Showing papers by "Bert Bolin published in 1955"

Numerical Forecasting with the Barotropic Model

Abstract: The experiments with numerical forecasting using the barotropic model have been continued and a number of 24, 48 and 72 hour forecasts are presented. The initial data for these forecasts covered an area of about 9,000 by 12,000 km. The results indicate that the boundary influences have been reduced to be unimportant in the centre of the area in the 24-hour forecasts but they may still cause errors in the 72-hour forecasts. In view of the approximations made very good 72-hour forecasts have been obtained in some cases. The most successful one gave a correlation of 0.87 and a relative error of the forecast height changes of 0.58. Most of these extended forecasts should be of definite value in forecasting the weather. Large errors are, however, still obtained in some cases. The neglection of baroclinic process is one of the reasons for these errors but it is quite obvious that the largest errors are of a different nature. Experiments are at present conducted to find the sources of these errors. One line of this research is a general re-analysis of the assumptions made in deriving the barotropic model which is presented in the latter part of this paper. A number of improvements are suggested for further tests. DOI: 10.1111/j.2153-3490.1955.tb01139.x

On «Results of forecasting with the barotropic model»

Abstract: Dear Sir, In a recent paper describing results of forecasting by numerical methods (STAFF MEMBERS, UNIVERSITY OF STOCKHOLM, 1954), it was stated that the correlation between observed and computed changes is not a satisfactory measure of the goodness of a forecast. Previously the same group (Staff Members, University of Stockholm, 1952) had raised the objection that a correlation coefficient measures the similarity in behaviour of two variables without any reference to systematic errors such as a difference in scale of the variations. DOI: 10.1111/j.2153-3490.1955.tb01163.x