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Cited by 151Climate variability and modelsUrban Heat Island MitigationHydrology and Drought Analysis

Methodology and results of calculating central California surface temperature trends: Evidence of human-induced climate change?

Christy, John R., Norris, William B., Redmond, Kelly, Gallo, Kevin P.·2006·Journal of Climate
DOI 10.1175/jcli3627.1
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Abstract

Abstract A procedure is described to construct time series of regional surface temperatures and is then applied to interior central California stations to test the hypothesis that century-scale trend differences between irrigated and nonirrigated regions may be identified. The procedure requires documentation of every point in time at which a discontinuity in a station record may have occurred through (a) the examination of metadata forms (e.g., station moves) and (b) simple statistical tests. From this “homogeneous segments” of temperature records for each station are defined. Biases are determined for each segment relative to all others through a method employing mathematical graph theory. The debiased segments are then merged, forming a complete regional time series. Time series of daily maximum and minimum temperatures for stations in the irrigated San Joaquin Valley (Valley) and nearby nonirrigated Sierra Nevada (Sierra) were generated for 1910–2003. Results show that twentieth-century Valley minimum temperatures are warming at a highly significant rate in all seasons, being greatest in summer and fall (> +0.25°C decade−1). The Valley trend of annual mean temperatures is +0.07° ± 0.07°C decade−1. Sierra summer and fall minimum temperatures appear to be cooling, but at a less significant rate, while the trend of annual mean Sierra temperatures is an unremarkable −0.02° ± 0.10°C decade−1. A working hypothesis is that the relative positive trends in Valley minus Sierra minima (>0.4°C decade−1 for summer and fall) are related to the altered surface environment brought about by the growth of irrigated agriculture, essentially changing a high-albedo desert into a darker, moister, vegetated plain.

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  • The pairwise method is similar to the graph theory approach used by Christy et al. (2006) except that the pairwise algorithm makes no attempt to compare climate series that do not overlap in time.

    “In this regard, the pairwise method is similar to the graph theory approach used by Christy et al. (2006) except that the pairwise algorithm makes no attempt to compare climate series that do not overlap in time.”

    From Homogenization of Temperature Series via Pairwise Comparisons (2009) · cites this paper as Christy et al. (2006)

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Related

Authors
Christy, J. R., Norris, W. B., Redmond, K., & Gallo, K. P.
Affiliations
  • University of Alabama in Huntsville (US)
  • Western Regional Climate Center, Reno, Nevada
  • National Oceanic and Atmospheric Administration (US)
ORCID
Venue
Journal of Climate
Publisher
American Meteorological Society
Published
2006-02-15
Volume
19
Issue
4
Pages
548-563
ISSN
  • 0894-8755 (ISSN-L)
  • 1520-0442
DOI
10.1175/jcli3627.1
OpenAlex
W2042939250
Cited by
151
References
29
Citations by year
2026: 2 · 2025: 3 · 2024: 2 · 2023: 6 · 2022: 6 · 2021: 1 · 2020: 5 · 2019: 8 · 2018: 6 · 2017: 3 · 2016: 13 · 2015: 5 · 2014: 7 · 2013: 13 · 2012: 10
FWCI
12.59
Type
journal article
Language
en
Open access
closed
Locations
  • Journal of Climate (publishedVersion)
  • Lincoln (University of Nebraska) (submittedVersion)
Topics
  • Physical Sciences › Environmental Science › Global and Planetary Change › Climate variability and models
  • Physical Sciences › Environmental Science › Environmental Engineering › Urban Heat Island Mitigation
  • Physical Sciences › Environmental Science › Global and Planetary Change › Hydrology and Drought Analysis
Keywords
surface temperature trends, climate change, irrigated agriculture, San Joaquin Valley, Sierra Nevada, minimum temperature, maximum temperature, station homogenization, albedo change, anthropogenic climate change

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