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A Comparison of Daily Temperature-Averaging Methods: Spatial Variability and Recent Change for the CONUS.
- Source :
- Journal of Climate; Feb2018, Vol. 31 Issue 3, p979-996, 18p, 4 Charts, 4 Graphs, 7 Maps
- Publication Year :
- 2018
-
Abstract
- Traditionally, the daily average air temperature at a weather station is computed by taking the mean of two values, the maximum temperature (Tmax) and the minimum temperature (Tmin), over a 24-h period. These values form the basis for numerous studies of long-term climatologies (e.g., 30-yr normals) and recent temperature trends and changes. However, many first-order weather stations-such as those at airports-also record hourly temperature data. Using an average of the 24 hourly temperature readings to compute daily average temperature has been shown to provide a more precise and representative estimate of a given day's temperature. This study assesses the spatial variability of the differences in these two methods of daily temperature averaging [i.e., (Tmax 1 Tmin)/2; average of 24 hourly temperature values] for 215 first-order weather stations across the conterminous United States (CONUS) over the 30-yr period 1981-2010. A statistically significant difference is shown between the two methods, as well as consistent overestimation of temperature by the traditional method [(Tmax 1 Tmin)/2], particularly in southern and coastal portions of the CONUS. The explanation for the long-term difference between the two methods is the underlying assumption for the twice-daily method that the diurnal curve of temperature is symmetrical. Moreover, this paper demonstrates a spatially coherent pattern in the difference compared to the most recent part of the temperature record (2001-15). The spatial and temporal differences shown have implications for assessments of the physical factors influencing the diurnal temperature curve, as well as the exact magnitude of contemporary climate change. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 08948755
- Volume :
- 31
- Issue :
- 3
- Database :
- Complementary Index
- Journal :
- Journal of Climate
- Publication Type :
- Academic Journal
- Accession number :
- 128525482
- Full Text :
- https://doi.org/10.1175/JCLI-D-17-0089.1