Seasonal and longitudinal variability of zooplankton assemblages along a river-dominated estuarine gradient

Abstract. The Mediterranean Sea is a semi-enclosed basin characterized by a strong thermal stratification during summer during which the atmosphere is the main source of new nutrients to the nutrient-depleted surface layer. From aerosol sampling and microcosm experiments performed during the TransMed BOUM cruise (June–July 2008) we showed that: (i) the Mediterranean atmosphere composition (Al, Fe, P) was homogeneous over ~28° of longitude and was a mixture with a constant proportion of anthropogenic contribution and a variable but modest contribution of crustal aerosols. This quite stable composition over a one month period and a long transect (~2500 km) allowed to define the Mediterranean atmospheric "background" that characterizes the summer season in the absence of major Saharan event and forest fires, (ii) primary production significantly increased at all tested stations after aerosols addition collected on-board and after Saharan dust analog addition, indicating that both additions relieved on-going (co)-limitations. Although both additions significantly increased the N2 fixation rates at the western station, diazotrophic activity remained very low (~0.2 nmol N L−1 d−1), (iii) due to the presence of anthropogenic particles, the probable higher solubility of nutrients associated with mixed aerosols (crustal + anthropogenic contribution), conferred a higher fertilizing potential to on-board collected aerosol as compared to Saharan dust analog. Finally, those experiments showed that atmospheric inputs from a mixed atmospheric event ("summer rain" type) or from a high-intensity Saharan event would induce comparable response by the biota in the stratified Mediterranean SML, during summer.

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A novel tropopause-related climatology of ozone profiles

Atmospheric Chemistry and Physics ◽

10.5194/acp-14-283-2014 ◽

2014 ◽

Vol 14 (1) ◽

pp. 283-299 ◽

Cited By ~ 12

Author(s):

V. F. Sofieva ◽

J. Tamminen ◽

E. Kyrölä ◽

T. Mielonen ◽

P. Veefkind ◽

...

Keyword(s):

Climate Model ◽

A Priori ◽

Stratospheric Aerosol ◽

Ozone Monitoring Instrument ◽

Earth Observing System ◽

Ozone Profile ◽

High Vertical Resolution ◽

Climate Model Simulations ◽

Longitudinal Variability

Abstract. A new ozone climatology, based on ozonesonde and satellite measurements, spanning the altitude region between the earth's surface and ~60 km is presented (TpO3 climatology). This climatology is novel in that the ozone profiles are categorized according to calendar month, latitude and local tropopause heights. Compared to the standard latitude–month categorization, this presentation improves the representativeness of the ozone climatology in the upper troposphere and the lower stratosphere (UTLS). The probability distribution of tropopause heights in each latitude–month bin provides additional climatological information and allows transforming/comparing the TpO3 climatology to a standard climatology of zonal mean ozone profiles. The TpO3 climatology is based on high-vertical-resolution measurements of ozone from the satellite-based Stratospheric Aerosol and Gas Experiment II (in 1984 to 2005) and from balloon-borne ozonesondes from 1980 to 2006. The main benefits of the TpO3 climatology are reduced standard deviations on climatological ozone profiles in the UTLS, partial characterization of longitudinal variability, and characterization of ozone profiles in the presence of double tropopauses. The first successful application of the TpO3 climatology as a priori in ozone profile retrievals from Ozone Monitoring Instrument on board the Earth Observing System (EOS) Aura satellite shows an improvement of ozone precision in UTLS of up to 10% compared with the use of conventional climatologies. In addition to being advantageous for use as a priori in satellite retrieval algorithms, the TpO3 climatology might be also useful for validating the representation of ozone in climate model simulations.

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Seasonal-longitudinal variability of equatorial plasma bubbles

Annales Geophysicae ◽

10.5194/angeo-22-3089-2004 ◽

2004 ◽

Vol 22 (9) ◽

pp. 3089-3098 ◽

Cited By ~ 76

Author(s):

W. J. Burke ◽

C. Y. Huang ◽

L. C. Gentile ◽

L. Bauer

Keyword(s):

Solar Cycle ◽

Phase Shifts ◽

Linear Growth Rate ◽

Cycle Phase ◽

Loss Cone ◽

Plasma Bubbles ◽

Equatorial Plasma Bubbles ◽

Evening Sector ◽

Radiation Belt Electrons ◽

Longitudinal Variability

Abstract. We compare seasonal and longitudinal distributions of more than 8300 equatorial plasma bubbles (EPBs) observed during a full solar cycle from 1989-2000 with predictions of two simple models. Both models are based on considerations of parameters that influence the linear growth rate, γRT, of the generalized Rayleigh-Taylor instability in the context of finite windows of opportunity available during the prereversal enhancement near sunset. These parameters are the strength of the equatorial magnetic field, Beq, and the angle, α, it makes with the dusk terminator line. The independence of α and Beq from the solar cycle phase justifies our comparisons. We have sorted data acquired during more than 75000 equatorial evening-sector passes of polar-orbiting Defense Meteorological Satellite Program (DMSP) satellites into 24 longitude and 12 one-month bins, each containing ~250 samples. We show that: (1) in 44 out of 48 month-longitude bins EPB rates are largest within 30 days of when α=0°; (2) unpredicted phase shifts and asymmetries appear in occurrence rates at the two times per year when α≈0°; (3) While EPB occurrence rates vary inversely with Beq, the relationships are very different in regions where Beq is increasing and decreasing with longitude. Results (2) and (3) indicate that systematic forces not considered by the two models can become important. Damping by interhemispheric winds appears to be responsible for phase shifts in maximum rates of EPB occurrence from days when α=0°. Low EPB occurrence rates found at eastern Pacific longitudes suggest that radiation belt electrons in the drift loss cone reduce γRT by enhancing E-layer Pedersen conductances. Finally, we analyze an EPB event observed during a magnetic storm at a time and place where α≈-27°, to illustrate how electric-field penetration from high latitudes can overwhelm the damping effects of weak gradients in Pedersen conductance near dusk.

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Assemblages of cryptic animals in coral rubble along an estuarine gradient spanning mangrove, seagrass, and coral reef habitats

Bulletin of Marine Science ◽

10.5343/bms.2013.1085 ◽

2014 ◽

Vol 90 (2) ◽

pp. 723-740 ◽

Cited By ~ 5

Author(s):

Yoshitake Takada ◽

Hideki Ikeda ◽

Yuriko Hirano ◽

Masayuki Saigusa ◽

Kazumasa Hashimoto ◽

...

Keyword(s):

Coral Reef ◽

Coral Rubble ◽

Estuarine Gradient

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Distribution and fractionation of rare earth elements in sediments and mangrove soil profiles across an estuarine gradient

Chemosphere ◽

10.1016/j.chemosphere.2020.128431 ◽

2021 ◽

Vol 264 ◽

pp. 128431

Author(s):

Tácila O.P. de Freitas ◽

Rodrigo M.A. Pedreira ◽

Vanessa Hatje

Keyword(s):

Rare Earth ◽

Rare Earth Elements ◽

Soil Profiles ◽

Estuarine Gradient ◽

Mangrove Soil

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On variability of total ozone derived from TOVS data over peninsular Indian sub-continent and adjoining oceanic area

MAUSAM ◽

10.54302/mausam.v53i4.1665 ◽

2022 ◽

Vol 53 (4) ◽

pp. 503-514

Author(s):

R. SURESH

Keyword(s):

Total Ozone ◽

Monsoon Season ◽

Lower Troposphere ◽

Southwest Monsoon ◽

Retrieval Algorithm ◽

Tropospheric Temperature ◽

Minimum Concentration ◽

Upper Troposphere ◽

Positive Correlation Coefficient ◽

Longitudinal Variability

The total ozone derived from TOVS data from NOAA 12 satellite through one step physical retrieval algorithm of International TOVS Processing Package (ITPP) version 5.0 has been used to identify its diurnal, monthly, latitudinal and longitudinal variability during 1998 over the domain Equator to 26° N / 60-100° E. The linkage of maximum total ozone with warmer tropopause and lower stratosphere has been re-established. The colder upper tropospheric temperature which is normally associated with maximum ozone concentration throughout the year elsewhere in the world has also been identified in this study but the relationship gets reversed during southwest monsoon months(June-September) over the domain considered. The moisture available in abundance in the lower troposphere gets precipitated due to the convective instability prevailing in the atmosphere during monsoon season and very little moisture is only available for vertical transport into the upper troposphere atop 500 hPa. The latent heat released by the precipitation processes warms up the middle and upper atmosphere. The warm and dry upper troposphere could be the reason for less depletion of ozone in the upper troposphere during monsoonal months and this is supported by the positive correlation coefficient prevailing in monsoon season between total ozone and upper tropospheric (aloft 300 hPa) temperature. The warmness in middle and upper troposphere which is associated with less depletion and/or production of more ozone in the upper troposphere may perhaps contribute for the higher total ozone during monsoon months than in other seasons over peninsular Indian region. The minimum concentration is observed during January (226 DU) over 6° N and the maximum (283DU) over 18° N during August. Longitudinal variability is less pronounced than the latitudinal variability.

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An evaluation of factors controlling the abundance of epiphytes on Zostera marina along an estuarine gradient in Yaquina Bay, Oregon, USA

Aquatic Botany ◽

10.1016/j.aquabot.2018.04.010 ◽

2018 ◽

Vol 148 ◽

pp. 53-63

Author(s):

Walter G. Nelson

Keyword(s):

Zostera Marina ◽

Estuarine Gradient

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Urbanization effects on sandy beach macrofauna along an estuarine gradient

Ecological Indicators ◽

10.1016/j.ecolind.2019.106036 ◽

2020 ◽

Vol 111 ◽

pp. 106036 ◽

Cited By ~ 3

Author(s):

L. Orlando ◽

L. Ortega ◽

O. Defeo

Keyword(s):

Sandy Beach ◽

Estuarine Gradient

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Spatial and seasonal effects on the delayed ionospheric response to solar EUV changes

10.5194/angeo-2019-91 ◽

2019 ◽

Author(s):

Erik Schmölter ◽

Jens Berdermann ◽

Norbert Jakowski ◽

Christoph Jacobi

Keyword(s):

Southern Hemisphere ◽

Geomagnetic Activity ◽

Correlation Coefficients ◽

Seasonal Effects ◽

Constant Delay ◽

Average Delay ◽

Ionospheric Response ◽

The Difference ◽

Longitudinal Variability ◽

The Impact

Abstract. This study correlates different ionospheric parameters with the integrated solar EUV radiation for an analysis of the delayed ionospheric response in order to confirm previous studies on the delay and to further specify variations of the delay. Several time series for correlation coefficients and delays are presented to characterize the trend of the delay from 2011 to 2013. The impact of the diurnal variations of ionospheric parameters in the analysis on hourly resolution for fixed locations are discussed and specified with calculations in different time scales and with comparison to solar and geomagnetic activity. An average delay for TEC of &approx; 18.7 hours and for foF2 of &approx; 18.6 hours is calculated at four European stations. Through comparison with the Australian region the difference between northern and southern hemisphere is analyzed and a seasonal variation of the delay between northern and southern hemisphere is calculated for TEC with &approx; 5 ± 0.7 hours and foF2 with &approx; 8 ± 0.8 hours. The latitudinal and longitudinal variability of the delay is analyzed for the European region and a decrease of the delay from &approx; 21.5 hours at 30° N to &approx; 19.0 hours at 70° N has been found. For winter months a roughly constant delay of &approx; 19.5 hours is calculated. In this study a North-South trend of the ionospheric delay during summer month has been observed with &approx; 0.06 hours per degree in latitude. The results based on solar and ionospheric data in hourly resolution and the analysis of the delayed ionospheric response to solar EUV show the seasonal and latitudinal variations. Results also indicate the dependence on the geomagnetic activity as well as on the 11-year solar cycle.

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