An aerosol vertical data assimilation system (NAQPMS-PDAF v1.0): development and application

[摘要] Aerosol vertical stratification is important for globalclimate and planetary boundary layer (PBL) stability, and no single methodcan obtain spatiotemporally continuous vertical profiles. This paperdevelops an online data assimilation (DA) framework for the Eulerianatmospheric chemistry-transport model (CTM) Nested Air Quality PredictionModel System (NAQPMS) with the Parallel Data Assimilation Framework (PDAF)as the NAQPMS-PDAF for the first time. Online coupling occurs based on amemory-based way with two-level parallelization, and the arrangement ofstate vectors during the filter is specifically designed. Scaling testsdemonstrate that the NAQPMS-PDAF can make efficient use of parallelcomputational resources for up to 25 000 processors with a weak scaling efficiency of up to 0.7. The 1-month long aerosol extinction coefficient profilesmeasured by the ground-based lidar and the concurrent hourly surfacePM 2.5 are solely and simultaneously assimilated to investigate theperformance and application of the DA system. The hourly analysis andsubsequent 1 h simulation are validated through lidar and surfacePM 2.5 measurements assimilated and not assimilated. The results showthat lidar DA can significantly improve the underestimation of aerosolloading, especially at a height of approximately 400 m in the free-running(FR) experiment, with the mean bias (BIAS) changing from −0.20 ( −0.14 ) km −1 to −0.02 ( −0.01 ) km −1 and correlation coefficients increasing from 0.33 (0.28) to0.91 (0.53) averaged over sites with measurements assimilated (notassimilated). Compared with the FR experiment, simultaneously assimilatingPM 2.5 and lidar can have a more consistent pattern of aerosol verticalprofiles with a combination of surface PM 2.5 and lidar, independentextinction coefficients from the Cloud-Aerosol Lidar with OrthogonalPolarization (CALIOP), and aerosol optical depth (AOD) from the AerosolRobotic Network (AERONET). Lidar DA has a larger temporal impact than thatin PM 2.5 DA but has deficiencies in subsequent quantification on thesurface PM 2.5 . The proposed NAQPMS-PDAF has great potential for furtherresearch on the impact of aerosol vertical distribution.

[学科分类] 土木及结构工程学