Adaptation analysis and fusion correction method of CMIP6 precipitation simulation data on the Qinghai-Tibetan Plateau

• Published in: Journal of mountain science Vol. 21; no. 2; pp. 555 - 573
• Main Authors: Peng, Hao, Qin, Dahui, Wang, Zegen, Zhang, Menghan, Yang, Yanmei, Yong, Zhiwei
• Format: Journal Article
• Language: English
• Published: Heidelberg Science Press 01.02.2024; Springer Nature B.V; School of Civil Engineering and Geomatics,Southwest Petroleum University,Chengdu 610500,China%School of Civil Engineering and Geomatics,Southwest Petroleum University,Chengdu 610500,China; School of Geoscience and Technology,Southwest Petroleum University,Chengdu 610500,China%School of Geoscience and Technology,Southwest Petroleum University,Chengdu 610500,China
• Subjects: Annual precipitation; Back propagation networks; Coefficients; Correlation coefficient; Correlation coefficients; Earth and Environmental Science; Earth Sciences; Ecology; Environment; Geography; Hydrologic data; Intercomparison; Neural networks; Original Article; Plateaus; Precipitation; Simulation; Trends; Variance analysis; Tibetan Plateau; GCM; CMIP6; BP-QM fusion correction; Spatio-temporal characteristics; Precipitation correction
• ISSN: 1672-6316; 1993-0321; 1008-2786
• DOI: 10.1007/s11629-023-8223-2

In order to obtain more accurate precipitation data and better simulate the precipitation on the Tibetan Plateau, the simulation capability of 14 Coupled Model Intercomparison Project Phase 6 (CMIP6) models of historical precipitation (1982–2014) on the Qinghai-Tibetan Plateau was evaluated in this study. Results indicate that all models exhibit an overestimation of precipitation through the analysis of the Taylor index, temporal and spatial statistical parameters. To correct the overestimation, a fusion correction method combining the Backpropagation Neural Network Correction (BP) and Quantum Mapping (QM) correction, named BQ method, was proposed. With this method, the historical precipitation of each model was corrected in space and time, respectively. The correction results were then analyzed in time, space, and analysis of variance (ANOVA) with those corrected by the BP and QM methods, respectively. Finally, the fusion correction method results for each model were compared with the Climatic Research Unit (CRU) data for significance analysis to obtain the trends of precipitation increase and decrease for each model. The results show that the IPSL-CM6A-LR model is relatively good in simulating historical precipitation on the Qinghai-Tibetan Plateau ( R =0.7, RSME=0.15) among the uncorrected data. In terms of time, the total precipitation corrected by the fusion method has the same interannual trend and the closest precipitation values to the CRU data; In terms of space, the annual average precipitation corrected by the fusion method has the smallest difference with the CRU data, and the total historical annual average precipitation is not significantly different from the CRU data, which is better than BP and QM. Therefore, the correction effect of the fusion method on the historical precipitation of each model is better than that of the QM and BP methods. The precipitation in the central and northeastern parts of the plateau shows a significant increasing trend. The correlation coefficients between monthly precipitation and site-detected precipitation for all models after BQ correction exceed 0.8.