Fig. 1. Flow chart of data matching between FY-4A and CloudSat

Fig. 2. Schemes of CBH retrieval for FY-4A designed in this paper

Fig. 3. Variation of RMSE of eight types of clouds with decision trees number in RF model and GBT model. (a) Variation of RMSE with decision trees number in RF model; (b) variation of RMSE with decision trees number in GBT model

Fig. 4. Variation of RMSE of eight types of clouds with maximum depth of decision trees in RF model and GBT model. (a) Variation of RMSE with maximum depth of decision trees in RF model; (b) variation of RMSE with maximum depth of decision trees in GBT model

Fig. 5. Variation of RMSE of samples on training and validation datasets with decision trees number in RF model and GBT model. (a) Variation of RMSE with decision trees number in RF model; (b) variation of RMSE with decision trees number in GBT model

Fig. 6. Variation of RMSE of samples on training and validation datasets with maximum depth of decision trees in RF model and GBT model. (a) Variation of RMSE with maximum depth of decision trees in RF model; (b) variation of RMSE with maximum depth of decision trees in GBT model

Fig. 7. Retrieval results of models of two schemes on test dataset. (a) Scheme one; (b) scheme two

Fig. 8. Retrieval flow of CBH for FY-4A in practical application

Fig. 9. CBH retrieved from models of two schemes and the comparison with CBH from CloudSat. (a) Cloud types obtained according by the model proposed in Ref. [32]; (b) CBH retrieved from the cloud types of Fig. 9(a) and the model of scheme one; (c) CBH retrieved from the model of scheme two; (d) comparison between the cloud types of CloudSat and the model proposed in Ref. [32], and comparison among CBH retrieved from models of two schemes and CBH from CloudSat on CloudSat track

Table 1. Parameters of FY-4A/AGRI channels

Table 2. Related cloud products of FY-4A/AGRI and corresponding channels

Table 3. Numbers of all types of clouds after data matching

Table 4. Decision trees number of two models for all types of clouds

Table 5. Maximum depth of decision trees of two models for all types of clouds

Table 6. Retrieval results of two models for all types of clouds on the test dataset

Table 7. Optimal CBH retrieval model of all types of clouds

Table 8. Retrieval results of RF model and GBT model on test dataset

Table 9. Retrieval results of RF model and GBT model for all types of clouds on test dataset

Table 10. Retrieval results of models of two schemes for all types of clouds on test dataset