Chester County PA - Analytical Battle of Actual vs. Altered Climate Data

[chubbs]

5 hours ago, ChescoWx said:

By the way Charlie that Phoenixville chart includes Ghastly ghost data from 1896 thru 1914.....wonder if that fake data impacted your charting??

5 hours ago, ChescoWx said:

Nope - Phoenixville 90 plus days are indeed decreasing

Once again you are jumping to the wrong conclusion. West Chester, Philadelphia and Kennett Square all agree well with the Phoenixville "ghost" data in the 1896-1914 period. All 3 stations show that the area had relatively few 90F days 100+ years ago. Makes sense, the "ghost" data is an IEM re-analysis product that uses nearby raw data.

The chart also shows that Phoenixville had a big spurious spike in 90F days starting in 1925. Starting your regression line in 1915 gives the bad Phoenixville data a big impact. Other than the 1925 and 1950 period, West Chester, Phoenixville and Philadelphia are all in reasonable agreement. The area has had a slow and irregular increase in 90F days. Of course the data isn't perfect: Phila transitioned from city to airport, West Chester cooled in 1970, and Phoenixville was too warm from 1925 to 1950 and too cool in the 1990s. All of those data problems worked to limit the increase in 90F days. The real increase may be even larger than the plot indicates.

As I stated above your analysis is biased by changes in the station population. As an illustration the 12 DEOS stations added between 2008 and 2014 only average 11 90F days per year. Much less than the Phoenixville, West Chester and Coatesville COOPs that dominate the county historical data. All you are showing is that rural parks are cooler than built up towns.

[chubbs]

47 minutes ago, donsutherland1 said:

Doesn't Atglen only go back to 2019? If your sample mix is changing over time, how do you know what seems to be a trend isn't, in fact, an artifact of the changing sample?

Typical Chesco, very misleading. Starts in 2010, a hot summer and per his table, many of the stations didn't operate over the entire period. Philly airport also shows a declining trend starting in 2010.

[ChescoWx]

1 hour ago, donsutherland1 said:

Doesn't Atglen only go back to 2019? If your sample mix is changing over time, how do you know what seems to be a trend isn't, in fact, an artifact of the changing sample?

2012 for Atglen

[ChescoWx]

18 minutes ago, chubbs said:

Typical Chesco, very misleading. Starts in 2010, a hot summer and per his table, many of the stations didn't operate over the entire period. Philly airport also shows a declining trend starting in 2010.

LOL!! so the cooling trend must be real if the UHI PHL Airport agrees!!

[donsutherland1]

1 minute ago, ChescoWx said:

2012 for Atglen

Thanks. That's still subsequent to your starting point. So, it appears that one is, in fact, dealing with a changing sample mix, which makes it tougher to discern the actual trend.

[ChescoWx]

34 minutes ago, donsutherland1 said:

Thanks. That's still subsequent to your starting point. So, it appears that one is, in fact, dealing with a changing sample mix, which makes it tougher to discern the actual trend.

If we exclude it the trend of course remains...

[donsutherland1]

3 hours ago, ChescoWx said:

If we exclude it the trend of course remains...

What are the trends for the last 30 years?

[chubbs]

The Avondale USCRN station which started in 2007 shows a slight upward trend. KMQS starting in 2008 is also increasing slowly. Given the noise in the 90F data these short-term trends may not be significant. Most of the other stations that are collecting data today started in 2012 or later, not 2010. Starting a 90F trendline in hot year like 2010 is misleading. Bottom-line - Considering how noisy the 90F data is there isn't much evidence that the long-term increasing trend established by Phoenixville and West Chester has changed. 

[ChescoWx]

8 minutes ago, chubbs said:

The Avondale USCRN station which started in 2007 shows a slight upward trend. KMQS starting in 2008 is also increasing slowly. Given the noise in the 90F data these short-term trends may not be significant. Most of the other stations that are collecting data today started in 2012 or later, not 2010. Starting a 90F trendline in 2010 is misleading. Bottom-line - Considering how noisy the 90F data is there isn't much evidence that the long-term increasing trend established by Phoenixville and West Chester has changed. 

Actually at Avondale 2N almost flat very slight upward trend mainly thanks to last year....after this low 90 plus season it will change! The clear data of remaining validated stations is a downward trend in 90 plus days!

[ChescoWx]

Which of these things is not like the other??? Can we say UHI contamination??? Wonder why we only show PHL on the local news???

[chubbs]

2 hours ago, ChescoWx said:

Which of these things is not like the other??? Can we say UHI contamination??? Wonder why we only show PHL on the local news???

Can we say UHI contamination? Yes we can. In your own Chesco analysis. Well documented in the previous 8 pages. Your network changes from town to predominantly rural and you don't remove the station changes. You have Chester County as warm as the Philadelphia airport (PHL) in the early 1940s. How ridiculous is that.

When you compare the Philadelphia airport to Chesco stations with a consistent set of measurement conditions, the Chesco stations and the airport both show significant warming. Since 1948, Coatesville has warmed by 3.8F vs 4.8F at the Philadelphia airport. Since 2007 both the Avondale USCRN station and the airport have warmed by over 1F per decade. The charts below show that the Philadelphia airport does a much better job of matching individual Chesco station data than you do. 

 

[ChescoWx]

Or is it UHI at the Airport? 1940's vs today of the problem that is our PHL Heat Island.

[ChescoWx]

Avondale 2012 average temp = 54.4 / 2023 = 54.4 / 2024 = 54.6 - scary warming trend there!!

 

[ChescoWx]

Below are the number of 90 plus days so far at the major climate/airport sites across the Northeast US - PHL 24 days. / ILG 15 days. /ACY 16 days. / ABE 8 days. / TTN 10 days. / RDG 17 days./ GED 20 days. / MPO 2 days. / EWR 24 days. / DCA 22 days./ BWI 17 days. / NYC Central Park 7 days.

 

Now let us contrast that with the 90 plus days across the Chester County sites London Grove 3 / Devault6 / Chester Springs 6 / West Bradford 6 / Kennett Square 6 / Warwick Twp. 4 / Nottingham 5 / Longwood Gardens 5 / KOQN Airport 7 / KMQS Airport 4 / West
Grove 3 / East Nantmeal 3 /Avondale 2N with 4 days.

[chubbs]

Very easy to check if the Philadelphia Airport is experiencing a worsening urban heat island. Compare it to nearby rural sites without station moves or other changes.. Below is a comparison to the Chesco sites that I have data for. There is no noticeable difference in the warming at these rural Chesco sites and the Philadelphia Airport. Yes the airport is in an urban heat island, but the heat island doesn't change much from year-to-year, or decade-to-decade.  No need to hand-wave, guess, or cherry pick, the Chesco and PHL raw data provides the answer. 

Like I said above the Philly airport does a much better job of matching warming in Chesco station data than you do. Why?? PHL is more consistent from year-to-year and decade-to-decade. Your network of stations changes dramatically with time, with a large reverse heat-island effect. Surprised a heat island expert like yourself can't see the difference between Coatesville City/West Chester Boro and Atglen, Warwick, Avondale 2N, etc. 

[ChescoWx]

Below is an analysis of excessive heat - represented by temperatures exceeding 100 degrees in Chester County PA by decade from the 1890's through today. There is a clear trend for less excessive heat days with 100-degree readings becoming a relatively rare event compared to the 1900's through the 1950's. On average Chester County PA is down to maybe 1 time per station per decade. The below shows the number of days, average days per station - this is included to take into account many less stations prior to the 1990's. Of interest is even though there are more current stations at similar elevations relatively close to those older historic stations excessive heat is just not like it was for our parents and grandparents.

[ChescoWx]

16 hours ago, chubbs said:

Very easy to check if the Philadelphia Airport is experiencing a worsening urban heat island. Compare it to nearby rural sites without station moves or other changes.. Below is a comparison to the Chesco sites that I have data for. There is no noticeable difference in the warming at these rural Chesco sites and the Philadelphia Airport. Yes the airport is in an urban heat island, but the heat island doesn't change much from year-to-year, or decade-to-decade.  No need to hand-wave, guess, or cherry pick, the Chesco and PHL raw data provides the answer. 

 

Fortunately we have actual factual raw data to show how PHL Airport is quite noticeably heating at a rate quite higher compared to PHL during our current warmer climate cycle. The last 25 years as the UHI continues to worsen is the telltale sign based on the analysis. The differences between PHL and Chesco continue to steepen. If we break the average temperature change down to simple 5 year increments highlighting the growing gap between PHL and Chester County we can clearly see the worsening urban heat island that is PHL.  From 2000-2004 +5.2% / 2005 - 2009 +5.5% / 2010-2014 +6.9% / 2015-2019 +7.1% / 2020-2024 +7.1% - can't be much clear than that! The gap continues to widen - I suspect with the PHL problems we may start seeing near double digit % gaps with the delta widening from where it is now in the +3.8 degree difference to somewhere near 4.5 degrees within the next decade or so!

[chubbs]

1 hour ago, ChescoWx said:

Fortunately we have actual factual raw data to show how PHL Airport is quite noticeably heating at a rate quite higher compared to PHL during our current warmer climate cycle. The last 25 years as the UHI continues to worsen is the telltale sign based on the analysis. The differences between PHL and Chesco continue to steepen. If we break the average temperature change down to simple 5 year increments highlighting the growing gap between PHL and Chester County we can clearly see the worsening urban heat island that is PHL.  From 2000-2004 +5.2% / 2005 - 2009 +5.5% / 2010-2014 +6.9% / 2015-2019 +7.1% / 2020-2024 +7.1% - can't be much clear than that! The gap continues to widen - I suspect with the PHL problems we may start seeing near double digit % gaps with the delta widening from where it is now in the +3.8 degree difference to somewhere near 4.5 degrees within the next decade or so!

Nope. No one measures the temperature of Chester County and there is no "actual factual raw data" for Chester County in your chart. Your line is a calculated value and you are making a rookie mistake which distorts the raw data. As I have mentioned before, taking the simple average of changing station network skews the trend. If you have cooler stations at the end vs the beginning you will combine the network and weather changes and bias the results.

Easy to demonstrate using the 90F data for Chesco stations that you posted recently. The table below sorts the Chesco stations you are using from high to low 90F days. For stations with a long record only the last 30 years of 90F data are used for a btter comparison to the current stations. Due to location, the older stations tend to be at the top of the 90F list and the newest stations at the bottom. The 90F day plot that you posted recently is skewed by the change in the station network from 1950 to today.  That's why your chart doesn't match the raw 90F data from Phoenixville, West Chester or Avondale, which all show an increasing in 90F days, not a decreasing trend.  Your 90F result is determined by the stations you have selected not our weather. 

Same thing happens with temperature. Your county estimate is biased and the bias increases the further back you go as the county network becomes warmer and warmer relative to today's network. The 1940s network is completely different than the one you have put together for today. 

[ChescoWx]

1 hour ago, chubbs said:

Nope. No one measures the temperature of Chester County and there is no "actual factual raw data" for Chester County in your chart. Your line is a calculated value and you are making a rookie mistake which distorts the raw data. As I have mentioned before, taking the simple average of changing station network skews the trend. If you have cooler stations at the end vs the beginning you will combine the network and weather changes and bias the results.

 

As always you deflect and distract from our actual data. You as always default to your standard answer about some speculative after the fact adjustments....I am presenting actual real data from stations over the last 25 years not back to your fictional post hoc adjustment periods....the actual real averages are clear that the real world stations that are the only data we have clearly show an increasing slope of variance between Chester County stations and PHL Airport....that is the facts!! You show nothing above to dispute these facts.