Water shortage is a major problem facing the world. Artificial
precipitation enhancement is an effective way to improve precipitation
conversion rate, but the selection of artificial precipitation
enhancement operation timing is the main difficulty, and the
precipitable water vapor(PWV) is a major index. The variation of PWV is
nonlinear and unstable due to complex factors, especially in the Qilian
mountains in the northeastern part of the Qinghai-Tibet Plateau, so it
is difficult to predict it accurately. Therefore, based on the analysis
of the observed data of microwave radiometer in Qilian Mountains, a new
combined model is constructed which considers both data decomposition
and prediction of several single models in this research. In the data
preprocessing stage, the complete ensemble empirical mode decomposition
with adaptive noise (CEEMDAN) technique is used to decompose and
de-noise the PWV sequence. In the prediction stage, four neural network
with unique characteristics, back propagation neural network (BPNN),
long short term memroy (LSTM), bidirectional gated recurrent unit
(BiGRU) and temporal convolutional network (TCN), are selected to
predict the decomposed data respectively. A variant of gray Wolf
optimization algorithm (IGWO) is used to determine the optimal weight of
the model, and finally the comprehensive predicted value is obtained by
weighting calculation. Through the analysis of experimental results, in
the longest 15-step prediction, compared with CEEMDAN-BP, CEEMDAN-LSTM,
CEEMDAN-BiGRU, CEEMDAN-TCN, the prediction accuracy can be improved by
54.17%, 35.05%, 22.38%, 23.86%, respectively. Other step size
prediction also achieves the highest prediction accuracy.