Question for El Cid - rainfall

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olive
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Question for El Cid - rainfall

Postby olive » Fri Dec 29, 2017 2:33 pm

I know you keep records of rainfall and although the year isn't over yet, have you a rough idea of how much rainfall you have measured compared with the norm? ( I realise that normal is a bit subjective as the climate is changing and generally getting drier here)

The reason for asking is that I have a rain gauge. I don't write down the amounts per wet spell but we have had shockingly little this year. In fact last year was very similar.

Does anyone else keep their own records?

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Re: Question for El Cid - rainfall

Postby Flexo » Fri Dec 29, 2017 7:22 pm

You have to measure over many years over a large area to make any trend calculations but I know this year was very dry and I think the two previous years was quite wet in the Cordoba province.

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Re: Question for El Cid - rainfall

Postby gavilan » Fri Dec 29, 2017 8:57 pm

I don't keep rainfall records but I do know that the last 2 winters here (Axarquia Alta) were very dry and we look as if this winter might be similar (but it's early days yet) ... I also know that, for the first time in the 18 years I have known it, the stream here has been bled almost dry by farmers diverting so much water for their crops because the usual sources of water have been diminishing ... that happened this summer but is still happening now, in late December ... I also know that our local reservoir, La Vinuela, is down to 22% of its capacity, last year at this time it was 36% ...

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Re: Question for El Cid - rainfall

Postby dxf » Fri Dec 29, 2017 11:37 pm

Hola

I have a weather station www.chiclana-weather-station.org and the rainfall for 2017 stands at 466mm; I would expect in excess of 600mm a year - 900mm being a wet year.

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Re: Question for El Cid - rainfall

Postby El Cid » Sun Dec 31, 2017 5:52 pm

Sorry I haven’t responded earlier Olive, but it’s not that simple!

Normally, rainfall here tends to be measured over the rainy season, ie from September to April. My system gives me annual figures from January to December. I need to work out manually the “rainy season” figure. When I have done that we will have some more appropriate figures - I will get back in due course.

So far this year from September we have had only 74mm which is appallingly low. I have seen that much in number of previous Septembers but this year there was none at all in September!

You also need to take into account that the further east you go along the coast the lower the rainfall so my figure will not be representative of Andalucia as a whole. Dfx has already posted figures from his very westerly region which are way higher than anything we get. Almería is the driest place in Spain and its only a few km up the road from us.

It could all make up the numbers between now and May but I doubt it. I was in Spain at the end of the previous big drought in 1995 when the reservoirs were even lower than now. It did eventually rain on December 5th and continued 2 days out of 3 until the end of March by which time the reservoirs were full, so it is possible but it would need heavy rain every day for 3 months to equal that.

Sid

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Re: Question for El Cid - rainfall

Postby olive » Sun Dec 31, 2017 7:39 pm

gavilan wrote:I don't keep rainfall records but I do know that the last 2 winters here (Axarquia Alta) were very dry and we look as if this winter might be similar (but it's early days yet) ... I also know that, for the first time in the 18 years I have known it, the stream here has been bled almost dry by farmers diverting so much water for their crops because the usual sources of water have been diminishing ... that happened this summer but is still happening now, in late December ... I also know that our local reservoir, La Vinuela, is down to 22% of its capacity, last year at this time it was 36% ...
That is one of my concerns but as a guiri I just keep my head down. A combination of shooting, smaller and smaller oases of vegetation and surface water I am sure is contributing to less and less wildlife around us. It could be that it is just moving elsewhere.

Sid. I didn't want you to have to go to a load of trouble. I admire anyone who can go to the trouble of emptying their rain gauge each day. I tend to wait till the first dry day and hope it isn't full. We seem to live in a micro climate which is drier than other places nearby. I think it can be explained by the geography as when I swap figures with other farmers their homes are consistently wetter but lie on higher ground in the direction the bad weather normally comes from. The last rain period they had 75 and 79 litros per Sq m to our 61. Am I right in my calculation that 100 litros per square metre is equivalent to 4 inches?

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Re: Question for El Cid - rainfall

Postby gavilan » Sun Dec 31, 2017 8:59 pm

I wrote: the stream here has been bled almost dry by farmers diverting so much water for their crops because the usual sources of water have been diminishing ' ... and I would add that those farmers' demand for water has been much exacerbated by their planting of thousands of avocado saplings in this area... they are water hungry trees at the best of times ...
but as olive wrote: ' as a guiri I just keep my head down' ... I can only hope thaat sooner rather then later, those said farmers will realise that the amount of water they and their crops are demanding is unsustainable ...

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Re: Question for El Cid - rainfall

Postby dxf » Sun Dec 31, 2017 10:43 pm

Hola

I hate to dispel the myth but rain gauges are automatic these days, the cup fills and the weight means the heavy side rotates downwards which allows the cup to empty- so it rises only to fill again.

The whole station is pretty much automatic even having a solar panel to recharge the batteries. All I do is to restart the Weather Station computer once a month updating the software as necessary.

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Re: Question for El Cid - rainfall

Postby El Cid » Sun Dec 31, 2017 11:36 pm

Agree. They are pretty automatic these days. I started with a €500 Oregon system about 15 years ago and when that gave up the ghost replaced it with another Oregon system for around €100 which works fine. It talks to the PC continuously (which is on 24/7). I haven’t bothered to put the output online but it’s pretty easy if you want to. It’s all wireless so installation is easy.

There are plenty of software programs to analyse the data and display it in very customisable options on the PC.

There are even cheaper systems but they tend not to have a PC connection. They all have the ability to record in/out temp and humidity, rainfall and wind speed and direction.

Sid

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Re: Question for El Cid - rainfall

Postby wollie » Mon Jan 01, 2018 9:16 am

Am I right in my calculation that 100 litros per square metre is equivalent to 4 inches.
100 litres is 11 gallons so this unlikely, 4 ins=64cu ins=1.05 L. i think this is what it means.
I did see on the news during the summer fires in Spain/Portugal that the biggest drought is in Spain for over 20 years.
I do hope there is more rain as the country needs levels recover to near normal levels.

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Re: Question for El Cid - rainfall

Postby El Cid » Mon Jan 01, 2018 9:31 am

olive wrote: Am I right in my calculation that 100 litros per square metre is equivalent to 4 inches?
Correct. One litre per m2 is equivalent to a depth of 1mm across that square metre
The common measurement is litres per square meter and you will often hear rainfall described in litres.

So 100 litre of rainfall is equivalent to 100mm which is about 4 inches.

Sid

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Re: Question for El Cid - rainfall

Postby dxf » Mon Jan 01, 2018 12:21 pm

Hola

A cubic foot of water is six and a half gallons and weighs 56 lbs? From memory when I had an aquarium.

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Re: Question for El Cid - rainfall

Postby El Cid » Mon Jan 01, 2018 12:42 pm

Why have we suddenly switched to Imperial rather than metric?

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Re: Question for El Cid - rainfall

Postby dxf » Mon Jan 01, 2018 12:49 pm

Hola

Because my memory pre-dates metric

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Re: Question for El Cid - rainfall

Postby El Cid » Mon Jan 01, 2018 2:30 pm

It’s a lot easier to think metric if you are measuring on the basis of specific volume of rain falling on a given area. However I think that complicates the issue as it is very difficult to visualise.

Once you start thinking more logically about the “height” of the water it gets much easier and it doesn’t involve the area and is just as easy to understand in inches or millimetres. In fact most rain gauges are a glass cylinder with inches or mm up the side.

Why the Spanish insist on quoting the crazy litres per square metre rather than just millimetres is lost on me, I know it is the official way of measuring rainfall almost universally, but few people understand what it means!

Sid

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Re: Question for El Cid - rainfall

Postby country boy » Mon Jan 01, 2018 4:23 pm

I keep monthly records. Rainfall for Pizarra in millimetres for the last 4 years start of the rainy season:

year 14, 15, 16, 17

Sept: 35, 51, 00, 00
Oct:: 45, 108, 62, 69
Nov: 160, 48, 179, 40
Dec: 10, 00, 298, 12

Total 250, 207, 539, 121

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Re: Question for El Cid - rainfall

Postby dxf » Mon Jan 01, 2018 7:22 pm

Hola

That's very interesting - I've never bothered with monthly totals but may well start.

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Re: Question for El Cid - rainfall

Postby gavilan » Wed Jan 03, 2018 7:08 pm

?and maybe here is another question for Sid and others, this time re wind speeds ... yesterday we had the mother of all winds here ... gusts up to 100 mph ... quite scary at times ... we often have high winds but nothing like that before! ... anyone else have similar?
then, after extraordinay wind yesterday, we have extraordinary warmth today ... 21 degrees ... and still 16 at 18,00 ... and to cap it all, weather underground website forecasts temps to drop on Friday ... and SNOW on Sunday ... crazy crazy weather!!!

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Re: Question for El Cid - rainfall

Postby gavilan » Sat Jan 06, 2018 12:39 pm

ZERO degrees on my patio at midday this morning ... thunder. lightening and 24mm of rain!

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Re: Question for El Cid - rainfall

Postby Enrique » Sat Jan 06, 2018 1:01 pm

Hi Gavilan,
What a contrast............here

............ 0c Snowing currently, 8cm so far and total silence..........
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