scholarly journals First Time Estimation of Thermospheric Neutral Density Profiles From Seed Perturbations of ESF Triggering: A Novel Evidence for Ionosphere Thermosphere Coupling

Author(s):  
G. Manju ◽  
R. P. Aswathy
Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1842
Author(s):  
Ziv Mor ◽  
Hallel Lutzky ◽  
Eyal Shalev ◽  
Nadav G. Lensky

Density, temperature, salinity, and hydraulic head are physical scalars governing the dynamics of aquatic systems. In coastal aquifers, lakes, and oceans, salinity is measured with conductivity sensors, temperature is measured with thermistors, and density is calculated. However, in hypersaline brines, the salinity (and density) cannot be determined by conductivity measurements due to its high ionic strength. Here, we resolve density measurements using a hydrostatic densitometer as a function of an array of pressure sensors and hydrostatic relations. This system was tested in the laboratory and was applied in the Dead Sea and adjacent aquifer. In the field, we measured temporal variations of vertical profiles of density and temperature in two cases, where water density varied vertically from 1.0 × 103 kg·m−3 to 1.24 × 103 kg·m−3: (i) a borehole in the coastal aquifer, and (ii) an offshore buoy in a region with a diluted plume. The density profile in the borehole evolved with time, responding to the lowering of groundwater and lake levels; that in the lake demonstrated the dynamics of water-column stratification under the influence of freshwater discharge and atmospheric forcing. This method allowed, for the first time, continuous monitoring of density profiles in hypersaline bodies, and it captured the dynamics of density and temperature stratification.


2012 ◽  
Vol 83 (10) ◽  
pp. 10D534 ◽  
Author(s):  
Deepak K. Gupta ◽  
B. H. Deng ◽  
K. Knapp ◽  
X. Sun ◽  
M. C. Thompson

2020 ◽  
Vol 12 (22) ◽  
pp. 3678
Author(s):  
Xuewu Cheng ◽  
Guotao Yang ◽  
Tao Yuan ◽  
Yuan Xia ◽  
Yong Yang ◽  
...  

Equipped with a 1-meter Cassegrain telescope with 6.2 meter focal length and an electronically gated Intensified Charge-Coupled Device (ICCD), a multilayer Na imager is designed and developed at Wuhan in China. This novel instrument has successfully achieved the first preliminary 3-D image of the mesospheric Sodium (Na) layer when running alongside a Na lidar. The vertical Na layer profile is measured by the lidar, while the horizontal structure of the layer at different altitudes is measured by the ICCD imaging with a horizontal resolution of ~3.7 urad. In this experiment, controlled by the delay and width of the ICCD gating signal, the images of the layer are taken with three-second temporal resolution for every 5 km. The results show highly variable structures in both the vertical and horizontal directions within the Na layer. Horizontal images of the Na layer at different altitudes near both the permanent layer (80–100 km) and a sporadic Na layer at 117.5 km are obtained simultaneously for the first time. The Na number density profiles measured by the lidar and those derived from this imaging technique show excellent agreement, demonstrating the success of this observational technique and the first 3-D imaging of the mesospheric Na layer.


2013 ◽  
Vol 59 (218) ◽  
pp. 1163-1169 ◽  
Author(s):  
Johannes Freitag ◽  
Sepp Kipfstuhl ◽  
Thomas Laepple ◽  
Frank Wilhelms

AbstractA new densification model, which simulates the effect of impurities on the densification of polar firn, is presented. The classical densification models of Herron and Langway (1980) and Pimienta and Barnola (Barnola and others, 1991) are modified by assuming that the activation energy for deformation is reduced by the impurities. Motivated by recent observations, the impurity effect is formulated on an empirical basis using the seasonally varying Ca2+ ion concentration. Excellent agreement between simulated and measured high-resolution density profiles confirms the new approach. The same parameterization applies for Greenland and Antarctica despite the one order of magnitude difference in impurity concentration. The new models allow us, for the first time, to simulate the density layering in firn down to the firn–ice transition. Our results emphasize the importance of impurities and density layering for the air entrapment and for dating gas records of deep ice cores, in particular for glacial climate conditions where the impurity concentrations are 10–100-fold higher than in modern firn.


2013 ◽  
Vol 31 (2) ◽  
pp. 219-227 ◽  
Author(s):  
P.W. Wachulak ◽  
L. Wegrzynski ◽  
A. Bartnik ◽  
T. Fok ◽  
R. Jarocki ◽  
...  

AbstractCharacterization measurements and modes of operation of a novel, dual-gas multi-jet target, developed for experiments on high-order harmonic generation, are presented. The target has been formed by pulsed injection of argon through a nozzle in a form of linearly oriented small orifices. The argon jets were separated with the helium jets formed by injection of helium through alternate orifices in the nozzle. The targets have been characterized by extreme ultraviolet backlighting at 13.5 nm wavelength. Density profiles for this type of targets have been obtained, to our knowledge, for the first time.


2015 ◽  
Vol 31 (6) ◽  
pp. 523-530
Author(s):  
Wonei Choi ◽  
Hyunkee Hong ◽  
Junsung Park ◽  
Hanlim Lee

2015 ◽  
Vol 22 (8) ◽  
pp. 082506 ◽  
Author(s):  
D. P. Stotler ◽  
F. Scotti ◽  
R. E. Bell ◽  
A. Diallo ◽  
B. P. LeBlanc ◽  
...  

1988 ◽  
Vol 59 (8) ◽  
pp. 1494-1496 ◽  
Author(s):  
J. A. Boedo ◽  
Roger D. Bengtson ◽  
A. Ouroua ◽  
P. M. Valanju

2015 ◽  
Vol 463 ◽  
pp. 897-901 ◽  
Author(s):  
D.P. Stotler ◽  
F. Scotti ◽  
R.E. Bell ◽  
B.P. LeBlanc ◽  
R. Raman

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