Objective analysis through Barnes scheme

Due to dispersion and lack of proper distribution in location of synoptic stations and need to have information about the climate in locations without weather station, method of interpolation and extrapolation can be used as a solution for overcoming or reducing the negative effects of this problem. In the other hand, numerical models for predicting the weather, require to the data on meteorological parameters in various parts of the region at regular intervals on a specific network for boundary layer and initial conditions. Objective analysis method can transmit the data of irregular synoptic stations to a network. In the other words, Transmit the data of irregular synoptic stations to network is called Objective analysis. Objective analysis scheme have to use interpolation of data for increasing the information, also it have to specified and omit the wrong data and do the internal discipline. Panofsky, Cressman and Barnes are three schemes that are widely used in few years ago. These schemes based on different techniques. In this study, Barnes method is used. Barnes’ technique is a combination of several sweeps. Each sweep uses a total weight of linear observation data in the area of influence around each point of the network. The estimated value of each variable point (I, J) in the network is calculated after the first sweep. When the initial field is zero the first sweep is completely similar to Cressman’s. The field at each station will estimate with average of data of four points in the network. Considering to data obtained from switch system in provincial forecast centers and need to increase the accuracy of forecasting, different schemes must run and the best of them must chose. The results of this study showed that:1 - Increasing the number of stations will increase the accuracy of output data in baron’s scheme.2 - Output data in Barnes and Cressman scheme were similar to ground data.3- Output data in Barnes and Cressman scheme were significantly different from upper data4 - Barnes scheme can determine the degree of smoothing before the experiment.5 - Barnes scheme does not require to Radius Affect.