scholarly journals Variability of Heat and Water Fluxes in the Red Sea Using ERA5 Data (1981–2020)

2021 ◽  
Vol 9 (11) ◽  
pp. 1276
Author(s):  
Hazem Nagy ◽  
Bayoumy Mohamed ◽  
Omneya Ibrahim
Keyword(s):  
Heat Flux ◽  
Red Sea ◽  
Linear Trend ◽  
Water Flux ◽  
Northeast Monsoon ◽  
Water Fluxes ◽  
Significant Linear Trend ◽  
Net Heat Flux ◽  
Essential Components ◽  
Net Water Flux

The study of heat and water fluxes is one of the most essential components for understanding the interactions and exchanges between the ocean and atmosphere. Heat transfer across the air–sea interface is an important process in ocean–atmosphere dynamics. In this study, a 40-year (1981–2020) high-resolution (0.25° × 0.25°) ERA-5 reanalysis dataset from the European Centre for Medium-Range Weather Forecasts (ECMWF) is used to estimate the variability and trends of heat and water flux components in the Red Sea. The results show that the surface net heat flux is negative (loss) in the Northern Red Sea (NRS) and positive (gain) in the Southern Red Sea (SRS). The highest seasonal surface net heat flux is observed in the spring and early summer, while the lowest is reported in the winter. A significant linear trend is found in the surface net heat flux over the NRS and SRS, with values of about −0.12 ± 0.052 (W/m2)/yr and +0.20 ± 0.021 (W/m2)/yr, respectively. The annual mean surface net water flux loss to the atmosphere over the entire Red Sea is +1.46 ± 0.23 m/yr. The seasonal surface net water flux peak occurs in winter as a result of the northeast monsoon wind, which increases evaporation rate over the whole length of the Red Sea. The highest surface net water flux (+2.1 m/yr) is detected during 2020, while the lowest value (+1.3 m/yr) is observed during 1985.

Asymmetry in osmotic response of frog gastric mucosa

1980 ◽  
Vol 238 (4) ◽  
pp. G298-G302
Author(s):  
L. Villegas
Keyword(s):  
Gastric Mucosa ◽  
Water Flux ◽  
Mucosal Surface ◽  
Ion Fluxes ◽  
Water Fluxes ◽  
Serosal Surface ◽  
Opposite Surface ◽  
Osmotic Water ◽  
Osmotic Response ◽  
Net Water Flux

The effects of hyperosmolality of the serosal and mucosal bathing solutions on the transmucosal net water and ion fluxes were studied in frog gastric mucosa. Addition of 100 mosM glucose to the solution at the serosal surface produces a reversed mucosal-to-serosal net water flux of 7.1 +/- 1.4 microliter . cm-2 . h-1. When added to the abolished spontaneous net water flux, this results in an increment in the net water flux of -17.8 +/- 1.4 microliter . cm-2 . h-1. Addition of the same amount of glucose to the solution at the mucosal surface produces an increment in the serosal-to-mucosal net water flux of 3.7 +/- 1.1 microliter . cm-2 . h-1 when the solution at the opposite surface was kept in 220 mosmol/kg H2O. Simultaneous increments of both solutions of 320 to 420 and 420 to 520 mosM changes the osmotic serosal-to-mucosal induced fluxes to 1.9 +/- 0.9 and 3.4 +/- 1.6 microliter . cm-2 . h-1, respectively. The initial spontaneous net water fluxes measured in 220, 320, and 420 mosM solutions were 11.3 +/- 0.9, 6.9 +/- 1.6, and -1.5 +/- 1.5 microliter . cm-2 . h-1. It is proposed that the osmotic water flux is asymmetric, independent of the solutions tonicities, and not significantly affected by the sweep of solutes at the mucosal surface.

scholarly journals High-resolution land surface fluxes from satellite and reanalysis data (HOLAPS v1.0): evaluation and uncertainty assessment

2016 ◽  
Vol 9 (7) ◽  
pp. 2499-2532 ◽  
Author(s):  
Alexander Loew ◽  
Jian Peng ◽  
Michael Borsche
Keyword(s):  
Heat Flux ◽  
High Resolution ◽  
Surface Energy ◽  
Latent Heat ◽  
Latent Heat Flux ◽  
Land Surface ◽  
Reanalysis Data ◽  
Surface Radiation ◽  
Water Fluxes ◽  
Essential Components

Abstract. Surface water and energy fluxes are essential components of the Earth system. Surface latent heat fluxes provide major energy input to the atmosphere. Despite the importance of these fluxes, state-of-the-art data sets of surface energy and water fluxes largely differ. The present paper introduces a new framework for the estimation of surface energy and water fluxes at the land surface, which allows for temporally and spatially high-resolved flux estimates at the quasi-global scale (50° S, 50° N) (High resOlution Land Atmosphere Parameters from Space – HOLAPS v1.0). The framework makes use of existing long-term satellite and reanalysis data records and ensures internally consistent estimates of the surface radiation and water fluxes. The manuscript introduces the technical details of the developed framework and provides results of a comprehensive sensitivity and evaluation study. Overall the root mean square difference (RMSD) was found to be 51.2 (30.7) W m−2 for hourly (daily) latent heat flux, and 84 (38) W m−2 for sensible heat flux when compared against 48 FLUXNET stations worldwide. The largest uncertainties of latent heat flux and net radiation were found to result from uncertainties in the solar radiation flux obtained from satellite data products.

scholarly journals Thirty-Nine-Year Wave Hindcast, Storm Activity, and Probability Analysis of Storm Waves in the Kara Sea, Russia

Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 648
Author(s):  
Stanislav Myslenkov ◽  
Vladimir Platonov ◽  
Alexander Kislov ◽  
Ksenia Silvestrova ◽  
Igor Medvedev
Keyword(s):  
Climate Change ◽  
Pareto Distribution ◽  
Linear Trend ◽  
Wind Waves ◽  
Kara Sea ◽  
The Arctic ◽  
Storm Events ◽  
Storm Activity ◽  
Significant Linear Trend ◽  
The Impact

The recurrence of extreme wind waves in the Kara Sea strongly influences the Arctic climate change. The period 2000–2010 is characterized by significant climate warming, a reduction of the sea ice in the Arctic. The main motivation of this research to assess the impact of climate change on storm activity over the past 39 years in the Kara Sea. The paper presents the analysis of wave climate and storm activity in the Kara Sea based on the results of numerical modeling. A wave model WAVEWATCH III is used to reconstruct wind wave fields for the period from 1979 to 2017. The maximum significant wave height (SWH) for the whole period amounts to 9.9 m. The average long-term SWH for the ice-free period does not exceed 1.3 m. A significant linear trend shows an increase in the storm wave frequency for the period from 1979 to 2017. It is shown that trends in the storm activity of the Kara Sea are primarily regulated by the ice. Analysis of the extreme storm events showed that the Pareto distribution is in the best agreement with the data. However, the extreme events with an SWH more than 6‒7 m deviate from the Pareto distribution.

Cylindrocarpon and Fusarium root colonization of Douglas-fir seedlings from British Columbia reforestation sites

1998 ◽  
Vol 28 (8) ◽  
pp. 1198-1206 ◽  
Author(s):  
Paige E Axelrood ◽  
William K Chapman ◽  
Keith A Seifert ◽  
David B Trotter ◽  
Gwen Shrimpton
Keyword(s):  
British Columbia ◽  
Pseudotsuga Menziesii ◽  
Root Colonization ◽  
Linear Trend ◽  
Poor Performance ◽  
Douglas Fir ◽  
Root Infection ◽  
Significant Linear Trend ◽  
Conifer Seedlings ◽  
Cylindrocarpon Destructans

Poor performance of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) plantations established in 1987 has occurred in southwestern British Columbia. Affected sites were planted with 1-year-old container stock that exhibited some root dieback in the nursery. A study was initiated in 1991 to assess Cylindrocarpon and Fusarium root infection in planted and naturally regenerating (natural) Douglas-fir seedlings from seven affected plantations. Percentages of seedlings harboring Cylindrocarpon spp.and percent root colonization were significantly greater for planted seedlings compared with natural seedlings. A significant linear trend in Cylindrocarpon root colonization was observed for planted seedlings with colonization levels being highest for roots closest to the remnants of the root plug and decreasing at distances greater than 10cm from that region. This trend in Cylindrocarpon colonization was not observed for natural seedlings. Cylindrocarpon destructans (Zins.) Scholten var. destructans and C.cylindroides Wollenw. var. cylindroides were the only species isolated from planted and natural conifer seedlings. For most sites, percentage of seedlings harboring Fusarium spp.and percent Fusarium root colonization were less than for Cylindrocarpon. Recovery of Fusarium spp.from seedlings and root colonization levels were not significantly different for planted and natural seedlings from all sites.

Learning as a Function of Subliminal Reinforcements

1963 ◽  
Vol 12 (2) ◽  
pp. 387-398
Author(s):  
Austin Jones ◽  
Melvin Manis ◽  
Bernard Weiner
Keyword(s):  
Relative Frequency ◽  
Probability Learning ◽  
Linear Trend ◽  
Stimulus Category ◽  
Time Intervals ◽  
Significant Linear Trend ◽  
Tachistoscopic Presentation ◽  
Stimulus Classes ◽  
Learning Trials ◽  
Correct Discrimination

Three studies were conducted to assess the effects of subliminal reinforcements on learning. In the first two, Ss were given a discrimination task in which five geometric forms, repeated over 100 trials, were to be assigned to one of two categories. The categories were unbalanced; four geometric forms comprised one category, the remaining form the other. Response was required on each trial. Immediately after each response, the appropriate reinforcing word, “Right” or “Wrong,” was flashed at a subliminal brightness-contrast In Exp. I, under low motivation (without money incentives), Ss showed no learning of the correct discrimination, nor any evidence of probability learning with respect to relative frequency of stimulus categories. In Exp. II, the above procedure was replicated with money as the incentive. There again was no evidence of discrimination learning, i.e., acquisition of the correct response. There was, however, a significant linear trend ( p < .05) in the proportion of responses made to the more frequent stimulus category; Ss showed an increasing tendency to “match” the relative frequency of their two classes of response with the corresponding two stimulus classes. In Exp. III, Ss who were motivated by a money incentive attempted to guess whether E was thinking of an odd or an even number. Following each response, Ss were reinforced by tachistoscopic presentation of the word “Right” or “Wrong,” at time intervals which were too brief to permit recognition; half of the Ss were positively reinforced for emitting the response “Odd,” and half for the response “Even.” After 100 learning trials had been completed, the reinforcement contingencies were switched for an additional 20 trials, e.g., Ss who had been reinforced for “Odd” were now reinforced for “Even.” Ss in Exp. III showed no evidence of probability learning. Some possible explanations for the conflicting results of Exps. II and III were discussed.

Linking soil water and solutes fluxes to soil properties and vegetation types: insights from a case-study in the high tropical Andes of Ecuador

2021 ◽  
Author(s):  
Sebastián Páez-Bimos ◽  
Veerle Vanacker ◽  
Marcos Villacis ◽  
Marlon Calispa ◽  
Oscar Morales ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Water Conservation ◽  
Water Flux ◽  
Water Fluxes ◽  
Vegetation Types ◽  
Tropical Andes ◽  
Conservation Area ◽  
Solute Fluxes ◽  
Doc Concentration ◽  
Water Conservation Area

&lt;p&gt;The high tropical Andes ecosystem, known as p&amp;#225;ramo, provides important hydrological services to densely populated areas in the Andean region. In order to manage these services sustainably, it is crucial to understand the biotic and abiotic processes that control both water quality and fluxes. Recent research in the p&amp;#225;ramo highlights a knowledge gap regarding the role played by soil-vegetation interactions in controlling soil-water processes and resulting water and solute fluxes.&lt;/p&gt;&lt;p&gt;Here, we determine the hydrological and geochemical fluxes in four soil profiles in the p&amp;#225;ramo of the Antisana&amp;#180;s water conservation area in northern Ecuador. Water fluxes were measured biweekly with field fluxmeters in the hydrological year Apr/2019- Mar/2020 under two contrasting vegetation types: tussock-like grass (TU) and cushion-forming plants (CU). Soil solution was collected in parallel with wick samplers and suction caps for assessing the concentrations of dissolved cations, anions and organic carbon (DOC). In addition, soil moisture was measured continuously in the upper meter of the soil profile, i.e. first three horizons (A, 2A and 2BC), using water content reflectometers. The vertical water flux in the upper meter of each soil profile was simulated using the 1D HYDRUS model. We carried out a Sobol analysis to identify sensitive soil hydraulic parameters. We then derived water fluxes by inverse modeling, based on the measured soil moisture. We validated the calculated water fluxes using the fluxmeter data. Solute fluxes were estimated by combining the water fluxes and the soil solution compositions.&lt;/p&gt;&lt;p&gt;Our preliminary results suggest that water fluxes and DOC concentration vary under different vegetation types. The fluxmeter data from the 2A horizon indicates that the cumulative water flux under TU (2.8 - 5.7 l) was larger than under CU (0.8 &amp;#8211; 1.1 l) during the dry season (Aug-Sep and Dec-Jan). However, the opposite trend was observed in the wet season for maximum water fluxes. Moreover, the DOC concentration in the uppermost horizon was higher under CU (47.3 &amp;#177;2.2 mg l&lt;sup&gt;-1&lt;/sup&gt;) than under TU (3.1 &amp;#177;0.2 mg l&lt;sup&gt;-1&lt;/sup&gt;) vegetation during the monitoring period. We associate the water and solute responses under different vegetation types to the contrasting soil hydro-physical and chemical properties (e.g., saturated hydraulic conductivity and organic carbon content) in the uppermost soil horizon. Our study illustrates the existence of a spatial association between vegetation types, water fluxes and solute concentrations in Antisana&amp;#180;s water conservation area. By modelling the hydrological balance of the upper meter of the soil mantle, the water and solute fluxes will be estimated for soils with different vegetation cover.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;

Net Fluxes of Water in the Isolated Gills of Anguilla Dieffenbachii

1974 ◽  
Vol 60 (3) ◽  
pp. 769-781
Author(s):  
T. J. SHUTTLEWORTH ◽  
R. F. H. FREEMAN
Keyword(s):  
Sea Water ◽  
Water Flux ◽  
Freshwater Teleost ◽  
Osmotic Permeability ◽  
Direct Measurements ◽  
Net Flux ◽  
Anguilla Dieffenbachii ◽  
Net Fluxes ◽  
Freshwater Eels ◽  
Net Water Flux

1. Measurements of net flux of water have been made on isolated gills removed from freshwater-adapted and seawater-adapted eels and incubated in various media of differing osmotic pressure. 2. From these measurements it has been possible to determine the osmotic permeability coefficient of the gill directly from the net water flux. The values obtained (0.50±0.14x10-5 cm.sec-1 for freshwater eels and 0.43±0.07x10-5 cm.sec-1 for seawater-adapted eels) indicate that there was no significant change in this parameter on adaptation of the eels to sea water. 3. The direct measurements made of the net water flux across the isolated gills appear to be compatible with the osmoregulatory pattern of eels as deduced by other workers using different techniques. In particular they illustrate and further emphasize the significance of drinking in the freshwater fish. 4. Calculations indicate that, for a freshwater teleost, the osmotic and ionic problems caused by drinking in fresh water have an insignificant energetic effect and hence, energetically, it matters little to the fish whether it drinks or not.

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