Impact of "blocking" structure in the troposphere on the wintertime persistent heavy air pollution in northern China.

In the winters of 2012-2018, a total of 25 'ultra-long' (≥6 days), wide-ranging pollution events occurred in northern China. The results showed that the atmospheric circulation pattern corresponding to 62.5% of the persistent 'most serious' and 'more serious' air pollution events in northern China were the blocking structures, and that 43.

Lidar data assimilation method based on CRTM and WRF-Chem models and its application in PM forecasts in Beijing.

A three-dimensional variational (3DVAR) lidar data assimilation method is developed based on the Community Radiative Transfer Model (CRTM) and Weather Research and Forecasting model coupled to Chemistry (WRF-Chem) model. A 3DVAR data assimilation (DA) system using lidar extinction coefficient observation data is established, and variables from the Model for Simulating Aerosol Interactions and Chemistry (MOSAIC) mechanism of the WRF-Chem model are employed. Hourly lidar extinction coefficient data from 12:00 to 18:00 UTC on March 13, 2018 at four stations in Beijing are assimilated into the initial field of the WRF-Chem model; subsequently, a 24 h PM concentration forecast is made.

Spatio-temporal variations in SO and NO emissions caused by heating over the Beijing-Tianjin-Hebei Region constrained by an adaptive nudging method with OMI data.

The Beijing-Tianjin-Hebei (BTH) region in China suffers from heavy air pollution, especially in heating period. SO and NO are two of the key primary gaseous pollutants emitted by coal burning. The increase in air pollution caused by heating in the south-central part of the BTH region is higher than that in the northern part.

[Variations in Aerosol Optical Depth over Three Northeastern Provinces of China, in 2003-2014].

Based on the MODIS-Aqua aerosol optical depth (AOD) products from 2003 to 2014, Nighttime Lights Time data from DMSP satellites and basic meteorological data, the AOD spatial distributions of interannual and seasonal variations over three northeastern provinces of China(Liaoning, Jilin, Heilongjiang) were analyzed. It was found that there was a northeast-southwest area of high annual average AOD composed of Dalian, Shenyang, Changchun, Harbin and other cities, the 12-year average AOD value was 0.4-0.