Long‐Term Trends of Persistent Synoptic Circulation Events in Planetary Boundary Layer and Their Relationships With Haze Pollution in Winter Half Year Over Eastern China

Abstract

Air quality in China has been gradually improving because of recent emission control policies, but synoptic circulations in the planetary boundary layer have become increasingly conducive to haze formation. The effect of persistent synoptic circulation (PSC) on long-term variation in haze episodes remains to be fully elucidated. This study identified and analyzed PSC similarity and its influence on haze during the winter half year from 1961 to 2013. We analyzed sea level pressure and geopotential heights at the 850-hPa level by using correlation coefficients and mean Hamming distance to quantify PSC similarity. A total of 1,754 PSC events were identified, of which 236 and 167 PSC events of 868 and 625 days, respectively, were associated with six polluted types and three clean types, respectively. The variations in occurrence frequencies of polluted PSC events exhibited different trends in the past decades over eastern China: an increase in 1961-1979, no obvious change in 1980-1999, and a rapid increase since 2000. The durations of polluted and clean PSC events in the planetary boundary layer over eastern China have tended to become longer and shorter, respectively, over the past decades. Our analyses suggest that the reduction in Arctic sea ice in autumn may be favorable for less cold activities and more polluted PSC events with longer durations in eastern China, positively contributing to the formation and maintenance of persistent haze pollution. This work provides convincing evidence that the occurrence frequencies and durations of haze episodes increased because of the increase in pollution-related PSC events.

The Trend Reversal of Dust Aerosol Over East Asia and the North Pacific Ocean Attributed to Large‐Scale Meteorology, Deposition, and Soil Moisture

“…Moving from the desert source regions toward the east coast of China, most of the observed dust is at altitudes below 2 km over northeast China. Depending on the dust source region, dust aerosols over the NPO generally reach higher altitudes (usually around 4–6 km but can be up to 10 km; shown in Figures d and e), likely due to the interactions of synoptic‐scale, mesoscale and local‐scale circulations (Guo et al, ; Yang et al, ). This tends to lift the aerosols that have originated from distant sources and are subsequently transported to the downwind regions by westerly winds in the middle and high troposphere (Guo et al, ).…”

Daily Global Solar Radiation in China Estimated From High‐Density Meteorological Observations: A Random Forest Model Framework

“…DGSR is also crucial for the utilization of solar energy through transformation of technologies (Wu et al, 2012(Wu et al, , 2016Tang et al, 2018;Prăvălie et al, 2019;Zou et al, 2019). In recent years, there has been an aggravation of air pollution in China induced by massive fossil fuel consumption and emissions coinciding with unfavorable weather conditions (Guo et al, 2016Lou et al, 2019;Yang, et al, 2018;Yang, Ye, et al, 2019;Zheng et al, 2019). On the one hand, this has significantly modulated the change in surface solar radiation (Che et al, 2005;Guo et al, 2018;Wang et al, 2012Wang et al, , 2013Wang & Wild, 2016;Zheng et al, 2018;He & Wang, 2020;Yang et al, 2020), while on the other hand, it has led to solar radiation becoming one of the fastest-growing and important sources of clean and renewable energy.…”

Preliminary Evaluation of the Atmospheric Infrared Sounder Water Vapor Over China Against High‐Resolution Radiosonde Measurements

“…The atmospheric flow with rainfall over China is significantly influenced by the East Asian summer monsoon (Li et al, ; Lu et al, ; Yang, Wang, et al, ). At the same time, China has undergone rapid economic growth with unfavorable meteorological conditions in recent decades, which has led to large emissions of aerosol and carbon dioxide (J. P. Guo et al, , ; Li et al, ; X. Y. Zhang et al, ; Yang, Wang, et al, , Yang, Zheng, et al, ), and thus these in turn induces rapid increases in temperature and inevitably changes the atmospheric water vapor due to the regional water vapor feedback effects resulting from climatic changes (Pan et al, ; Takahashi et al, ). However, current water vapor research remains at the case study level in certain local regions of China, and verification work on the accuracy of AIRS parameter inversions over China is scarce (Gui et al, ; Y. Zhang et al, ).…”