurements

Inland Waters ◽  
2018 ◽  
Vol 8 (4) ◽  
pp. 461-473 ◽  
Author(s):  
Jovana Kokic ◽  
Erik Sahlée ◽  
Sebastian Sobek ◽  
Dominic Vachon ◽  
Marcus B. Wallin
Keyword(s):  
Spatial Variability ◽  
Gas Transfer ◽  
Transfer Velocity ◽  
Turbulence Measurements ◽  
Gas Transfer Velocity ◽  
High Spatial Variability

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 Oceanic convective mixing and the impact on air-sea gas transfer velocity

2011 ◽  
Vol 38 (2) ◽  
pp. n/a-n/a ◽  
Author(s):  
A. Rutgersson ◽  
A. Smedman ◽  
E. Sahlée
Keyword(s):  
Gas Transfer ◽  
Transfer Velocity ◽  
Gas Transfer Velocity ◽  
Convective Mixing ◽  
The Impact

scholarly journals On the Susceptibility of Cold Tropical Cirrus to Ice Nuclei Abundance

2016 ◽  
Vol 73 (6) ◽  
pp. 2445-2464 ◽  
Author(s):  
Eric J. Jensen ◽  
Rei Ueyama ◽  
Leonhard Pfister ◽  
Thaopaul V. Bui ◽  
R. Paul Lawson ◽  
...  
Keyword(s):  
High Frequency ◽  
Regional Distribution ◽  
Ice Nucleation ◽  
Small Scale ◽  
Height Distribution ◽  
Microphysical Properties ◽  
Ice Nuclei ◽  
High Frequency Waves ◽  
The Impact

Abstract Numerical simulations of cirrus formation in the tropical tropopause layer (TTL) during boreal wintertime are used to evaluate the impact of heterogeneous ice nuclei (IN) abundance on cold cloud microphysical properties and occurrence frequencies. The cirrus model includes homogeneous and heterogeneous ice nucleation, deposition growth/sublimation, and sedimentation. Reanalysis temperature and wind fields with high-frequency waves superimposed are used to force the simulations. The model results are constrained by comparison with in situ and satellite observations of TTL cirrus and relative humidity. Temperature variability driven by high-frequency waves has a dominant influence on TTL cirrus microphysical properties and occurrence frequencies, and inclusion of these waves is required to produce agreement between the simulated and observed abundance of TTL cirrus. With homogeneous freezing only and small-scale gravity waves included in the temperature curtains, the model produces excessive ice concentrations compared with in situ observations. Inclusion of relatively numerous heterogeneous ice nuclei (NIN ≥ 100 L−1) in the simulations improves the agreement with observed ice concentrations. However, when IN contribute significantly to TTL cirrus ice nucleation, the occurrence frequency of large supersaturations with respect to ice is less than indicated by in situ measurements. The model results suggest that the sensitivity of TTL cirrus extinction and ice water content statistics to heterogeneous ice nuclei abundance is relatively weak. The simulated occurrence frequencies of TTL cirrus are quite insensitive to ice nuclei abundance, both in terms of cloud frequency height distribution and regional distribution throughout the tropics.

scholarly journals Impact of a Mean Current on the Internal Tide Energy Dissipation at the Critical Latitude

2017 ◽  
Vol 47 (6) ◽  
pp. 1457-1472 ◽  
Author(s):  
O. Richet ◽  
C. Muller ◽  
J.-M. Chomaz
Keyword(s):  
Large Scale ◽  
Internal Tide ◽  
Internal Tides ◽  
Small Scale ◽  
Latitudinal Dependence ◽  
Propagating Waves ◽  
Parametric Subharmonic Instability ◽  
The Impact ◽  
Mean Current ◽  
Critical Latitude

AbstractPrevious numerical studies of the dissipation of internal tides in idealized settings suggest the existence of a critical latitude (~29°) where dissipation is enhanced. But observations only indicate a modest enhancement at this latitude. To resolve this difference between observational and numerical results, the authors study the latitudinal dependence of internal tides’ dissipation in more realistic conditions. In particular, the ocean is not a quiescent medium; the presence of large-scale currents or mesoscale eddies can impact the propagation and dissipation of internal tides. This paper investigates the impact of a weak background mean current in numerical simulations. The authors focus on the local dissipation of high spatial mode internal waves near their generation site. The vertical profile of dissipation and its variation with latitude without the mean current are consistent with earlier studies. But adding a weak mean current has a major impact on the latitudinal distribution of dissipation. The peak at the critical latitude disappears, and the dissipation is closer to a constant, albeit with two weak peaks at ~25° and ~35° latitude. This disappearance results from the Doppler shift of the internal tides’ frequency, which hinders the nonlinear transfer of energy to small-scale secondary waves via the parametric subharmonic instability (PSI). The new two weak peaks correspond to the Doppler-shifted critical latitudes of the left- and right-propagating waves. The results are confirmed in simulations with simple sinusoidal topography. Thus, although nonlinear transfers via PSI are efficient at dissipating internal tides, the exact location of the dissipation is sensitive to large-scale oceanic conditions.

scholarly journals High frequency radio wave method in the correction of involute skin changes

2019 ◽  
Vol 18 (2) ◽  
pp. 92-95
Author(s):  
Zhanna Yu. Yusova ◽  
Inga A. Akhmedbaeva ◽  
Anzhelika S. Likhtareva
Keyword(s):  
Radio Wave ◽  
High Frequency ◽  
Well Being ◽  
Small Scale ◽  
Wave Method ◽  
Frequency Method ◽  
Skin Changes ◽  
Face Area ◽  
The Face ◽  
The Impact

The study presents data on the impact of the monopolar radiofrequency method on the morphofunctional state of the skin. Patients were observed with various morphotypes of involute skin changes. 49 patients aged 45 to 55 years were observed. All patients were divided into 3 groups depending on the prevailing morphotype of involute skin changes: fine-wrinkled, deformed, and mixed. In all groups, a single exposure was performed using the monopolar radio frequency method according to the approved Protocol of work in the face area. Objective research methods included ultrasound sonography of the epidermis and dermis, adapted dermatological indices of quality of life (DIQ) and SAN (well-being, activity, mood). The results were evaluated 3, 6 and 12 months after the treatment. The obtained data showed that the high-frequency radio-wave method is more effective in deformational and mixed types of aging compared to small-scale wrinkling.

scholarly journals Distribution of dissolved inorganic carbon and related parameters in the Thermaikos Gulf (Eastern Mediterranean)

2006 ◽  
Vol 7 (1) ◽  
pp. 63 ◽  
Author(s):  
E. KRASAKOPOULOU ◽  
CH. ANAGNOSTOU ◽  
E. SOUVERMEZOGLOU ◽  
E. PAPATHANASSIOU ◽  
S. RAPSOMANIKIS
Keyword(s):  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Eastern Mediterranean ◽  
Co2 Exchange ◽  
Extensive Study ◽  
Atmospheric Co2 ◽  
Small Scale ◽  
Gas Transfer ◽  
Transfer Velocity

Data on the distribution of dissolved inorganic carbon (measured as TCO2) and related parameters in the Thermaikos Gulf were obtained during May 1997. High TCO2 concentrations were recorded close to the bottom, especially in the northern part of the gulf, as a result of organic matter remineralisation. The positive relatively good correlation between TCO2 and both apparent oxygen utilisation (AOU) and phosphate at the last sampling depth confi rmed the regenerative origin of a large proportion of TCO2. The comparatively conservative behaviour of alkalinity, together with the relatively low value of the homogenous buffer factor β (β = ∂lnfCO2/∂lnTCO2) revealed that calcifi cation or carbonate dissolution takes place on a very small scale, simultaneously with the organic carbon production. The correlations between fCO2 and chlorophyll α, as well as AOU and the surface temperature, revealed that the carbon dioxide fi xation through the biological activity is the principal factor that modulates the variability of fCO2. A rough first estimate of the magnitude of the air-sea CO2 exchange and the potential role of the Thermaikos Gulf in the transfer of atmospheric CO2 was also obtained. The results showed that during May 1997, the Thermaikos Gulf acted as a weak sink for atmospheric CO2 at a rate of -0.60 - -1.43 mmol m-2 d-1, depending on which formula for the gas transfer velocity was used, and in accordance to recent reports regarding other temperate continental shelves. Extensive study of the dissolved inorganic carbon and related parameters, and continuous shipboard measurements of fCO2 a and fCO2 w during all seasons are necessary to safely quantify the role of the Thermaikos Gulf in the context of the coastal margins CO2 dynamics.

scholarly journals The impact of diurnal variability in sea surface temperature on the atlantic air-sea CO<sub>2</sub> flux

2008 ◽  
Vol 8 (4) ◽  
pp. 15825-15853 ◽  
Author(s):  
H. Kettle ◽  
C. J. Merchant ◽  
C. D. Jeffery ◽  
M. J. Filipiak ◽  
C. L. Gentemann
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Co2 Flux ◽  
Sea Surface ◽  
Temperature Fields ◽  
Gas Transfer ◽  
Transfer Velocity ◽  
Diurnal Variability ◽  
Diurnal Warming ◽  
The Impact

Abstract. The effect of diurnal variations in sea surface temperature (SST) on the air-sea flux of CO2 over the central Atlantic ocean and Mediterranean Sea is evaluated for 2005–2006. We use high resolution hourly satellite SST data to determine the diurnal warming (ΔSST). The CO2 flux is then computed using three different temperature fields – a foundation temperature (Tf, measured at a depth where there is no diurnal variation), Tf plus the hourly ΔSST and Tf plus monthly-averaged ΔSST. This is done in conjunction with a physically-based parameterisation for the gas transfer velocity (NOAA-COARE). The differences between the fluxes evaluated for these three different temperature fields quantifies the effects of both diurnal warming and diurnal covariations. We find that including diurnal warming increases the CO2 flux out of the Atlantic for 2005–2006 from 9.6 Tg C a−1 to 30.4 Tg C a−1 (hourly ΔSST) and 31.2 Tg C a−1 (monthly ΔSST). Diurnal warming, therefore, has a large impact on the annual net CO2 flux but diurnal covariations in variables are negligible implying that CO2 fluxes may be adequately computed using monthly averaged ΔSSTs along with a suitable foundation temperature.

Can Values of Honesty, Hard Work, Loyalty and Discipline Predict Entrepreneurial Orientation of Muslim Owner Managers?

2015 ◽  
Vol 3 (1) ◽  
pp. 31 ◽  
Author(s):  
Rohani Mohd ◽  
Badrul Hisham Kamaruddin ◽  
Khulida Kirana Yahya ◽  
Elias Sanidas
Keyword(s):  
Entrepreneurial Orientation ◽  
Two Dimensions ◽  
Hard Work ◽  
Small Scale ◽  
Sampling Frame ◽  
Policy Makers ◽  
Learning Institutions ◽  
Innovative Orientation ◽  
The Impact ◽  
True Values

The purpose of the present study is twofold: first, to investigate the true values of Muslim owner managers; second, to examine the impact of these values on entrepreneurial orientations of Muslim small-scale entrepreneurs. 850 Muslim owner managers were selected randomly using the sampling frame provided by MajlisAmanah Rakyat Malaysia (MARA). 162 completed questionnaires were collected and analyzed. For this paper only two dimensions of entrepreneurial orientations were analyzed: proactive orientation and innovative orientation. Interestingly, the findings revealed that Muslim businessmen/women are honest, loyal, disciplined and hard working. Loyalty and honesty are positively related to proactive orientation, while discipline and hard-work are positively related to innovative orientation. The findings provide implications for existing relevant theories, policy makers, practitioners and learning institutions. 

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