Abstract
The effect of topography and influence of the vorticity flow near 35°N lat. on the height change of isobaric surface along 50°N latitude circle are discussed, which are, among others, necessary for the prediction of the height change of 500-mb surface over the northern hemisphere by harmonic coefficients computed along every latitude circle.
It was found 1) that topography has a considerable effect in low latitudes, but, on the whole, little in our case, and 2) that we must take the area from the pole to 20°N lat. at least as a prediction area.
