Surface ozone(O_(3))is a major air pollutant and draw increasing attention in the Pearl River Delta(PRD),China.Here,we characterize the spatial-temporal variability of ozone based on a dataset obtained from 57 nationa...Surface ozone(O_(3))is a major air pollutant and draw increasing attention in the Pearl River Delta(PRD),China.Here,we characterize the spatial-temporal variability of ozone based on a dataset obtained from 57 national monitoring sites during 2013-2019.Our results show that:(1)the seasonal difference of ozone distribution in the inland and coastal areas was significant,which was largely affected by the wind pattern reversals related to the East Asian monsoon,and local ozone production and destruction;(2)the daily maximum 8hr average(MDA8 O_(3))showed an overall upward trend by 1.11 ppbv/year.While the trends in the nine cities varied differently by ranging from-0.12 to 2.51 ppbv/year.The hot spots of ozone were spreading to southwestern areas from the central areas since 2016.And ozone is becoming a year-round air pollution problem with the pollution season extending to winter and spring in PRD region.(3)at the central and southwestern PRD cities,the percentage of exceedance days from the continuous type(defined as≥3 days)was increasing.Furthermore,the ozone concentration of continuous type was much higher than that of scattered exceedance type(<3 days).In addition,although the occurrence of continuous type starts to decline since2017,the total number of exceedance days during the continuous type is increasing.These results indicate that it is more difficult to eliminate the continuous exceedance than the scatter pollution days and highlight the great challenge in mitigation of O_(3)pollution in these cities.展开更多
Based on long-term tide gauge observations in the last 60 years,the temporal and spatial variation characteristics of sea level change along the coast of China are analyzed.The results indicate that the sea level alon...Based on long-term tide gauge observations in the last 60 years,the temporal and spatial variation characteristics of sea level change along the coast of China are analyzed.The results indicate that the sea level along the coast of China has been rising at an increasing rate,with an estimated acceleration of 0.07 mm/a2.The rise rates were 2.4 mm/a,3.4 mm/a and 3.9 mm/a during 1960–2020,1980–2020 and 1993–2020,respectively.In the last 40 years,the coastal sea level has risen fastest in the South China Sea and slowest in the Yellow Sea.Seasonal sea levels all show an upward trend but rise faster in winter and spring and slower in autumn.Sea level change along the coast of China has significant periodic oscillations of quasi-2 a,4 a,7 a,11 a,quasi-19 a and 30–50 a,among which the 2–3 a,11 a,and 30–50 a signals are most remarkable,and the amplitude is approximately 1–2 cm.The coastal sea level in the most recent decade reached its highest value in the last 60 years.The decadal sea level from 2010 to 2019 was approximately 133 mm higher than the average of 1960–1969.Empirical orthogonal function analysis indicates that China’s coastal sea level has been changing in a north-south anti-phase pattern,with Pingtan and Fujian as the demarcation areas.This difference was especially obvious during 1980–1983,1995–1997 and 2011–2013.The coastal sea level was the highest in 2016,and this extreme sea level event was analyzed to be related mainly to the anomalous wind field and ENSO.展开更多
基金supported by the Guangdong Major Project of Basic and Applied Basic Research (No.2020B0301030004)the National Natural Science Foundation of China (No.42175111)+1 种基金the Guangdong science and technology plan project (No.2019B121201002)the Fundamental Research Funds for the Central Universities,Sun Yat-sen University (No.22qntd1908)。
文摘Surface ozone(O_(3))is a major air pollutant and draw increasing attention in the Pearl River Delta(PRD),China.Here,we characterize the spatial-temporal variability of ozone based on a dataset obtained from 57 national monitoring sites during 2013-2019.Our results show that:(1)the seasonal difference of ozone distribution in the inland and coastal areas was significant,which was largely affected by the wind pattern reversals related to the East Asian monsoon,and local ozone production and destruction;(2)the daily maximum 8hr average(MDA8 O_(3))showed an overall upward trend by 1.11 ppbv/year.While the trends in the nine cities varied differently by ranging from-0.12 to 2.51 ppbv/year.The hot spots of ozone were spreading to southwestern areas from the central areas since 2016.And ozone is becoming a year-round air pollution problem with the pollution season extending to winter and spring in PRD region.(3)at the central and southwestern PRD cities,the percentage of exceedance days from the continuous type(defined as≥3 days)was increasing.Furthermore,the ozone concentration of continuous type was much higher than that of scattered exceedance type(<3 days).In addition,although the occurrence of continuous type starts to decline since2017,the total number of exceedance days during the continuous type is increasing.These results indicate that it is more difficult to eliminate the continuous exceedance than the scatter pollution days and highlight the great challenge in mitigation of O_(3)pollution in these cities.
文摘Based on long-term tide gauge observations in the last 60 years,the temporal and spatial variation characteristics of sea level change along the coast of China are analyzed.The results indicate that the sea level along the coast of China has been rising at an increasing rate,with an estimated acceleration of 0.07 mm/a2.The rise rates were 2.4 mm/a,3.4 mm/a and 3.9 mm/a during 1960–2020,1980–2020 and 1993–2020,respectively.In the last 40 years,the coastal sea level has risen fastest in the South China Sea and slowest in the Yellow Sea.Seasonal sea levels all show an upward trend but rise faster in winter and spring and slower in autumn.Sea level change along the coast of China has significant periodic oscillations of quasi-2 a,4 a,7 a,11 a,quasi-19 a and 30–50 a,among which the 2–3 a,11 a,and 30–50 a signals are most remarkable,and the amplitude is approximately 1–2 cm.The coastal sea level in the most recent decade reached its highest value in the last 60 years.The decadal sea level from 2010 to 2019 was approximately 133 mm higher than the average of 1960–1969.Empirical orthogonal function analysis indicates that China’s coastal sea level has been changing in a north-south anti-phase pattern,with Pingtan and Fujian as the demarcation areas.This difference was especially obvious during 1980–1983,1995–1997 and 2011–2013.The coastal sea level was the highest in 2016,and this extreme sea level event was analyzed to be related mainly to the anomalous wind field and ENSO.
