[160m] Medium Wave Propagation Outlook #2002-2

[KN4LF, Thomas Giella]

Outlook #2002-2 Published 4:00 PM EST 01/14/02 For 01/15/02-01/21/02

PROTON FLUX-

Per our previous outlook, a short duration >10 MeV (10+2)  proton event
began on 01/10/02 at approximately 2045 UTC, peaked at 91 pfu on 01/11/02 at
approximately 0530 UTC and ended on 01/13/02 at 1425 UTC.

A proton flux level above 10 MeV (10+1) creates elevated D absorption on
medium wave frequencies.

SOLAR FLUX-

Also per our previous outlook, solar flux values finally fell below 200 for
the first time since 08/19/01, bottoming out at 188 on 01/07/02.
Unfortunately it has rapidly risen above 200 again, sitting at 241 on
01/13/02. A daily solar flux peak as high as 270 is possible in intervening
days, which would be a boon to 6 meters ops. looking for F2 propagation
openings.

High solar flux values are generally considered to be detrimental to
propagation of medium wave signals both domestic and TA/TP, as more
absorption can be present via the transmitted signals two trips through the
D layer. Most long haul medium wave DX signals in excess of 3000 miles is
via the E/F layer ducting and/or E valley propagation modes. Therefore high
solar flux values can aid in long haul medium wave propagation paths in
excess of 3000 miles, as a high solar flux value ensures a strong E and F
layer duct mechanism. However high solar activity in the form of increase
ionization created by ultraviolet and x-ray radiation can fill in the E
Valley region and interfere with the E/F layer ducting mechanism. In a sense
the E/F layer duct is closed and the transmitted RF signal only propagates
between the E layer and land/ocean surface, with a higher angle and more
loss.

SUNSPOT REGIONS-

Solar region #'s 9773, 9775 and
9778 contain twisted delta class magnetic fields and are our best bet for
large M5 class or higher proton solar flares in coming days. Actually these
two regions are capable of huge X1 or larger proton emitting solar flares.

All other solar regions are quiet and stable or slowly growing or decaying
at this moment.

SOLAR FLARES-

I place the likelihood of an M 1-4 class solar flare at 100%, an M5 class or
higher solar flare at 90% and X1 class or higher solar flare at 60% during
the upcoming 7 day outlook period.

A day side earthward bound M5 or higher class solar flare will move the
proton flux above 10o (10 MeV) and initiate large scale high latitude
propagation path absorption but even smaller M4 class flares and weaker,
including C7-4 flares are the culprit behind night to night variations in
signal strength on the AM broadcast band and 160 meters, both stateside and
DX. 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.

GEOMAGNETIC INDICES-

Per our previous outlook, the geomagnetic Kp index was elevated to a level
of 4 at times, with a peak of 5 during the previous 7 day period, as the
Earth entered a high-speed solar wind stream flowing from a coronal hole on
the Sun. No coronal holes are currently approaching geoeffective positions
but a renewed elevation of the Kp index above 4 is probable by 01/16/02 due
to a probable earth directed CME, ejected by an M4+ class solar flare
earlier today.

As the Kp index reaches 3 or higher, the aurora oval regions begin expanding
equatorward in magnetic latitude and generally begin have a possible
negative impact on mediumwave propagation. A Kp index of 5 or higher begins
to have a negative on high frequency shortwave propagation.

If the path over which you are communicating lies along or inside one of the
auroral ovals, you will experience degraded propagation in one of several
different forms: strong signal absorption, brief periods of strong signal
enhancement, which is mainly caused by tilts in the ionosphere that allow
signals to become focused at your location or very erratic signal behavior
in the form of strong and rapid fading, etc., caused by a variety of effects
such as multipathing, anomalous and rapid variations in absorption,
non-great-circle propagation, and polarization changes.

STRATOSPHERIC WARMING-

There is currently no stratospheric warming taking place. However with
Arctic air on the move again in coming days across the north pole from
Siberian Russia to North America during the period, some increased D layer
absorption of signals caused by the stratospheric warming will probably
occur. Sporadic E  (Es) propagation is also possible.

As the stratosphere lies below the ionosphere, which is at mesosphere and
thermosphere height, you might not normally expect to see stratospheric
warming effect the AM broadcast band and 160 meter propagation in any way
BUT mediumwave frequency signals do refract off of temperature inversions
and moisture discontinuities and  temperature and moisture inversions are
involved with stratospheric warming. So it's possible that a mediumwave
signal signal could do any number of things when refracting off of a
temperature inversion, at any height.

Just as the E layer is the main refraction medium for medium wave signal
propagation within approximately 3100 miles, so is Sporadic E (Es). Like
stratospheric level warming and tropospheric level temperature and moisture
discontinuities, Sporadic E can depending on the circumstances absorb, block
and refract medium wave RF signals in an unpredictable manner.

OUTLOOK-

The bottom line for the next 7 days?

Due to the growing mid winter anomaly expect fair to good stateside
propagation on the AM broadcast band and good on 160 meters out to
approximately 3000 miles.

High latitude (TA) Trans Atlantic and (TP) Trans Pacific propagation  will
be poor on the AM broadcast band and fair on 160 meters. improving to fair
on the AM broadcast band and good on 160 meters, barring any sudden proton
event.

Most stateside AM broadcast band frequencies will contain co-channel North
and Central/South American stations, with South American stations dominating
at times.

There will also be some occasional lightning induced QRN across the northern
hemisphere, with an endless series of winter time approaching cold fronts
and surface extra-tropical low pressure systems.






73,
Thomas Giella, KN4LF

Plant City, FL
Grid Square- EL88wx
CQ Zone 5
ITU Zone 8

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

Florida Meteorological & Climatic Institute:
http://64.176.157.9/sub/fmci.htm

Giella Website Designs:
http://www.giellawoodsignandwebsitedesigns.com


---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.314 / Virus Database: 175 - Release Date: 1/11/02