[HCDX] KN4LF 7 Day MF RX Prop Outlook #2002-26

["Thomas Giella, KN4LF" <kn4lf@xxxxxxxxxxxxxxx>]

KN4LF 7 Day Medium Frequency Radio Propagation Outlook #2002-26
Published 2:00 PM EDT 02/09/29 For 02/09/30-02/10/06.

Though this outlook is aimed primarily at medium frequencies, virtually all
the following propagation data is applicable to HF frequencies.

This 7 day medium frequency (300-3000 kc) propagation outlook and other
solar, space weather and propagation data can be found on my website at:
http://www.kn4lf.com/kn4lf5.htm .

Also for my subscribers interested in tropical cyclones I have a website
called 2002 FMCI Florida Region Daily Tropical Discussion which is at:
http://www.kn4lf.com/sub/fmci5.htm . that might be found of interest.

Due to the international scope of the Amateur Radio/SWL radio community I
have adopted the date format of yy/mm/dd.


REVIEW-
The week of 02/09/23-02/09/29 was very quiet considering that we are now
just past the Fall/Spring Equinox. Also MF radio propagation conditions were
very good, the best in a long time, HF too.


ENERGETIC PROTON FLUX-

During the previous seven day period no >10 MeV (10+0) energetic proton
event occurred.

During the new outlook period the probability of an elevated energetic
proton flux event >10 MeV (10+0) is placed at 30%.


An elevated energetic proton flux level greater then (10+0) on 160 meters
and greater then (10-1) on the medium frequency broadcast band creates
noticeably increased winter time day and year round night time D layer
absorption of medium wave frequencies, especially on high latitude
propagation paths but it can also negatively impact mid latitudes, depending
on the intensity of the event. Elevated energetic proton events too small to
be categorized as a Polar Cap Absorption event (PCA) can still impact high
and mid level medium frequency propagation paths in the form of excessive D
layer absorption. This fact is still stubbornly opposed by some otherwise
very knowledgeable space weather physicists over dependent on threshold
Riometer readings.

((((Note, high latitude medium frequency radio propagation paths can still
be disturbed for days and up to weeks, following the end of an official >10
MeV (10+0) proton event.))))



SOLAR FLUX-

During the previous 7 day period the daily solar flux values ranged between
162 and 136.

During the new outlook period the daily solar flux values should range
between approximately 200 and 130.
-----
NOTICE!!! During the outlook period F-1/2 layer propagation openings on 6
meters are improbable. However daily solar flux values may support some F2
layer propagation during the week of October 7-14, 2002.
-----
Occasional auroral propagation is probable, with Sporadic E (Es) and Trans
Equatorial Scatter (TEQ) openings also probable.

During the previous 7 day period the background X-ray flux levels ranged
between C1.3 and B4.8.


Elevated background X-ray flux levels can impact propagation of medium
frequency signals in a negative manner. Background X-ray flux levels of C2
or greater creates increased D-layer absorption of 160 and 120 meter signals
and C1 or greater creates increased D-layer absorption of AM broadcast band
signals.

High solar flux values are generally considered to be detrimental to
propagation of medium frequency signals both domestic and Trans Atlantic
(TA) & Trans Pacific (TP), as more absorption can be present via the
transmitted signals' two trips through the D layer at the takeoff and
arrival points.

Most "strong" longer haul medium frequency DX signals in excess of 3000
miles is via the E Valley-F layer ducting and/or Chordal Hop propagation
modes. Therefore high solar flux values can aid in long haul medium
frequency propagation paths in excess of 3000 miles, as a high solar flux
value ensures a strong F layer part of the E Valley-F layer duct or Chordal
Hop propagation mechanism.

However high solar activity in the form of increased ionization created by
Ultraviolet and X-Ray radiation can fill in the E Valley region and
interfere with the E Valley-F layer ducting mechanism. In a sense the E
Valley-F layer duct is closed on one or both ends of a propagation path and
the transmitted MF RF signal only propagates between the E layer and
land/ocean surface, with a higher angle and more loss.



SUNSPOT REGIONS/SOLAR FLARES-

During the previous 7 day period three M class and to strong C class solar
flares occurred.

The largest was a M2.7 solar flare which occurred at 0634-0644 UTC on
02/09/29.

Sunspot region #10134 located at N11E15 contains a beta-gamma-delta class
magnetic signature and harbors energy for medium sized M class solar flares
and also possibly isolated huge X class solar flares.

During the outlook period I place the chance of a C class solar flare at
100%, an M class at 50% and an X class at 30%.


An earthward facing C4 or higher class solar flare "can" elevate the proton
flux above 10 MeV (10+0) and initiate large scale high and mid latitude
propagation path absorption on the AM broadcast band, 160 and 120 meters,
both stateside and DX, as a transfer of increased density and RF signal
absorption from the day side D layer to night side of the ionosphere occurs
through high level neutral winds. Unfortunately even smaller C3 solar flares
can create hour to hour and night to night variations in signal strength on
medium frequencies.

High and mid latitude Trans Atlantic (TA) and Trans Pacific (TP) propagation
paths tend to open up after a significant period of time passes without an
elevated energetic proton event of >10 MeV (10+0). This fact is still
stubbornly opposed by some otherwise very knowledgeable space weather
physicists over dependent on threshold Riometer readings.

Openings also occur when the solar background x-ray level falls back to or
below C1 for 160 and 120 meters and B9 for the AM broadcast band.



CORONAL MASS EJECTIONS/IONOSPHERIC STORMS/VISIBLE AURORA-

During the previous 7 day period no geo-effective (Earth facing) Coronal
Mass Ejection (CME) impacted the Earth. However numerous non geo-effective
(Earth facing)CME's did occur.

During the previous 7 day period our planet did not encounter a Solar Wind
Stream flowing from a geo-effective (Earth facing) coronal hole.

During the new outlook period a geo-effective (Earth facing) Coronal Hole
and related Solar Wind Stream is expected beginning on 02/09/29-30.

During the outlook period the probability of a geo-effective (Earth facing)
Coronal Mass Ejection (CME) is placed at 20%.

During the outlook period the probability of unsettled (Kp-3) to active
(Kp-4) geomagnetic conditions is placed at 40%.

During the outlook period the probability of at least a moderate ionospheric
storm (Kp-5)(G1) is placed at 30%.

During the outlook period the probability of a visible mid latitude Aurora
display is placed at 30%.

At 1800 UTC on 02/09/29 the Bz is 1.6 nt south.

The Wang-Sheeley Interplanetary Magnetic Field (IMF) Model which predicts
Earth's IMF polarity, forecasts a positive polarity from 02/09/29-02/10/06.


When the polarity of the IMF is negative a visible mid latitude Aurora
display is likely when a CME strikes the Earth's magnetic field. When the
polarity of the IMF is positive a visible mid latitude Aurora display is
unlikely as a CME strikes the Earth's magnetic field.

A Coronal Mass Ejection is the name given to an ejection of a large amount
of matter from the Sun's outer atmosphere or corona. These ejections
typically comprise millions of tons of material in the form of charged
particles, and can be seen because the material reflects sunlight. When one
of these ejections is directed towards the Earth (or conversely, directly
away from the Earth), it looks like a roughly circular "halo" surrounding
the Sun.

The "Halo CME's" then are those CME's which are more likely to impact the
Earth than those which are shot out at right angles to the Earth-Sun line.
Energetic protons emitted during CME's play a major role in increased day
time and night-time D-layer absorption of mediumwave frequencies.

Coronal Mass Ejections were once thought to be completely initiated by solar
flares. However it is now known that many (CME's) are not associated with
Solar Flares. If a (CME) collides with the Earth, it can excite a
Geomagnetic Storm if the polarity of the IMF has a negative sign. We must be
vigilant in watching for geoeffective (CME's), in order to not be caught by
surprise with a seemingly sudden and unexpected Geomagnetic Storm.

As the Kp index reaches 3-4, the aurora oval begins expanding equatorward in
magnetic latitude and
generally begins having a negative impact on high latitude medium frequency
propagation paths. A Kp index of 5 or higher begins to have a negative
impact on high latitude high frequency shortwave propagation paths. However
at times skewed path propagation conditions can compensate for high latitude
propagation path auroral absorption.


STRATOSPHERIC WARMING-

During the outlook period increased winter like day and year round night
time D layer absorption of medium frequency signals tied to stratospheric
warming in the northern hemisphere is possible.


Stratospheric warming is a major temperature change of the winter time polar
and middle atmosphere from the tropopause (where the troposphere transitions
into the stratosphere) to the base (D-layer) of the ionosphere, lasting for
many days at a time and characterized by a warming of the stratospheric
temperature by some tens of degrees (temperature inversion).

As the stratosphere lies below the ionosphere, which is at mesosphere and
thermosphere height, you would not expect to see stratospheric warming
effect medium frequency propagation in any way BUT medium frequency signals
do refract off of temperature inversions and moisture discontinuities and a
temperature inversion is involved with stratospheric warming. So it's
possible that a medium
frequency signal could do any number of things when refracting off of a
temperature inversion, at any height.

Also stratospheric warming (STRATWARM) has a negative effect on medium
frequency propagation, due to increasing medium frequency radio wave
absorption by the D layer, via upward propagating Internal Gravity Waves
(IGW).

Also I have observed that stratospheric warming usually coincides with major
jetstream circulation pattern changes and movement of Arctic air masses from
Siberian Russia across the pole to Canada and the U.S.

This phenomenon also occurs in southern hemisphere winter but seems to be
less pronounced.



7 DAY FORECAST OUTLOOK-

As we are at the fall/spring equinox propagation conditions are more
balanced in both hemispheres but as is the norm geomagnetic activity
increases.

During the previous 7 day period MF propagation conditions were very good,
probably better then all of the 2001-2002 DX season.

During the outlook period very good MF propagation conditions should
continue.


Expect very good domestic propagation conditions in the northern hemisphere
out to approximately 1050 miles.

Expect very good domestic propagation conditions in the southern hemisphere
out to approximately 1050 miles.


"High latitude" northern hemispheric (TA) Trans Atlantic, (TP) Trans Pacific
and cross equatorial propagation conditions in excess of approximately 3000
miles should be good.

"High latitude" southern hemispheric (TA) Trans Atlantic, (TP) Trans Pacific
and cross equatorial propagation conditions in excess of approximately 3000
miles should be good.


"Mid latitude" northern hemisphere (TA) Trans Atlantic, (TP) Trans Pacific
and cross equatorial propagation conditions in excess of approximately 3000
miles should be good to very good.

"Mid latitude" southern hemisphere (TA) Trans Atlantic, (TP) Trans Pacific
and cross equatorial propagation conditions in excess of approximately 3000
miles should be good to very good.


"Low latitude" northern hemisphere (TA) Trans Atlantic, (TP) Trans Pacific
propagation conditions in excess of approximately 3000 miles should be very
good.

"Low latitude" southern hemisphere (TA) Trans Atlantic, (TP) Trans Pacific
propagation conditions in excess of approximately 3000 miles should be very
good.


There will be "moderate to high" lightning induced QRN levels in mid and low
latitude areas of the northern hemisphere tied to warm and cold season
thunderstorms, tropical systems, cold/warm fronts and extra-tropical low
pressure systems during the forecast period.

There will be "moderate to high" lightning induced QRN levels in mid and low
latitude areas of the southern hemisphere tied to warm and cold season
thunderstorms, tropical systems, cold/warm fronts and extra-tropical low
pressure systems during the forecast period.

High to moderate lightning induced QRN will continue in the vicinity of the
tropical ITCZ and across equatorial regions.

73,
Thomas Giella, KN4LF
Plant City, FL, USA

KN4LF 160 Meter Amateur Radio Resources:
http://www.kn4lf.com

KN4LF Daily Solar Space Weather Geomagnetic Data Plus
MF Propagation Outlook:
http://www.kn4lf.com/kn4lf5.htm

FL Meteorological & Climatic Institute:
http://www.kn4lf.com/sub/fmci.htm

FMCI 2002 FL Region Daily Tropical Discussion:
http://www.kn4lf.com/sub/fmci5.htm




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