So we looked at Salt Lake City, Utah and Reno, Nevada in the just made prior posting here:
http://chiefio.wordpress.com/2012/07/26/salt-lake-city-airport/
Where we found a general upward trend to a trend line plotted through a scatter plot of ‘nearby’ stations listed in the order of presentation on Wunderground. We also found a very significant increase in the Airport temperature when compared to the average of ‘nearby’ stations (tossing out the highest and lowest as potential ‘outliers’).
I then went looking for a 3 rd station and ran smack into Atlanta, Georgia that had 2 identical highs and 2 identical lows ‘nearby’ (so do I toss out one of each, both of each, or none?…) and had a flatter trend line (but the Airport temperature still above the average). OK, I can now either ‘cherry pick’ number three, present Atlanta as #3, or add another item #4 as a continuation and see if Atlanta is less like the pattern or if the next one matches it or matches the prior two… So I’m doing two in this posting. Turns out the fourth one tried (Chicago) is very much like Salt Lake City and Reno Nevada… So at this point we have 2 patterns: Rising temperatures as stations are higher in the list and nearly flat trend line with list position; but in both cases with the Airport above the average.
In this comparison I also wanted to answer the question of “How much does tossing outliers matter?” so there are 4 graphs total. With and without the outliers. For Atlanta I toss all 4 or keep all 4 as I have no reason to pick one of the two identical temperatures over the other. For the ones with the data removed, I left the position in place, but blank, so the length of the graph does not change making visual comparisons easier.
With that, here are the graphs, the average and delta to average temperatures, and the data sets I snagged.
Chicago Midway
I chose Midway as the airport is closer to town. ORD was an Orchard (thus the symbol ORD) and it’s a long taxi ride to town…
Chicago Midway vs Wunder-nearby all data 25 July 2012
And with the highest and lowest removed from the series:
Chicago Midway minus H & L outliers vs Wunder-nearby list 25 July 2012
For Chicago the airport temperature is 75 F 73.77 1.23 0.68
While the mean is 73.77 and 71.50 F for the all data and the H/L left out versions. The “differences” are 1.23 F and 0.68 C for the first (all data) case. 3.50 F and 1.95 C in the second (high / low left out) case.
Altlanta
In some ways much more interesting. What makes Atlanta different from the others? Location of the airport? Particulars of the relative stations? Local topography? At any rate, here are the graphs:
All data:
Atlanta Ga KATL vs Wunder-nearby all data 25 July 2012
For Atlanta the airport temperature is listed as 78 F.
While the mean is 76.35 and 76.33 F for the all data and the H/L left out versions. The “differences” are 1.65 F and 0.92 C for the first case. 1.67 F and 0.93 C in the second.
And with the Highest and Lowest removed:
Atlanta Ga KATL -HL 25 July 2012 vs Wunder-nearby stations
In Conclusion
It looks to me like tossing the high and low has a minor impact, but doesn’t change the conclusion in any significant way. It also looks like though Atlanta has a different distribution of stations down the list (in terms of temperature trend) the station at the airport is clearly still reading above the average.
Now I’ve taken a load of rocks tossed at me by Warmistas over my complaints about averaging temperatures. They repeatedly trot out the same old argument that averaging enough temperatures will fix the errors. OK then: That same argument says that the thermometers at Airports are WRONG and do not represent the average of the areas nearby and regularly report high values. I now respectfully request that all airport data be purged from any data set used for making policy recommendations or for use to show the presence of a “Global Warming Trend”. The averages show they are outliers. But a lot.
The Data
Here are the data grabs for these two stations, perhaps folks more familiar with the area can make more sense of the patterns.
Chicago
Chicago Weather at a Glance Weather Station Chicago Midway (KMDW) Elevation 620 ft Station Select Now Partly Cloudy Temperature 75 °F Feels Like 75 °F Wind(mph) 7 Sunrise / Set 5:37 AM 8:15 PM Weather Stations Station Location Temp. Heat Index Dew Point Humidity Wind Precipitation Elevation Updated Type Website Chicago, IL 74.3 °F 76 °F 65 °F 73% SE at 4.0 mph 0.00 in / hr 0 ft 43 sec ago Rapid Fire River North, Chicago, IL 74.8 °F 76 °F 65 °F 72% North at 2.0 mph 0.00 in / hr 623 ft 26 sec ago Rapid Fire U.S. Cellular Field, Chicago, IL 75.1 °F 77 °F 63 °F 66% South at 1.0 mph 0.00 in / hr 590 ft 8 min 40 sec ago Normal Bucktown, Chicago, IL 74.0 °F 76 °F 64 °F 70% North at 0.0 mph 0.00 in / hr 600 ft 0 sec ago Rapid Fire DePaul Geography, Chicago, IL 75.6 °F 77 °F 65 °F 69% North at 0.0 mph 0.00 in / hr 650 ft 3 min 57 sec ago Rapid Fire South Lakeview, Chicago, IL 75.1 °F 77 °F 62 °F 62% SSE at 0.0 mph 0.00 in / hr 607 ft 0 sec ago Rapid Fire West Lakeview, Chicago, IL 74.9 °F 77 °F 64 °F 69% SSE at 2.0 mph 0.00 in / hr 636 ft 11 min 20 sec ago Normal Lakeview East, Chicago, IL 75.6 °F 77 °F 66 °F 69% ENE at 6.9 mph 0.00 in / hr 630 ft 5 sec ago Rapid Fire Irving Park, Chicago, IL 74.5 °F 76 °F 66 °F 74% ESE at 4.0 mph 0.00 in / hr 600 ft 1 sec ago Rapid Fire North Park University, Chicago, IL 74.3 °F 75 °F 66 °F 75% SSE at 3.0 mph 0.00 in / hr 617 ft 12 min 48 sec ago Normal Oak Park, IL, Oak Park, IL 73.2 °F 74 °F 66 °F 78% South at 2.0 mph 0.00 in / hr 617 ft 8 sec ago Rapid Fire APRSWXNET Berwyn IL , Berwyn, IL 74 °F 75 °F 67 °F 79% South at 1 mph 0.00 in / hr 620 ft 25 min 53 sec ago MADIS Peterson Woods, Chicago, IL 73.6 °F 74 °F 66 °F 78% SSW at 0.2 mph 0.00 in / hr 614 ft 3 min 22 sec ago Normal Midway Airport SE corner runway 13C 12/0, Chicago, IL 72.3 °F 75 °F 61 °F 67% South at 4.0 mph 0.00 in / hr 620 ft 1 min 33 sec ago Normal West Rogers Park, Chicago, IL 75.7 °F 77 °F 64 °F 68% North at 0.0 mph 0.00 in / hr 595 ft 1 sec ago Rapid Fire Garfield Ridge, Chicago, IL 73.6 °F 76 °F 63 °F 70% NE at 3.1 mph 0.00 in / hr 604 ft 4 sec ago Rapid Fire Historic East Side, Harwood Heights, IL 73.5 °F 75 °F 65 °F 73% South at 1.0 mph 0.00 in / hr 635 ft 1 min 47 sec ago Normal Lincolnwood, Lincolnwood, IL 73.8 °F 75 °F 64 °F 72% SSE at 3.0 mph 0.00 in / hr 0 ft 4 min 45 sec ago Normal Evanston KU9Z.Net, Evanston, IL 73.8 °F 75 °F 65 °F 74% WSW at 0.0 mph 0.00 in / hr 600 ft 9 sec ago Rapid Fire Lyons Police Department, Lyons, IL 74.0 °F 75 °F 66 °F 75% North at 1.0 mph 0.00 in / hr 615 ft 2 sec ago Rapid Fire South Evanston, Evanston, IL 73.3 °F 74 °F 67 °F 80% South at 0.0 mph 0.00 in / hr 640 ft 35 sec ago Normal KC9HZC, Brookfield, IL 71.1 °F - 69 °F 92% NE at 0.0 mph 0.00 in / hr 617 ft 40 sec ago Rapid Fire Irving Park Rd & Pacific Ave, Chicago, IL 73.0 °F 73 °F 66 °F 80% ESE at 0.0 mph 0.00 in / hr 635 ft 7 sec ago Rapid Fire Lyons Illinois Weather, Lyons, IL 73.1 °F 74 °F 65 °F 76% ESE at 0.0 mph 0.00 in / hr 620 ft 2 min 45 sec ago Normal MARITIME , Chicago, IL 74 °F 72 °F - - SSE at 16 mph 0.00 in / hr 577 ft 42 min 53 sec ago MADIS Brookfield, IL 73.1 °F 74 °F 66 °F 78% SSE at 1.0 mph 0.00 in / hr 659 ft 14 min 35 sec ago Normal APRSWXNET Norridge IL , Chicago, IL 73 °F 74 °F 66 °F 78% East at 0 mph 0.00 in / hr 656 ft 1 hr 5 min 53 sec ago MADIS APRSWXNET Oak Lawn IL, Hometown, IL 72 °F 73 °F 65 °F 79% North at 0 mph 0.00 in / hr 620 ft 22 min 53 sec ago MADIS Mr. Hammes's Weather, Westchester, IL 70.9 °F 74 °F 61 °F 71% ESE at 0.0 mph 0.00 in / hr 641 ft 2 sec ago Rapid Fire Norwood Park Township, IL 73.8 °F 74 °F 68 °F 81% South at 3.8 mph 0.00 in / hr 646 ft 1 sec ago Rapid Fire Gladstone Park Area, Westchester, IL 72.5 °F 73 °F 65 °F 78% SSE at 1.0 mph 0.00 in / hr 640 ft 4 min 29 sec ago Normal KA9UMG 91th and Mobile, Oak Lawn, IL 74.0 °F 76 °F 64 °F 70% SSE at 2.1 mph 0.00 in / hr 627 ft 3 sec ago Rapid Fire
Atlanta
Atlanta, GA 5:23 AM EDT on July 25, 2012 (GMT -0400) Elev: 876 ft Lon: 84.4° W Lat: 33.9° NSource Rapid Fire Updates™ Updated 32 min 46 sec ago Get Free Weather Stickers® Share: Tropical Weather: Invest 98l (North Atlantic) Invest 90e (East Pacific) View WunderPhotos® in: Atlanta, Georgia Visit Our Video Section Weather Summary Jessica Parker Weather Underground Forecast for Wednesday, July 25, 2012. A low pressure system over the Northern Plains is expected to move eastward Wednesday and Thursday and become the main weather producer for the nation. Showers and thunderstorms will continue from the Northern and Central Plains to the Great Lakes and Ohio Valley. In particular, a slight risk of severe thunderstorms is expected from the Upper Mississippi and Mid-Missouri valleys across the Great Lakes, with the main threat of hail and damaging winds. Apart from this system, a frontal boundary will remain over the Mid-Atlantic and parts of the Tennessee Valley and Southeast. Showers and thunderstorms are anticipated with this system. Elsewhere, unsettled weather will persist over portions of the Gulf States. Expect showers and thunderstorms to become more widespread in the afternoon and evening especially over the coastal region. In addition, monsoonal flow will keep scattered showers and thunderstorms going over the Four Corners region. Farther north, a weak front in the northern Intermountain West may trigger a few showers and thunderstorms. Another hot day is in store for portions of the Central Plains, Mississippi Valley and Ohio Valley Wednesday and Thursday. Afternoon temperatures are expected in the 100s with possible heat indicies 105 to 110. Moreover, minimum nighttime temperatures will only fall into the mid-70s. Continue Reading… Weather Underground Broadcast Network Atlanta Weather at a Glance Weather Station Atlanta (KATL) Elevation 1024 ft Station Select Now Clear Temperature 78 °F Feels Like 78 °F Wind(mph) 6 Sunrise / Set 6:44 AM 8:43 PM Weather Stations Station Location Temp. Heat Index Dew Point Humidity Wind Precipitation Elevation Updated Type Website Buckhead, Atlanta, GA 76.1 °F 77 °F 72 °F 81% WSW at 1.0 mph 0.00 in / hr 1042 ft 4 sec ago Rapid Fire Buckhead: The Wakefield, Atlanta, GA 76.8 °F 78 °F 73 °F 87% ENE at 0.0 mph 0.00 in / hr 1240 ft 24 min 29 sec ago Normal Sandy Springs, Atlanta, GA 74.7 °F 73 °F 72 °F 92% North at 0.0 mph 0.00 in / hr 1020 ft 9 min 48 sec ago Normal Midtown/Buckhead, Atlanta, GA 75.3 °F 74 °F 72 °F 91% NW at 0.0 mph 0.00 in / hr 918 ft 4 sec ago Rapid Fire Marist School, Atlanta, GA 74.1 °F 77 °F 59 °F 59% NW at 0.0 mph 0.00 in / hr 880 ft 10 min 35 sec ago Normal Georgia Tech (Midtown), Atlanta, GA 78.6 °F 81 °F 70 °F 75% SW at 0.0 mph 0.00 in / hr 1050 ft 1 sec ago Rapid Fire Smynings, Smyrna, GA 77.4 °F 79 °F 71 °F 82% NW at 0.7 mph 0.00 in / hr 1076 ft 0 sec ago Rapid Fire Druid Hills, Atlanta, GA 78.3 °F 81 °F 72 °F 80% WNW at 0.0 mph 0.00 in / hr 1022 ft 6 min 1 sec ago Normal Lakeside, Atlanta, GA 77.5 °F 79 °F 72 °F 83% North at 0.0 mph 0.00 in / hr 971 ft 4 min 45 sec ago Normal Murphey Candler, Atlanta, GA 75.9 °F 77 °F 69 °F 79% North at 0.0 mph 0.00 in / hr 930 ft 1 sec ago Rapid Fire Chattahoochee Plantation, Marietta, GA 74.0 °F 72 °F 74 °F 93% WNW at 0.0 mph 0.00 in / hr 1018 ft 1 sec ago Rapid Fire Williams Park, Smyrna, GA 76.9 °F 78 °F 71 °F 82% WNW at 0.0 mph 0.00 in / hr 1099 ft 31 sec ago Normal Clairemont-Great Lakes, Decatur, GA 76.3 °F 77 °F 70 °F 81% SE at 0.0 mph 0.00 in / hr 0 ft 1 sec ago Rapid Fire PepperMill, Marietta, GA 73.6 °F 70 °F 72 °F 95% South at 0.0 mph 0.00 in / hr 978 ft 9 min 57 sec ago Normal Wyntercreek/Meadowcreek, Dunwoody, GA 75.0 °F 77 °F 63 °F 67% WNW at 0.0 mph 0.00 in / hr 1072 ft 10 sec ago Rapid Fire Meadowcreek Estates, Dunwoody, GA 75.6 °F 76 °F 69 °F 80% WNW at 0.0 mph 0.00 in / hr 1072 ft 9 sec ago Rapid Fire Glenwood Estates, Decatur, GA 75.2 °F 74 °F 72 °F 91% East at 0.0 mph 0.00 in / hr 1016 ft 6 sec ago Rapid Fire Kirkwood, Atlanta, GA 75.9 °F 76 °F 72 °F 88% North at 0.0 mph 0.00 in / hr 1050 ft 4 min 25 sec ago Normal Storybook Estates, Decatur, GA 73.9 °F 75 °F 67 °F 78% NE at 0.0 mph 0.00 in / hr 0 ft 1 sec ago Rapid Fire Grant Park, Atlanta, GA 79.3 °F 82 °F 70 °F 74% NE at 0.0 mph 0.00 in / hr 1050 ft 4 min 34 sec ago Normal Lake Colony, Marietta, GA 76.8 °F 78 °F 57 °F 49% WNW at 0.0 mph 0.00 in / hr 1023 ft 2 sec ago Rapid Fire Rose Arbor, Atlanta, GA 79.3 °F 83 °F 73 °F 80% NW at 0.0 mph 0.00 in / hr 980 ft 41 sec ago Normal East Atlanta Village, Atlanta, GA 76.1 °F 77 °F 72 °F 87% North at 0.0 mph 0.00 in / hr 1020 ft 5 sec ago Rapid Fire City of Avondale Estates, Avondale Estates, GA 78.8 °F 83 °F 78 °F 98% WNW at 1.6 mph - / hr 1079 ft 2 min 35 sec ago Normal Providence Place, Marietta, GA 73.6 °F 74 °F 67 °F 81% NW at 0.0 mph 0.00 in / hr 1072 ft 0 sec ago Rapid Fire Avondale Estates, Avondale Estates, GA 77.2 °F 79 °F 70 °F 79% NW at 0.6 mph 0.00 in / hr 1027 ft 2 sec ago Rapid Fire Oak Creek, Avondale Estates, GA 76.0 °F 77 °F 71 °F 85% West at 0.0 mph 0.00 in / hr 975 ft 4 min 29 sec ago Normal Ladywiz, Mableton, GA 76.4 °F 77 °F 72 °F 87% North at 1.0 mph 0.00 in / hr 1000 ft 1 hr 32 min 1 sec ago Normal Fair Oaks, Marietta, GA 76.3 °F 78 °F 68 °F 76% West at 0.0 mph 0.00 in / hr 1096 ft 3 sec ago Rapid Fire Eagle Ridge, Marietta, GA 77.7 °F 80 °F 72 °F 82% NNW at 1.0 mph 0.00 in / hr 1170 ft 2 sec ago Rapid Fire Blackjack Mtn, Marietta, GA 76.5 °F 78 °F 71 °F 84% WNW at 2.0 mph 0.00 in / hr 1299 ft 44 sec ago Rapid Fire
Kind of hard to believe that after all these years somebody checked nearby thermometers against airport thermometers. As a former light aircraft pilot I knew that there was an updraft over the airfield pavement that wasn’t there over grass fields. All of that pavement is energy conductive and a much higher energy storage mass then soil. Much of the surface materials research that I have seen only deals with reflectivity and surface absorption of energy, nothing on conduction and storage of heat energy. This certainly demonstrates that airport thermometers are a poor substitute for open field stations. Large paved airfields have a heat bubble or bulge over them, similar to the one over cities. Man made global warming,……….. pavement. pg
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@P.G.Sharrow:
Having flown in hot air balloons and taken glider lessons, I’m pretty sensitive to the “lift” you get near tarmac and runways… It can be dramatic in a glider.
At any rate, this little “trick” with Wunderground lets anyone do a ‘sanity check’ on nearby stations… at least until Wunderground pulls the station list under pressure from warmers ;-)