scholarly journals Mapping Diurnal Variability of the Wintertime Pearl River Plume Front from Himawari-8 Geostationary Satellite Observations

Water ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 43
Author(s):  
Zifeng Hu ◽  
Guanghao Xie ◽  
Jun Zhao ◽  
Yaping Lei ◽  
Jinchi Xie ◽  
...  
Keyword(s):  
High Frequency ◽  
Spring Tide ◽  
River Plume ◽  
Geostationary Satellite ◽  
Pearl River ◽  
Diurnal Variability ◽  
Plume Front ◽  
Sequential Images ◽  
First Time ◽  
Considerable Detail

the spatial pattern of the wintertime Pearl River plume front (PRPF), and its variability on diurnal and spring-neap time scales are characterized from the geostationary meteorological Himawari-8 satellite, taking advantage of the satellite’s unique 10-minutely sea surface temperature sequential images. Our findings suggest that the PRPF in winter consists of three subfronts: the northern one north of 22°N 20′, the southern one south of 21°N 40′, and the middle one between 22°N 20′ and 21°N 40′. The time-varying trend of the frontal intensity generally exhibits a strong-weak-strong pattern, with the weakest plume front occurring at about 06:00 UTC, which is closely associated with net surface heat flux over the region. The comparison in frontal variability between the spring and neap tides shows that the plume front during the spring tide generally tends to be more diffuse for the frontal probability, move further offshore for the frontal position, and be weaker for the frontal intensity than those found during the neap tide. These great differences largely depend on the tidally induced stronger turbulent mixing during the spring tide while the wind stress only plays a secondary role in the process. To best of our knowledge, the distinct diurnal variations in PRPF with wide coverage are observed for the first time. This study demonstrates that the Himawari-8 geostationary satellite has great potential in characterizing high-frequency surface thermal fronts in considerable detail.

Observation of the supercritical Pearl River plume front under the downwelling-favorable winds

2015 ◽  
Vol 58 (11) ◽  
pp. 2059-2066 ◽  
Author(s):  
Peng Bai ◽  
YanZhen Gu ◽  
Lin Luo ◽  
WanLei Zhang ◽  
KaiGuo Fan
Keyword(s):  
River Plume ◽  
Pearl River ◽  
Plume Front

scholarly journals High-Frequency Variations in Pearl River Plume Observed by Soil Moisture Active Passive Sea Surface Salinity

2020 ◽  
Vol 12 (3) ◽  
pp. 563 ◽  
Author(s):  
Xiaomei Liao ◽  
Yan Du ◽  
Tianyu Wang ◽  
Shuibo Hu ◽  
Haigang Zhan ◽  
...  
Keyword(s):  
Soil Moisture ◽  
High Frequency ◽  
River Plume ◽  
Sea Surface ◽  
Sea Surface Salinity ◽  
Pearl River ◽  
Surface Salinity ◽  
The Pearl River ◽  
Offshore Transport ◽  
Frequency Variations

River plumes play an important role in the cross-margin transport of phytoplankton and nutrients, which have profound impacts on coastal ecosystems. Using recently available Soil Moisture Active Passive (SMAP) sea surface salinity (SSS) data and high-resolution ocean color products, this study investigated summertime high-frequency variations in the Pearl River plume of China and its biological response. The SMAP SSS captures the intraseasonal oscillations in the offshore transport of the Pearl River plume well, which has distinct 30–60 day variations from mid-May to late September. The offshore transport of freshwater varies concurrently with southwesterly wind anomalies and is roughly in phase with the Madden–Julian Oscillation (MJO) index in phases 1–5, thus implying that the MJO exerts a significant influence. During MJO phases 1–2, the southwest wind anomalies in the northeastern South China Sea (SCS) enhanced cross-shore Ekman transport, while the northeast wind anomalies during MJO phases 3–5 favored the subsequent southwestward transport of the plume. The high chlorophyll-a concentration coincided well with the low-salinity water variations, emphasizing the important role of the offshore transport of the Pearl River plume in sustaining biological production over the oligotrophic northern SCS. The strong offshore transport of the plume in June 2015 clearly revealed that the proximity of a cyclonic eddy plays a role in the plume’s dispersal pathway. In addition, heavy rainfall related to the landfall of tropical cyclones in the Pearl River Estuary region contributed to the episodic offshore transport of the plume.

scholarly journals Hearing from the ocean and into the river: the evolution of the inner ear of Platanistoidea (Cetacea: Odontoceti)

Paleobiology ◽  
2021 ◽  
pp. 1-21
Author(s):  
Mariana Viglino ◽  
Maximiliano Gaetán ◽  
Mónica R. Buono ◽  
R. Ewan Fordyce ◽  
Travis Park
Keyword(s):  
Inner Ear ◽  
High Frequency ◽  
Sound Production ◽  
Marine Species ◽  
Late Oligocene ◽  
Evolutionary Patterns ◽  
Ear Morphology ◽  
Cochlear Morphology ◽  
First Time ◽  
Hearing Abilities

Abstract The inner ear of the two higher clades of modern cetaceans (Neoceti) is highly adapted for hearing infrasonic (mysticetes) or ultrasonic (odontocetes) frequencies. Within odontocetes, Platanistoidea comprises a single extant riverine representative, Platanista gangetica, and a diversity of mainly extinct marine species from the late Oligocene onward. Recent studies drawing on features including the disparate tympanoperiotic have not yet provided a consensus phylogenetic hypothesis for platanistoids. Further, cochlear morphology and evolutionary patterns have never been reported. Here, we describe for the first time the inner ear morphology of late Oligocene–early Miocene extinct marine platanistoids and their evolutionary patterns. We initially hypothesized that extinct marine platanistoids lacked a specialized inner ear like P. gangetica and thus, their morphology and inferred hearing abilities were more similar to those of pelagic odontocetes. Our results reveal there is no “typical” platanistoid cochlear type, as the group displays a disparate range of cochlear anatomies, but all are consistent with high-frequency hearing. Stem odontocete Prosqualodon australis and platanistoid Otekaikea huata present a tympanal recess in their cochlea, of yet uncertain function in the hearing mechanism in cetaceans. The more basal morphology of Aondelphis talen indicates it had lower high-frequency hearing than other platanistoids. Finally, Platanista has the most derived cochlear morphology, adding to evidence that it is an outlier within the group and consistent with a >9-Myr-long separation from its sister genus Zarhachis. The evolution of a singular sound production morphology within Platanistidae may have facilitated the survival of Platanista to the present day.

scholarly journals Translocation of silica nanospheres through giant unilamellar vesicles (GUVs) induced by a high frequency electromagnetic field

RSC Advances ◽  
2021 ◽  
Vol 11 (50) ◽  
pp. 31408-31420
Author(s):  
Palalle G. Tharushi Perera ◽  
Nevena Todorova ◽  
Zoltan Vilagosh ◽  
Olha Bazaka ◽  
The Hong Phong Nguyen ◽  
...  
Keyword(s):  
Electromagnetic Field ◽  
Membrane Permeability ◽  
Electromagnetic Fields ◽  
High Frequency ◽  
Model Systems ◽  
Membrane Model ◽  
Silica Nanospheres ◽  
Giant Unilamellar Vesicles ◽  
High Frequency Electromagnetic Field ◽  
First Time

Membrane model systems capable of mimicking live cell membranes were used for the first time in studying the effects arising from electromagnetic fields (EMFs) of 18 GHz where membrane permeability was observed following exposure.

scholarly journals Eimeria spp. infection in lambs from southern Brazil

2020 ◽  
Vol 40 (11) ◽  
pp. 871-874
Author(s):  
Natália S. Martins ◽  
Sara P. da Motta ◽  
Carolina C. Santos ◽  
Andrios S. Moreira ◽  
Nara A.R. Farias ◽  
...  
Keyword(s):  
High Frequency ◽  
Eimeria Species ◽  
Rio Grande ◽  
Wide Distribution ◽  
Southern Brazil ◽  
Rio Grande Do Sul ◽  
Sheep Industry ◽  
Eimeria Spp ◽  
Potential Damage ◽  
First Time

ABSTRACT: Eimeria infections are common in the sheep industry worldwide. Lambs are more susceptible to coccidiosis, especially in stressful conditions, being infected by different species of the parasite. Eimeria crandallis and Eimeria ovinoidalis are considered the most pathogenic, causing reduced growth, dehydration, anorexia, and death. In this study, the frequency of Eimeria species was evaluated in lambs from the southern region of the Rio Grande do Sul state, Brazil. Fecal samples from 248 lambs, from 19 farms, were tested for the presence of oocysts. The positive samples were re-examined and the sporulated oocysts analyzed morphometrically to identify the presence of Eimeria species. In 100% of the evaluated farms, there were animals positive for the protozoan. The frequency of Eimeria species was: E. ovinoidalis (94.74%), E. crandallis (89.47%), E. granulosa (78.95%), E. parva (68.42%), E. ahsata (63.13%), E. punctata (42.11%), E. bakuensis (36.84%), E. faurei (10.53%), and E. pallida (5.26%). Mixed infection was found in 94.74% of the samples. This research describes, for the first time, the occurrence of E. crandallis and E. ovinoidalis infecting lambs in the study area. The wide distribution of this protozoan and the high frequency of pathogenic species show the importance and potential damage of sheep coccidiosis in herds from Rio Grande do Sul.

scholarly journals Effects of Typhoon Paths on Storm Surge and Coastal Inundation in the Pearl River Estuary, China

2020 ◽  
Vol 12 (11) ◽  
pp. 1851
Author(s):  
Mei Du ◽  
Yijun Hou ◽  
Po Hu ◽  
Kai Wang
Keyword(s):  
Storm Surge ◽  
River Estuary ◽  
Pearl River Estuary ◽  
Pearl River ◽  
Coastal Inundation ◽  
The Pearl River Estuary ◽  
Typhoon Center ◽  
The Pearl River ◽  
Holland Model ◽  
First Time

A coastal inundation simulation system was developed for the coast of the Pearl River estuary (PRE), which consists of an assimilation typhoon model and the coupled ADCIRC (Advanced Circulation) + SWAN (Simulating Waves Nearshore) model. The assimilation typhoon model consists of the Holland model and the analysis products of satellite images. This is the first time an assimilation typhoon model has been implemented and tested for coastal inundation via case studies. The simulation results of the system agree well with the real measurements. Three observed typhoon paths (Hope, Nida, and Hato) were chosen to be the studied paths based on their positions relative to the PRE, China. By comparing the results of experiments with different forcing fields, we determined that the storm surge and the coastal inundation were mainly induced by wind forcing. By simulating coastal inundation for different typhoon center speeds, the Hato3 path most easily causes coastal inundation in the PRE. Moreover, the moving speed of the typhoon’s center significantly affects the coastal inundation in the PRE. The inundation becomes very serious as the movement of the typhoon center was slow down. This study provides a new reference for future predictions of coastal inundations.

scholarly journals The Atmospheric δ13C Record as Derived from 56 Pinyon Trees at 14 Sites in the Southwestern United States

Radiocarbon ◽  
1989 ◽  
Vol 31 (03) ◽  
pp. 469-474 ◽  
Author(s):  
S W Leavitt ◽  
Austin Long
Keyword(s):  
High Frequency ◽  
Ice Core ◽  
Ring Width ◽  
Ice Cores ◽  
The Other ◽  
Core Data ◽  
Single Tree ◽  
Pinyon Pine ◽  
The Individual ◽  
First Time

We have developed a master δ13C chronology from 14 pinyon pine sites in 6 states of the southwestern U S. Two of the individual isotopic chronologies, reported here for the first time, and 10 of those previously reported (Leavitt & Long, 1986; 1988) are from sites where cores from 4 trees were pooled prior to analysis, and the other 2 are merged from groups of 4 single-tree chronologies (sites) developed in an earlier phase of research (Leavitt & Long, 1985). Regressions of first differences of ring-width indices and δ13C values from each site were used to “correct” individual δ13C chronologies for climate effects which appear primarily related to high-frequency δ13C fluctuations, many of which are common among sites. These climate-corrected chronologies were normalized as deviations from their respective 1800–1849 δ13C means, and these normalized chronologies were averaged into the master. The overall δ13C drop from 1600 to the present is ca 1.2–1.4, consistent with recent ice-core data showing a drop of 1.14 ± 0.15% from 1740 to present (Friedli et al, 1986). However, the δ13C decline in the late 19th and early 20th centuries is greater in the pinyon chronology than that of the ice cores, thus supporting a greater biospheric CO2 input to the atmosphere than that indicated in the ice-core data.

scholarly journals Phase-Shift Optimization in AA/PVA Photopolymers by High-Frequency Pulsed Laser

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1887
Author(s):  
Daniel Puerto ◽  
Sergi Gallego ◽  
Jorge Francés ◽  
Andrés Márquez ◽  
Inmaculada Pascual ◽  
...  
Keyword(s):  
Phase Shift ◽  
High Frequency ◽  
Large Scale ◽  
Pulsed Laser ◽  
Laser Exposure ◽  
Continuous Laser ◽  
Frequency Limit ◽  
Optical Elements ◽  
First Time ◽  
532 Nm

Photopolymers can be used to fabricate different holographic optical elements, although maximization of the phase-shift in photopolymers has been a challenge for the last few decades. Different material compositions and irradiation conditions have been studied in order to achieve it. One of the main conclusions has been that with continuous laser exposure better results are achieved. However, our results show for the first time that higher phase-shift can be achieved using a pulsed laser. The study has been conducted with crosslinked acrylamide-based photopolymers exposed with a pulsed laser (532 nm). The increment of the phase-shift between the pulsed laser and continuous laser exposure is 17%, achieving a maximum phase-shift of 3π radians and a refractive index shift of 0.0084 at the zero spatial frequency limit, where monomer diffusion does not take place. This allows this photopolymer to be used in large-scale manufacturing.

Response of Seasonal Simulations of a Regional Climate Model to High-Frequency Variability of Soil Moisture during the Summers of 1988 and 1993

2007 ◽  
Vol 8 (4) ◽  
pp. 738-757 ◽  
Author(s):  
Song Yang ◽  
S-H. Yoo ◽  
R. Yang ◽  
K. E. Mitchell ◽  
H. van den Dool ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Water Vapor ◽  
Diurnal Cycle ◽  
High Frequency ◽  
Large Scale ◽  
Climate Model ◽  
Regional Climate ◽  
Water Vapor Transport ◽  
Diurnal Variability ◽  
High Frequency Variability

Abstract This study employs the NCEP Eta Regional Climate Model to investigate the response of the model’s seasonal simulations of summer precipitation to high-frequency variability of soil moisture. Specifically, it focuses on the response of model precipitation and temperature over the U.S. Midwest and Southeast to imposed changes in the diurnal and synoptic variability of soil moisture in 1988 and 1993. High-frequency variability of soil moisture increases (decreases) precipitation in the 1988 drought (1993 flood) year in the central and southern-tier states, except along the Gulf Coast, but causes smaller changes in precipitation along the northern-tier states. The diurnal variability and synoptic variability of soil moisture produce similar patterns of precipitation change, indicating the importance of the diurnal cycle of land surface process. The increase (decrease) in precipitation is generally accompanied by a decrease (increase) in surface and lower-tropospheric temperatures, and the changes in precipitation and temperature are attributed to both the local effect of evaporation feedback and the remote influence of large-scale water vapor transport. The precipitation increase and temperature decrease in 1988 are accompanied by an increase in local evaporation and, more importantly, by an increase in the large-scale water vapor convergence into the Midwest and Southeast. Analogous but opposite-sign behavior occurs in 1993 (compared to 1988) in changes in precipitation, temperature, soil moisture, evaporation, and large-scale water vapor transport. Results also indicate that, in regions where the model simulates the diurnal cycle of soil moisture reasonably well, including this diurnal cycle in the simulations improves model performance. However, no notable improvement in model precipitation can be found in regions where the model fails to realistically simulate the diurnal variability of soil moisture.

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