Journal cover Journal topic
Climate of the Past An interactive open-access journal of the European Geosciences Union
Clim. Past, 7, 975-983, 2011
© Author(s) 2011. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
31 Aug 2011
Temperature trends at the Mauna Loa observatory, Hawaii
B. D. Malamud1, D. L. Turcotte2, and C. S. B. Grimmond1 1King's College London, Department of Geography, Strand, London, WC2R 2LS, UK
2University of California, Department of Geology, Davis, CA 95616, USA
Abstract. Observations at the Mauna Loa Observatory, Hawaii, established the systematic increase of anthropogenic CO2 in the atmosphere. For the same reasons that this site provides excellent globally averaged CO2 data, it may provide temperature data with global significance. Here, we examine hourly temperature records, averaged annually for 1977–2006, to determine linear trends as a function of time of day. For night-time data (22:00 to 06:00 LST (local standard time)) there is a near-uniform warming of 0.040 °C yr−1. During the day, the linear trend shows a slight cooling of −0.014 °C yr−1 at 12:00 LST (noon). Overall, at Mauna Loa Observatory, there is a mean warming trend of 0.021 °C yr−1. The dominance of night-time warming results in a relatively large annual decrease in the diurnal temperature range (DTR) of −0.050 °C yr−1 over the period 1977–2006. These trends are consistent with the observed increases in the concentrations of CO2 and its role as a greenhouse gas (demonstrated here by first-order radiative forcing calculations), and indicate the possible relevance of the Mauna Loa temperature measurements to global warming.

Citation: Malamud, B. D., Turcotte, D. L., and Grimmond, C. S. B.: Temperature trends at the Mauna Loa observatory, Hawaii, Clim. Past, 7, 975-983,, 2011.
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