Publication Date:
2016-04-23
Description:
Changes in Diurnal Temperature Range (DTR) over global land areas are compared from a broad range of independent datasets. All datasets agree that global-mean DTR has decreased significantly since 1950, with most of that decrease occurring over 1960-1980. The since-1979 trends are not significant, with inter-dataset disagreement even over the sign of global changes. Inter-dataset spread becomes greater regionally and in particular at the gridbox level. Despite this, there is general agreement that DTR decreased in N. America, Europe and Australia since 1951, with this decrease being partially reversed over Australia and Europe since the early 1980s. There is substantive disagreement between datasets prior to the mid-20 th Century, particularly over Europe, which precludes making any meaningful conclusions about DTR changes prior to 1950, either globally or regionally. Several variants that undertake a broad range of approaches to post-processing steps of gridding and interpolation were analyzed for two of the datasets. These choices have a substantial influence in data sparse regions or periods. The potential of further insights is therefore inextricably linked with the efficacy of data rescue and digitization for maximum and minimum temperature series prior to 1950 everywhere, and in data sparse regions throughout the period of record. Over North America, station selection and homogeneity assessment is the primary determinant. Over Europe, where the basic station data is similar, the post-processing choices are dominant. We assess that globally-averaged DTR has decreased since the mid-twentieth Century, but that this decrease has not been linear.
Print ISSN:
0148-0227
Topics:
Geosciences
,
Physics
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