March Madness

[vortex95]

1 hour ago, dendrite said:

Well I actually think ASOS is pretty good. The bigger issues in my mind are siting and a lack up upkeep in sensor maintenance. GYX had issues at CON years ago because airport maintenance decided to put dark mulch around the ASOS so they didn’t have to mow anymore. BDL just had an issue fixed last year that was causing them to run a solid 2F too warm. But I don’t have an issue with digital thermometers and fan aspiration.

And I seem to recall someone telling me once that they had wanted to have automation take over at the Visitor Center, but the digital temps consistently ran cooler than the max/min in the Stevenson screen so it never happened.

The same thing happened at Central Park when that poor excuse for an ASOS replaced the COOP.

ASOS not so good here (see news clip below).  And the statement it is considered ok as long as it is +- 2 F from actual temp?  So given 2 F whole deg error, how is it proper accuracy calculating a monthly mean temp out to a tenth of a degree?  You are over an order of magnitude off given the overall temp sensor's accuracy and not following significant digit rules.

Also, ASOS first and foremost job is to aviation, so temp takes a back seat.  A documented case, not unique, is Reno NV touted as the fastest warming city in the U.S.  Not true, b/c the ASOS placement has been checked as too warm from adjacent infrastructure.  The NWS wanted to move it to a better location at the airport, but the FAA said no.

EWR had a big problem several years ago that existed for some time.  It would always come in around 2 F warmer every month compared to NYC/LGA/JFK/BDR/ISP.  Not sure if it still exists, but this is a first-order climate and GHCN site.

And AWOS?, they make up the bulk of the hourly observations we see at airports now, and they have worse issues that ASOS.  They are notorious bad for dew points, esp. when high.

So it is more than just the sensor accuracy/calibration themselves, ASOS/AWOS primary purpose is not meant for climate records.  Is this not of significant concern?  This data is used for make many, many decisions, big and small.

Site that are good?  Mesonet sites, like the one OK has had for over 30 years.  Those are sited properly and are geared for climate data.

 

[MJO812]

We had the blizzard one month ago on this date.

[dryslot]

Just some snizzle out now,31/31F

[powderfreak]

1 hour ago, vortex95 said:

ASOS not so good here (see news clip below).  And the statement it is considered ok as long as it is +- 2 F from actual temp?  So given 2 F whole deg error, how is it proper accuracy calculating a monthly mean temp out to a tenth of a degree?  You are over an order of magnitude off given the overall temp sensor's accuracy and not following significant digit rules.

Also, ASOS first and foremost job is to aviation, so temp takes a back seat.  A documented case, not unique, is Reno NV touted as the fastest warming city in the U.S.  Not true, b/c the ASOS placement has been checked as too warm from adjacent infrastructure.  The NWS wanted to move it to a better location at the airport, but the FAA said no.

EWR had a big problem several years ago that existed for some time.  It would always come in around 2 F warmer every month compared to NYC/LGA/JFK/BDR/ISP.  Not sure if it still exists, but this is a first-order climate and GHCN site.

And AWOS?, they make up the bulk of the hourly observations we see at airports now, and they have worse issues that ASOS.  They are notorious bad for dew points, esp. when high.

So it is more than just the sensor accuracy/calibration themselves, ASOS/AWOS primary purpose is not meant for climate records.  Is this not of significant concern?  This data is used for make many, many decisions, big and small.

Site that are good?  Mesonet sites, like the one OK has had for over 30 years.  Those are sited properly and are geared for climate data.

 

From a 50,000 foot view though, are they *all* wrong?

There absolutely are going to be some instrumentation issues, siting issues, etc… but looking at the collective from afar, are they all wrong?  Are mesonets and other climate recording sites that are deemed ok, showing conflicting data?

What about sensors running too cold?  Plenty of those too, but the focus here seems to be the warm ones… or is it just a general statement because of MSM latching onto the warm ones?

[dendrite]

PHNL was a joke from the get go. The siting was pure sand.  

Lots of manned obs were trash too. MHT ran too warm for years before ASOS. Lots of bad COOP data too. I think CON was on the side of a brick building in the 1800s. Wherever you look you can find bad obs in different eras.

The ASOS temp is very accurate, but like any readings, it’s only as good as its siting and maintenance. 

[dendrite]

I don’t even think we disagree?

The instrumentation is accurate when sited and functioning properly and maintained. Unfortunately it’s a struggle to accomplish those things sometimes. Those Vaisala sensors have accuracy greater than 0.1C, but it doesn’t mean a lot if your siting doesn’t accurately represent the 2m temp.

But we’ve called out bad ASOS data here a lot…CON, BOS, ORH, BDL, DAW…they’ve all had issues time to time. It’s usually easy to pick out the error on MADIS charts because most of them have a step change. 

[dendrite]

Anyway…enough about that.

32.4° with L-

Pack is around 2”

[vortex95]

1 hour ago, powderfreak said:

From a 50,000 foot view though, are they *all* wrong?

There absolutely are going to be some instrumentation issues, siting issues, etc… but looking at the collective from afar, are they all wrong?  Are mesonets and other climate recording sites that are deemed ok, showing conflicting data?

What about sensors running too cold?  Plenty of those too, but the focus here seems to be the warm ones… or is it just a general statement because of MSM latching onto the warm ones?

These are great questions.

No. they are not all wrong, but when we are talking avg temps out to the tenth or hundredth of deg in long-term climate, what is a minor error for a daily temp, becomes major monthly and longer.  It's not a big deal daily if a sensor runs 0.5 F too warm, but that shows up once you get to monthly, and that 0.5 F become more significant as you avg over longer and longer periods.

There are a couple of hard facts that indicate warm bias.

1) Urbanization and the location of climate sites is a significant issue and growing larger w/ time.  Many climate sites are located in and near urban areas, and this means warmer locally/mesoscale practically by default.  But only about 2% of the world is urbanized, so how can this be an good representation of avg global temp when so many climate sites are located near and in this 2%? 

2) Even w/o urbanization, having infrastructure nearby (like at airports) can and do bias warmer b/c so much of our infrastructure gives off or retains heat.  Things like paved areas, concrete/metal structures, solar panels, jet exhaust, AC units, etc. they are all extra heat sources.  How many artificial cold sources are there overall comparatively?  Not much. 

3)  Digital thermometers have largely replaced glass thermometers, and record a continuous record of temps.  They more sensitive to passing artificial external heat sources.  So instantaneous spikes are recorded more.  If one does avg temp, say hourly, to get value for a day, this error is washed out, but that's not done a lot.  Absolute max and min for a day are used to get an avg temp.

Yes, sensor calibration can run cold, but this seems largely masked by items 1 and 2 above,  I mean, how often do we see or notice, "that sensor is running cold."?

I don't know about studies comparing mesonet to ASOS/AWOS, but look at siting of most mesonet sites, they are more remote and placed better.  That means less artificial heat contamination.

Another items to consider for records, we have far more wx stations now, and they increase all the time.  So certain wx records, such a state's highest temp or max 24 hr precip, as two examples, are more likely to be detected and go into the record.  This gives the perception that things are more intense or worse, when technology has merely allowed us to see better what has always been there or can happen due to more data recording points.  How our observation network changes and the technology associated w/ it over time are factors, just another caveat about comparing wx/climate over long periods of time.

This doesn't discount warming trends overall, both from natural variability and added CO2., but it is not wrong to be skeptical and ask questions about methods and networks as to how we record and process wx data.  And there are many ways to do this w/ data, all have their pluses and minuses, and can be manipulated to produce desired results.  Not necessarily wrong, but calculated in a way that isn't what it seems, or have practical/noticeable/meaningful effects, such as being statistically significant.  I recommended this book:
https://en.wikipedia.org/wiki/How_to_Lie_with_Statistics
 

[WinterWolf]

10 minutes ago, vortex95 said:

These are great questions.

No. they are not all wrong  but when we are talking avg temps out of the tenth or hundredth of deg in long-term climate, what is a minor error for a daily temp, becomes major monthly and longer.  It's not a big deal daily if a sensor runs 0.5 F too warm, but that shows up once to get to monthly, and that 0.5 F become more significant as you avg over longer and longer periods.

There are a couple of hard facts that indicate warm bias.

1) Urbanization and the location of climate sites is a significant issue and growing larger w/ time.  Many climate sites are located in and near urban areas, and this means warmer locally/mesoscale practically by default.  But only about 2% of the world is urbanized, so how can this be an good representation of avg global temp when so many climate sites are located near and in this 2%? 

2) Even w/o urbanization, having infrastructure nearby (like at airports) can and do  bias warmer b/c so much of our infrastructure gives off or retains heat.  Things like paved areas, concrete/metal structures, solar panels, jet exhaust, AC units, etc. they are all extra heat sources.  How many artificial cold sources are there overall comparatively?  Not much. 

3)  Digital thermometers have largely replaced glass thermometers, and record a continuous record of temps.  They more sensitive to passing artificial external heat sources.  So instantaneous spikes are recorded more.  If one does avg temp, say hourly, to get value for a day, this error is washed out, but that's not done a lot.  Absolute max and min for a day are used to get an avg temp.

Yes, sensor calibration can run cold, but this seems largely masked by items 1 and 2 above,  I mean, how often do we see or notice, "that sensor is running cold."?

I don't know about studies comparing mesonet to ASOS/AWOS, but look at siting of most mesonet sites, they are more remote and placed better.  That means less artificial heat contamination.

Another items to consider for records, we have far more wx stations now, and they increase all the time.  So certain wx records, such a state's highest temp or max 24 hr precip, as two examples, are more likely to be detected and go into the record.  This gives the perception that things are more intense or worse, when technology has merely allowed us to see better what has always been there or can happen due to more data recording points.  How our observation network changes and the technology associated w/ it over time are factors, just another caveat about comparing wx/climate over long periods of time.

This doesn't discount warming trends overall, both from natural variability and added CO2., but it is not wrong to be skeptical and ask questions about methods and networks as to how we record and process wx data.  And there are many ways to do this w/ data, all have their pluses and minuses, and can be manipulated to produce  desire results.  Not necessarily wrong, but calculated in a way that isn't what it seems, or have practical/noticeable/meaningful effects, such as being statistically significant.  I recommended this book:
https://en.wikipedia.org/wiki/How_to_Lie_with_Statistics
 

Great info. 

[Ginx snewx]

Gorgeous here at Sunday River about 8 down light snow 

[vortex95]

52 minutes ago, dendrite said:

PHNL was a joke from the get go. The siting was pure sand.  

Lots of manned obs were trash too. MHT ran too warm for years before ASOS. Lots of bad COOP data too. I think CON was on the side of a brick building in the 1800s. Wherever you look you can find bad obs in different eras.

The ASOS temp is very accurate, but like any readings, it’s only as good as its siting and maintenance. 

Is +-2 F good enough?  I would say not when you are calculating averages out to the 1/10 or 1/100 of a deg.  Or when you are counting days reaching, say 90 or 100, when you have some fixed values as benchmark for a record.

Recall the first 100 F at Tampa last year?  And how the ASOS is sited at the turn point for taxiing jets?  Here's where it gets more psychological than physical, but has real world impacts.  We love numbers ending in 0 or 5, and powers of 10?, forget it!  So when Tampa hit 100 F for the first time, it was treated like the second coming for news.  Really?  99 vs. 100?, that's not a big deal, but we make it a make deal.  As a result this skews perception about things like heat and warming more than it should.  It can put it this way, if Tampa hit 99 instead of 98 this day, it would have been nothing for news.

So minor things are not always so minor as to their effects.

[vortex95]

9 minutes ago, WinterWolf said:

Great info. 

Thank you.  Not trying to score points or be dogmatic, just presenting food for thought.