A study of spatial and temporal dynamics of total ozone over Southwest China with multi-source remote-sensing data

Parrish²,

et al. 2022

Preprint

Abstract. In the past decade, ozone (O3) pollution has become a severe environmental problem in major cities in China. Here, based on available observational records, we investigated the long-term trend of ozone pollution in China during 2014–2020. Ozone concentrations were higher in urban areas than in non-urban areas. During these seven years, the highest ozone concentrations primarily occurred in summer in northern China, and in autumn or spring in southern China. Although ozone precursors, including nitrogen oxides (NOx) and carbon monoxide (CO), continuously decreased throughout the seven years, four ozone metrics that were used to characterize ozone exposure levels increased from 2014 to 2017 and reached a plateau after 2017. The long-term trend of ozone concentrations differed across seasons; especially from 2019 to 2020 when ozone concentrations decreased in summer and increased in winter. To analyze the causes of this observed trend, a photochemical box model was used to investigate the change in ozone sensitivity regime in two representative cities – Beijing and Shanghai. Our model simulations suggest that the summertime ozone sensitivity regime in urban areas of China has changed from a VOC-limited regime to a transition regime during 2014–2020; by 2020, the urban photochemistry is in a transition regime in summer but in a VOC-limited regime in winter. This study helps to understand the distinct trends of ozone in China and provides insights into efficient future ozone control strategies in different regions and seasons.

Section: Zero-dimension Photochemical Box Modelsupporting

confidence: 93%

Long-term trend of ozone pollution in China during 2014–2020: distinct seasonal and spatial characteristics

Parrish²,

et al. 2022

Preprint

“…This is consistent with a previous study reporting that the Yunnan province and northeast China had peak O 3 in spring 2014-2017 (Yin et al, 2019). A springtime maximum was also found for the column O 3 in Yunnan, retrieved from satellite data (Xiao and Jiang, 2013). The occurrence of maximum O 3 concentrations in spring has been attributed to several factors, including (1) the peak occurrence of stratospheric intrusions, (2) photochemistry of precursors built up during winter, and (3) biomass-burning either as forest fires or for land clearance (Monks et al, 2015).…”

Section: Resultsmentioning

confidence: 76%

Long-term trend of ozone pollution in China during 2014–2020: distinct seasonal and spatial characteristics and ozone sensitivity

Parrish²,

et al. 2022

Atmos. Chem. Phys.

Abstract. In the past decade, ozone (O3) pollution has become a severe environmental problem in China's major cities. Here, based on available observational records, we investigated the long-term trend of O3 pollution in China during 2014–2020. The O3 concentrations were slightly higher in urban areas than in non-urban areas. During these 7 years, the highest O3 concentrations primarily occurred during summer in northern China, and during autumn or spring in southern China. Although O3 precursors, including nitrogen oxides (NOx) and carbon monoxide (CO), continuously decreased, O3 concentrations generally increased throughout the 7 years with a slower increasing rate after 2017. The long-term trend of O3 concentrations differed across seasons, especially from 2019 to 2020, when O3 concentrations decreased in summer and increased in winter. To analyse the causes of this observed trend, a photochemical box model was used to investigate the change in the O3 sensitivity regime in two representative cities – Beijing and Shanghai. Our model simulations suggest that the summertime O3 sensitivity regime in urban areas of China has changed from a VOC-limited regime to a transition regime during 2014–2020. By 2020, the urban photochemistry was in a transition regime in summer but in a VOC-limited regime in winter. This study helps to understand the distinct trends of O3 in China and provides insights into efficient future O3 control strategies in different regions and seasons.

Genome Biology and Evolution

“…In addition to hypoxia, strong UV radiation environments in high-altitude areas are also the main limiting factor for the successful colonization of animals. Over the higher altitude of Tibetan Plateau, the UV erythemal dose has a higher value with the multi-yearly mean value is about 5,500 J·m –2 , and over some regions, the value is up to 6,000 J·m –2 , whereas the low-altitude area is only 1,500 J·m –2 ( Xiao and Jiang 2013 ). Many significantly contracted gene families in the HL were distributed in olfactory receptor activity (GO:0004984) and immune response (GO:0006955).…”

Section: Resultsmentioning

confidence: 99%

Chromosome-level Genome Assembly of the High-altitude Leopard (Panthera pardus) Sheds Light on Its Environmental Adaptation

Zhou

Liu

Zhang

et al. 2022

The leopard (Panthera pardus) has the largest natural distribution from low to high altitude areas of any wild felid species, but recent studies have revealed that leopards have disappeared from large areas, probably owing to poaching, a decline of prey species, and habitat degradation. Here we reported the chromosome-scale genome assembly of the high-altitude leopard (HL) based on nanopore sequencing and high-throughput chromatin conformation capture (Hi-C) technology. Panthera genomes revealed similar repeat composition, and there was an appreciably conserved synteny between HL and the other two Panthera genomes. Divergence time analysis based on the whole genomes revealed that the high-altitude leopard (HL) and the low-altitude leopard (LL) differentiate from a common ancestor approximately 2.2 Mya. Through comparative genomics analyses, we find molecular genetic signatures that may reflect high-altitude adaptation of the HL. Three HL-specific missense mutations were detected in two positively selected genes i.e. ITGA7 (Ala112Gly, Asp113Val and Gln115Pro) and NOTCH2 (Ala2398Ser), which is likely to be associated with hypoxia adaptation. The chromosome-level genome of the HL provides valuable resources for the investigation of high-altitude adaptation and protection management of the vulnerable leopard.