scholarly journals Iterative Tomography: A Key to Providing Time-Dependent 3-D Reconstructions of the Inner Heliosphere and the Unification of Space Weather Forecasting Techniques

2020 ◽  
Vol 7 ◽  
Author(s):  
Bernard V. Jackson ◽  
Andrew Buffington ◽  
Lucas Cota ◽  
Dusan Odstrcil ◽  
Mario M. Bisi ◽  
...  
Keyword(s):  
Weather Forecasting ◽  
Kinematic Model ◽  
Thomson Scattering ◽  
Time Dependent ◽  
Environmental Research ◽  
Reconstruction Technique ◽  
Wide Field ◽  
Interplanetary Scintillation ◽  
Solar Mass ◽  
Inner Heliosphere

Over several decades, UCSD has developed and continually updated a time-dependent iterative three-dimensional (3-D) reconstruction technique to provide global heliospheric parameters—density, velocity, and component magnetic fields. For expediency, this has used a kinematic model as a kernel to provide a fit to either interplanetary scintillation (IPS) or Thomson-scattering observations. This technique has been used in near real time over this period, employing Institute for Space-Earth Environmental Research, Japan, IPS data to predict the propagation of these parameters throughout the inner heliosphere. We have extended the 3-D reconstruction analysis to include other IPS Stations around the Globe in a Worldwide Interplanetary Scintillation Stations Network. In addition, we also plan to resurrect the Solar Mass Ejection Imager Thomson-scattering analysis as a basis for 3-D analysis to be used by the latest NASA Small Explorer heliospheric imagers of the Polarimeter to Unify the Corona and Heliosphere mission, the All Sky Heliospheric Imager, and other modern wide-field imagers. Better data require improved heliospheric modeling that incorporates non-radial transport of heliospheric flows, and shock processes. Looking ahead to this, we have constructed an interface between the 3-D reconstruction tomography and 3-D MHD models and currently include the ENLIL model as a kernel in the reconstructions to provide this fit. In short, we are now poized to provide all of these innovations in a next step: to include them for planned ground-based and spacecraft instruments, all to be combined into a truly global 3-D heliospheric system which utilizes these aspects in their data and modeling.

scholarly journals Data assimilation method in flood forecasting for Red river system using high performent computer

2015 ◽  
Vol 37 (1) ◽  
pp. 29-42
Author(s):  
Nguyen Thanh Don ◽  
Nguyen Van Que ◽  
Tran Quang Hung ◽  
Nguyen Hong Phong
Keyword(s):  
Data Assimilation ◽  
Flow Rate ◽  
New Technologies ◽  
Weather Forecasting ◽  
Initial Conditions ◽  
River System ◽  
Red River ◽  
Time Dependent ◽  
Complex Case ◽  
Flood Model

Around the world, the data assimilation framework has been reported to be of great interest for weather forecasting, oceanography modeling and for shallow water flows particularly for flood model. For flood model this method is a power full tool to identify time-independent parameters (e.g. Manning coefficients and initial conditions) and time-dependent parameters (e.g. inflow). This paper demonstrates the efficiency of the method to identify time-dependent parameter: inflow discharge with a real complex case Red River. Firstly, we briefly discuss about current methods for determining flow rate which encompasses the new technologies, then present the ability to recover flow rate of this method. For the case of very long time series, a temporal strategy with time overlapping is suggested to decrease the amount of memory required. In addition, some different aspects of data assimilation are covered from this case.

scholarly journals Eddy growth and mixing in mesoscale oceanographic flows

1997 ◽  
Vol 4 (4) ◽  
pp. 223-235 ◽  
Author(s):  
G. Haller ◽  
A. C. Poje
Keyword(s):  
Direct Relationship ◽  
Kinematic Model ◽  
Fluid Flows ◽  
Time Dependent ◽  
Two Dimensional ◽  
Two Dimensional Flow ◽  
Fluid Particles ◽  
Lagrangian Tracers ◽  
Particle Paths ◽  
General Time

Abstract. We study the relation between changes in the Eulerian topology of a two dimensional flow and the mixing of fluid particles between qualitatively different regions of the flow. In general time dependent flows, streamlines and particle paths are unrelated. However, for many mesoscale oceanographic features such as detaching rings and meandering jets, the rate at which the Euierian structures evolve is considerably slower than typical advection speeds of Lagrangian tracers. In this note we show that for two-dimensional, adiabatic fluid flows there is a direct relationship between observable changes in the topology of the Eulerian field and the rate of transport of fluid particles. We show that a certain class of flows is amenable to adiabatic or near adiabatic analysis, and, as an example, we use our results to study the chaotic mixing in the Dutkiewicz and Paldor (1994) kinematic model of the interaction of a meandering barotropic jet with a strong eddy.

scholarly journals Interplanetary scintillation signatures in the inner heliosphere of the deepest solar minimum in the past 100 years

2012 ◽  
Vol 8 (S294) ◽  
pp. 83-84
Author(s):  
Susanta Kumar Bisoi ◽  
P. Janardhan
Keyword(s):  
Solar Minimum ◽  
Interplanetary Scintillation ◽  
Solar Cycles ◽  
Significant Drop ◽  
The Past ◽  
Inner Heliosphere

AbstractWe have used interplanetary scintillation (IPS) observations at 327 MHz spanning years 1983-2009 to study microturbulence levels in the inner heliosphere. We find that the microturbulence levels show a steady and significant drop in the entire inner heliosphere starting from around 1995. The fact that the solar polar fields have also shown a similar declining trend provides a consistent result showing the buildup to the solar minimum between the solar cycles 23 and 24, the deepest in the past 100 years, actually began more than a decade earlier.

scholarly journals Inverse reconstruction technique based on time-dependent Petschek-type reconnection model: first application to THEMIS magnetotail observations

2009 ◽  
Vol 27 (12) ◽  
pp. 4369-4377
Author(s):  
V. Ivanova ◽  
J. Liu ◽  
S. Kiehas ◽  
V. Semenov ◽  
H. Biernat
Keyword(s):  
Electric Field ◽  
Total Duration ◽  
Time Dependent ◽  
Reconstruction Technique ◽  
Field Variation ◽  
Magnetic Field Variation ◽  
Two Dimensional ◽  
Line Position ◽  
Inverse Reconstruction ◽  
Reconnection Model

Abstract. We apply the inverse reconstruction technique based on the two-dimensional time-dependent Petschek-type reconnection model to a dual bipolar magnetic structure observed by THEMIS B probe in the Earth's magnetotail during a substorm on 22 February 2008 around 04:35 UT. The technique exploits the recorded bipolar magnetic field variation as an input and provides the reconnection electric field and the location of the X-line as an output. As a result of the technique application, we get (1) the electric field, reaching ~1.1 mV/m at the maximum and consisting of two successive pulses with total duration of ~6 min, and (2) the approximate X-line position located in the magnetotail between 18 and 20 RE.

scholarly journals The prelude to the deep minimum between solar cycles 23 and 24: Interplanetary scintillation signatures in the inner heliosphere

2011 ◽  
Vol 38 (20) ◽  
pp. n/a-n/a ◽  
Author(s):  
P. Janardhan ◽  
Susanta Kumar Bisoi ◽  
S. Ananthakrishnan ◽  
M. Tokumaru ◽  
K. Fujiki
Keyword(s):  
Interplanetary Scintillation ◽  
Solar Cycles ◽  
Deep Minimum ◽  
Inner Heliosphere

scholarly journals Time‐dependent magnetohydrodynamic simulations of the inner heliosphere

2016 ◽  
Vol 121 (4) ◽  
pp. 2866-2890 ◽  
Author(s):  
V. G. Merkin ◽  
J. G. Lyon ◽  
D. Lario ◽  
C. N. Arge ◽  
C. J. Henney
Keyword(s):  
Time Dependent ◽  
Magnetohydrodynamic Simulations ◽  
Inner Heliosphere
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