Last 12 Decades suburban - Outside of heat island analysis - Chester County PA

[ChescoWx]

Not that any one location either supports or refutes climate change (IMO... of course climate it is always changing - but it's just cyclical)

However, If summer (June-July-Aug) ended today here in the leafy Western burbs of Philadelphia (35 miles west of PHL airport) our current summer average temperature of 73.8 degrees would represent our warmest summer in the philly burbs outside of the PHL Airport heat island since 2002 and 16th warmest since records began here in Chester County in 1894. I use the NWS Coop data set and my data which represents continuous daily data since January 1st , 1894. Of note there is some relative elevation differences that may account for some of the differences with Chester County data being observed at over 650ft ASL while PHL Airport lies near sea level on the Delaware River.  The top 2 hottest summers? way back in 1900 & 1901. I also did some data analysis (see below) comparing the average suburban temperatures by decade outside of the PHL airport heat island impact to the official PHL readings. I only had PHL decade data for the last 70 years (7 decades)

As you can see there has not been much warming in fact a clear warmer cycle in the early part of the 20th century followed starting with the 1940's with 4 straight decades with declining temps and now the last 4 decades starting with the 1980's showing warming....but nowhere near like the PHL heat island is indicating - in fact the 1990's were exactly the same as the 1st decade of the 20th century. While the 2010's were the warmest decade it was only by 0.3 degrees. It is interesting to note the much sharper and consistent rise at the PHL airport. 

[BillT]

simple common sense = an area that was mostly trees and grass would be cooler then than it is now with it is mostly concrete and blacktop, and both the cool and warmth are LOCAL not global in nature.

[ChescoWx]

2 hours ago, BillT said:

simple common sense = an area that was mostly trees and grass would be cooler then than it is now with it is mostly concrete and blacktop, and both the cool and warmth are LOCAL not global in nature.

Indeed....why we need to be careful with what is truly warming based on what we now deem "official" sites....hence my analysis

[BillT]

that is the reality of the urban heat island effect....they are taking a reading from the warmest locations around our cities and calling it the temperature for a very wide area........claiming the very localized warming is much larger and a general area wide warming when it clearly is not......in any persons yard the north side is cooler than the south side, temperature variances in very small areas.

[bdgwx]

Clearly there are circumstances that are causing the PHL site to warm but not the Chester County site. There could be various reasons for this including the obvious urban heat island effect. While most urban sites are no longer experiencing significant increases in urban heating there are, of course, many location (both in the US and worldwide) that are.

Scientists who develop and maintain datasets that publish a global mean surface temperature (GMST) are well aware of the urban heat island effect and take necessary steps to make sure it is not biasing the warming trends either way. It is also a very misunderstood topic by laypeople. Many people have the mistaken belief that the UHI effect on the GMST warming trend can only ever be positive and is always increasing. This couldn't be further from the truth.  

Berkeley Earth did an analysis a few years ago and determined that the UHI effect may actually be biasing global mean surface warming trends too low for the post-WWII era, albeit by a small amount.

"We observe the opposite of an urban heating effect over the period 1950 to 2010, with a slope of -0.10 ± 0.24°C/100yr (2σ error) in the Berkeley Earth global land temperature average."

 

[chubbs]

37 minutes ago, bdgwx said:

Clearly there are circumstances that are causing the PHL site to warm but not the Chester County site. There could be various reasons for this including the obvious urban heat island effect. While most urban sites are no longer experiencing significant increases in urban heating there are, of course, many location (both in the US and worldwide) that are.

Scientists who develop and maintain datasets that publish a global mean surface temperature (GMST) are well aware of the urban heat island effect and take necessary steps to make sure it is not biasing the warming trends either way. It is also a very misunderstood topic by laypeople. Many people have the mistaken belief that the UHI effect on the GMST warming trend can only ever be positive and is always increasing. This couldn't be further from the truth.  

Berkeley Earth did an analysis a few years ago and determined that the UHI effect may actually be biasing global mean surface warming trends too low for the post-WWII era, albeit by a small amount.

"We observe the opposite of an urban heating effect over the period 1950 to 2010, with a slope of -0.10 ± 0.24°C/100yr (2σ error) in the Berkeley Earth global land temperature average."

 

There is no way to isolate an urban heat island effect from Chesco's plot because he has inappropriately combined different stations into a single record for comparison to the Philadelphia airport.  Per the chart below, the pre-1950 data from Coatesville ( a steel town) has a warm bias. Also the Coatesville data are collected at a site that is further south and lower elevation than the post-1983 data. The second chart below shows that Chesco's recent data (C2WKQMS+E Nant) are warming at roughly the same rate as the Philadelphia airport (phl) and the region as a whole.

[LibertyBell]

7 hours ago, BillT said:

that is the reality of the urban heat island effect....they are taking a reading from the warmest locations around our cities and calling it the temperature for a very wide area........claiming the very localized warming is much larger and a general area wide warming when it clearly is not......in any persons yard the north side is cooler than the south side, temperature variances in very small areas.

even if what you say is true, urban heat island aint a good thing- too much concrete...and higher overnight mins during the summer in urban areas leads to various health problems.  It's why you need to switch to green

[LibertyBell]

1 hour ago, chubbs said:

There is no way to isolate an urban heat island effect from Chesco's plot because he has inappropriately combined different stations into a single record for comparison to the Philadelphia airport.  Per the chart below, the pre-1950 data from Coatesville ( a steel town) has a warm bias. Also the Coatesville data are collected at a site that is further south and lower elevation than the post-1983 data. The second chart below shows that Chesco's recent data (C2WKQMS+E Nant) are warming at roughly the same rate as the Philadelphia airport (phl) and the region as a whole.

and whats being completely ignored is where the concrete that leads to the urban heat island effect comes from as well as the health impact of this so-called "local effect" it's not local, more and more of the planet is becoming urbanized and it has a deleterious health impact, not to mention the ugly air pollution increase from more people driving more dirty fuel powered vehicles....air pollution shortens life expectancy more than tobacco does.

concrete, plastic, etc., all this garbage has but one source.....

 

[BillT]

2 hours ago, LibertyBell said:

even if what you say is true, urban heat island aint a good thing- too much concrete...and higher overnight mins during the summer in urban areas leads to various health problems.  It's why you need to switch to green

what %age of the earth do you think is covered in concrete?  and indeed the urban heat island effect is VERY local not global in any way.

[csnavywx]

How many more nails do we need to drive into this UHI coffin before the zombie finally stops moving?

[LibertyBell]

On 8/30/2020 at 10:51 PM, BillT said:

what %age of the earth do you think is covered in concrete?  and indeed the urban heat island effect is VERY local not global in any way.

the oceans comprise 70% of the planet and yes it matters if the most densely populated areas of the world have it, because it leads to different forms of pollution and hardship.  Cutting down trees aint a good thing, particularly when they are needed as carbon sinks for the emissions.

[LibertyBell]

On 8/31/2020 at 5:04 AM, csnavywx said:

How many more nails do we need to drive into this UHI coffin before the zombie finally stops moving?

seize the assets of the fossil fuel industry and move them to building architecture to combat sea level rise.

once the fossil fuel industry is castrated, you wont see any more of this propaganda.

We also need to go after PhRMA and big pharma in general for the propaganda they put out against universal healthcare.

A lot of things need to change in this country.

 

[donsutherland1]

It should be noted that for West Chester (2 NW), which includes data for most years from 1893 through 2016, summer 1900 was tied for 7th warmest (mean temperature: 75.0) and summer 1901 was tied for 15th warmest (mean temperature: 74.7). Summer 1988 was the warmest with a mean temperature of 76.7.