Quality and potential utility of ENSO-based forecasts of spring rainfall and wheat yield in south-eastern Australia

Anwar, M. R. and Rodriguez, D. and Liu, D. L. and Power, S. and O'Leary, G. J. (2008) Quality and potential utility of ENSO-based forecasts of spring rainfall and wheat yield in south-eastern Australia. Australian Journal of Agricultural Research, 59 (2). pp. 112-126. ISSN 0004-9409


Reliable seasonal climate forecasts are needed to aid tactical crop management decisions in south-eastern Australia (SEA). In this study we assessed the quality of two existing forecasting systems, i.e. the five phases of the Southern Oscillation Index (SOI) and a three phase Pacific Ocean sea-surface temperatures (SSTs), to predict spring rainfall (i.e. rainfall from 1 September to 31 November), and simulated wheat yield. The quality of the forecasts was evaluated by analysing four attributes of their performance: their reliability, the relative degree of shift and dispersion of the distributions, and measure of forecast consistency or skill. Available data included 117 years of spring rainfall and 104 years of grain yield simulated using the Agricultural Production Systems Simulator (APSIM) model, from four locations in SEA. Average values of spring rainfall were 102-174 mm with a coefficient of variation (CV) of 47%. Average simulated wheat yields were highest (5609 kg/ha) in Albury (New South Wales) and lowest (1668 kg/ha) in Birchip (Victoria). The average CV for simulated grain yields was 36%. Griffith (NSW) had the highest yield variability (CV = 50%). Some of this year-to-year variation was related to the El Nino Southern Oscillation (ENSO). Spring rainfall and simulated wheat yields showed a clear association with the SOI and SST phases at the end of July. Important variations in shift and dispersion in spring rainfall and simulated wheat yields were observed across the studied locations. The forecasts showed good reliability, indicating that both forecasting systems could be used with confidence to forecast spring rainfall or wheat yield as early as the end of July. The consistency of the forecast of spring rainfall and simulated wheat yield was 60-83%. We concluded that adequate forecasts of spring rainfall and grain yield could be produced at the end of July, using both the SOI and SST phase systems. These results are discussed in relation to the potential benefit of making tactical top-dress applications of nitrogen fertilisers during early August.

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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Faculty/School / Institute/Centre: No Faculty
Faculty/School / Institute/Centre: No Faculty
Date Deposited: 06 Jan 2022 03:34
Last Modified: 06 Jan 2022 03:34
Uncontrolled Keywords: Absolute median difference; APSIM; Dispersion; Reliability; Simulated yield; Skill
Fields of Research (2008): 07 Agricultural and Veterinary Sciences > 0703 Crop and Pasture Production > 070304 Crop and Pasture Biomass and Bioproducts
04 Earth Sciences > 0401 Atmospheric Sciences > 040105 Climatology (excl.Climate Change Processes)
Fields of Research (2020): 41 ENVIRONMENTAL SCIENCES > 4101 Climate change impacts and adaptation > 410199 Climate change impacts and adaptation not elsewhere classified
Socio-Economic Objectives (2008): D Environment > 96 Environment > 9603 Climate and Climate Change > 960301 Climate Change Adaptation Measures
Socio-Economic Objectives (2020): 19 ENVIRONMENTAL POLICY, CLIMATE CHANGE AND NATURAL HAZARDS > 1901 Adaptation to climate change > 190199 Adaptation to climate change not elsewhere classified
Identification Number or DOI: https://doi.org/10.1071/AR07061
URI: http://eprints.usq.edu.au/id/eprint/42454

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