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An Improved model for determining degree-day values from daily temperature data

Cesaraccio, Carla and Spano, Donatella Emma Ignazia and Duce, Pierpaolo and Snyder, Richard L. (2001) An Improved model for determining degree-day values from daily temperature data. International Journal of Biometeorology, Vol. 45 (4), p. 161-169. eISSN 1432-1254. Article.

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DOI: 10.1007/s004840100104

Abstract

Although using hourly weather data offers the greatest accuracy for estimating growing degree-day values, daily maximum and minimum temperature data are often used to estimate these values by approximating the diurnal temperature trends. This paper presents a new empirical model for estimating the hourly mean temperature. The model describes the diurnal variation using a sine function from the minimum temperature at sunrise until the maximum temperature is reached, another sine function from the maximum temperature until sunset, and a square-root function from then until sunrise the next morning. The model was developed and calibrated using several years of hourly data obtained from five automated weather stations located in California and representing a wide range of climate conditions. The model was tested against an additional data-set at each location. The temperature model gave good results, the root-mean-square error being less than 2.0 °C for most years and locations. The comparison with published models from the literature showed that the model was superior to the other methods. Hourly temperatures from the model were used to calculate degree-day values. A comparison between degree-day estimates determined from the model and those obtained other selected methods is presented. The results showed that the model had the best accuracy in general regardless of the season.

Item Type:Article
ID Code:5296
Status:Published
Refereed:Yes
Uncontrolled Keywords:Maximum temperature, minimum temperature, daily temperature trend, degree-days, phenology
Subjects:Area 07 - Scienze agrarie e veterinarie > AGR/03 Arboricoltura generale e coltivazioni arboree
Divisions:002 Altri enti e centri di ricerca del Nord Sardegna > CNR-Consiglio Nazionale delle Ricerche > Istituto di biometeorologia, Sassari
001 Università di Sassari > 01 Dipartimenti > Economia e sistemi arborei
Publisher:Springer Berlin / Heidelberg
eISSN:1432-1254
Copyright Holders:© ISB 2001
Deposited On:10 Jan 2011 15:44

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