[Dave K]

I know we had a whole thread somewhere dedicated to debate about the Al Aziziyah world high temperature record of 58 °C, but I just can't find it using the search funcion so an new thread, just to highlight that according to http://www.wundergro...tml?entrynum=82

Quote

...the WMO review of Africa’s (and the world’s) hottest temperature of 58°C (136.4°F) at Azizia, Libya on September 13, 1922 is nearing its conclusion. Results should be released sometime in the next month or so.

This item also posts a potentially new record for the lowest temperature recorded in Africa: -24.1 °C at Oussikis in the Moroccan Atlas mountains on 11 Feb 1935. The current accepted record is -24.0 at nearby Ifrane also in the Moroccan Atlas on the same date. Both are high altitude sites, Ifrane 1 635 masl and Oussikis 2 100 masl.

[Chris Alder]

I think I started that thread about four years ago, just looked but couldn't find it. The al azizyah record is defo wrong, I saw a snapshot of the official log from al azizyah and had daily maxes of 56c either side and a run of other 50c+ days, it just looked wrong, not to mention the time of year.

[Dave K]

Chris Alder, on 21 July 2012 - 16:14, said:

I think I started that thread about four years ago, just looked but couldn't find it. The al azizyah record is defo wrong, I saw a snapshot of the official log from al azizyah and had daily maxes of 56c either side and a run of other 50c+ days, it just looked wrong, not to mention the time of year.

Yes, I just wonder if after all this time (I'm sure it was under review at the time of the original thread) the judgement will be that the site readings have to be disregarded entirely or a slight cop-out that it's believed to be X °C too high. If it't the former then Death Valley should have the undisputed world high.

[Chris Alder]

But which death valley high? As there are questions around the 57c there?

[StratoQ]

Chris Alder, on 21 July 2012 - 18:14, said:

But which death valley high? As there are questions around the 57c there?

Christopher Burt has a very interesting article on this topic here:

http://www.wundergro...html?entrynum=3

It seems Death Valley's 53.9 may be the most reliable world max now.

[Dave K]

StratoQ, on 21 July 2012 - 22:19, said:

Christopher Burt has a very interesting article on this topic here:

http://www.wundergro...html?entrynum=3

It seems Death Valley's 53.9 may be the most reliable world max now.

Thanks for the link.

So for Africa, we are still really looking at the 51.0 °C at Aswan on 4th July 1918 as being the most likely candidate for the continental high temperature. Nothing above that from Algeria, Tunisia or Libya looks at all reliable; although the WMO report may be limited to ratification of the Al Aziziyah reading only.

[Dave K]

Well as we now all know the Al Aziziyah record has been scrubbed ( see http://www.ukweather...o-death-valley/ )

We now await the WMO findings for the revised African record which appears to be still under review.

[Dave K]

Dave K, on 22 July 2012 - 10:24, said:

So for Africa, we are still really looking at the 51.0 °C at Aswan on 4th July 1918 as being the most likely candidate for the continental high temperature. Nothing above that from Algeria, Tunisia or Libya looks at all reliable; although the WMO report may be limited to ratification of the Al Aziziyah reading only.

Currently the WMO is showing the record high for Africa as 55.0 °C at Kebili, Tunisia on 7th July 1931 which frankly seems questionable too!

Quote

SOURCE: World Survey of Climatology: Vol.10, Climates of Africa, p.42
NOTES: This site is on the Gefara Plain along the Mediterranean Sea as is Al Azizia, Libya and subject to the Ghibili (foehn-like) wind phenomena. However, no modern temperature above 124°F (52°C) has yet be measured here.

http://www.wundergro...html?entrynum=3

This post has been edited by Dave K: 15 September 2012 - 11:56

[Mesogeiakos]

The foehn effect in areas around Libya and Tunisia etc can be really strong and you can get really high readings from time to time but 55C seems too much...

[Dave K]

Christopher C Burt examines the candidate readings for the African high temp record: http://www.wundergro...tml?entrynum=90

[StratoQ]

You would wonder about a lot of those pre WWII readings in Africa.

"Aside from Kebili, there have been a number of 130°F+ (54°C) temperatures reported during this period at half a dozen or so different locations in Mali, Algeria, Tunisia, and Libya. Yet following the Second World War to the present, the hottest verified temperature measured at any location in North Africa has only been 50.7° (123.3°C) at Smara (also known as as-Samarah), Western Sahara (claimed by Morocco) on July 13, 1961".

So it hasnt risen above 51 C in Africa since before the 1940s.

[Dave K]

StratoQ, on 28 September 2012 - 10:15, said:

You would wonder about a lot of those pre WWII readings in Africa.

"Aside from Kebili, there have been a number of 130°F+ (54°C) temperatures reported during this period at half a dozen or so different locations in Mali, Algeria, Tunisia, and Libya. Yet following the Second World War to the present, the hottest verified temperature measured at any location in North Africa has only been 50.7° (123.3°C) at Smara (also known as as-Samarah), Western Sahara (claimed by Morocco) on July 13, 1961".

So it hasnt risen above 51 C in Africa since before the 1940s.

You'd think too that these stations with dubious pre WWII records were set up and run by the offices of the colonial powers who really should have had their fingers on the pulse with regard to accurate siting and reading/recording. So there are a couple of possibilites: that the issues relate to inadequate siting or shielding in unfamiliar ground terrain surfaces/topography or a poor managed handover to locals resulting in inaccurate readings; or maybe both.

BTW Max who was banned from UKWW for the content and tone of his messages here has been incredibly scathing and/or outright insulting on the Wunderground blog comments about those he deems responsible for treating these and other readings as accurate and reliable. Yet he refuses to entertain any notion of the Catetanuova (Sicily) reading being questionable even though it is not ratified by the WMO as Europe's highest. So I have to wonder if he is truly impartial in these matters when considering data for his own lists.

This post has been edited by Dave K: 28 September 2012 - 11:01

[skanky]

Dave K, on 28 September 2012 - 11:00, said:

You'd think too that these stations with dubious pre WWII records were set up and run by the offices of the colonial powers who really should have had their fingers on the pulse with regard to accurate siting and reading/recording. So there are a couple of possibilites: that the issues relate to inadequate siting or shielding in unfamiliar ground terrain surfaces/topography or a poor managed handover to locals resulting in inaccurate readings; or maybe both.

The quality of some of the colonial officials will not always have been up to scratch, either.
I can't imagine a desert edge fort being the plumb job for a meticulous high flyer.


On th subject, how likely is it that some areas have got hotter than 51C but just aren't covered by a surface station?
From my recollection, there's a lot of big gaps in coverage, and some of the hotter areas are likely to be the ones with lowest coverage.

[Dave K]

skanky, on 28 September 2012 - 12:45, said:

The quality of some of the colonial officials will not always have been up to scratch, either.
I can't imagine a desert edge fort being the plumb job for a meticulous high flyer.


On th subject, how likely is it that some areas have got hotter than 51C but just aren't covered by a surface station?
From my recollection, there's a lot of big gaps in coverage, and some of the hotter areas are likely to be the ones with lowest coverage.

That was my point, these were probably initially looked after by military or local government personnel billeted in the colonies but quite possibly without input from specialised meteorologist observers used to reading the old mercury max/min thermometers, or those with a knowledge of how the topography, local weather oddities and stony/sandy surfaces and winds blowing hot sand might give misleading reports to a badly sited screen. Add to that maybe a less than diligent handover especially if there was a rebellion for independance going on...!

I'm sure that there are hot zones not covered by the weather station networks but there is a limit to what can be done in very sparsely populated areas without infrastructure where there are more pressing concerns for locals such as simple survival!

[skanky]

Dave K, on 28 September 2012 - 13:02, said:

That was my point, these were probably initially looked after by military or local government personnel billeted in the colonies but quite possibly without input from specialised meteorologist observers used to reading the old mercury max/min thermometers, or those with a knowledge of how the topography, local weather oddities and stony/sandy surfaces and winds blowing hot sand might give misleading reports to a badly sited screen. Add to that maybe a less than diligent handover especially if there was a rebellion for independance going on...!

Sorry I got most of it, was just adding to it - but I missed that you'd already referred to that.

Dave K, on 28 September 2012 - 13:02, said:

I'm sure that there are hot zones not covered by the weather station networks but there is a limit to what can be done in very sparsely populated areas without infrastructure where there are more pressing concerns for locals such as simple survival!

Yes, I wasn't saying coverage should be better. I wonder whether reanalysis can be used to infer probabilities of say a >51C temperature somewhere, especially seeing as they were used in the case of the Libya temperature. We know what the highest recorded temperature (probably) was, I just wonder if it's possibly to come up with a best guess as to what the highest actual temperature was - making the assumption that that is what would have been recorded by a properly sited screen, etc.

I'm sure there are better uses of the time and effort though.

[Dave K]

I suppose that we will never really know although satellite imagery can give an indication of the highest ground surface temperatures (not equivalent to standard surface temperature readings from screened instruments of course). Africa doesn't do that well really considering that it looks to have such a large surface area in the sub-tropics for potentially high temps.

http://eoimages.gsfc...2003-09_lrg.jpg

[skanky]

Dave K, on 28 September 2012 - 14:13, said:

I suppose that we will never really know although satellite imagery can give an indication of the highest ground surface temperatures (not equivalent to standard surface temperature readings from screened instruments of course). Africa doesn't do that well really considering that it looks to have such a large surface area in the sub-tropics for potentially high temps.

http://eoimages.gsfc...2003-09_lrg.jpg

I'd not seen that image before, thanks.