Abstract. An ensemble Kalman filter data assimilation (DA) system has been developed to improve air quality forecasts using surface measurements of PM10, PM2.5, SO2, NO2, O3, and CO together with an online regional chemical transport model, WRF-Chem (Weather Research Forecasting Chemistry). This DA was applied simultaneously adjust the initial conditions (ICs) emission inputs species affecting concentrations during extreme haze episode that occurred in early October 2014 over East Asia....

Abstract Top‐down methods commonly use atmospheric CO 2 concentration observations to constrain carbon source and sinks. Despite the increase in spaceborne ground‐based measurements, inversions are usually limited by uncertainties chemical transport models (CTMs) when relating fluxes observed mole fractions. eddy covariance (EC) flux measurements have been widely used directly measure over various ecosystems, but they rarely as constraints top‐down estimations. In this study, we focused on...

This study uses GPM DPR and Himawari-8 cloud-top infrared data to classify the precipitating cloud (PC) into three life stages: developing, mature, dissipating. Based on from April June 2018–2022, this research investigates microphysical features of convective stratiform precipitation over South China. The generated by developing stage PC contains largest proportion precipitation, area in mature PC, smallest with lowest dissipating PC. For height 0 °C level is marginally above top Bright...

Abstract. Top-down inversions of China's terrestrial carbon sink are known to be uncertain because errors related the relatively coarse resolution global transport models and sparseness in situ observations. Taking advantage regional chemistry for mesoscale simulation spaceborne sensors spatial coverage, Greenhouse Gases Observing Satellite (GOSAT) retrievals column-mean dry mole fraction dioxide (XCO2) were introduced Models-3 (a flexible software framework) Community Multi-scale Air...

Abstract. In order to optimize surface CO2 fluxes at grid scales, a regional flux inversion system (Carbon Flux Inversion and Community Multi-scale Air Quality, CFI-CMAQ) has been developed by applying the ensemble Kalman filter (EnKF) constrain concentrations smoother (EnKS) fluxes. The smoothing operator is associated with atmospheric transport model constitute persistence dynamical forecast scaling factors. this implementation, "signal-to-noise" problem can be avoided; plus, any useful...

Abstract In the context of China's clean air policy, meteorological impacts on improved particulate matter (PM 2.5 ) quality during 2016–2019 are investigated based a four‐year high‐resolution atmospheric composition reanalysis data‐set, which has been produced by Joint Data Assimilation System to resolve long‐term fine‐scale variability over China. The assimilates surface observations using Weather Research and Forecasting model coupled with Chemistry an ensemble‐based assimilation...

Abstract In order to guarantee good air quality for the 15th International Association of Athletics Federations World Championships (22–30 August) and China Victory Day parade (3 September) in Beijing, a series comprehensive emissions regulations were implemented Beijing surrounding provinces from 20 August 3 September 2015. During this period, intensity regulation was enhanced step by run‐up event. This period therefore allowed us quantitatively estimate reduction as result under different...

Abstract The impacts of assimilating meteorological observations on source emissions estimate and chemical simulations are investigated. Using 6‐hr Global Forecast System (GFS) analyses or cycling ensemble assimilation have similar diurnal variations emissions. Compared to experiment without analyses, using GFS provides stronger SO 2 NO emissions, further strengthens the variations. When independently verified against observed PM 2.5 , concentrations, simulation forced by posterior with...

Abstract Most of China's carbon sink inversion research uses global atmospheric transport models to assimilate natural fluxes, which quantifies the biosphere and ocean budget with a relative coarse spatial resolution long timescale from weekly or monthly perspective. Toward high‐resolution CO 2 novel flux forecast model was developed in this study, then further used carry out assimilation based on regional chemical (CMAQ) at higher (64 × 64 km ) temporal (1 hr) resolutions. An Ensemble...

Many efforts have been made to control PM2.5 pollution in China during the National 13th Five-Year Plan and concentrations significantly declined nationwide. Meteorological conditions emissions play most important roles pollution. However, extant quantitative estimations of contributions meteorological anthropogenic emission reductions period were mostly based on surface observations data. Using a reanalysis dataset from 2016 2020, our results reveal that annual average reduced yearly four...

Abstract. Timely, continuous, and dynamics-based estimates of PM2.5 emissions with a high temporal resolution can be objectively optimally obtained by assimilating observed surface concentrations using flow-dependent error statistics. The annual averaged over mainland China for the years 2016–2020 without biomass burning are 7.66, 7.40, 7.02, 6.62, 6.38 Tg, respectively, which very closed to values Multi-resolution Emission Inventory (MEIC). Annual in have consistently decreased...

A regional surface carbon dioxide (CO2) flux inversion system, the Tan-Tracker-Region, was developed by incorporating an assimilation scheme into Community Multiscale Air Quality (CMAQ) chemical transport model to resolve fine-scale CO2 variability over East Asia. The proper orthogonal decomposition-based ensemble four-dimensional variational data approach (POD-4DVar) is core algorithm for joint framework, and simultaneous assimilations of concentrations fluxes are applied help reduce...

We evaluated the ability of Beijing Climate Center models on different horizontal resolutions (BCC-CSM1.1 approximately 280-km resolution and BCC-CSM1.1m 110-km resolution) in simulating nearsurface wind speeds (NWS) China during 1961–2005. The spatial distribution annual mean NWS over is better captured by than BCC-CSM1.1 due to finer resolution. weakened 1961–2005 cannot be reproduced BCC-CSM1.1, whereas able simulate decreasing trend autumn North China, although magnitude about 1/3...

The four-dimensional variational data assimilation (4DVar) method is one of the most popular techniques used in numerical weather prediction. Nevertheless, needs adjoint model and linearization forecast largely limit wider applications 4DVar. 4D ensemble-variational methods (4DEnVars) exploit strengths Ensemble Kalman Filter 4DVar, use ensemble trajectories to directly estimate background error covariance. This study evaluates role empirical orthogonal function (EOF) analysis 4DEnVars....

Abstract. An Ensemble Kalman Filter data assimilation (DA) system has been developed to improve air quality forecasts using surface measurements of PM10, PM2.5, SO2, NO2, O3 and CO together with an online regional chemical transport model, WRF-Chem (Weather Research Forecasting Chemistry). This DA was applied simultaneously adjust the initial conditions (ICs) emission inputs species affecting concentrations during extreme haze episode that occurred in early October 2014 over North China...

During 2014-2017, the number of haze days and air pollution declined year by obviously in Beijing. The average mass concentrations PM2.5, PM10, SO2, NO2 also decreased with alleviated level. These decreases were more obvious during heating period, especially November December. In order to analyze reasons for improvement quality, changes meteorological factors emission-reduction have been discussed quantified this study. This work was based on numerical simulation model WRF-CHEM large data...

Abstract. In order to optimize surface CO2 fluxes at finer scales, a regional flux inversion system (Carbon Flux Inversion and Community Multi-scale Air Quality, CFI-CMAQ) has been developed by simultaneously assimilating concentrations into the modeling system, CMAQ. The smoothing operator is associated with atmospheric transport model constitute persistence dynamical forecast scaling factors. this implementation, "signal-to-noise" problem can be avoided; plus, any useful observed...