Annual average surface temperature anomalies in Hawai‘i at high and low elevations, 1919-2006

Figure 2-3 Annual average surface temperature anomalies are increasing at both high- and low-elevation stations in Hawai‘i (a total of 21). Temperature anomalies are calculated first as the departure from the monthly mean and then averaged into a calendar year. Anomalies greater than zero indicate temperatures that are above average, while anomalies less than zero indicate below-average temperatures. A seven-year running-mean filter (curved line) has been applied to the data to create a smoothed trend curve (black line). Linear trends have been computed for two periods, 1919–2006 and 1975–2006, where the latter period shows the observed enhanced warming. The steeper warming trend in high-elevation stations (>800 meters or >0.5 mile) is visible in the bottom panel, especially when compared to that of the low-elevation stations in the middle panel (<800 meters or <0.5 mile). Error bars show a standard deviation of +0.5. Asterisks indicate slopes significant at p = 0.05. (© 2008 American Geophysical Union. Reproduced/modified from Giambelluca et al. [2008]) by permission of American Geophysical Union.)