Mountain system artificially inflates temperature increases at higher elevations

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Image credit: Wikimedia Commons.

In a recent study, University of Montana and Montana Climate Office researcher Jared Oyler found that while the western U.S. has warmed, recently observed warming in the mountains of the western U.S. likely is not as large as previously supposed.

His results, published Jan. 9 in the journal Geophysical Research Letters, show that sensor changes have significantly biased temperature observations from the Snowpack Telemetry (SNOTEL) station network.

More than 700 SNOTEL sites monitor temperature and snowpack across the mountainous western U.S. SNOTEL provides critical data for water supply forecasts. Researchers often use SNOTEL data to study mountain climate trends and impacts to mountain hydrology and ecology.

Oyler and his co-authors applied statistical techniques to account for biases introduced when equipment was switched at SNOTEL sites in the mid-1990s to mid-2000s.

His revised datasets reduced the biases to reveal that high-elevation minimum temperatures were only slightly more than minimum temperatures at lower elevations.

"Observations from other station networks clearly show that the western U.S. has experienced regional warming," Oyler said, "but to assess current and future change impacts to snowpack and important mountain ecosystem processes, we need accurate observations from the high elevation areas only covered by the SNOTEL network. The SNOTEL bias has likely compromised our ability to understand the unique drivers and in western U.S. mountains."

Co-authors on the paper "Artificial Amplification of Warming Trends Across the Mountains of the Western United States" include UM researchers Solomon Dobrowski, Ashley Ballantyne, Anna Klene and Steve Running. It is available online at onlinelibrary.wiley.com/enhanc … 0.1002/2014GL062803/ .


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Study improves temperature modeling across mountainous landscapes

Journal information: Geophysical Research Letters

Citation: Mountain system artificially inflates temperature increases at higher elevations (2015, January 12) retrieved 27 May 2019 from https://phys.org/news/2015-01-mountain-artificially-inflates-temperature-higher.html
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Jan 12, 2015
Another confirmation of instrument and measurement bias that has been noted by meteorologists and others. Here is a published study that shows that locating a significant number of gauges in the U.S. near artificial heat sources has artificially inflated the average warming measured.

http://pielkeclim...-367.pdf

The fact that average nighttime temperatures account for the majority of the increase in warming (versus daytime temperatures) suggests that the urban heat island effect is more pronounced than we've been lead to believe.

https://www2.ucar...cross-us

Alarmists claim that the nighttime temperature increase validates predictions made by computer models, but it's more likely an artifact of increasing urbanization around weather stations as the climate models are famously inaccurate.

http://www.climat...g1-4.jpg

Jan 13, 2015
"We have also studied station quality. Many US stations have low quality rankings according to a study led by Anthony Watts. However, we find that the warming seen in the "poor" stations is virtually indistinguishable from that seen in the "good" stations"

http://www.scient...hearing/

"Again, Muller is sanguine: "There were no mistakes in that paper. McKitrick had comments and found things he thought were mistakes, but we wrote back to him and told him he was wrong." He adds: "I think the conclusion that urban heat islands contribute essentially zero to the warming we see is on very solid ground." Indeed, due to BEST and studies that went before it, Muller says that the question of whether urban heating skews warming data is no longer a legitimate quibble with data that shows warming."

http://www.carbon...d-muller

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