Feb 22, 2011

The identification of distinct patterns in California temperature trends

Eugene C. Cordero, Wittaya Kessomkiat, John Abatzoglou, Steven A. Mauget
Climatic Change
  • Analyzes regional changes in California surface temperatures over the last 80 years
  • Analysis shows a distinctly different spatial and temporal patterns in trends of maximum temperature (Tmax) compared to trends of minimum temperature (Tmin)
  • Finds that for trends computed between 1918 and 2006, the rate of warming in Tmin is greater than that of Tmax
  • Finds that trends computed since 1970 show an amplified warming rate compared to trends computed from 1918, and the rate of warming is comparable between Tmin and Tmax
  • Compares annual trends across regions for two time periods, 1918-2006 and 1970-2006 and identifies an accelerated warming trend from 1970-2006
  • Finds statewide maximum temperature trends between 1970-2006 were +0.27°C per decade—more than three times as large as the trend between 1918-2006, of +0.07°C per decade

  • Figure: California annual maximum (top) and minimum (bottom) temperatures computed from the USHCN network between 1918–2006. The linear trends (in °C dec−1) are shown where an asterisk indicates that the trend is statistically significant at the 95% confidence level. Accompanying each statewide time series, statistically significant Z values (at the 95% and 99% confidence level) for the MWU analysis are shown, where blue shading indicates cool periods and red shading indicates warm periods
  • Figure: Annual temperature trends (°C dec−1) for the 11 climate regions labeled A-K computed between 1918–2006 for TmaxTmin (right), where the trends that are statistically significant at the 95% confidence level are indicated with an asterisk