c now determine suggested number of EOFs in training c based on rule N applied to the proxy data alone c during the interval t > iproxmin (the
minimum c year by which each proxy is required to have started, c note that default is iproxmin = 1820 if variable c proxy network is allowed (latest begin date c in network) c c we seek the n first eigenvectors whose
eigenvalues c exceed 1 / nproxy» c c nproxy» is the effective climatic spatial degrees of freedom c spanned by the proxy network (typically an appropriate c estimate is 20 - 40)