Climate Change Indices Derived from Daily In Situ Data

Long-term climate change has historically been primarily identified by changes in means, such as changes in global mean temperature. However, identifying changes in means does not necessarily identify the impacts of climate change. For example, increasing or decreasing of the frost free period may have a much greater impact than changes in mean temperature. To determine the length of the frost free period and many other relevant indices requires daily in situ data. At the National Climatic Data Center, we have been assembling a multi-nation set of long-term - on the order of a half-century - daily station maximum temperature, minimum temperature and precipitation data. From these data we have derived approximately two dozen indices. Analysis of some of these indices reveals strong global or regional changes in climate while others do not. This presentation will describe what climate change insights analyses of these indices can provide.