经验正交函数分解，求时空场f(m,n)的特征向量egvt(m,mnl)，时间系数ecof(mnl,n)，特征值er(mnl,1)，累积特征值er(mnl,2)，解释方差er(mnl,3)，累积解释方差er(mnl,4)-Empirical orthogonal function, f (m, n) seeking spacetime the eigenvectors egvt (m, MNL), the time coefficient ecof (MNL, n), the characteri