{"id":251864,"date":"2023-04-08T19:59:36","date_gmt":"2023-04-08T17:59:36","guid":{"rendered":"https:\/\/climatescience.press\/?p=251864"},"modified":"2023-04-08T19:59:43","modified_gmt":"2023-04-08T17:59:43","slug":"classifying-land-temperature-stations-as-either-urban-or-rural-in-uhi-studies-proves-nothing-about-spurious-temperature-trends","status":"publish","type":"post","link":"https:\/\/climatescience.press\/?p=251864","title":{"rendered":"Classifying Land Temperature Stations as Either \u201cUrban\u201d or \u201cRural\u201d in UHI Studies Proves Nothing about Spurious Temperature Trends"},"content":{"rendered":"\n
\"\"<\/figure>\n\n\n\n

<\/p>\n\n\n\n

By Roy W. Spencer, Ph. D.<\/a><\/p>\n\n\n\n

As I spend more time working on a research project, the more time I have to reflect on things that others have simply assumed to be true. And in the process I sometimes have an epiphany than clarifies my thinking on a subject.<\/p>\n\n\n\n

As I continue to investigate how to quantify urban heat island (UHI) effects for the purpose of determining the extent to which land surface temperature trends have been spuriously inflated by urbanization effects, there is one recurring theme I find has not been handled well in previously published papers on the subject. I\u2019ve mentioned it before, but it\u2019s so important, it deserves its own (brief) blog post.<\/p>\n\n\n\n

It has to do with the common assumption that \u201curban\u201d thermometer sites experience spurious warming over time, while \u201crural\u201d sites do not.<\/p>\n\n\n\n

Obviously, at any given point in time urban environments are warmer than rural environments, especially at night. And urbanization has increased around temperature monitoring sites over the last 50 to 100 years (and longer). Yet, a number of studies over the years have curiously found that urban and rural sites have very similar temperature trends. This has led investigators to conclude that temperature datasets such as the Global Historical Climate Network (GHCN), especially after \u201chomogenization\u201d, is largely free of spurious warming effects from urbanization.<\/p>\n\n\n\n

But the conclusion is wrong\u2026all it shows is that temperature trends between rural and urban sites are similar\u2026 not that those trends are unaffected by urbanization effects.<\/p>\n\n\n\n

Instead, studies have demonstrated that the greatest rate of warming as population increases is for nearly-rural sites, not urban. The one-fourth power relationship found by Oke (1973)<\/a> and others (and which I am also finding in GHCN data in the summer) means that a population density increase from 1 to 10 persons per sq. km (both \u201crural\u201d) produces more warming than an urban site going from 1,000 to 1,700 persons per sq. km.<\/em><\/p>\n\n\n\n

Thus, \u201crural\u201d sites cannot be assumed to be immune to spurious warming from urbanization. This means that studies that have compared \u201crural\u201d to \u201curban\u201d temperature trends haven\u2019t really proved anything.<\/p>\n\n\n\n

The mistake people have made is to assume that just because urban locations are warmer than rural locations\u00a0at any given time<\/em>\u00a0that they then have a much larger spurious warming impact on\u00a0trends over time<\/em>.\u00a0<\/p>\n\n\n\n

That is simply not true.<\/em><\/strong><\/p>\n","protected":false},"excerpt":{"rendered":"

That is simply not true.<\/p>\n","protected":false},"author":121246920,"featured_media":251867,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_coblocks_attr":"","_coblocks_dimensions":"","_coblocks_responsive_height":"","_coblocks_accordion_ie_support":"","_crdt_document":"","advanced_seo_description":"","jetpack_seo_html_title":"","jetpack_seo_noindex":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2},"jetpack_post_was_ever_published":false},"categories":[1],"tags":[691818159,691818161,691818160],"class_list":{"0":"post-251864","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","6":"hentry","7":"category-uncategorized","8":"tag-land-temperature-stations","9":"tag-temperature-trends","10":"tag-urban-heat-island-uhi-effects","12":"fallback-thumbnail"},"jetpack_publicize_connections":[],"jetpack_featured_media_url":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/04\/040272.jpg?fit=1000%2C1000&ssl=1","jetpack_likes_enabled":true,"jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/paxLW1-13wk","jetpack-related-posts":[{"id":378577,"url":"https:\/\/climatescience.press\/?p=378577","url_meta":{"origin":251864,"position":0},"title":"Our Urban Heat Island Paper Has Been Published","author":"uwe.roland.gross","date":"05\/16\/2025","format":false,"excerpt":"It took the better part of two years to satisfy the reviewers, but finally our paper\u00a0Urban Heat Island Effects in U.S. Summer Surface Temperature Data, 1895\u20132023\u00a0has been published in the AMS\u00a0Journal of Applied Meteorology and Climatology.","rel":"","context":"In \"GHCN stations\"","block_context":{"text":"GHCN stations","link":"https:\/\/climatescience.press\/?tag=ghcn-stations"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/09\/00glo-urban-heat-island-effect.webp?fit=1200%2C690&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/09\/00glo-urban-heat-island-effect.webp?fit=1200%2C690&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/09\/00glo-urban-heat-island-effect.webp?fit=1200%2C690&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/09\/00glo-urban-heat-island-effect.webp?fit=1200%2C690&ssl=1&resize=700%2C400 2x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/09\/00glo-urban-heat-island-effect.webp?fit=1200%2C690&ssl=1&resize=1050%2C600 3x"},"classes":[]},{"id":338783,"url":"https:\/\/climatescience.press\/?p=338783","url_meta":{"origin":251864,"position":1},"title":"Right, Washington Post, Rural Areas Are Significantly Cooler Than Cities, But Please Learn How to Convert Celsius to Fahrenheit","author":"uwe.roland.gross","date":"08\/08\/2024","format":false,"excerpt":"An August 3rd article in The Washington Post (WaPo), \u201ctitled Study suggests nearby rural land can cool cities by nearly 30 percent,\u201d admits what others, including The Heartland Institute, have noted for years: rural areas are much cooler than cities. What is new is they are suggesting that the rural\u2026","rel":"","context":"In \"Celsius\"","block_context":{"text":"Celsius","link":"https:\/\/climatescience.press\/?tag=celsius"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2024\/08\/0daef4-6a010536b58035970c017744ad1afa970d-pi.jpg?fit=1200%2C648&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2024\/08\/0daef4-6a010536b58035970c017744ad1afa970d-pi.jpg?fit=1200%2C648&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2024\/08\/0daef4-6a010536b58035970c017744ad1afa970d-pi.jpg?fit=1200%2C648&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2024\/08\/0daef4-6a010536b58035970c017744ad1afa970d-pi.jpg?fit=1200%2C648&ssl=1&resize=700%2C400 2x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2024\/08\/0daef4-6a010536b58035970c017744ad1afa970d-pi.jpg?fit=1200%2C648&ssl=1&resize=1050%2C600 3x"},"classes":[]},{"id":284165,"url":"https:\/\/climatescience.press\/?p=284165","url_meta":{"origin":251864,"position":2},"title":"New paper submission: Urban heat island effects in U.S. summer temperatures, 1880-2015","author":"uwe.roland.gross","date":"10\/20\/2023","format":false,"excerpt":"Urban heat islands concern both the temperature of various surfaces (streets, roofs, etc.) and the atmosphere.\u00a0The absorbed\u00a0heat during the day by the urban infrastructure is given away slowly \u2013 therefore also at night. 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After years of dabbling\u2026","rel":"","context":"In \"John Christy\"","block_context":{"text":"John Christy","link":"https:\/\/climatescience.press\/?tag=john-christy"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/10\/0shutterstock_666649831-1024x629-1.png?fit=1024%2C629&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/10\/0shutterstock_666649831-1024x629-1.png?fit=1024%2C629&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/10\/0shutterstock_666649831-1024x629-1.png?fit=1024%2C629&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/10\/0shutterstock_666649831-1024x629-1.png?fit=1024%2C629&ssl=1&resize=700%2C400 2x"},"classes":[]},{"id":267979,"url":"https:\/\/climatescience.press\/?p=267979","url_meta":{"origin":251864,"position":3},"title":"The Urban Heat Island Effect in GHCN Station Temperatures: Urban Locations show Large Spurious Warming Effects","author":"uwe.roland.gross","date":"07\/17\/2023","format":false,"excerpt":"It has been a while since I have posted progress on our DOE-funded research into the Urban Heat Island (UHI) effect in the GHCN station temperatures used to monitor land-based global warming. It should be remembered that everything I post on this subject is (as is usually the case) a\u2026","rel":"","context":"In \"GHCN station temperatures\"","block_context":{"text":"GHCN station temperatures","link":"https:\/\/climatescience.press\/?tag=ghcn-station-temperatures"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/07\/03_urbanheatisland.webp?fit=1024%2C552&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/07\/03_urbanheatisland.webp?fit=1024%2C552&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/07\/03_urbanheatisland.webp?fit=1024%2C552&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/07\/03_urbanheatisland.webp?fit=1024%2C552&ssl=1&resize=700%2C400 2x"},"classes":[]},{"id":348954,"url":"https:\/\/climatescience.press\/?p=348954","url_meta":{"origin":251864,"position":4},"title":"Urban Heat Island Effects Have Not Yet Been Removed from Official GHCN Warming Trends","author":"uwe.roland.gross","date":"10\/26\/2024","format":false,"excerpt":"Our paper (co-authored by John Christy and Danny Braswell) on computing the urban heat island (UHI) effect as a function of population density (PD) is now in the final stages of review after a 3rd round of edits, and I\u2019m hopeful it will be accepted for publication soon.","rel":"","context":"In \"GHCN Warming Trends\"","block_context":{"text":"GHCN Warming Trends","link":"https:\/\/climatescience.press\/?tag=ghcn-warming-trends"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2024\/10\/0Screenshot-2024-10-26-083344.png?fit=1200%2C851&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2024\/10\/0Screenshot-2024-10-26-083344.png?fit=1200%2C851&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2024\/10\/0Screenshot-2024-10-26-083344.png?fit=1200%2C851&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2024\/10\/0Screenshot-2024-10-26-083344.png?fit=1200%2C851&ssl=1&resize=700%2C400 2x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2024\/10\/0Screenshot-2024-10-26-083344.png?fit=1200%2C851&ssl=1&resize=1050%2C600 3x"},"classes":[]},{"id":280654,"url":"https:\/\/climatescience.press\/?p=280654","url_meta":{"origin":251864,"position":5},"title":"Summer warming 1895-2023 in U.S. cities exaggerated by 100% from the urban heat island effect","author":"uwe.roland.gross","date":"09\/27\/2023","format":false,"excerpt":"We are now getting close to finalizing our methodology for computing the urban heat island (UHI) effect as a function of population density, and will be submitting our first paper for publication in the next few weeks. 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