Saturday, April 13, 2013

Most U.S. State Maximum Temperatures Occurred Before 1990

A new paper in BAMS evaluated the record of extreme weather in the U.S., state-by-state, going back into data archives and ensuring the same methodology was used through time.

The end result was this table of extremes for each of the 50 states.

Interesting, there is only one 1.5 maximum temperature records that was set in the 2000s -- in South Carolina in 2012, and a tie in South Dakota in 2006 -- and only 4.5 in the 1990s (one was a tie). All others occurred before that, many in the 1930s.


Nick said...

"Of the 250 reviewed record values [the 5 elements for 50 states] 105 were revised"

Bob K said...

I made up this graphic of both highs and lows from the table you mentioned back in January which I imagine is still current.

Actually in the 2000s there was also a record high tied in 2006 in addition to your mention of a new one in 2012.

The 1930s certainly dominate for both highs and lows.

Les Johnson said...

David: Intersting. So you and Steve Goddard agree on this issue. Most US temp records occured pre 1990, and most in the 1930s.

Anonymous said...

I prefer the usual "look out my window and I can see global warming happening" approach to climate change typically found in current media coverage. Data like that in the NOAA state extremes project only creates doubt in the belief that I am special and that what I think is happening to me has never happened to any other human being in any state before. ;-)

Paul S said...

Looking at the details of stations producing record maximum temperatures, of the first five, the periods of record are as follows:


So, two couldn't possibly produce a record temperature post-1990, two are very unlikely to do so, only being active for a few years post-1990, and one couldn't possibly do anything other than produce a post-1990 record.

What we're looking at here are records from stations positioned in the warmest locations and the times when these stations were active. It says very little about climate change.

David Appell said...

Paul S: While I agree these records say very little about climate change, I don't think you're interpretating these correctly.

Take the first, Alabama. As you note, the period of record for the station with the highest reading is 1916-1974:

But there are other stations in Alabama, with different dates of record.

Of all the stations, regardless of their date of record, this particular one has the highest temperature reading, and it occurred in 1925. That is, no station anywhere in Alabama ever had a higher reading.

The records are for the set of all stations in a state, not for each particular station.

Paul S said...

What you describe was my interpretation. However, a state's temperature is not uniform - some locations are just generally warmer than others. Looking at various stations around Alabama using the GISS station selector I can see variation between 15 - 21 ÂșC, just in terms of typical annual mean temperature, within a 250km radius.

It is the warmest locations - micro-climates - which are most likely to be selected by the criteria of this study. In other words, it isn't random which stations will report the highest temperatures. You can see this by how many of the ties are between different dates at the same station.

It's therefore a significant matter that most record stations don't report at all post-1990. At least, you can't say what these warmer stations would have reported over the past twenty years.

That said, the BEST analysis indicates that maximum (though not minimum) temperatures during July and August (when you'd get highest temperature records) in the mid-1930s were comfortable a match for those in the 2000s.

David Appell said...

Of course it isn't random which stations will report the highest temperature -- it's the stations in the warmest areas of a state.

And ALL stations report their local microclimate. There could be a spot 100 feet away that's a few degrees warmer or colder. You seem to be saying it's impossible to say anything about the temperature in a state, maximum or otherwise, unless it was absolutely blanketed with thermometers, all of which worked perfectly forever. So, like all measurements, this is a record of extremes IN THE NETWORK.

I didn't write that it said anything about climate change.

Anonymous said...

The South Carolina "record" in 2012 is crap. It is from an urban site 20 meters from a parking lot, and less than 20 meters from a stone railroad bed. At best a CRN Class 3 station.

The "previous" record was set in 1925.


Anonymous said...

This is news?
Climate sceptics like Paul Homewood and Steven Goddard have been pointing out this fact for years!

Paul S said...

You seem to be saying it's impossible to say anything about the temperature in a state, maximum or otherwise, unless it was absolutely blanketed with thermometers, all of which worked perfectly forever.

My point isn't that the network is imperfect, but rather that the network has changed over time, so the specifics of its imperfections have changed over time. This is why attempts to bring these individual measurements into regional/national/global time series take steps to account for these network changes - usually called homogenisation - so something sensible can be said about temperature as a function of time.

My comments have been in response to your presentation of these data with particular focus on the dates as a point of interest, including the title "Before 1990". My point has been that the dates of these records are really not very meaningful, or at least could be ascribed an incorrect meaning, because there haven't been any attempts to account for changes in network characteristics in this particular study.

I'm not saying this is all worthless, just that the dates of records should be put in a reasonable context to avoid confusion.