Estimating grass minimum temperatures from screen minimum values and other climatological parameters
✍ Scribed by A. Bootsma
- Publisher
- Elsevier Science
- Year
- 1976
- Weight
- 615 KB
- Volume
- 16
- Category
- Article
- ISSN
- 0002-1571
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✦ Synopsis
Bootsma, A., 1976
. Estimating grass minimum temperatures from screen minimum values and other climatological parameters. Agric. Meteorol., Differences between night-time screen and grass minimum temperatures in a standard climate station were related to general weather parameters, using stepwise multiple linear regression and correlation techniques. Opacity (cloud cover) and wind speed were found to be the most significant parameters in regression, explaining up to 74% of the variation in the differences in temperature between the screen and grass thermometers. There is evidence that absolute air temperature and dew-point depression may, on some occasions, significantly influence the screen to grass minimum temperature difference. The relationships were relatively conservative from season to season and year to year. Wind was not an important parameter at speeds less than 1.8 m sec -1. At low wind speeds the minimum 2-h average opacity was better correlated with the dependent variable than were either longer or shorter opacity averages. In independent data tests, the average screen to grass minimum temperature difference for 82 cases was estimated within 0.1°C of the measured value. Standard error of estimates ranged from 1.5 to 2.0°C. Attempts to obtain significant correlations for weather stations located on slopes in hilly terrain were unsuccessful.