Abstract: Study on the characteristics and prediction of summer precipitation in Tibet during 1981-2017 was carried out using the Empirical Orthogonal Functions (EOF),cross-validation,anomaly correlation coefficient (ACC),time correlation coefficient (TCC) and some other methods.The results showed that the spatial distribution of summer precipitation was very uneven,and the precipitation decreased from the southeast to the northwest.In addition to some regions,the precipitation was in an increase trend in most areas of Tibet,but the increase trend was not significant.There was not only a regional similarity in spatial distribution of summer precipitation in Tibet,but also a regional variation from the south to the north and from the east to the west.The results suggested that,when a one-year sample was randomly removed,the temporal stability of the first three EOF modes was high.It was attempted to predict summer precipitation in Tibet on the basis of the stability of EOF modes for the first time,and the key indices which were found had a good prediction capability for PCs coefficient of stable modes.The anomaly correlation coefficient between the observed and predicted values of summer precipitation could be reached 0.31.The temporal correlation coefficient was higher than zero in most areas.TCC passed the significance test of α=0.05 in most areas.The predicted results of summer precipitation were ideal,and the application prospect was wide.

Key words: summer precipitation, empirical orthogonal function model(EOF), spatial distribution, Tibet