Spatial and temporal variations in sediment grain size in tidal wetlands, Yangtze Delta: On the role of physical and biotic controls

2008 ◽  
Vol 77 (4) ◽  
pp. 657-671 ◽  
Author(s):  
S.L. Yang ◽  
H. Li ◽  
T. Ysebaert ◽  
T.J. Bouma ◽  
W.X. Zhang ◽  
...  
Keyword(s):  
Grain Size ◽  
Temporal Variations ◽  
Spatial And Temporal Variations ◽  
Tidal Wetlands ◽  
Yangtze Delta ◽  
Sediment Grain Size ◽  
Biotic Controls

scholarly journals Model-Assisted Analysis of Spatial and Temporal Variations in Fruit Temperature and Transpiration Highlighting the Role of Fruit Development

PLoS ONE ◽  
2014 ◽  
Vol 9 (3) ◽  
pp. e92532 ◽  
Author(s):  
Thibault Nordey ◽  
Mathieu Léchaudel ◽  
Marc Saudreau ◽  
Jacques Joas ◽  
Michel Génard
Keyword(s):  
Fruit Development ◽  
Temporal Variations ◽  
Spatial And Temporal Variations ◽  
Assisted Analysis

Mineralogy of agglutinated benthic foraminifera; implications for paleo-environmental reconstructions

2008 ◽  
Vol 179 (6) ◽  
pp. 583-592 ◽  
Author(s):  
Eric Armynot du Chatelet ◽  
Philippe Recourt ◽  
Vincent Chopin
Keyword(s):  
Grain Size ◽  
Benthic Foraminifera ◽  
Tidal Marsh ◽  
Environmental Parameters ◽  
Mineralogical Composition ◽  
Test Construction ◽  
Taxonomic Composition ◽  
Tidal Elevation ◽  
Sediment Grain Size

Abstract Benthic foraminifera of recent salt marsh environments are often dominated by species with an agglutinated test. The grains used for test construction by these foraminifera are collected from their surrounding environment. In this study we investigate the role of sediment grain size and mineralogical composition for richness, population density and taxonomic composition of agglutinating foraminifera. Foraminifera from 15 stations of the tidal marsh of the Canche estuary (Pas-de-Calais, France) were studied. The species richness depends on the grain size of the sediment, whereas the density is not related to sediment grain size. The distribution of foraminifera species throughout the tidal marsh may depend on many environmental parameters such as OM as well as tidal elevation, already largely discussed in literature. The mineralogical composition of the agglutinated grains in Trochammina inflata and Arenoparrella mexicana is very different from that of sediment; the composition of Jadammina macrescens is generally different from that of the sediment with some exceptions, and in Miliammina fusca, Paratrochammina haynesi and Remaneica plicata the mineralogical compositions are similar to those of the sediment. The studied species may be able to select their preferred grains based upon composition even if a particular mineral is scarce in the sediment.

Role of spatial and temporal variations in the computation of radiative forcing due to sulphate aerosols: A regional study

2002 ◽  
Vol 128 (581) ◽  
pp. 973-989 ◽  
Author(s):  
Gunnar Myhre ◽  
Jan E. Jonson ◽  
Jerzy Bartnicki ◽  
Frode Stordal ◽  
Keith P. Shine
Keyword(s):  
Radiative Forcing ◽  
Temporal Variations ◽  
Spatial And Temporal Variations ◽  
Regional Study ◽  
Sulphate Aerosols

scholarly journals Role of Convective Entrainment in Spatial Distributions of and Temporal Variations in Precipitation over Tropical Oceans

2014 ◽  
Vol 27 (23) ◽  
pp. 8707-8723 ◽  
Author(s):  
Nagio Hirota ◽  
Yukari N. Takayabu ◽  
Masahiro Watanabe ◽  
Masahide Kimoto ◽  
Minoru Chikira
Keyword(s):  
Large Scale ◽  
Lower Troposphere ◽  
Temporal Variations ◽  
Spatial And Temporal Variations ◽  
Spatial Distributions ◽  
Atmospheric Models ◽  
Tropical Oceans ◽  
Appropriate Treatment ◽  
Precipitation Events

Abstract The authors demonstrate that an appropriate treatment of convective entrainment is essential for determining spatial distributions of and temporal variations in precipitation. Four numerical experiments are performed using atmospheric models with different entrainment characteristics: a control experiment (Ctl), a no-entrainment experiment (NoEnt), an original Arakawa–Schubert experiment (AS), and an AS experiment with a simple empirical suppression of convection depending on cloud-layer humidity (ASRH). The fractional entrainment rates of AS and ASRH are constant for each cloud type and are very small in the lower troposphere compared with those in the Ctl, in which half of the buoyancy-generated energy is consumed by entrainment. Spatial and temporal variations in the observed precipitation are satisfactorily reproduced in the Ctl, but their amplitudes are underestimated with a so-called double intertropical convergence zone bias in the NoEnt and AS. The spatial variation is larger in the Ctl because convection is more active over humid ascending regions and more suppressed over dry subsidence regions. Feedback processes involving convection, the large-scale circulation, free tropospheric moistening by congestus, and radiation enhance the variations. The temporal evolution of precipitation events is also more realistic in the Ctl, because congestus moistens the midtroposphere, and large precipitation events occur once sufficient moisture is available. The large entrainment in the lower troposphere, increasing free tropospheric moistening by congestus and enhancing the coupling of convection to free tropospheric humidity, is suggested to be important for the realistic spatial and temporal variations.

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