Re: Crying in the wind
- From: Weatherlawyer <Weatherlawyer@xxxxxxxxxxx>
- Date: Sat, 7 Nov 2009 03:43:30 -0800 (PST)
On Nov 6, 4:27 pm, Alastair <a...@xxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
On Nov 6, 9:38 am, Weatherlawyer <Weatherlaw...@xxxxxxxxxxx> wrote:
Anyone with a lot more ability than me and of course access to the
exquisite willing to give me an hand with this:
Mountain Winds May Create Atmospheric Hotspots
WASHINGTON - Rapidly fluctuating wind gusts blowing over mountains and
hills can create "hotspots" high in the atmosphere and significantly
affect regional air temperatures. A research paper to be published
this month in the Journal of Geophysical Research-Space Physics
reports that the actions of such winds can create high-frequency
acoustic waves and could stimulate a 1000-Kelvin [1,000-degree
Celsius; 2,000-degree Fahrenheit] spike in a short period of time in
the thermosphere, at an altitude of 200-300 kilometers [100-200
miles]. Such exceptional temperature increases would require
continuous waves, and the heating rate would likely be diminished with
intermittent winds.
Ocean waves and earthquakes are known to produce similar waves, which
strengthen as they propagate higher in the atmosphere. The authors
speculate that the waves can heat the atmosphere at prodigious rates
and could account for a large part of the unusual and unexplained high-
altitude background heating seen above the mountainous landscape in
parts of South America.<<<<
[I'm looking at warm pool causes and want to get a little more
circumspection before dipping my feet in.]
"We show that that the acoustic waves generated by gusty flow over
rough terrain might be a significant source of heating in the upper
atmosphere," Hickey says. "These mysterious so-called 'hotspots'
observed above the Andes Mountains could be explained by such acoustic
wave heating."
Previous observations near the Andes Mountains in Peru had found that
the atmosphere directly above some peaks was approximately 100 Kelvin
[100 degrees Celsius; 200 degrees Fahrenheit] hotter than in nearby
regions and that the difference occasionally reached as much as 400
Kelvin [400 degrees Celsius; 700 degrees Fahrenheit].
[How does this sort of stuff redound? (Wild guesses accepted.)]
Other research had recorded similar effects near the Rocky Mountains
in Colorado. After comparing simulations of atmospheric gravity waves
and acoustic waves, the researchers found that the acoustic waves
reached higher altitudes than the gravity waves, leading them to
speculate that the acoustic waves constituted a far more plausible
source of the observed hot spots. They then identified wind
fluctuations as the most likely source of the heating, noting that the
upwind waves could only be generated by unsteady wind flow.
They cite further evidence indicating that the high- frequency
acoustic waves in the thermosphere originated from the ground,
including proof that nighttime atmospheric motion (convection) is not
a plausible source of the persistent heating. In addition, they note
that only high-frequency acoustic waves could cause the thermospheric
heating, as the slower-speed gravity waves are not fast enough to
reach the higher altitudes and therefore could not produce the
substantial effects at that height in the atmosphere.
The paper indicates that moderately strong winds, reaching speeds of
approximately 10 meters [30 feet] per second, can generate wave
amplitudes of nearly four meters [10 feet] per second above rough
terrain. In addition, the authors found that steeply sloping terrain
further enhanced the waves, which are generated by rapid variations in
the up-and-down turbulence in the air. Wider hills and those spaced
further apart can also have a similar wave- generating effect, but the
authors found that the wind effects typically do not propagate
vertically near isolated hills as they do around rougher terrain.
The researchers note that there are very few detailed field studies of
the wind field over hills at present. They report, however, that
models and previous research indicates that even weak interactions
from acoustic waves can produce significant effects in the
thermosphere.
[I'd always suspected that acoustic heating takes place on a larger
scale than is creditied in the eath's overall heat balance. Only I am
not subscribed to get PDFs and etc., from the satanic mills.
(Not that I'd have much success with the maths and et., etc.,)
Pease don't all shout at once, the balance of the earth being what it
is and the country so near to the Arctic and etc., etc.
You don't give a citation or even a link so it is not possible even
with access to find the PDF.
No apologies as this is what happens if you test the defences of some
of these turnips:
Journal of Atmospheric and Solar-Terrestrial Physics
Volume 71, Issues 8-9, June 2009, Pages 816-822
Font Size:
Rerun your search for "heat Acoustic waves generated by gusty flow
over hilly terrain " on ScienceDirect. Search
Abstract
Abstract - selected
Article
Figures/Tables
Figures/Tables - selected
References
References - selected
Purchase PDF (694 K)
Article Toolbox
E-mail Article
Add to my Quick Links
Cited By in Scopus (0)
Related Articles in ScienceDirect
Evidence for solar signals in the mesopause temperature...
Journal of Atmospheric and Solar-Terrestrial Physics
Evidence for solar signals in the mesopause temperature variability?
Journal of Atmospheric and Solar-Terrestrial Physics, Volume 69,
Issues 4-5, April 2007, Pages 431-448
Kathrin Höppner, Michael Bittner
Abstract
Nocturnal temperatures are almost continuously derived from OH* (3,1)
near-infrared emissions in the upper mesosphere (around 87 km) above
Wuppertal, Germany (51°N, 7°E) from ground-based measurements since
1980. The time series analyzed covers the time interval from 1980
until 2005 and consists of 4628 well documented night mean temperature
data. OH* temperature fluctuations on temporal scales of about 3–20
days are derived by removing seasonal and longer term trends from the
data record by means of applying various spectral analysis techniques
such as the harmonic analysis, maximum entropy method (MEM) and the
wavelet transform, respectively. The residuals are found to reflect
planetary wave activity.
Spectral intensity of oscillations in the 3–20 days regime shows a
longer term modulation peaking around 1981 and 1996, while minima are
encountered around 1986 and 2005. Thus, no conclusive correlation with
the solar F10.7 cm flux is found. Reasonable agreement of planetary
wave activity with the general solar bipolar magnetic field (22-year
Hale cycle) is found instead. Further agreement is found with the
variations of the length of the day (ΔLOD) implying that the internal
terrestrial magnetic field is superimposed by the solar magnetic field
(Hale cycle) causing modulations of the total magnetic field in the
Earth's interior and which leads—in turn—to a modulation of the
electromagnetic coupling of angular momentum between the Earth's core
and the Earth's mantle. As a result the Earth's rotation period Ω—and
thus the activity of planetary waves—should be modulated with the
solar magnetic flux, e.g. the quasi-22-year Hale cycle.
Planetary wave activity is further found to be modulated by a quasi-2-
year oscillation. The modulation is strongest around 1994/1995 and
lowest around 1988 and 2004, respectively. It is found that wave
activity is mostly enhanced when the wind direction of the mean zonal
wind of the equatorial quasi-biennial oscillation (QBO) reverses from
westerly to easterly.
Purchase PDF (1984 K)
Dependence of the energy budget at mesopause heights on...
Advances in Space Research
Dependence of the energy budget at mesopause heights on variable
circulation patterns
Advances in Space Research, Volume 17, Issue 11, 1996, Pages 111-116
U. Berger, A. Ebel
Abstract
The global energy budget of the mesopause region strongly depends on
the variable circulation patterns, controlling in particular the heat
transport. A better understanding of this dependence is desirable.
Regarding the complexity of the problem and the difficulties in
obtaining suitable measured data on a global scale numerical models
appear to be a convenient and necessary tool to approach the problem.
In this paper energy budget studies are presented employing a
mechanistic 3-d circulation model of the middle atmosphere (0–150 km).
Special attention is drawn to two terms of the mesopause heat budget:
the adiabatic heating by vertical motions and diabatic heating by eddy
heat fluxes. The model calculations show heating and cooling rates of
more than 100 Kelvin per day which can even occur at high latitudinal
regions due to the wave — mean flow interaction of stationary and
planetary waves. A high variability of the eddy heat fluxes in space
and time is found according to temporal and spatial changes of tidal,
gravity and planetary wave activity. The major component of mechanical
dissipation is contributed by gravity wave drag, which plays an
essential role in controling the strength and variability of the
circulation patterns at mesopause heights.
Purchase PDF (644 K)
Forcing of the ionosphere by waves from below
Journal of Atmospheric and Solar-Terrestrial Physics
Forcing of the ionosphere by waves from below
Journal of Atmospheric and Solar-Terrestrial Physics, Volume 68,
Issues 3-5, February 2006, Pages 479-497
Jan Laštovička
Abstract
Meteorological processes in the lower-lying layers, particularly in
the troposphere, affect the ionosphere predominantly through the
upward propagating waves and their modifications and modulations.
Those waves are planetary waves, tidal waves, gravity waves, and
almost forgotten infrasonic waves. A part of wave activity can be
created in situ at ionospheric heights as primary (e.g., diurnal tide,
gravity waves) or secondary waves (e.g., some gravity or planetary
waves), but this paper is focused on the upward propagating waves from
below the ionosphere. They propagate into the ionosphere mostly
directly but the planetary waves can propagate upwards to the F region
heights only indirectly, via various potential ways like modulation of
the upward propagating tides. The waves may be altered during upward
propagation via non-linear interactions, particularly in the MLT
region. A brief overview of effects on the ionosphere of upward
propagating waves from lower-lying regions is given, separately for
the lower ionosphere, for the E-region ionosphere, and for the F-
region ionosphere. The upward propagating waves of the neutral
atmosphere origin are important both from the point of view of
vertical coupling in the atmosphere–ionosphere system, and for
applications in radio propagation/telecommunications, as they are
responsible for a significant part of uncertainty of the radio wave
propagation condition predictions.
Purchase PDF (564 K)
Midlatitude mesosphere/lower thermosphere meridional wi...
Advances in Space Research
Midlatitude mesosphere/lower thermosphere meridional winds and
temperatures measured with meteor radar
Advances in Space Research, Volume 39, Issue 8, 2007, Pages 1278-1283
Ch. Jacobi, K. Fröhlich, C. Viehweg, G. Stober, D. Kürschner
Abstract
A meteor radar to measure hourly mean horizontal winds in the 80–100
km height range and daily temperatures near 90 km is operating at
Collm (51.3°N, 13°E) since summer 2004. Here we present changes of the
meridional wind jet in comparison with temperature fluctuations from
August 2004 to May 2006 at time scales of 11–30 days. Whereas in
summer no direct correlation between wind and temperature is visible,
the meridional circulation at 85 km in winter is positively correlated
and nearly in phase with temperatures, so that northward/southward
winds are generally accompanied by higher/lower temperatures. This
behaviour is in accordance with the dynamical forcing of mesopause
region temperatures, which is modulated by planetary waves, gravity
wave fluctuations and stratospheric warmings. Numerical modelling of
MLT planetary waves show that temperature oscillations at 90 km and
winds at 85 km due to those waves have a phase difference of several
days, so that planetary waves probably are not the reason for the
temperature/wind coupling.
Purchase PDF (803 K)
Detection of solar activity signatures in OH* temperatu...
Journal of Atmospheric and Solar-Terrestrial Physics
Detection of solar activity signatures in OH* temperature
fluctuations possibly related to the differential rotation of the Sun
Journal of Atmospheric and Solar-Terrestrial Physics, Volume 71, Issue
12, August 2009, Pages 1287-1292
Kathrin Höppner, Michael Bittner
Abstract
Measurements of the hydroxyl rotational temperatures at about 87 km
altitude above Wuppertal (51.3°N, 7.2°E), Germany, are analysed. The
time series covers the time interval from 1987 until 2005 and consists
of more than 4000 night mean temperature data. Seasonal and longer-
term trends are removed from the data set and OH* temperature
fluctuations on temporal scales of about 3–40 days are derived.
Various spectral analysis techniques (harmonic analysis, maximum
entropy method and wavelet transform) are applied. Can – due to the
Sun's rotation – the irregular pattern of sunspots on the solar disc
lead to OH* temperature fluctuations? Pronounced spectral components
in the OH* temperature fluctuations around a period from 27 to 31 days
are frequently observed. We tentatively attribute these signatures to
the differential rotation of the Sun: Sun's equatorial regions rotate
faster (taking only about 27 days) than the polar regions. Sunspots
occur at heliographic latitudes at about ±40°, which correspond to a
rotation rate of about 27–31 days. The OH* temperature fluctuations
within this period range show a long-term modulation of 11 years.
Thus, tracking the spectral intensity of the 27- to 31-day component
should allow the indirect monitoring of the solar sunspot cycle.
Purchase PDF (460 K)
View More Related Articles
View Record in Scopus
doi:10.1016/j.jastp.2009.03.008
Copyright © 2009 Elsevier Ltd All rights reserved.
Infrasound from tropospheric sources: Impact on mesopause
temperature?
References and further reading may be available for this article. To
view references and further reading you must purchase this article.
C. Pilger, a, and M. Bittnera
aGerman Aerospace Center (DLR-DFD), 82 234 Wessling, Germany
Received 20 October 2008; revised 12 February 2009; accepted 8 March
2009. Available online 20 March 2009.
Abstract
Three- to six-day oscillations in the mesopause temperature have been
observed all over the year. While these oscillations can be explained
by planetary wave activity in wintertime, their summertime appearance
is still under discussion.
One effect possibly contributing to such summertime oscillations in
the mesopause is acoustic heating. Infrasound generated by low-
pressure areas or thunderstorm cells propagates into the upper
atmosphere and deposits heat in this region. It is speculated that the
oftentimes about weekly variation of low-pressure areas due to
troposphere planetary wave activity is a potential source mechanism
for mesopause temperature oscillations through infrasound as a
transporting mechanism.
The modeling structure of infrasound propagation as well as of
acoustic heating is presented. It leads to the quantification of
expected temperature fluctuations and acoustic heating rates at the
mesopause height, which both appear to be too small to give a sole
explanation for the 3–6-day oscillation.
Keywords: Infrasound; Acoustic heating; Planetary waves; Mesopause
airglow
That's one off the bat but there was a recent one mentioned in the
Earth Observatory site not that I can find it without getting
sidetracked.
(A serious lump of my computer fell into my hands the other day. I am
pretty sure the copper on the back of the fan on a CPU is not supposed
to come away with it.
But what do I know?)
However, my reading is that the atmosphere, like the oceans, is a
fluid and so there are atmospheric tides. Just as the tidal range is
amplified by shelving sea beds, the atmospheric tides will be
amplified by mountains. The thermosphere is at the top of the
atmosphere (TOA), where it is heated by radiation from the sun. Thus
it is very hot anyway. Being at the TOA, that is where the atmospheric
waves break. If the Andes are creating a similar effect to that which
creates the Severn Bore, then the mixing of the upper thermospheric
air at 1000 C with lower thermospheric air at -100C would cause
dramatic rises in temperature.
No. Any tidal action will be restored in 6 to 12 hours by the laws of
motion etc.
It was about the effect of acoustics on the air. It seems that
channeling and reverberation of certain frequency (modulations?) has
an heating effect.
Anothe rchap is busy working on the way that seismic waves ignored as
background can denote mised storm records. It's na handy way to build
a database back into the past.
I'm temepted to tell him the rest of it too. But I thought first, I'd
pep up my own background knowledge as far as I can.
.
- References:
- Crying in the wind
- From: Weatherlawyer
- Re: Crying in the wind
- From: Alastair
- Crying in the wind
- Prev by Date: Re: C.Booker.The real Global etc....
- Next by Date: Re: C.Booker.The real Global etc....
- Previous by thread: Re: Crying in the wind
- Next by thread: Re: Crying in the wind
- Index(es):
Relevant Pages
|
