Propagation Summary
The Solar Flux charts have shown a sharp increase in sunspot activity since mid November and by the end of November, average sunspot numbers have actually risen to 95 for the first time since 2003. This has even exceeded the predicted peak forecast for the first quarter of 2013. http://www.swpc.noaa.gov/SolarCycle/
Solar activity was at very low levels on 19 December and increased to low levels from 20–24 December, and finally ending the period (25 December) at moderate levels. Region 1376 was the most active group with frequent B– and C–class flare production until 25 December when new Region 1387 began producing multiple C–class flares and one M–class flare. On 22 December at 0208 UTC, Region 1381 produced a C5 flare associated with weak Types II and IV radio sweeps and a faint CME, determined to be non–geoeffective. Region 1386 produced a C5/Sf flare at 0839 UTC. Region 1376 produced a long–duration C4 flare on the west limb at 1236 UTC associated with a non–Earth–directed CME. On 25 December at 1816 UTC, Region 1387 produced an M4/1N flare that was accompanied by Type II and Type IV radio emissions. A slight proton enhancement was observed on 25 December and achieved a max flux of 3 pfu at 0135 UTC. More information can be found at: http://www.windows2universe.org/sun/solar_activity.html
Solar activity is expected to be at low to moderate levels until 31 December when Region 1387 is forecast to rotate off the disk. Activity is expected to return to low levels with a slight chance for isolated M–class activity for the remainder of the period. No proton events are expected at geosynchronous orbit. The greater than 2 MeV electron flux is expected to be at normal to moderate levels during the period. Geomagnetic field activity is expected to be at active levels from 28–29 December due to CME (Coronal Mass Ejection) arrivals. Diminishing effects from said CMEs will have brought geomagnetic field activity to unsettled levels by 30 December. Mostly quiet conditions were predicted for 31 December, 3–4 and 7–23 January. Activity is expected to be at predominately quiet to unsettled levels 1–2 and 5–6 January due to recurrent coronal hole high speed streams. Although radio blackout warnings have been issued at the end of December, reception conditions are predicted to be good during the quiet periods. ( http://www.swpc.noaa.gov/SolarCycle/ )
2012 Meteor Showers
The next major meteor shower will be the Quadrantid shower, which is expected to peak after midnight on the morning of January 4, 2012. This shower favours northerly latitudes in the Northern Hemisphere. If the peak happens as predicted – at 0700 to 0800 UTC, means eastern North America might be in a good position to watch the 2012 Quadrantid shower. Predicting the peak and the intensity of a meteor shower is always a tricky business, though. No matter where you live, the best time to watch is before dawn on January 4. Best months of the year for meteor scatter are August, October, November, December, and early January. Actually, anytime of the year is good. Sometimes certain dates are just better than others, due to the occurrence of meteor showers. Average peak daily time for night time showers: 0500 to 1200 local time (There are a handful of daytime showers that almost rival the big night time showers and the only way you can be aware of them is to do some research of when they occur.) Best frequencies for meteor scatter: 50MHz to 100 MHz. (The entire 88 to 108MHz band is usable for meteor scatter dxing.) General distance of reception is 600 – 1200 miles. Receiving satisfactory meteor skip signals depends on where you live, what type of equipment you are using, and availability to the peak times of the day ( http://earthsky.org/astronomy–essentials/earthskys–meteor–shower–guide ) Links to these articles can be found at http://www.jameswelsh.org.uk/ .
Thanks to Ken Fletcher and Mike Terry for regular updates during 2011
Thursday, 12 January 2012
Thursday, 20 October 2011
November 2011
Propagation Summary
The Solar flux has peaked at 140 on September 27-28th but there is again a downward trend, which will see a drop to 105 by November 7th. The only noticeable disturbance on propagation conditions was on October 5-6, with the Boulder A index peaking at 18, and the K Index peaking at 5. The general trend for sunspot activity is up, although certainly not to the predicted levels. Daily updates can be found at http://www.wm7d.net/hamradio/solar/27d_forecast.shtml
Historical Solar charts going back to 1950 are available at http://www.solen.info/solar/history/
Implications for Long Term Space Climate Change
“The recent solar minimum was the longest and deepest of the space age, with the lowest average sunspot numbers for nearly a century. The Sun appears to be exiting a grand solar maximum (GSM) of activity which has persisted throughout the space age, and is headed into a significantly quieter period. Indeed, initial observations of solar cycle 24 (SC24) continue to show a relatively low heliospheric magnetic field strength and sunspot number (R), despite the average latitude of sunspots and the inclination of the heliospheric current sheet showing the rise to solar maximum is well underway. We extrapolate the available SC24 observations forward in time by assuming R will continue to follow a similar form to previous cycles, despite the end of the GSM, and predict a very weak cycle 24, with R peaking at ∼65–75 around the middle/end of 2012. Similarly, we estimate the heliospheric magnetic field strength will peak around 6nT. We estimate that average galactic cosmic ray fluxes above 1GV rigidity will be ∼10% higher in SC24 than SC23 and that the probability of a large SEP event during this cycle is 0.8, compared to 0.5 for SC23. Comparison of the SC24 R estimates with previous ends of GSMs inferred from 9300 years of cosmogenic isotope data places the current evolution of the Sun and heliosphere in the lowest 5% of cases, suggesting Maunder Minimum conditions are likely within the next 40 years.” From: http://www.agu.org/pubs/crossref/2011/2011GL049328.shtml
Solar Flare Alerts by Text or Phone
Real time solar activity alerts to your mobile phone or landline phone can be set up online at http://spaceweathertext.com (text) and http://spaceweatherphone.com (voice).
Future Sunspot Cycle Predictions
Sunspot Cycles are Difficult to Accurately Predict. Solar physicists believe the speed of a massive circulating current of hot plasma within the Sun predicts the amplitudes of sunspot Cycles approximately twenty years into the future. In the years prior to 2006 that speed had become lower than ever before. Based on the plasma-speed/future-cycle-amplitude theory, a team led by physicist Mausumi Dikpata of the National Centre for Atmospheric Research predicted Cycle 24 would be intense. NASA solar physicist David Hathaway agreed, but predicted Solar Cycle 25 will be very weak.
VHF Propagation Software
A new VHF propagation gadget is available from SV2AGW. There are two Windows Vista Side Bar gadgets, for Europe and North America. They display Aurora and Sporadic-e propagation using the dxrobot images. George Rossopoulos, SV2AGW has also produced software for AX.25 Packet / APRS, which can be downloaded from his website. http://www.sv2agw.com/downloads/default.htm (Via Mike Terry)
Thanks to Mike Terry and Ken Fletcher for regular updates. The next Propagation report will be in January. Links to these articles and more are available at http://www.jameswelsh.org.ukMonday, 22 August 2011
September 2011
Propagation Summary
August began with a peak in the Solar Flux of 130, which then dipped to 96 by August 14th. This pattern repeats roughly every 14 days. The next peak is estimated to be around September 6th , but the general trend is a downward one. The prediction charts on Solarcycle24.com show that, if the prediction charts are correct, Solar flux would need to reach 140 by the end of 2011, but during August they have actually dropped to the same levels as in January.
G0KYA's Amateur Radio Blog (Steve Nichols)
“We are moving away from the summer solstice, but we are a long way from the better autumnal HF conditions that we should start to see in mid September. The summer sporadic E season should also be diminishing. The last month or so has been characterised by big swings in the solar flux index and pretty poor conditions, although it doesn't pay to generalise. A chance glance at 17m a week or so ago showed a station from Los Angeles, calling CQ and with very few takers. He was about the only signal on the band! “ Steve’s blog and podcasts can be found at: http://g0kya.blogspot.com/
Sun storms 'could be more disruptive within decades' By Judith Burns. BBC News
Within decades, solar storms are likely to become more disruptive to planes and spacecraft, say researchers at Reading University. The work, published in Geophysical Research Letters, predicts that "In a grand solar maximum, the peaks of the 11-year sunspot cycle are larger and the average number of solar flares and associated events such as coronal mass ejections are greater. "On the other hand in a grand solar minimum there are almost no sunspots for several decades. The last time this happened was during the Maunder Minimum, between about 1650 and 1700." The research indicates that most radiation hits the Earth during periods of middling solar activity. Increased radiation is a particular problem for aviation and communications - technology that did not exist the last time the sun cycle ended its grand maximum.
http://www.bbc.co.uk/news/science-environment-14580995
Via Ken Fletcher
Space Weather Turns into an International Problem (NASA Science News)
Sometimes a problem is so big, one country cannot handle it alone.
That's the message scientists were delivering at July's International Living with a Star (ILWS) meeting in Bremen, Germany, and representatives from more than 25 of the world's most technologically-advanced nations gathered to hear what they had to say. "The problem is solar storms, and figuring out how to predict them and stay safe from their effects," says ILWS Chairperson Lika Guhathakurta of NASA headquarters. "We need to make progress on this before the next solar maximum arrives around 2013." While it probably will not be the biggest peak on record, human society has never been more vulnerable. The basics of daily life, from communications to weather forecasting to financial services—depend on satellites and high-tech electronics. http://science.nasa.gov/science-news/science-at-nasa/2010/16jul_ilws/
Spacecraft Sees Solar Storm Engulf Earth (August 18, 2011)
for the first time, a spacecraft far from Earth has turned and watched a solar storm engulf our planet. The movie, released during a NASA press conference, has galvanized solar physicists, who say it could lead to important advances in space weather forecasting.
“The movie sent chills down my spine,” says Craig DeForest of the Southwest Research Institute in Boulder, Colorado. "It shows a CME swelling into an enormous wall of plasma and then washing over the tiny blue speck of Earth where we live. I felt very small.” The video can be viewed at: http://science.nasa.gov/science-news/science-at-nasa/2011/18aug_cmemovie/
August began with a peak in the Solar Flux of 130, which then dipped to 96 by August 14th. This pattern repeats roughly every 14 days. The next peak is estimated to be around September 6th , but the general trend is a downward one. The prediction charts on Solarcycle24.com show that, if the prediction charts are correct, Solar flux would need to reach 140 by the end of 2011, but during August they have actually dropped to the same levels as in January.
G0KYA's Amateur Radio Blog (Steve Nichols)
“We are moving away from the summer solstice, but we are a long way from the better autumnal HF conditions that we should start to see in mid September. The summer sporadic E season should also be diminishing. The last month or so has been characterised by big swings in the solar flux index and pretty poor conditions, although it doesn't pay to generalise. A chance glance at 17m a week or so ago showed a station from Los Angeles, calling CQ and with very few takers. He was about the only signal on the band! “ Steve’s blog and podcasts can be found at: http://g0kya.blogspot.com/
Sun storms 'could be more disruptive within decades' By Judith Burns. BBC News
Within decades, solar storms are likely to become more disruptive to planes and spacecraft, say researchers at Reading University. The work, published in Geophysical Research Letters, predicts that "In a grand solar maximum, the peaks of the 11-year sunspot cycle are larger and the average number of solar flares and associated events such as coronal mass ejections are greater. "On the other hand in a grand solar minimum there are almost no sunspots for several decades. The last time this happened was during the Maunder Minimum, between about 1650 and 1700." The research indicates that most radiation hits the Earth during periods of middling solar activity. Increased radiation is a particular problem for aviation and communications - technology that did not exist the last time the sun cycle ended its grand maximum.
http://www.bbc.co.uk/news/science-environment-14580995
Via Ken Fletcher
Space Weather Turns into an International Problem (NASA Science News)
Sometimes a problem is so big, one country cannot handle it alone.
That's the message scientists were delivering at July's International Living with a Star (ILWS) meeting in Bremen, Germany, and representatives from more than 25 of the world's most technologically-advanced nations gathered to hear what they had to say. "The problem is solar storms, and figuring out how to predict them and stay safe from their effects," says ILWS Chairperson Lika Guhathakurta of NASA headquarters. "We need to make progress on this before the next solar maximum arrives around 2013." While it probably will not be the biggest peak on record, human society has never been more vulnerable. The basics of daily life, from communications to weather forecasting to financial services—depend on satellites and high-tech electronics. http://science.nasa.gov/science-news/science-at-nasa/2010/16jul_ilws/
Spacecraft Sees Solar Storm Engulf Earth (August 18, 2011)
for the first time, a spacecraft far from Earth has turned and watched a solar storm engulf our planet. The movie, released during a NASA press conference, has galvanized solar physicists, who say it could lead to important advances in space weather forecasting.
“The movie sent chills down my spine,” says Craig DeForest of the Southwest Research Institute in Boulder, Colorado. "It shows a CME swelling into an enormous wall of plasma and then washing over the tiny blue speck of Earth where we live. I felt very small.” The video can be viewed at: http://science.nasa.gov/science-news/science-at-nasa/2011/18aug_cmemovie/
Friday, 22 July 2011
August 2011
Propagation Summary
According to the forecast at http://www.swpc.noaa.gov/ftpdir/weekly/WKHF.txt solar activity is expected to be very low. However, there is a chance that new, rapidly emerging flux regions could increase activity to moderate levels at any time during the outlook period.
No proton events are expected at geosynchronous orbit.
The greater than 2 MeV electron flux at geosynchronous orbit is expected to be at background or moderate levels for most of the outlook interval. However, increases to high levels are expected for 6-9 August in response to recurrent high speed streams.
Geomagnetic field activity was unsettled on 20-22 July due to a coronal hole. An increase to unsettled levels is expected on 27 July to 2 August due to another recurrent coronal hole. Quiet levels are expected for 3 August followed by another increase to unsettled levels for 04-10 August due to recurrence. 11-13 August is expected to be quiet and an increase to unsettled is expected for 14-15 August, again due to recurrence.
The Sunspot trend chart at http://www.solarham.com/sunspots.htm shows a sharp drop in sunspot activity which would suggest that the estimated peak forecast for the first quarter of 2013 will be well below the estimated number of 90.
Perseid Meteor Shower Peak August 12, 2011.
Good news for Meteor Shower DX’ers. The maximum of the Perseid activity in 2011 is expected during the night of the 12th August. The Perseids is the name of a prolific meteor shower. The shower is visible from mid-July each year, with the peak in activity being between August 9 and 14, depending on the particular location of the stream. During the peak, the rate of meteors reaches 60 or more per hour.
( http://earthsky.org/astronomy-essentials/earthskys-meteor-shower-guide )
Understanding Propagation
Here is a very useful article about Propagation modes. “Hop length is the ground distance covered by RF after it has been reflected once from the Ionosphere and returned to Earth. Maximum hop length is set by the height of the Ionosphere and curvature of the earth. The maximum hop length shown assumes antenna radiation of 4 degrees and the E and F layer heights as specified.” It is in PDF format and can be viewed, downloaded or printed from: http://www.hamqsl.com/Understanding%20Propagation.pdf
The UK Meteorological Office is developing a Space Weather forecasting system.
The key aims are to produce near real-time space weather ‘nowcasts’ and short-range forecasts by developing existing empirical analysis and modelling techniques as well as research with more sophisticated space weather models and to build an upgraded forecasting system. More details at: www.metoffice.gov.uk/
According to the forecast at http://www.swpc.noaa.gov/ftpdir/weekly/WKHF.txt solar activity is expected to be very low. However, there is a chance that new, rapidly emerging flux regions could increase activity to moderate levels at any time during the outlook period.
No proton events are expected at geosynchronous orbit.
The greater than 2 MeV electron flux at geosynchronous orbit is expected to be at background or moderate levels for most of the outlook interval. However, increases to high levels are expected for 6-9 August in response to recurrent high speed streams.
Geomagnetic field activity was unsettled on 20-22 July due to a coronal hole. An increase to unsettled levels is expected on 27 July to 2 August due to another recurrent coronal hole. Quiet levels are expected for 3 August followed by another increase to unsettled levels for 04-10 August due to recurrence. 11-13 August is expected to be quiet and an increase to unsettled is expected for 14-15 August, again due to recurrence.
The Sunspot trend chart at http://www.solarham.com/sunspots.htm shows a sharp drop in sunspot activity which would suggest that the estimated peak forecast for the first quarter of 2013 will be well below the estimated number of 90.
Perseid Meteor Shower Peak August 12, 2011.
Good news for Meteor Shower DX’ers. The maximum of the Perseid activity in 2011 is expected during the night of the 12th August. The Perseids is the name of a prolific meteor shower. The shower is visible from mid-July each year, with the peak in activity being between August 9 and 14, depending on the particular location of the stream. During the peak, the rate of meteors reaches 60 or more per hour.
( http://earthsky.org/astronomy-essentials/earthskys-meteor-shower-guide )
Understanding Propagation
Here is a very useful article about Propagation modes. “Hop length is the ground distance covered by RF after it has been reflected once from the Ionosphere and returned to Earth. Maximum hop length is set by the height of the Ionosphere and curvature of the earth. The maximum hop length shown assumes antenna radiation of 4 degrees and the E and F layer heights as specified.” It is in PDF format and can be viewed, downloaded or printed from: http://www.hamqsl.com/Understanding%20Propagation.pdf
The UK Meteorological Office is developing a Space Weather forecasting system.
The key aims are to produce near real-time space weather ‘nowcasts’ and short-range forecasts by developing existing empirical analysis and modelling techniques as well as research with more sophisticated space weather models and to build an upgraded forecasting system. More details at: www.metoffice.gov.uk/
Wednesday, 29 June 2011
July 2011
Propagation Summary
Sunspot numbers are continuing on a downward trend. June started with a Solar Flux of 115 and is forecast to peak roughly every 21 days. There was a peak forecast for June 26 at 105, and in July, there is a peak of just 100 forecast around the 14th. The dips in between could be as low as 85 on 7-10 July. The average daily Solar Flux reading for April was 112, dropping to 98.1 in May and averaging 98.5 in June (based on information available).
There has only been 1 spotless day in 2011 so far, compared with 51 spotless days in 2010 and 260 in 2009. The total number of spotless days since 2007 is 850.
Reception conditions are likely to remain the same during July with the Boulder A index averaging at 8.4 and the K index at 2.7. You can receive the latest accurate updates via email by subscribing to: http://www.spaceweather.com/
Europe to get space radiation-storm warning service
“International experts met in London in March, with the aim of setting up a European solar radiation-storm warning service. With the Sun expected to belch forth increasing amounts of bad "space weather" in coming years, the scientists warn that billions of pounds' worth of damage could be done to satellites in orbit.” (Lewis Page The Register: http://www.theregister.co.uk/2011/01/28/space_met_office/ . See also: http://www.bu.edu/cism/ )
Is a Dalton/Maunder Minimum possible?
Thomas F. Giella, writing in his blog recently has the following theory about the current solar conditions: “I personally believe we are headed for a "Dalton" type solar minimum but a "Maunder" type solar minimum is possible. As far as radio wave propagation is concerned, the higher HF bands would really be poor for decades, as the global climate is actually cooling not warming. Either a Dalton or Maunder solar minimum would be a global catastrophe where millions would starve and/or freeze to death and it would not be limited to the second or third world nations. (Thomas F Giella 15 June 2011 http://www.solarcycle24data.org/ )
Sunspot numbers are continuing on a downward trend. June started with a Solar Flux of 115 and is forecast to peak roughly every 21 days. There was a peak forecast for June 26 at 105, and in July, there is a peak of just 100 forecast around the 14th. The dips in between could be as low as 85 on 7-10 July. The average daily Solar Flux reading for April was 112, dropping to 98.1 in May and averaging 98.5 in June (based on information available).
There has only been 1 spotless day in 2011 so far, compared with 51 spotless days in 2010 and 260 in 2009. The total number of spotless days since 2007 is 850.
Reception conditions are likely to remain the same during July with the Boulder A index averaging at 8.4 and the K index at 2.7. You can receive the latest accurate updates via email by subscribing to: http://www.spaceweather.com/
Europe to get space radiation-storm warning service
“International experts met in London in March, with the aim of setting up a European solar radiation-storm warning service. With the Sun expected to belch forth increasing amounts of bad "space weather" in coming years, the scientists warn that billions of pounds' worth of damage could be done to satellites in orbit.” (Lewis Page The Register: http://www.theregister.co.uk/2011/01/28/space_met_office/ . See also: http://www.bu.edu/cism/ )
Is a Dalton/Maunder Minimum possible?
Thomas F. Giella, writing in his blog recently has the following theory about the current solar conditions: “I personally believe we are headed for a "Dalton" type solar minimum but a "Maunder" type solar minimum is possible. As far as radio wave propagation is concerned, the higher HF bands would really be poor for decades, as the global climate is actually cooling not warming. Either a Dalton or Maunder solar minimum would be a global catastrophe where millions would starve and/or freeze to death and it would not be limited to the second or third world nations. (Thomas F Giella 15 June 2011 http://www.solarcycle24data.org/ )
About Sunspots
Sunspots are dark spots on the Sun caused by it’s magnetic field. The spots are dark because they are cooler than the area of the Sun that surrounds them and are often as big as the Earth.
The number of sunspots is controlled by the amount of distortion of the Sun's magnetic field. The magnetic field becomes distorted because the Sun's equator and core rotate more quickly than its other parts. As a result, sunspot activity varies over an average 11-year cycle. Over approximately 11 years, the Sun goes from a solar minimum (fewer spots) to a solar maximum (more spots) and back to a minimum again.
( http://www.bbc.co.uk/science/space/solarsystem/solar_system_highlights/solar_cycle )
Thanks to Ken Fletcher and Mike Terry for regular contributions
Thursday, 19 May 2011
June 2011
Propagation Summary
May began with sunspot numbers of 115 dropping to 110 for 5 days on the 6th, then by the end of May sunspot numbers had dropped to 105. The Boulder A and K indices have remained at their ‘norm’ of 5 and 2 during May, except for the 9th and 10th, with a peak of 15. May should finish with a rise to 15 once more.
Sunspot numbers in June should start at 105 but are likely to drop to as low as 92 by Jun 13. The A and K indices should peak at 12 and 4 by June 11th.
According to the trend charts at: http://www.solarham.com/sunspots.htm the predicted sunspot numbers were back to predicted levels during April but sunspot numbers are likely to have fallen back by the end of May. From: http://www.wm7d.net/hamradio/solar/27d_forecast.shtml
Maximum Usable Frequencies
The estimated MUF’s for Western Europe, are 4 MHz (0100-0400), 5 MHz (0500-0600), 6Mhz (0700-1000), 7 MHz (1100-1800), 6 MHz (1900-2200) and 5 MHz (2300-0000). (Times in UTC). This and other regional estimates can be found at: http://hfradio.org/fot_7.html
Sporadic E
The Sporadic E season should be under way from around 1st May. Look for short skip on 15 and 10m. More details about sporadic E and HF propagation can be found in Steve Nichols’ blog and Podcast at: http://g0kya.blogspot.com/
Summertime Sporadic E, or Es as it’s often referred to, is one of the most exciting VHF propagation modes. This is especially true when the MUF reaches 144 MHz. Below is a guide to Summertime Sporadic E, what to listen for and how to work the DX.
What is Sporadic E?
There are three layers to the ionosphere F, D and E. We all know about the importance of the F layer to HF propagation and the way in which it refracts radio waves making world wide communication possible. The D layer and the E layer play little part in this, indeed they can have a detrimental effect to HF conditions by absorbing the transmitted signal before it reaches the F layer. This is particularly true of the E layer when it is heavily ionised.
During the summer months from May to September but in particular June and July, very intense clouds of ionization can occur. While not good for HF it does mean that VHF signals can be refracted by these clouds allowing contacts way in excess of the normal VHF range.
The cause of this intense ionization is unknown and of course very sporadic in nature. But some aspects have a degree of probability and with careful monitoring of the VHF range a good indication of a likely opening can be gained. Openings are more likely to occur early in the morning, early afternoon and in the evening although they can occur at almost any time.
From http://g3vre.org.uk/ES.asp (Chippenham and District ARC)
Solar Cycle Prediction
The current prediction for Sunspot Cycle 24 gives a smoothed sunspot number maximum of about 69 in June of 2013. We are currently over two and a half years into Cycle 24. Two consecutive months with average daily sunspot numbers in the 50s has raised the predicted maximum above the 64.2 for the Cycle 14 maximum in 1907. The predicted size would make this the smallest sunspot cycle in over 100 years.
Predicting the behaviour of a sunspot cycle is fairly reliable once the cycle is well underway (about 3 years after the minimum in sunspot number occurs. Prior to that time the predictions are less reliable but nonetheless equally as important. Planning for satellite orbits and space missions often require knowledge of solar activity levels years in advance. (NASA Solar Physics) http://solarscience.msfc.nasa.gov/predict.shtml
Links to these articles and more can be found at: www.jameswelsh.org.uk
May began with sunspot numbers of 115 dropping to 110 for 5 days on the 6th, then by the end of May sunspot numbers had dropped to 105. The Boulder A and K indices have remained at their ‘norm’ of 5 and 2 during May, except for the 9th and 10th, with a peak of 15. May should finish with a rise to 15 once more.
Sunspot numbers in June should start at 105 but are likely to drop to as low as 92 by Jun 13. The A and K indices should peak at 12 and 4 by June 11th.
According to the trend charts at: http://www.solarham.com/sunspots.htm the predicted sunspot numbers were back to predicted levels during April but sunspot numbers are likely to have fallen back by the end of May. From: http://www.wm7d.net/hamradio/solar/27d_forecast.shtml
Maximum Usable Frequencies
The estimated MUF’s for Western Europe, are 4 MHz (0100-0400), 5 MHz (0500-0600), 6Mhz (0700-1000), 7 MHz (1100-1800), 6 MHz (1900-2200) and 5 MHz (2300-0000). (Times in UTC). This and other regional estimates can be found at: http://hfradio.org/fot_7.html
Sporadic E
The Sporadic E season should be under way from around 1st May. Look for short skip on 15 and 10m. More details about sporadic E and HF propagation can be found in Steve Nichols’ blog and Podcast at: http://g0kya.blogspot.com/
Summertime Sporadic E, or Es as it’s often referred to, is one of the most exciting VHF propagation modes. This is especially true when the MUF reaches 144 MHz. Below is a guide to Summertime Sporadic E, what to listen for and how to work the DX.
What is Sporadic E?
There are three layers to the ionosphere F, D and E. We all know about the importance of the F layer to HF propagation and the way in which it refracts radio waves making world wide communication possible. The D layer and the E layer play little part in this, indeed they can have a detrimental effect to HF conditions by absorbing the transmitted signal before it reaches the F layer. This is particularly true of the E layer when it is heavily ionised.
During the summer months from May to September but in particular June and July, very intense clouds of ionization can occur. While not good for HF it does mean that VHF signals can be refracted by these clouds allowing contacts way in excess of the normal VHF range.
The cause of this intense ionization is unknown and of course very sporadic in nature. But some aspects have a degree of probability and with careful monitoring of the VHF range a good indication of a likely opening can be gained. Openings are more likely to occur early in the morning, early afternoon and in the evening although they can occur at almost any time.
From http://g3vre.org.uk/ES.asp (Chippenham and District ARC)
Solar Cycle Prediction
The current prediction for Sunspot Cycle 24 gives a smoothed sunspot number maximum of about 69 in June of 2013. We are currently over two and a half years into Cycle 24. Two consecutive months with average daily sunspot numbers in the 50s has raised the predicted maximum above the 64.2 for the Cycle 14 maximum in 1907. The predicted size would make this the smallest sunspot cycle in over 100 years.
Predicting the behaviour of a sunspot cycle is fairly reliable once the cycle is well underway (about 3 years after the minimum in sunspot number occurs. Prior to that time the predictions are less reliable but nonetheless equally as important. Planning for satellite orbits and space missions often require knowledge of solar activity levels years in advance. (NASA Solar Physics) http://solarscience.msfc.nasa.gov/predict.shtml
Links to these articles and more can be found at: www.jameswelsh.org.uk
Saturday, 26 March 2011
April 2011
Propagation Summary
The Solar Flux has reached the100 mark for a total of 15 days during March peaking at 110 from the 13th to the 15th. The Solar flux trend charts at Solarcycle24.com are showing a sharp rise toward the predicted peak of 130 following the dip in mid February. April will start on a high of 100 which should last for around 10 days, peaking at 115 by the 18th. The Boulder A Index has remained fairly steady during March and should remain mostly at 5 during early April. The Boulder K index should stay mainly at 2 as it has done during March. Charts can be found at www.solarcycle24.com . A 28 day forecast from NOAA is updated daily at: http://www.wm7d.net/hamradio/solar/27d_forecast.shtml
Lyrid Meteor Shower
A Lyrid Meteor Shower is due from 19-24 April. However, any Meteor Scatter propagation will depend on where you are in the world. The best time of the year for MS DX’ing is between October and early January. More at: http://www.jt6m.org/meteor-scatter.php
Researchers Crack the Mystery of the Missing Sunspots (NASA Science News)
In 2008-2009, sunspots almost completely disappeared for two years. Solar activity dropped to hundred-year lows; Earth's upper atmosphere cooled and collapsed; the sun’s magnetic field weakened, allowing cosmic rays to penetrate the Solar System in record numbers. It was a big event, and solar physicists openly wondered, where have all the sunspots gone? Now they know. An answer has been published in the March 3rd edition of Nature. Plasma currents deep inside the sun interfered with the formation of sunspots and prolonged solar minimum," says lead author Dibyendu Nandi of the Indian Institute of Science Education and Research in Kolkata. "Our conclusions are based on a new computer model of the sun's interior." For years, solar physicists have recognized the importance of the sun's "Great Conveyor Belt." A vast system of plasma currents called ‘meridional flows’ (akin to ocean currents on Earth) travel along the sun's surface, plunge inward around the poles, and pop up again near the sun's equator. These looping currents play a key role in the 11-year solar cycle.
The Solar Flux has reached the100 mark for a total of 15 days during March peaking at 110 from the 13th to the 15th. The Solar flux trend charts at Solarcycle24.com are showing a sharp rise toward the predicted peak of 130 following the dip in mid February. April will start on a high of 100 which should last for around 10 days, peaking at 115 by the 18th. The Boulder A Index has remained fairly steady during March and should remain mostly at 5 during early April. The Boulder K index should stay mainly at 2 as it has done during March. Charts can be found at www.solarcycle24.com . A 28 day forecast from NOAA is updated daily at: http://www.wm7d.net/hamradio/solar/27d_forecast.shtml
Lyrid Meteor Shower
A Lyrid Meteor Shower is due from 19-24 April. However, any Meteor Scatter propagation will depend on where you are in the world. The best time of the year for MS DX’ing is between October and early January. More at: http://www.jt6m.org/meteor-scatter.php
Researchers Crack the Mystery of the Missing Sunspots (NASA Science News)
In 2008-2009, sunspots almost completely disappeared for two years. Solar activity dropped to hundred-year lows; Earth's upper atmosphere cooled and collapsed; the sun’s magnetic field weakened, allowing cosmic rays to penetrate the Solar System in record numbers. It was a big event, and solar physicists openly wondered, where have all the sunspots gone? Now they know. An answer has been published in the March 3rd edition of Nature. Plasma currents deep inside the sun interfered with the formation of sunspots and prolonged solar minimum," says lead author Dibyendu Nandi of the Indian Institute of Science Education and Research in Kolkata. "Our conclusions are based on a new computer model of the sun's interior." For years, solar physicists have recognized the importance of the sun's "Great Conveyor Belt." A vast system of plasma currents called ‘meridional flows’ (akin to ocean currents on Earth) travel along the sun's surface, plunge inward around the poles, and pop up again near the sun's equator. These looping currents play a key role in the 11-year solar cycle.
When sunspots begin to decay, surface currents sweep up their magnetic remains and pull them down inside the star; 300,000 km below the surface, the sun’s magnetic dynamo amplifies the decaying magnetic fields. Re-animated sunspots become buoyant and bob up to the surface like a cork in water. For the first time, Nandi’s team believes they have developed a computer model that gets the physics right for all three aspects of this process--the magnetic dynamo, the conveyor belt, and the buoyant evolution of sunspot magnetic fields. "According to our model, the trouble with sunspots actually began in back in the late 1990s during the upswing of Solar Cycle 23,"
Sunspot cycles of the last century
Links to these articles can be found at http://www.jameswelsh.org.uk/
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