Journal home   ·   This volume   ·   Previous abstract   ·   Next abstract

New Zealand Plant Protection 66 (2013): 124-131

How accurate are methods for predicting phenology in New Zealand?

J.M. Kean

ABSTRACT

Thermal accumulation ('degree day') methods are routinely used to predict plant and insect phenology. Depending on the data available, prediction may involve three separate steps with associated errors: estimating daily heat units from maximum and minimum temperatures; interpolating daily maxima and minima from monthly averages; and predicting future monthly averages from past climate, potentially including climate change. This research investigated the potential error in thermal accumulation totals arising from each of these factors at nine New Zealand sites. Ten simple heat unit calculations were tested, including two little-known and three new methods. Those utilising the true daily mean temperature performed best, followed by 4-step, triangle and sine approximations. Interpolating between monthly mean temperature extremes introduced much error into daily estimates, and the use of predicted, rather than observed, monthly normals further increased error. Specific recommendations are made for thermal accumulation methods depending on what temperature data are available.

Keywords: temperature, climate, development, prediction error.

Related articles
pdfModelling winter survival, mating and trapping of Queensland fruit fly in Auckland, New Zealand
J.M. Kean (2016)
New Zealand Plant Protection 69: 153-159
pdfMeta-analysis, validation and application of fruit fly development times
J.M. Kean (2015)
New Zealand Plant Protection 68: 44-53
pdfPredicting the seasonal phenology of fall webworm (Hyphantria cunea) in New Zealand
J.M. Kean and L.B. Kumarasinghe (2007)
New Zealand Plant Protection 60: 279-285
pdfAnalysis of thermal summation models
S.P. Worner and D.R. Penman (1983)
Proceedings of the NZ Weed and Pest Control Conference 36: 250-254

Copyright © 2013 New Zealand Plant Protection Society (Inc.).

Please refer to the terms of use.