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#846784 - 16/03/2010 17:33 Re: Observations of climate variation [Re: aerology]
apocalypse Offline
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Registered: 22/02/2007
Posts: 1838
Loc: Wagga Wagga NSW
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#855531 - 28/03/2010 16:55 Re: Observations of climate variation [Re: apocalypse]
Surly Bond Offline
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Registered: 23/08/2003
Posts: 2193
Loc: Manilla, near Tamworth NSW
Subsoil Temperature Cycles


At Manilla subsoil temperature does not relate to air temperature quite as one might expect. Soil temperature lags well behind air temperature from March to August, then moves in lock-step from September to February (Even the "bump" in October temperature is seen in both.).
In spring and summer soil temperature (at 750 mm) is very close to daily mean air temperature; in autumn and winter soil temperature is about four degrees above it.

There is a seasonal lag.
This makes the minimum temperatures occur later than the winter solstice and maximum temperatures occur later than the summer solstice. Manilla has the pattern noted in Wikipedia:
"In mid-latitude continental climates, [the lag] is approximately 20-25 days in winter and 25-35 days in summer."
To judge by Wikipedia, Manilla's winter lag is unusually short.

Manilla's winter lags are:
Daily max: 17 days;
Daily mean: 19 days;
Daily min: 22 days;
Subsoil (750); 33 days.

Manilla's summer lags are:
Daily max: 31 days;
Daily mean: 35 days;
Daily min: 42 days;
Subsoil (750); 46 days.

For air temperatures, these summer lags are close to 1.9 times winter lags.
For subsoil temperature, the summer lag is only 1.4 times the winter lag.


These are the 11-year records of monthly mean air temperature and subsoil temperature for Manilla.
Peaks on the two curves almost coincide. Generally the subsoil peaks are a little higher. February 2007 is much higher; February 2005 is lower. Subsoil troughs are generally four degrees warmer than mean temperature troughs. In July 2007 the subsoil was six degrees warmer; in August 2005, only two degrees warmer.

I have fitted linear trend lines to the traces. In this time-frame, the subsoil temperature is about two degrees higher than mean air temperature. I don't know of a ready explanation.
The trends also differ. The mean air temperature is rising at about one degree in 75 years, in line with global figures. The subsoil temperature is rising at only half that rate: about one degree in 150 years.

Could the air temperature be trying very hard to catch up with the subsoil temperature?


Notes
I measure subsoil temperature at 750 mm depth in a lithosol on weathered shale. The site slopes west at about 10%. It is five metres west of the house, and is partly shaded by white box trees and shrubs. The sensor/transmitter is an "Ewig" housed at ground level, with a wire to depth in a plastic conduit, and a radio link to the house. The receiver stores maximum and minimum values. When I read these daily, the values rarely differ as much as 0.3 degrees.
Clearly, at this site the daily temperature cycle is almost damped out at a depth of 750 mm.
Data begin 27/5/05. Data before that date are estimates based on Gunnedah Soil Research Stastion readings at 500 mm, with corrections for zero error, range, and lag.
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#856013 - 30/03/2010 12:52 Re: Observations of climate variation [Re: Surly Bond]
Surly Bond Offline
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Registered: 23/08/2003
Posts: 2193
Loc: Manilla, near Tamworth NSW
Subsoil Temp Anomalies vs. Max Air Temp Anomalies

Sometimes smoothed subsoil temp anomalies follow smoothed max air temp anomalies with a month or two of lag. Sometimes there is no lag. Sometimes the subsoil does not respond.


A cooling loop from September 1999 reached min air temp in December 1999 and minimum subsoil temp a month later. Subsoil and air warmed together until October 2000, when subsoil temp hardly changed in the 16 months to February 2002. The warming loop then resumed, reaching max air temp in October 2002 (drought) and max subsoil temp a month later. The loop continued with cooling to min air temp in May 2003 and min subsoil temp three months later. A series of small loops ended with slightly low subsoil temps and slightly high air temps by December 2005.


For four months from January 2006 subsoil temp anomaly did not change while air temp anomaly fell. A very big loop then began, with max air temp anomaly in December 2006 and an extremely high subsoil temp anomaly (+1.80) three months later in March 2007. In the thirteen months to April 2008 the subsoil temp anomaly fell dramatically by 2.9 degrees to -1.09. This followed two months after the very low minimum in the air temp anomaly of February 2008.
A linear increase in both air and subsoil anomalies prevailed from May 2008 to June 2009. Since then, a swing to very high air temperature and down again has not been reflected in subsoil temperatures.

Very large swings in temperature anomalies must surely stress plants that are adapted to particular localities. Broadly, a temperature difference of three degrees is like a latitude difference (in Australia) of five degrees (600 km) or an altitude difference of 500 metres. Some trees thrive only in a zone as narrow as that.
This graph shows that Manilla has just swung from a negative anomaly in daily maximum temperature of -1.4 in February 2008 to a (provisional) +2.3 in November 2009, a rise of 3.7 degrees. Perhaps the plants are equally affected by subsoil temperature. In this case the corresponding swing in subsoil temperature was only about 1.9 degrees. However, the smaller down-swing in daily maximum temperature anomaly of 2.2 degrees during the year 2007 was accompanied by the very serious down-swing of 2.9 degrees in subsoil temperature anomaly.
Certainly, I was unaware that such a large down-swing in subsoil temperature anomaly had occurred during 2007, I wonder if anyone else noticed it, or found unusual evidence of stress in plants at that time.
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#856424 - 31/03/2010 17:25 Re: Observations of climate variation [Re: Surly Bond]
Surly Bond Offline
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Registered: 23/08/2003
Posts: 2193
Loc: Manilla, near Tamworth NSW
March 2010 Update
Smoothed monthly climate anomalies for Manilla NSW


These four graphs update similar plots in recent posts.

Each month is marked by a diamond, but each January is marked by a larger square. Solid red symbols mark values that are smoothed using a gaussian window of half-width 6 months. Uncoloured symbols mark values for the latest six months, which are smoothed with progressively narrower windows, until the final month's value is not smoothed at all.

1. The anomaly of maximum daily temperature appears on the x-axis of each graph. On earlier graphs the values for November and December 2009 had exceeded +2.0 degrees, but increased smoothing has now brought them lower. Anomalies for the months of 2010 are closer to zero. THE HEAT WAVE IS OVER!

2. Rainfall anomalies paused at rather high negative values during the summer (i.e. SUMMER WAS RATHER DRY). The raw data point for March is more negative (little rain), but it is not clear whether the trend is up or down.


3. Cloudiness anomalies remained strongly positive through the last thirty months. And it's STILL VERY CLOUDY!


4. Humidity (Dew Point) anomalies rose quite rapidly after a low value in October 2009. It's HUMID AGAIN!


5. The subsoil temperature anomaly failed to rise with maximum air temperature anomaly from June to November 2009. The two anomalies now seem to be falling together back down the line of the rising trends of early 2009.

Notes
These graphs show only data for the last 36 months; long enough to include one climatic cycle. As in much of Australia, Manilla's climate variation is dominated by "Quasi biennial oscillations" named by Barrie Pittock in 1971. Wasyl Drosdowsky uses the Three-Letter-Acronym "QBO". In the full version of
this paper he uses spectral analysis to show that cycles in the two to three year range are important in Australian regional climates, as they are in the Southern Oscillation record.
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#858512 - 11/04/2010 23:38 Re: Observations of climate variation [Re: Surly Bond]
Surly Bond Offline
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Registered: 23/08/2003
Posts: 2193
Loc: Manilla, near Tamworth NSW
The Quasi-biennial oscillation (QBO)

Why hasn't anyone chipped me on my ignorance about this subject?

Here it is in Wikipedia:
http://en.wikipedia.org/wiki/Quasi-biennial_oscillation

"The QBO (quasi-biennial oscillation) is a quasi-periodic oscillation of the equatorial zonal wind between easterlies and westerlies in the tropical stratosphere with a mean period of 28 to 29 months."

It seems that Pittock and Drosdowsky are simply referring to Australian observations of a known phenomenon.

Me too.
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#859739 - 19/04/2010 23:55 Re: Observations of climate variation [Re: Surly Bond]
Surly Bond Offline
Weatherzone Addict

Registered: 23/08/2003
Posts: 2193
Loc: Manilla, near Tamworth NSW
Smoothed monthly anomalies of daily temperature range

In these plots, I have labelled climates with the widest daily temperature ranges as "Extreme". Extreme climates with the lowest daily max temperature anomalies are "Cold Extreme" climates, as in Siberia; extreme climates with the highest daily max temperature anomalies are "Hot Extreme" climates, as in the Sahara.
Climates with the narrowest daily temperature ranges are labelled "Equable". Equable climates with the lowest daily max temperature anomalies are "Cold Equable" climates, as in Macquarie Island; equable climates with the highest daily max temperature anomalies are "Hot Equable" climates, as in the central Pacific Ocean.

In the first plot, daily temperature range anomaly tends to relate linearly to daily maximum temperature anomaly, with slope 1:1. This pattern prevails from April 2000 to December 2005. Clockwise loops show that temperature range anomaly leads max temperature anomaly by one to six months.
In the drought of August-September 2002, the climate approached "Saharan", and then rapidly swung towards the "Macquarie Island" type eight months later.
The nearest approach to the "Siberian" type was in November 2001 (also December 1999) when the temperature range anomaly was 0.8 degrees higher than the maximum temperature anomaly.

In the second plot, the linear relation is only intermittent. Positive temperature range anomalies are now much smaller (+0.8 vs. +1.2) and negative anomalies much larger (-1.1 vs. -0.6). The large negative temperature range anomalies came with low max temperatures, making the climate approach the cold equable "Macquarie Island" type. This persisted from June 2007 to January 2008, and from September to November 2008.
As in the first plot, temperature range anomalies 0.8 degrees above max temp anomalies ("Siberian" type) occur: in May 2006 and March 2008.
In a new development for this data set, a swing to high temperature has not brought a high temperature range: the climate is as close to the hot equable "Pacific" type as to the hot extreme "Sahara" type. In June 2009 the temperature range anomaly fell to 0.8 degrees below the max temperature anomaly. This relation seems to have prevailed to the present time.


Note.
I have realised that these graphs are parametric plots. Each of the two variables plotted is a function of the parameter: Time. The curves track the parameter, and I have labeled noteworthy values of the parameter.
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#860161 - 22/04/2010 11:58 Re: Observations of climate variation [Re: Surly Bond]
Surly Bond Offline
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Registered: 23/08/2003
Posts: 2193
Loc: Manilla, near Tamworth NSW
Smoothed minimum vs. maximum temp anomalies

These parametric plots compare anomalies of daily minimum temperatures with those of daily maximum temperatures. This data was included in previous non-parametric plots in Post #3782 (9/9/09), but these parametric plots clarify the leads and lags between maxima and minima.

In the latest Post, #859739, "extreme" climates, with wide temperature ranges were at the top of the parametric plots, and "equable" climates with narrow temperature ranges were at the bottom but, in the plots of this Post, "extreme" climates and "equable" climates are at the bottom left and top right, separated by a 1:1 trend line on which daily maxima and daily minima move together and the daily temperature range anomaly remains normal.

The first plot (1999-2005) shows temperature anomalies moving close to the 1:1 trend line for much of the time. The exception is the cycle in and out of the 2002 drought. This forms an anti-clockwise loop that is almost circular. After temperature anomalies both reached a low point in October 2001, minima did not rise as rapidly as maxima until, from April to June 2002, minima were not rising at all. During the drought peak, from July to September 2002, maxima and minima rose together, but with the anomaly of minima now 1.2 degrees lower than that of maxima. (That is, the daily temperature range was 1.2 degrees wider than normal: an "extreme" climate.)
From October 2002, the daily minimum anomaly fell much more slowly than the daily maximum anomaly, moving to an "equable" climate by April 2003, and then the daily maximum anomaly stayed the same for four months while the daily minimum anomaly fell, returning the plot to the 1:1 trend line by August 2003.

In the second plot, the year 2006 had max and min temperature anomalies falling, then rising again along a steeper trend line. This had the effect of moving the climate towards "extreme" in May 2006 (the month with lowest anomalies) and back again. In the first half of 2007, maximum anomalies fell steadily from a peak in January, while minimum anomalies peaked in April. After June 2007, anomaly values fell in a period of "equable" climate as noted in the previous post. The lowest anomalies of the decade came in February 2008 for daily max (-1.41) and in March 2008 for daily min (-0.92). Since then, apart from an excursion towards "equable" climate in October 2008, daily max and daily min anomalies have risen together to decade record high values, perhaps peaking in November 2009.
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#860240 - 22/04/2010 21:54 Re: Observations of climate variation [Re: Surly Bond]
Surly Bond Offline
Weatherzone Addict

Registered: 23/08/2003
Posts: 2193
Loc: Manilla, near Tamworth NSW
Time-sequence of climate indicators

As the climate at Manilla goes through a quasi-biennial oscillation of "droughts and flooding rains", the anomaly values of various climate indicators reach maximal or minimal peaks that are more-or-less in step.
A "drought" peak has maximal values of Daily Max Temperature, Daily Min Temperature, Daily Temperature Range, and Subsoil Temperature, and minimal values of Rainfall, Cloud, and early morning Dew Point.
A "flooding-rains" peak has these minimal and maximal values reversed.

However, the indicators reach peaks at somewhat different times. In this short record a typical sequence seems to be as follows:

For a "drought" peak:
First: Daily Temperature Range (max);
One month later: Rainfall (min), Cloud (min);
Two months later: Daily Max Temperature (max), Dew Point (min);
Four months later: Daily Min Temperature (max), Subsoil Temperature (max).

For a "flooding-rains" peak:
First: Daily Temperature Range (min);
One month later: Rainfall (max), Cloud (max);
Two months later: Daily Max Temperature (min), Dew Point (max);
Four months later: Daily Min Temperature (min), Subsoil Temperature (min).

As mentioned in Post #810237, it makes sense that a peak of Daily Max Temperature should follow after a trough in Rainfall, and a trough of Daily Max Temperature should follow after a peak in Rainfall as a result of changed evapotranspiration.

To me, the real surprise in this pattern is that the very first indicator to reach a peak (maximal or minimal) is the Daily Temperature Range.

What could cause that?

I am also surprised that the Dew Point peak (maximal or minimal) comes so late. I would have expected increased humidity to be a pre-condition for increased rainfall or cloudiness. Perhaps early morning Dew Point, measured near the ground, is a consequence of the developing extreme state of evapotranspiration rather than a measure of the prior humidity of the incoming air mass.
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#861249 - 01/05/2010 00:02 Re: Observations of climate variation [Re: Surly Bond]
Surly Bond Offline
Weatherzone Addict

Registered: 23/08/2003
Posts: 2193
Loc: Manilla, near Tamworth NSW
Manilla Smoothed Monthly Anomalies of Climate Variables
Parametric Plots

Update for April 2010

Notes.
These Parametric Plots show anomalies of climate variables observed at Manilla NSW in the last 36 months. Anomaly values are smoothed using a gaussian window of half-width 6 months. The last six values are smoothed with progressively narrower windows, until the last month is a raw value.
Earlier plots had y-axes with positive anomaly values always at the top. Now the plots all have values related to "drought" at the top, on the right side. Negative anomaly values are now at the top for Rainfall, Cloud, and Dew Point.
Fully smoothed data points are marked with red diamonds. Open diamonds mark points smoothed with a narrower window. An orange diamond marks the latest (raw) data value. Blue diamonds are extreme values of the smoothed data set, beginning in September 1999.


Daily Maximum Temperature
On each plot, the x-axis has the smoothed anomaly of mean daily maximum temperature. The trend was still rising through very high values at the last fully-smoothed data point in October 2009. Very likely a peak will come in November 2009. Partially smoothed data points suggest cooling and re-warming since then.

Monthly Total Rainfall
Fully-smoothed monthly rainfall anomalies have stayed close to -15 mm/month since June 2009. This is a mild drought, much less severe than in winter 2002 (-27 mm/month).


Cloudy Mornings %
All points on this plot are positive anomalies. The anomaly has remained near +8% for many months, and seems to be getting even more positive.


Early Morning Dew Point
Dew Point anomaly fell with rising max temp anomaly to September 2009, then began to rise. The raw value is now far into the realm of "Hot Humid" (or "Interglacial") climate. The record began with even higher humidity in 1999, but has seldom been high since.


Daily Temperature Range
From June to October 2009, temperature range rose with max temp, but barely broke into positive values. The climate was between "Saharan" and "Pacific". It now seems closer to "Pacific".
The instrumental readings on this plot, and those on the Dew Point plot support the observations on the Cloudy Mornings plot. They all show a recent shift from "Continental" towards "Maritime" climate.


Daily Minimum Temperature
Fully-smoothed anomalies of min temp fell and rose with those of max temp. Since October 2009 they seem to have continued to rise and fall together.


Subsoil Temperature
Since April 2009, subsoil temperature anomalies have been small.
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#863016 - 12/05/2010 20:21 Re: Observations of climate variation [Re: Surly Bond]
Surly Bond Offline
Weatherzone Addict

Registered: 23/08/2003
Posts: 2193
Loc: Manilla, near Tamworth NSW
Thread stats

I have been tracking the stats for this thread. I am happy to say that the mean views per day has trended up from 20 at the beginning of March to 30 now. There have been several days with very many views, including 155 on Sunday 11th April and 111 on Thursday 22nd April. I can see no pattern in this at all.

It is a bit lonely here. cry
There have been nearly 1500 "Views" since the last "Reply" (not counting my posts).
I really would appreciate feedback, Or any kind of discussion, whether amateur, like me, or professional.
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#863777 - 18/05/2010 12:46 Re: Observations of climate variation [Re: Surly Bond]
Seina Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7770
Loc: Adelaide Hills
Could you describe your 30-year oscillation in simpleton terms?

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#863801 - 18/05/2010 14:46 Re: Observations of climate variation [Re: Seina]
Surly Bond Offline
Weatherzone Addict

Registered: 23/08/2003
Posts: 2193
Loc: Manilla, near Tamworth NSW
Hi Nazdeck, happy to oblige.

It is not 30 years, it is 30 months. It first came up in this thread in a graph that I had in Post #3745, but I stupidly wiped the graph. It is now re-presented in Post #3781 on Page 4. By that time Keith and Arnost had contributed graphs showing the same cycle. I guessed the period was about 5/3 years (i.e. 20 months).

In Post #810237 on Page 5, you will find graphs of the 60-year record of Australian smoothed monthly anomalies of rainfall and maximum temperature. It is quite clear that there is a two to three year cycle. Points of lowest maximum temperature faithfully follow points of highest rainfall about one month later. I did a fourier analysis that showed the cycle to be 29.8 months (Post #846194).

No-one volunteered an explanation of why this cycle might occur.

By the time of Post #810237 I had discovered that Barrie Pittock had mentioned a "quasi-biennial cycle" in Australian climates in 1971. However, I still do not have access to his paper.

On Page 7, Post #856424, in my "Notes" at the bottom I link to a (VERY technical) paper by Wasyl Drosdowsky that gives some detail about how quasi-biennial oscillations (about 30 months long) act differently in various regions of Australia.

Finally I looked in Wikipedia, and there it was! (See Post #858512, Page 7.)
"The QBO (quasi-biennial oscillation) is a quasi-periodic oscillation of the equatorial zonal wind between easterlies and westerlies in the tropical stratosphere with a mean period of 28 to 29 months."

The 30-month oscillation in my data (and the BoM rainfall and temperature data for the whole country) seems very likely to relate to the QBO defined as a reversal pattern in tropical stratospheric winds, but I have no idea how.

In broad terms, my climate data shows cycles of about 30 months, with rough coincidence of peaks in:
minimum rainfall,
minimum cloudiness,
minimum early morning dew point,
maximum max daily temperature,
maximum min daily temperature,
maximum daily temperature range,
maximum subsoil temperature.

I call this the cycle of "droughts and flooding rains". It is completely different to the cycle of glacials and interglacials. I have dramatised this in the labels in the four corners of the first graph in Post #861249 on Page 7.

Just ask about any point that is not clear. Cheers!


Edited by Surly Bond (18/05/2010 14:49)
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#866367 - 01/06/2010 11:38 Re: Observations of climate variation [Re: Surly Bond]
Surly Bond Offline
Weatherzone Addict

Registered: 23/08/2003
Posts: 2193
Loc: Manilla, near Tamworth NSW
Manilla Smoothed Monthly Anomalies of Climate Variables
Parametric Plots
Update for May 2010

Manilla's climate in the last three years has been marked mainly by cloudier skies and a narrower daily temperature range.



Daily Maximum Temperature
On each plot, the x-axis has the smoothed anomaly of mean daily maximum temperature. The min value in Feb 2008 (-1.61) and max value in Nov 2009 (+1.35) are also the extremes of the data set. Partially smoothed data points suggest cooling to a near-normal temp since then.


Monthly Total Rainfall
Smoothed monthly rainfall anomalies, declining from a peak of +16.7 mm/month in Oct 2008, have stayed close to -15 mm/month since June 2009. Extremes of rainfall occurred earlier in the decade: a max of +20 mm/month in Nov 2005 and a min of -27 mm/month in Jul 2002.



Cloudy Mornings %
All points on this plot are positive anomalies (very cloudy). The anomaly has remained near +8% for many months, and seems to be getting even more positive. The very high anomaly for May 2010 is a raw value. Raw values for several other points on the graph have been even higher. Recent positive anomalies are in stark contrast to the extreme negative anomaly (-11.3%) of the drought month of Oct 2002.


Early Morning Dew Point
Dew Point anomaly fell with rising max temp anomaly to September 2009, then began to rise into the realm of "Hot Humid" climate. The record began with very high humidity (+1.67) in Sep 1999, but has seldom been high since.



Daily Temperature Range
From June to October 2009, temperature range anomaly rose with max temp, but barely broke into positive values. Then it fell rapidly, so the plot moved closer to the "Pacific" type. The positive extreme of temperature range (+1.23) was in Aug 2002 (drought).



Daily Minimum Temperature
Smoothed anomalies of min temp fell and rose with those of max temp. A new extreme positive anomaly of about +1.5 seems likely in Dec 2009.



Subsoil Temperature
The extreme positive anomaly of subsoil temp (+1.80) came in Mar 2007, just before the plotted sequence, and the extreme negative anomaly (-1.09) in May 2008, following two months behind the extreme negative anomaly of daily max temp.
Since April 2009, subsoil temperature anomalies have stayed close to +0.3.

Notes.
These Parametric Plots show anomalies of climate variables observed at Manilla NSW in the last 36 months. Anomaly values (red diamonds) are smoothed using a gaussian window of half-width 6 months. The last six values (open diamonds) are smoothed with progressively narrower windows, until the last month (orange diamond) is a raw value.
Blue diamonds are extreme values of the smoothed data set, beginning in September 1999. A blue rectangle is drawn through these points.
Some errors in calculating "normals" have been corrected, giving rise to discrepancies with earlier graphs.
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#866374 - 01/06/2010 12:14 Re: Observations of climate variation [Re: Surly Bond]
ROM Offline
Meteorological Motor Mouth

Registered: 29/01/2007
Posts: 6628
SB, in your assessment of cloudiness, just what type and characteristics of the various cloud categories do you include in your cloud cover assessment.
And has there been a shift during your data period in the cloud cover type?

There has been a shift in cloud cover and type down here in west Vic this last summer with much higher cu's of a thermal origin showing up for a number of days in succession.
Bases up around the 8 to 12 thou feet.
This was the pattern of the late 60's to late 70's when I was really doing some long distance soaring.

[ Gossip! Cracked a 730 km triangle in 1974 in my Std Cirrus which unknown to any of us down here until a couple of years later was then apparently the biggest triangle ever flown in the world.
I was aiming for 800kms [ 500 miles as we were just moving out of the imperial measurements to metric ] but had to turn short to get home so no record and didn't even bother to try and claim anything as I already had my three diamonds by 1968 [ officially No 6 but reality No 4 in Australia and International No 994 ] in a Boomerang out of Horsham.
Started flying Tiger Moths in 1959 and gliders in 1963. Towing through a southern mid winter in a Tiger puts you off Tigers for life!
Best tow height, 14,000 feet in a Tiger with the Boomer on the back in weak wave down at the Grampians ]

This pattern seems to be tied in with a shift in a fairly stationary type of trough line system which positions here in southern Australia over the late summer period.
Troughs barrel in from the Bight and crawl to a halt around mid Vic and then sort of just sit there for days at a time..
East of the trough is excellent high, strong thermal conditions such as Benalla, Tocumal, Corowa have been experiencing for the last couple of decades.
West of the trough is stable, low inversion, relatively weak thermal conditions and bloody hard work soaring any real distances.
This semi permanent late summer trough type system now seems to be migrating back westwards and our soaring conditions this last season have improved quite dramatically.
So what are you seeing or are you seeing anything in the way of significant shifts in all the criteria you are recording?


Edited by ROM (01/06/2010 12:18)

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#866380 - 01/06/2010 12:44 Re: Observations of climate variation [Re: ROM]
Surly Bond Offline
Weatherzone Addict

Registered: 23/08/2003
Posts: 2193
Loc: Manilla, near Tamworth NSW
Hi ROM

I have not yet tackled sorting out changes in the type of cloud. I will, but I haven't put those observations on the computer yet.
I note up to three cloud types as well as total octas. So I can use the traditional classes of high, middle and low cloud.
I will have to make up a scheme to assign proportions to my daily list of observed types. Of course, a low level overcast obscures any higher cloud. I will have to assume that that factor has not changed with time.
I will not be able to say anything about cloud-base height. I know it on days that I fly, but I don't keep a record of that. Cumulus cloud-base in November 2009 (14,000 feet) was some 50% higher than in recent summers, when it was about 9,000 feet.

Only one of my Diamonds was in the heroic days of wood (Canberra Gliding Club Boomerang).
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#868256 - 13/06/2010 23:50 Re: Observations of climate variation [Re: Surly Bond]
Seina Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7770
Loc: Adelaide Hills
Surly, I have some climate data I could put forward if you wanted to have a look at it.

Are you familiar with MATLAB?


Edited by Nazdeck (13/06/2010 23:58)

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#868290 - 14/06/2010 08:10 Re: Observations of climate variation [Re: Seina]
Surly Bond Offline
Weatherzone Addict

Registered: 23/08/2003
Posts: 2193
Loc: Manilla, near Tamworth NSW
Thanks, Nazdeck, but I encourage people who have data to do some quite simple examination of it themselves. Their findings would make this thread more interesting. Sites other than mine must have a similarly intricate dance going on between temperature, rainfall, humidity, cloudiness and other variables.

I am afraid I am not strong in maths. MATLAB is not for me.
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#868307 - 14/06/2010 10:41 Re: Observations of climate variation [Re: Surly Bond]
Seina Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7770
Loc: Adelaide Hills
Originally Posted By: Surly Bond
I am afraid I am not strong in maths. MATLAB is not for me.

Fair enough, that's ok smile.

I noticed you mentioned subsoil temperature as one of your variables. Are you aware of the theory, by D. L. Nofziger, on soil temperature variations with time and depth. There is a paper written on it with some very promising results/equations that might be of interest to you: see here.

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#868311 - 14/06/2010 11:01 Re: Observations of climate variation [Re: Seina]
Keith Offline
Meteorological Motor Mouth

Registered: 16/12/2001
Posts: 6453
Loc: Kings Langley, NSW
Naz, how would one use Nofziger's model to predict future values of the data?

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#868319 - 14/06/2010 12:50 Re: Observations of climate variation [Re: Keith]
Surly Bond Offline
Weatherzone Addict

Registered: 23/08/2003
Posts: 2193
Loc: Manilla, near Tamworth NSW
Nazdeck, thanks for linking to that paper by Dr Hofziger of Oklahoma State University. It is very relavant to my subsoil temperature observations in Post #855531.
I think his "Theory" is simply an implementation of the very old model of daily and annual waves of solar heat moving down through the soil. He presents data for a soil site in Hebei, China.
My surprise at the Manilla results was that they did not closely follow the model, given that I was using air temperature to represent the heat source. Mean annual temperature at 750 mm was 2 degrees warmer than mean annual air temperature.
Now, Hofziger's Fig. 3 and discussion also show that temperatures at depth are 2 degrees higher than would be predicted from air temperatures, rather than soil surface temperatures.
There is no pattern of anomalous lags in the Hebei data. The Manilla data show large lags in the cooling part of the curve, making soil temperature (at 750 mm) 4 degrees warmer than mean air temperature (in fact, closer to mean daily maximum temperature) at that season.

At Manilla, the very high subsoil temperature anomaly of 1.8 degrees in March 2007 remains a mystery.
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