Thursday, February 05, 2009

Environmental Changes afoot

This post is in reply to a comment made by Denis Wilson recently, which raises the subject of shifting environmental patterns - a subject of interest to me, as I have moved to a new set of climatic conditions of late.

The section of his comment bearing relevance to this post is:

"........Its still dry in Robbo (well, mists, but no rain. Hillsides around Roboo have gone brown, would you believe it?
So too dry for much fungal activity here. You must have caught some local thunderstorm activity. Dry to the south (Victoria) and to the north. Interesting." Denis Wilson

I feel it is very interesting also.
Please look at the map provided below.
It comes from the D.T. Brown seed company (hey,I'm using their image..A free add for their seeds is no problem).

Look at the climatic "interchange" on the NSW / Vict East coast ( purple/blue).

It is my belief that this interchange existed, some 30 years ago, around Wollongong.
I believe it to exist around Batemans Bay at the present time.

This interchange does not rely on geographic situations to manifest itself, it relies on weather patterns involving subtleties including, though not limited to, ice sheet sizes in Antarctica and coastal water temperatures.

One important piece of evidence to support this idea, of a shifted interchange, is the spectacular event known as a "Southerly Buster" - a wave of cloud, moving at incredible speeds from South to North, bringing cool air and relief from high temperatures.
It has been 30 years since I have seen a good one in the Wollongong area...whereas, in my new location south of Batemans bay, I have seen 2 good ones in a 6 month period and a handful of smaller events.
Another event sadly missing north of me is the afternoon thunder storm.
As a child in Wollongong you could expect that a huge, though short lived, thunderstorm would give a cooling end to a hot sunny day...not as regular any more, though still a regular event down south.

Why do I believe this interchange to be situated around Batemans Bay?
Move south of there and early summer can be raging NE winds...not so further north.
Observed cloud patterns on BOM showing interchange events.
Temp differences noticeable North and south of that area.
I would even suggest that rainfall in the Batemans Bay area, on average, has decreased less over the last 30 years in relation to areas further north, keeping in mind that rainfall has been decreasing statewide for many years.

There is a red section on the map (in SA and WA)..this is a different climatic condition again.
I believe it to have spread across southern Victoria providing the hotter, drier conditions experienced there of late.

So, what does it all mean?

Climatic changes and less stability within those climates.
Adapt or perish cry the evolutionists.
Sadly much will perish.
New environments are being created all over the world within lifetimes.
With new climatic conditions must come new solutions.
Oh to live in interesting times.

UPDATE (16.02.09):
Recently Robertson, and surrounding areas got some rain (see Post by Denis Wilson)
I was able to monitor this activity, courtesy of the BOM website located here.
I have included a few shots, taken over nearly a 3 hour period, of the storm.
I found it interesting that the activity was limited to a little north of Batemans Bay and that the storm remained basically stationary during that time.
Also look at the way the storm moved at its South Western end.
It seems that an air flow drove the storm, at that point, to the east while the rest of the storm remained stationary. This looks to me like a classic "eddy" with a flow of air to the south, around Batemans Bay, helping to contain the storm within the area.
I would suggest that a similar situation existed above the storm north of Port Macquarie.
Credit, and thanks, to the BOM for the following shots.

I will monitor this area for the proposed interchange event I have suggested and make additions to this post as material supporting this theory presents itself.


  1. Hi David
    Nice thought provoking essay.
    Love the seed company map of climatic zones.
    I feel you are right. Certainly Vic and SA have experienced (are still experiencing) savage heat. Sydney is about to get the hot North-westerlies, but they are created by different processes from those in lower latitudes.
    But Robbo, for example, has hardly had a thunderstorm to speak of, whereas the storms of which you speak are normal for this zone. We usually get the tail end of tropical storms washing down from Qld - but so far nothing.
    I am waiting for 6 March, before I declare it an official change. That's the Robbo Show. Local tradition has it that it always rains for the Robbo Show. The last 2 years have been dry on the weekend itself, but rain has fallen just prior.
    February and March are our wettest months, but January of often very wet. Hardly a drop this year. As I say, I am holding my breath before declaring it a change, but it certainly feels that way.
    Just think - all this, from your comment about your Fungi fruiting down there, because of all the rain. Not here. 150 Km males a big difference it seems.
    Nicely observed, David.

  2. Hi Denis,
    The post had been on my mind for a while..your comment was the catalyst needed :)
    I checked records from the BOM going back 20 years and, although the patterns are all over the place year to year, it does seem as though there is a trend towards a moe distinct change.



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