Rog

"Welcome to 1970's weather Arapiles."

No, I remember the 70s - it was one of the wettest periods in the last century.

"Wetter than most of the rest of Aus apparently."

Yes, but Australia's a big country - the rainfall patterns are different depending on where you are. For example, Northern Australia is monsoonal. It's supposed to be raining here more than there in July.

"About 20% more rain than this time last year too"

According to the map, just 25 mm more than last year - and that's compared to a very dry winter last year. That's roughly an inch - when I was living in London in 2007 we were getting that in a day.

So, even though Melbourne's dams are better than they were this time last year, they're still only at 35.3% capacity.

Edited by Arapiles on 07/31/2010 00:57:46 MDT.

"About 20% more rain than this time last year too."

Rog

The same data set you were drawing your graphs from has this:



"This map compares the rainfall received since the start of the current Southern Wet Season with the long-term average for the entire season (April to November)."

You'll note that most of Victoria has had between 200mm and 600mm LESS than the long-term average for April to November. Given that they're forecasting a very warm spring, odds are that we're not going to get that missing rain.

Edited by Arapiles on 07/30/2010 19:08:17 MDT.

Rog

Here's a more interesting one:



This shows rainfall anomalies in Victoria from 1 July 2007 to 30 June 2010. See that big yellow blob to the right of Melbourne? That shows that in the three years to date that area has had 1000 mm LESS rain than expected - so a metre less rain. Pity they don't show the 10 year anomaly.

Melbourne gets its water from rainfall run-off into storages. Want to guess where Melbourne's water storages are located?

Edited by Arapiles on 07/30/2010 19:09:09 MDT.

> This map compares the rainfall received since the start of the current Southern Wet Season

And looking closely at the Alpine region around Kosci, you will see that the area is in quite severe drought. Which means no snow, and no ski-touring. Snarl.

Cheers

"It's been a very cold winter in the Australian Alpine Regions this year - more so than normal, but the amount of precipitation has been abysmal. Consistent with the general drought we have been expriencing"

And as has been said before, less humidity = clearer skies = lower temps.

Interestingly, during the Federation Drought they had record lows across many parts of Australia. Just like now.

I'm on the West Coast of Aus, the image below shows ice on my shoes and the grass while out on a recent hike. This is a first ever for me and I have lived here my whole life (32 years).

Cheers

Arapiles said:
You'll note that most of Victoria has had between 200mm and 600mm LESS than the long-term average for April to November.

You emphasis LESS, but you'd hardly expect there to have been MORE rain in the first few months of the wet season than is normal for the whole of the wet season would you?

I recognise there has been a long drought in your corner of Aus, but it's not an unprecedented event, and droughts haven't become more frequent over the C20th. I put it to you it's natural cyclicity in longer term weather patterns at work, not alleged co2 driven climate change.

Given that they're forecasting a very warm spring, odds are that we're not going to get that missing rain.

The BOM habitually forecast warmer than average seasons, it's what their co2 driven climate model tells them to say. After forecasting a warmer than normal winter for the last two freezing winters (2009 - coldest in 30 years) the UK met office has stopped issueing seasonal forecasts altogether. :-)

dams

It's a waste of time discussing dam levels, unless you provide metrics on human water usage trends, including garnering of runoff in the catchments, as well as increased consumption from the reservoirs, as well as the dates of construction of the reservoirs, and losses from cracked linings. I know you know this, so dial it back on the dam rhetoric please.

Edited by tallbloke on 07/31/2010 02:25:02 MDT.

"It's a waste of time discussing dam levels, unless you provide metrics on human water usage trends, including garnering of runoff in the catchments, as well as increased consumption from the reservoirs, as well as the dates of construction of the reservoirs, and losses from cracked linings."

Re runoff in the catchments - that's what the chart above (the one with the big yellow blob) shows. Just so it's clear, Melbourne's dams don't store water pumped from elsewhere, they catch what falls around them.

Re usage, for the last few years Melbourne has had a daily target per person water use of 155 litres - last week it was 134 litres per person per day. Here's the website if you'd like to stay up to date:

http://www.melbournewater.com.au/content/water_storages/water_report/weekly_water_report.asp?bhcp=1

(ps Note their comment about 1mm of rain being somewhat less than the normal 27mm)

"I know you know this, so dial it back on the dam rhetoric please."

But the dams ARE the issue - and your comment comes across as a tad discourteous.

Re runoff in the catchments - that's what the chart above (the one with the big yellow blob) shows. Just so it's clear,

I was referring to the changing drainage around farms etc. I know this is an issue in the MD basin, maybe not where you are.

But the dams ARE the issue - and your comment comes across as a tad discourteous.

Apologies, unintented double entendre. Let me rephrase:
"dial it back on the rhetoric about dam levels please."

I still think reservoir levels are a poor measure of 'climate change' though. Why not just use the extensive network of rain guages so nicely collated by BOM? They will give you a better measure. I appreciate that dam levels are the big issue for people, but that should not be conflated and confused with the climatology of the continent, or the world.

That's my point. Why go to the trouble of subtracting out all the difficult to measure factors from dam levels when you can go to the source data, rainfall. That's the best measure of precipitation changes in the climate, the rainclouds aren't affected by how many or few dams you have, or how much the population has increased, or whether or not individual humans are using a bit less than they were in urban dwellings. Just use the measurements of how much rain they drop into accurate guages. It's a no brainer.

The politicians blaming dam levels on global warming is just a smokescreen for their failure to do enough about providing water to the taxpayer. Water shortage is better addressed by spending taxes on reservoir construction, not by spending taxes on scam schemes to reduce co2 emission.

Rainfall across Australia is up over the C20th, Local dam levels have nothing to do with global climate. Don't be fooled by the pollys.

Edited by tallbloke on 07/31/2010 04:01:37 MDT.

"Why go to the trouble of subtracting out all the difficult to measure factors from dam levels when you can go to the source data, rainfall."

Precisely - and as the records show, there hasn't been much rain around.

There are two parts of Australia which have undergone severe decreases in rainfall since the 1970s - southern Western Australia and Victoria.

To quote from BOM's Special Climate Statement 9

"The decade from October 1996 to September 2006 has been a notably dry one in large parts of
southern and eastern Australia. Whilst much of tropical and central Australia has seen wet
conditions through most of the last ten years, for many parts of the south 1996 was the last year
with significantly above-average rainfall.
The most extreme rainfall anomalies have been in the area around Melbourne, where falls during
the last 10 years have widely been about 20% below the long-term average, and 10% below those
of any other 10-year period in recorded history. Other areas where rainfall over the last 10 years has
been the lowest on record are parts of western Victoria and adjoining south-eastern South Australia,
parts of eastern Tasmania, the area around Perth in Western Australia, and a few locations in the
Darling Downs and Burnett regions of south-eastern Queensland.
October 1996 is taken as the starting point for this statement, as September 1996 was the last in a
sequence of months with above-average rainfall in most of Victoria, as well as the end of the main
1996 rainfall season in south-west Western Australia, which preceded a run of eight successive
drier-than-average years in Perth. In New South Wales and Queensland, the downturn in rainfall
has generally been a more recent phenomenon, generally starting in 2000 near the east coast and
2001 further inland. It is noteworthy that in some of these parts the last 5-7 years have been dry
enough as to register on the 10-year deficiency analysis."

And that was in 2006 - the last 4 years have been no better. So make that a 14 year drought.

Arapiles quoted:
""South American cold surges are a year round feature of
the synoptic climatology of the region (Garreaud, 2000; Vera
and Vigliarolo, 1999; Seluchi and Marengo, 2000), with a
near weekly periodicity, but with a large range in their intensity
and meridional extent. Extreme wintertime episodes
(one every few years) produce near freezing conditions and
severe agricultural damage from central Argentina to southern
Bolivia and Brazil

The Andes climate and weather
R. D. Garreaud
Department of Geophysics, Universidad de Chile, Santiago, Chile

http://www.guardian.co.uk/world/2010/aug/01/peru-freezing-weather-emergency
"Peru has declared a state of emergency after hundreds of children died from freezing conditions that have seen temperatures across much of the South American country plummet to a 50-year low. In 16 of Peru's 25 regions, temperatures have fallen below -24C."

50 year low huh?
This looks like more than the weekly cold surge to me.

It's not just local winter weather either. Large swathes of South America are 6-10C below average temperatures for the time of year. This may well be associated with the sudden stratospheric warming event I linked the amimation of the other day.

The last big SSW in the northern hemisphere brought a sever cold snap to Canada, and it then showed up in the UK and scandinavia a week or so later. That's why I think Aus might be about to get it. But I could be wrong.

I'm not trying to make out anything about longer term climate here, it's just a fascinating aspect of the way our global climate system operates that we have a poor understanding of that interests me, and hopefully other people with enquiring minds.

Edited by tallbloke on 08/01/2010 04:02:00 MDT.

"50 year low huh?
This looks like more than the weekly cold surge to me."

Agreed. The link you provided links to an earlier one from the Observer: it sounds like a horrible situation.

Any idea which NGOs are working in the area?

And it occurs to me that BPL members may have spare warm/waterproof clothing.

An excellent thought Arapiles. I know Americans up and down the two continents are generous people. Speed is of the essence.

Hi Rog

> you'd hardly expect there to have been MORE rain in the first few months of
> the wet season than is normal for the whole of the wet season would you?

Ahhhh ... you don't know Australia very well, do you?
Yes, we have had this sort of downpour in some areas.

In fact, it would be fair to say that 'normal' is not a concept which can always be safely used in discussing Australian weather. It can be a land of extremes.

Cheers

As already mentioned, NZ has had it's coldest, and one of it's wettest winters since records have been kept. Lots of snow! Yippeeeee

Frozen Haven in a -6 C frost, at sea level...

Roger C said:
"In fact, it would be fair to say that 'normal' is not a concept which can always be safely used in discussing Australian weather. It can be a land of extremes."

I think it generally true worldwide that the east side of continents are drier, due to the Earth's direction of rotation. The prevailing winds coming off the oceans make landfall in the west, and dump thier moisture as they cross the landmass. I'm sure that some circulatory eddy patterns make exceptions to the rule though.

Lynn on NZ has a more maritime climate, similar to the UK's. The oceans have gathered up a lot of solar heat-energy in the second half of the C20th, and coastal areas will fair better in the cold times ahead as the oceans burp out their accumulated heat.

Nice 'pup tent' Lynn. ;-)

Edited by tallbloke on 08/01/2010 17:27:36 MDT.

"Nice 'pup tent' Lynn. ;-)"

Yeah, lucky I retightened it before I took the photo. It was a very sad looking pup tent when I first crawled out of it.

Slightly Off Topic, but get outside tomorrw night somewhere with a clear view towards the nearest terrestrial magnetic pole. Folk in higher latitudes have a good chance of seeing some spectacular aurorae as a coronal mass ejection from the Sun slams into Earth's magnetosphere.

http://news.discovery.com/space/incoming-the-sun-unleashes-cme-at-earth.html

You might want to disconnect sensitive elctronics from the electricity grid too.

Edited by tallbloke on 08/02/2010 04:56:28 MDT.

I presume you mean in the Northern Hemisphere?

> I think it generally true worldwide that the east side of continents are drier,
> due to the Earth's direction of rotation.

Once again, beware of making generalisations about Australian weather. Our East coast is MUCH wetter than anywhere inland.

Why? Because Australia is so large that it 'controls' the prevailing winds over a huge area. The Highs and Lows don't always cross Australia: they get deflected below Australia and curl around the East coast. The inland stays dry (drought), while the East coast gets pasted.

New Zealand - a little to the S of Australia, and its West coast cops all the fronts which have been pushed South by Australia. I am not sure I would call it "similar to the UK's" though.

Yeah, maybe you could call all this a HUGE eddy in a way.
Cheers