Space Weather - Science topic

Hi, I have been writing some routines to read such data from .cdf files in Python. I can share those if you are interested.

Are you suggesting that there might be a tendency for Bz to have one sign or the other (+/-) in correlation with the velocity of the solar wind? I can imagine that there might be something related to the solar cycle, where by the polarity of the sun's magnetic field changes, but I'd think that would be very weakly manifest (say) in the IMF by the time it reaches Earth, what with the IMF being distorted by solar wind and CMEs, etc. I'd be very surprised if you find a strong correlation. And, then, if you did, what would you do with it? Just asking.

I contacted Dr. Bruinsma and he told me that DTM uses the observed values.

The Parker solar probe data are not important for everybody except those who are really interested and motivated to explore the stability behaviors of the solar wind with respect to its well-defined equilibrium

People use this book in the US:

Russell, C. T., Luhmann, J. G., & Strangeway, R. J. (2016). Space physics: An introduction. Cambridge, United Kingdom: Cambridge University Press.

This is the version I used when I was in graduate school:

Kivelson, M. G., & Russell, C. T. (1996). Introduction to Space Physics. Cambridge, MA: Cambridge University Press.

In Europe, I guess people use ore this one:

Baumjohann, W., & Treumann, R. (2009). Basic Space Plasma Physics. London, United Kingdom: Imperial College Press.

This AGU monograph has lots of references and a modern view of the solar wind:

As for historical enrichment, I would recommend the articles of Eugene Parker (1950's, 1960;s, ApJ) and the ones with the first observations of the solar wind by Mariner II:

Hope this helps :)

Ashok Silwal Are you performing the right kind of multi-step forecasting? If it is closely related to its neighbours then choose RNN which provides the possibility to model time series dynamic systems and and for accuracy you may want to create two different models for each output.

Good luck

Dear Sujan Prasad Gautam , I hope you will find it useful:

Generally a "magnetic storm" is defined by a decrease (negative values) in Dst from its quiet-time, near-zero baseline, something caused by an increase in the strength of the magnetospheric equatorial ring current. Magnetic disturbance can, however, be manifest in different ways, and the field is never completely still. So, you can see very mild levels of disturbance with only small decreases in Dst. Sudden commencements (that often precede storms) are manifest as an increase (positive values) in Dst.

Dear Fatema Miah,

Thank you for your response. Yes, these are important issues in the context of the issues discussed in this discussion.

Thank you, Regards,

Dariusz Prokopowicz

Up to 10km, most capacitors work well. check the datasheet for high altitude usage.

Mohamed,

Try as a potential starting point, the article makes many good points concerning the class of the problems you may encounter. To astrophysics in general I would add the coronal heating issue, the galactic halo velocity problem, the pioneer anomaly, and even the angular velocity of each sub-ring of Saturn's rings. From a chemistry point of view (rotational-vibrational energy coupling, etc), there seems to be a coupling of energy of some sort that applies to all of these issues. Like many good questions, yours could be the start of a lifelong conversation.

Solar flares and type II radio bursts have different origins and thus their durations should not be similar. It is believed that solar flares are caused by release of energy and plasma heating/acceleration due to sudden disruption of magnetic structures of parent active regions. Type II bursts are related to shock waves which can be generated in the low corona and can propagate far away in the interplanetary medium that can lasts dozens of hours. Life time of shock waves is, in general, independent of duration of an accompanying flare, even in the case when a flare is a driver of a shock wave (the case of a blast wave). In such case, a flare just generate a blast shock impulsively, and the shock is propagating freely after that. There is another case, when a shock is driven by a coronal mass ejection (the case of a piston shock). In such case, the shock wave and an associated type II burst is not dependant on an accompanying flare at all.

Very well said Arif! I see the Space Weather goal has predicting, now and future atmospheric state, in real-time. While the Space Climate focus is rather on history, its goal being to construct the inventory of atmospheric states, using re-analysis. But nowadays, with so much future climate concerns and speculations, humans are also trying to predict, and eventually control, future climate at various scales in space and time. To the best of my knowledge, I recall humans are also trying to control the near-future weather, for example by having planes spreading certain chemicals in order to provoke precipitations. Since the global society is migrating into a climate management era, climate everything, past climate, future climate, local climate, global climate, etc. Weather refers to a single moment in time while climate is an integration of these moments in time. Your questions are interesting. Hope this provides some insights towards better answers.

Let me clarify a few things here.

- The "solar constant" (SC) is the average Total Solar Irradiance (TSI) over many solar cycles and for the mean sun-earth distance. It is really a constant within 0.2%.

- The extraterrestrial irradiance is the value of TSI (or for all practical purposes, SC) for that moment corrected for the actual sun-earth distance, which varies seasonally within about +/-3%.

- The irradiance incident on a building is a function of a lot of things: surface's tilt and azimuth, sun position, atmospheric conditions of the moment (clouds, aerosols, water vapor, etc.), site's elevation, ground albedo and shading. That's where you can spend a lifetime improving the modeling methods...

Hello Arun.

As you for sure know there exist several datasets from satellite and ground-based data that you can combine and check depending on your specific need.

Anyway, a possible answer to your question could come from reading the following literature:

Bormann, K. J., M. F. McCabe, and J. P. Evans, 2012: Satellite based observations for seasonal snow cover detection and characterisation in Australia. Rem. Sens. Environ., 123, 57-71.

Nolin, A. W., 2011: Recent advances in remote sensing of seasonal snow, J. Glaciol., 56, 1141-1150.

Notarnicola, C., M. Duguay, N. Moelg, T. Schellenberger, A. Tetzlaff, R. Monsorno, A. Costa, C. Steurer, and M. Zebisch, 2013: Snow Cover Maps from MODIS Images at 250 m Resolution, Part 1: Algorithm Description. Remote Sens., 5, 110-126.

Sirguey, P., R. Mathieu, and Y. Arnaud, 2009: Subpixel monitoring of the seasonal snow cover with MODIS at 250 m spatial resolution in the Southern Alps of New Zealand: Methodology and accuracy assessment. Rem. Sens. Environ., 113, 160-181.

Hope it helps somehow...

 Hi Robert,

I am not sure if we truly know, but projects are on going to try and assess the impact of these events. I suggest you look into some recent work by Karel (Carolus) Schrijver  (see links) who is one of the guys leading this from the science side. I know in his latest preprint he discusses some of the previous risk assessments that have taken place (http://www.lmsal.com/~schryver/Public/ms/swxopinion.pdf).

Hopefully that's of some use and a good starting point!

Richard

Thank you very much!

Space applications have characteristics different from Traditional WSN applications, the primary being the long distance between the motes and the high mote's velocity.

This tool can be used to simulate WSN space applications.

Cooja Simulator: http://anrg.usc.edu/contiki/index.php/Cooja_Simulator

Corresponding literature: http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=5345364&url=http%3A%2F%2Fieeexplore.ieee.org%2Fiel5%2F5340227%2F5345316%2F05345364.pdf%3Farnumber%3D5345364

Making such a calculation from scratch is a bit complicated, it is better to use existing model such as the SPICE kernel from NASA: http://naif.jpl.nasa.gov/naif/toolkit.html or the web-interface of JPL's Horizons: http://ssd.jpl.nasa.gov/?horizons.

Rather than answering your question in frequency, it would be more realistic to answer in energy, simply the frequency is so high that gamma ray behave more like a particle (photon) than a wave. The CGRO and other satellite experiment can detect gamma ray only up to several 100s GeV or < 1TeV = 1.E12 eV. Higher than that, the flux is so low that satellite instruments loss detection power or their discrimination power to separate gamma from much higher flux of cosmic rays. The Ground gamma ray telescope can detect gamma photons interaction with atmosphere via indirect measurement. The highest energy of gamma ray  of those experiments can reach approximately 1.E14 eV, in terms of frequency ~ 2.4E28 Hertz.

There are some known effects already studied for several decades such as ionoshperic scintillations. In a very simple and crude method, the signal strength of a VHF (or UHF) signal from a satellite can be monitored continuously. In the 1990s I was associated with such a setup around 400MHz with a crossed YAGI array to receive a signal from a Japanese satellite. So, to conclude, yes there are ionospheric effects observed for the VHF/UHF signals. I may be wrong but I am not in favor to assume that there are no ionospheric/space weather effects observed on VHF/UHF signals. Also, if you go beyond the ionosphere, i.e. in the space vacuum, again there are some disturbances observed in the propagation of radio signals. These are referred as the interplanetary scintillations. Physical Research Laboratory in Ahmedabad, India was operating at Thaltej one such IPS Radio Telescope around 103MHz which falls in the VHF band. Unfortunately it is not active and totally dismantled. But you can search for literature in this field.

In recent years, GPS signals are used to study the ionospheric variations including to determine the electronic density or Total Electroinc Contents (TEC) of the ionosphere. Although the GPS frequencies operate well above the VHF band or the upper end of UHF usually called as microwave frequencies (L-Band), so yes, there are very-well known effects that are studied and vast literature is available in this area too!

I hope this gives a satisfactory answer to your question.

Wishing you best luck in your work!

As it seems to me... It is difficult to make a short answer... It should be known what means "unusual solar activity" and what actualy means "atmospheric distubances". But generaly we could say that there is a tight relation between solar activity (space weather) and atmosphere (thermosphere, ionosphere), plasmasphere and magnetosphere. But it depends on the parameters of solar disturbances. This relation could apear on the diferent altitudes and latitudinal regions. 

The solar eclipse effects the earth's ionosphere at short time scales i.e. during the period of the eclipse. Normally, the ionization drops during the time of the eclipse as the source is cut off and because the shadow moves at supersonic speed, perturbations in the earth atmosphere system occur. These perturbations may propagate from the troposphere to the ionosphere get amplified and seen as modulations in the F region ionization or total electron content. Many reports on the effect of total solar eclipse on the ionosphere/ atmosphere are available in literature.

Regarding the lunar eclipse, since the eclipse occurs during fool moon, there may be corresponding effect on the oceanic tides.

Every student is different of course (and structure and length of PhD is different in different countries), but with my students recently I try to start them off for first year on a mini-project looking at an event or events, probably using other people's software. By end of mini-project you know the student's capabilities and weaknesses whilst they have learnt a lot on the field and other skills. I think it's pretty important that the student has a chance to develop their own code later in the PhD. Surely one of the most powerful aspects of research today is being able to solve a problem by directly writing your own code.

1) what do you call saturation?

2) Geomagnetic disturbances are the results of a) solar disturbances as CME, solar Flare, high speed solar Wind and also b) atmospheric disturbances.

For example a solar Flare produces a strong increase of ionization and ionospheric electric currents and as a consequence you can see the geomagnetic disturbance called a crochet.

Many geomagnetic disturbances depend of the ionospheric disturbances or magnetospheric disturbances

When the hF > 300 there is no need to make chemical correction.

The reason why h'F and hmF2 are more often often used for obtaining vertical drift is simply because they are standard parameters more easily accessible in the ionosonde data bank. It is more appropriate to use an intermediate height, preferably the true height. Any virtual height should also be okay since the time rate of change may not be very different between the true and virtual heights. I am sending you some reprints in your e-mail address.

Hi Francis,

In the following paper you can find a partial answer to your question and also, references to other articles where validation procedures are reported.

Nava B, Coïsson P, Radicella SM, 2008. A new version of the NeQuick ionosphere electron density model. Journal of Atmospheric and Solar-Terrestrial Physics 70. doi:10.1016/j.jastp.2008.01.015

Besides, several researchers are nowadays comparing (and updating) NeQuick's procedure to compute ionospheric parameters, using FORMOSAT-3/COSMIC electron density profiles.

Regards.