{"id":252651,"date":"2023-04-13T16:33:11","date_gmt":"2023-04-13T14:33:11","guid":{"rendered":"https:\/\/climatescience.press\/?p=252651"},"modified":"2023-04-13T16:33:23","modified_gmt":"2023-04-13T14:33:23","slug":"classifying-land-temperature-stations-as-either-urban-or-rural-in-uhi-studies-proves-nothing-about-spurious-temperature-trends-2","status":"publish","type":"post","link":"https:\/\/climatescience.press\/?p=252651","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

From Dr. Roy Spencer\u2019s Global Warming Blog<\/a><\/p>\n\n\n\n

April 8th, 2023 by Roy W. Spencer, Ph. D.<\/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 at any given time<\/em> that they then have a much larger spurious warming impact on trends over time<\/em>. That is simply not true.<\/em><\/strong><\/p>\n","protected":false},"excerpt":{"rendered":"

The mistake people have made is to assume that just because urban locations are warmer than rural locations\u00a0at any given time\u00a0that they then have a much larger spurious warming impact on\u00a0trends over time.\u00a0That is simply not true.<\/p>\n","protected":false},"author":121246920,"featured_media":252656,"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":[691818159,691818161,691818386],"class_list":{"0":"post-252651","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","12":"fallback-thumbnail"},"jetpack_publicize_connections":[],"jetpack_featured_media_url":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/04\/0-ghost-45.jpeg?fit=1500%2C1236&ssl=1","jetpack_likes_enabled":true,"jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/paxLW1-13J1","jetpack-related-posts":[{"id":251864,"url":"https:\/\/climatescience.press\/?p=251864","url_meta":{"origin":252651,"position":0},"title":"Classifying Land Temperature Stations as Either \u201cUrban\u201d or \u201cRural\u201d in UHI Studies Proves Nothing about Spurious Temperature Trends","author":"uwe.roland.gross","date":"08\/04\/2023","format":false,"excerpt":"That is simply not true.","rel":"","context":"In \"Land Temperature Stations\"","block_context":{"text":"Land Temperature Stations","link":"https:\/\/climatescience.press\/?tag=land-temperature-stations"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/04\/040272.jpg?fit=1000%2C1000&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/04\/040272.jpg?fit=1000%2C1000&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/04\/040272.jpg?fit=1000%2C1000&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/04\/040272.jpg?fit=1000%2C1000&ssl=1&resize=700%2C400 2x"},"classes":[]},{"id":267979,"url":"https:\/\/climatescience.press\/?p=267979","url_meta":{"origin":252651,"position":1},"title":"The Urban Heat Island Effect in GHCN Station Temperatures: Urban Locations show Large Spurious Warming Effects","author":"uwe.roland.gross","date":"17\/07\/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 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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":243950,"url":"https:\/\/climatescience.press\/?p=243950","url_meta":{"origin":252651,"position":3},"title":"Evidence that Statistical Adjustments and Urbanization Spuriously Warm Temperature Trends","author":"uwe.roland.gross","date":"09\/02\/2023","format":false,"excerpt":"Urbanization Effects on GHCN Temperature Trends, Part II: Evidence that Homogenization Spuriously Warms Trends","rel":"","context":"Similar post","block_context":{"text":"Similar post","link":""},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/02\/image-360.png?fit=990%2C765&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/02\/image-360.png?fit=990%2C765&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/02\/image-360.png?fit=990%2C765&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/02\/image-360.png?fit=990%2C765&ssl=1&resize=700%2C400 2x"},"classes":[]},{"id":243718,"url":"https:\/\/climatescience.press\/?p=243718","url_meta":{"origin":252651,"position":4},"title":"Urbanization Effects on GHCN Temperature Trends, Part II: Evidence that Homogenization Spuriously Warms Trends","author":"uwe.roland.gross","date":"07\/02\/2023","format":false,"excerpt":"So, what effect does urbanization measured in this manner have on GHCN temperatures?\u00a0And, especially, on temperature trends used for monitoring global warming?","rel":"","context":"Similar post","block_context":{"text":"Similar post","link":""},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/02\/image-305.png?fit=1200%2C600&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/02\/image-305.png?fit=1200%2C600&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/02\/image-305.png?fit=1200%2C600&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/02\/image-305.png?fit=1200%2C600&ssl=1&resize=700%2C400 2x, https:\/\/i0.wp.com\/climatescience.press\/wp-content\/uploads\/2023\/02\/image-305.png?fit=1200%2C600&ssl=1&resize=1050%2C600 3x"},"classes":[]},{"id":239579,"url":"https:\/\/climatescience.press\/?p=239579","url_meta":{"origin":252651,"position":5},"title":"Urbanization Effects on GHCN Temperature Trends, Part I: The Urbanization Characteristics of the GHCN Stations","author":"uwe.roland.gross","date":"14\/01\/2023","format":false,"excerpt":"Anthony Watts has\u00a0approached this problem\u00a0for the U.S. temperature monitoring stations by physically visiting the sites and documenting the exposure of the thermometers to spurious heat sources (active and passive), and comparing trends from well-sited instruments to trends from poorly sited instruments. 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