The Response of Spring Wheat Yield to Anomalous Climate Sequences in the United States

Abstract

The response of spring wheat yield to anomalous climate sequences in the United States is estimated using monthly mean temperature and total precipitation for the years 1932 to 1971. A particular anomaly sequence, which is characteristic of the entire spring wheat season from pre-planting through harvest, is constructed from a regression of detrended yield on the coefficients of eigenvectors of the climate variables. This anomaly sequence is chosen in such a way that its coefficient is maximally correlated with yield variations. The coefficient of this anomaly sequence is then used to predict yield in the years 1972?75. The time series of eigenvector coefficients and several measures of climatic variability are examined for evidence of climatic change.