scholarly journals IASI observations of seasonal and day-to-day variations of tropospheric ozone over three highly populated areas of China: Beijing, Shanghai, and Hong Kong

2010 ◽  
Vol 10 (8) ◽  
pp. 3787-3801 ◽  
Author(s):  
G. Dufour ◽  
M. Eremenko ◽  
J. Orphal ◽  
J.-M. Flaud
Keyword(s):  
Hong Kong ◽  
Tropospheric Ozone ◽  
Asian Summer Monsoon ◽  
Regional Scale ◽  
Early Summer ◽  
Air Masses ◽  
Ozone Maximum ◽  
The Pacific ◽  
Summer Minimum ◽  
One Year

Abstract. IASI observations of tropospheric ozone over the Beijing, Shanghai and Hong Kong areas during one year (2008) have been analysed, demonstrating the capability of space-borne infrared nadir measurements to probe seasonal and even day-to-day variations of lower tropospheric ozone (0–6 km partial columns) on the regional scale of highly populated areas. The monthly variations of lower tropospheric ozone retrieved from IASI clearly show the influence of the Asian summer monsoon that brings clean air masses from the Pacific during summer. They exhibit indeed a sharp ozone maximum in late spring and early summer (May–June) followed by a summer minimum. The time periods and the intensities of the maxima and of the decreases are latitude-dependent: they are more pronounced in Hong Kong and Shanghai than in Beijing. Moreover, IASI provides the opportunity to follow the spatial variations of ozone over the surroundings of each megacity as well as its daily variability. We show here that the large lower tropospheric ozone amounts (0–6 km partial columns) observed with IASI are mainly downwind the highest populated areas in each region, thus possibly suggesting the anthropogenic origin of the large ozone amounts observed. Finally, an analysis of the mean ozone profiles over each region – for selected days with high ozone events – in association with the analysis of the meteorological situation shows that the high ozone amounts observed during winter are likely related to descents of ozone-rich air from the stratosphere, whereas in spring and summer the tropospheric ozone is likely enhanced by photochemical production in polluted areas and/or in air masses from fire plumes.

scholarly journals IASI measurements of tropospheric ozone over Chinese megacities: Beijing, Shanghai, and Hong Kong

2009 ◽  
Vol 9 (6) ◽  
pp. 23103-23140
Author(s):  
G. Dufour ◽  
M. Eremenko ◽  
J. Orphal ◽  
J.-M. Flaud
Keyword(s):  
Hong Kong ◽  
Tropospheric Ozone ◽  
Asian Summer Monsoon ◽  
Regional Scale ◽  
Early Summer ◽  
Ozone Maximum ◽  
The Pacific ◽  
Summer Minimum ◽  
One Year ◽  
In Fire

Abstract. IASI observations of tropospheric ozone over Beijing, Shanghai and Hong Kong during one year have been analysed, demonstrating the capability of space-borne infrared nadir measurements to probe both seasonal and daily variations of lower tropospheric ozone around megacities on the regional scale. The monthly variations of lower tropospheric ozone retrieved from IASI show the influence of the Asian summer monsoon that brings clean air masses from the Pacific during summer. They exhibit indeed a sharp ozone maximum in late spring and early summer (May–June) followed by a summer minimum. The time periods and the intensities of the maxima and of the decreases are latitude-dependent: they are more pronounced in Hong Kong and Shanghai than in Beijing. Moreover, IASI provides the opportunity to follow the spatial variations of ozone over the surroundings of each megacity as well as its daily variability. We show indeed that the large lower tropospheric ozone amounts observed with IASI are consistent with the highest population density distribution in each region, thus suggesting the anthropogenic origin of the large ozone amounts observed. Finally an analysis of the mean daily ozone profiles over each region for selected periods with high ozone events shows that the high ozone amounts observed during winter are likely related to descents of ozone-rich air from the stratosphere whereas in spring and summer the tropospheric ozone is likely enhanced by photochemical production in polluted areas and/or in fire plumes.

Dynamical drivers of the 2020 Mei Yu floods over China

2021 ◽  
Author(s):  
Mark Muetzelfeldt ◽  
Ambrogio Volonté ◽  
Reinhard Schiemann ◽  
Andrew Turner ◽  
Nicholas Klingaman
Keyword(s):  
Asian Summer Monsoon ◽  
Yangtze River Basin ◽  
Heavy Precipitation ◽  
Early Summer ◽  
Monthly Precipitation ◽  
Air Masses ◽  
Westerly Jet ◽  
Automated Method ◽  
The Yangtze River Basin ◽  
Asian Summer

<p>Large parts of East and South Asia were affected by heavy precipitation and flooding during early summer 2020. This study provides both a statistical and dynamical characterisation of these events. By aggregating daily and monthly precipitation over river basins across Asia, it is shown that the Yangtze River Basin (YRB) is one of the areas that was particularly affected. June and July 2020 rainfalls were higher than in the previous 20 years, and the YRB experienced anomalously high rainfall across most of its sub-basins. An automated method detecting the daily position of the East Asian Summer Monsoon Front (EASMF) is applied to show that the anomalously high YRB precipitation was associated with an anomalously slow northward progression of the EASMF and prolonged Mei Yu conditions over the YRB lasting more than one month. Lagrangian trajectory analysis is employed to study the convergence of air masses in the EASMF during two 5-day heavy-precipitation episodes, 12-16 June and 4-8 July 2020. Despite heavy precipitation and the convergence of monsoonal and subtropical air masses seen in both episodes, clear differences are identified between these episodes in the location/strength of the Subtropical Westerly Jet and the location of the Western North Pacific Subtropical High. This study contextualises heavy precipitation in Asia in summer 2020 and showcases a number of analysis tools developed by the authors for the study of such events.</p>

scholarly journals Global-scale distribution of ozone in the remote troposphere from ATom and HIPPO airborne field missions

2020 ◽  
Author(s):  
Ilann Bourgeois ◽  
Jeffrey Peischl ◽  
Chelsea R. Thompson ◽  
Kenneth C. Aikin ◽  
Teresa Campos ◽  
...  
Keyword(s):  
Tropospheric Ozone ◽  
Large Scale ◽  
Marine Boundary Layer ◽  
Global Scale ◽  
Ozone Production ◽  
Commercial Aircraft ◽  
Air Masses ◽  
The Pacific ◽  
Vertical Distributions ◽  
Remote Troposphere

Abstract. Ozone is a key constituent of the troposphere where it drives photochemical processes, impacts air quality, and acts as a climate forcer. Large-scale in situ observations of ozone commensurate with the grid resolution of current Earth system models are necessary to validate model outputs and satellite retrievals. In this paper, we examine measurements from the Atmospheric Tomography (ATom, 4 deployments in 2016–2018) and the HIAPER Pole-to-Pole Observations (HIPPO; 5 deployments in 2009–2011) experiments, two global-scale airborne campaigns covering the Pacific (HIPPO and ATom) and Atlantic (ATom) basins. ATom and HIPPO represent the first global-scale, vertically resolved measurements of O3 distributions throughout the troposphere, with HIPPO sampling the Pacific basin and ATom sampling both the Pacific and Atlantic basins. Given the relatively limited temporal resolution of these two campaigns, we first compare ATom and HIPPO ozone data to longer-term observational records to establish the representativeness of our dataset. We show that these two airborne campaigns captured on average 53, 54, and 38 % of the ozone variability in the marine boundary layer, free troposphere, and upper troposphere/lower stratosphere (UTLS), respectively, at nine well-established ozonesonde sites. Additionally, ATom captured the most frequent ozone concentrations measured by regular commercial aircraft flights in the northern Atlantic UTLS. We then use the repeated vertical profiles carried out during these two campaigns to provide a global-scale picture of tropospheric ozone spatial and vertical distributions throughout the remote troposphere. We highlight a clear hemispheric gradient, with greater ozone in the northern hemisphere consistent with greater precursor emissions. We also show that the ozone distribution below 8 km was similar in the extra-tropics of the Atlantic and Pacific basins due to zonal circulation patterns. However, twice as much ozone was found in the tropical Atlantic than in the tropical Pacific, due to well-documented dynamical patterns transporting continental air masses over the Atlantic. We finally show that the seasonal variability of tropospheric ozone over the Pacific and the Atlantic basins is driven by transported continental plumes and photochemistry, and the vertical distribution is driven by photochemistry and mixing with stratospheric air. This new dataset is essential for improving our understanding of both ozone production and loss processes in remote regions, as well as the influence of anthropogenic emissions on baseline ozone.

scholarly journals Magnitude, Scale, and Dynamics of the 2020 Mei-yu Rains and Floods over China

2021 ◽  
Author(s):  
Ambrogio Volonté ◽  
Mark Muetzelfeldt ◽  
Reinhard Schiemann ◽  
Andrew G. Turner ◽  
Nicholas Klingaman
Keyword(s):  
Asian Summer Monsoon ◽  
Yangtze River Basin ◽  
Heavy Precipitation ◽  
Early Summer ◽  
Monthly Precipitation ◽  
Air Masses ◽  
Automated Method ◽  
The Yangtze River Basin ◽  
Asian Summer ◽  
Upper Level

AbstractLarge parts of East and South Asia were affected by heavy precipitation and flooding during early summer 2020. This study provides both a statistical and dynamical characterization of rains and floods affecting the Yangtze River Basin (YRB). By aggregating daily and monthly precipitation over river basins across Asia, it is shown that the YRB is one of the areas that was particularly affected. June and July 2020 rainfall was higher than in the previous 20 years, and the YRB experienced anomalously high rainfall across most of its sub-basins. YRB discharge also attained levels not seen since 1998/1999. An automated method detecting the daily position of the East Asian Summer Monsoon Front (EASMF) is applied to show that the anomalously high YRB precipitation was associated with a halted northward progression of the EASMF and prolonged mei-yu conditions over the YRB lasting more than one month. Two 5-day heavy-precipitation episodes (12–16 June and 4–8 July 2020) are selected from this period for dynamical characterization, including Lagrangian trajectory analysis. Particular attention is devoted to the dynamics of the airstreams converging at the EASMF. Both episodes display heavy precipitation and convergence of monsoonal and subtropical air masses. However, clear differences are identified in the upper-level flow pattern, substantially affecting the balance of airmass advection towards the EASMF. This study contextualizes heavy precipitation in Asia in summer 2020 and showcases several analysis tools developed by the authors for the study of such events.

1497-P: Secular Trends in Incidence and One-Year Mortality Rates of Lower Extremity Amputation in People with Diabetes in Hong Kong between 2001 and 2016

Diabetes ◽  
2020 ◽  
Vol 69 (Supplement 1) ◽  
pp. 1497-P
Author(s):  
HONGJIANG WU ◽  
AIMIN YANG ◽  
ERIC S. LAU ◽  
RONALD C. MA ◽  
ALICE P. KONG ◽  
...  
Keyword(s):  
Hong Kong ◽  
Lower Extremity ◽  
Mortality Rates ◽  
Secular Trends ◽  
Lower Extremity Amputation ◽  
One Year ◽  
Extremity Amputation

scholarly journals Seasonal Rainfall Forecasts for the Yangtze River Basin in the Extreme Summer of 2020

2021 ◽  
Author(s):  
Philip E. Bett ◽  
Gill M. Martin ◽  
Nick Dunstone ◽  
Adam A. Scaife ◽  
Hazel E. Thornton ◽  
...  
Keyword(s):  
Linear Regression ◽  
River Basin ◽  
Yangtze River ◽  
Asian Summer Monsoon ◽  
Yangtze River Basin ◽  
Early Summer ◽  
Lead Times ◽  
Seasonal Forecasts ◽  
June July ◽  
The Impact

AbstractSeasonal forecasts for Yangtze River basin rainfall in June, May–June–July (MJJ), and June–July–August (JJA) 2020 are presented, based on the Met Office GloSea5 system. The three-month forecasts are based on dynamical predictions of an East Asian Summer Monsoon (EASM) index, which is transformed into regional-mean rainfall through linear regression. The June rainfall forecasts for the middle/lower Yangtze River basin are based on linear regression of precipitation. The forecasts verify well in terms of giving strong, consistent predictions of above-average rainfall at lead times of at least three months. However, the Yangtze region was subject to exceptionally heavy rainfall throughout the summer period, leading to observed values that lie outside the 95% prediction intervals of the three-month forecasts. The forecasts presented here are consistent with other studies of the 2020 EASM rainfall, whereby the enhanced mei-yu front in early summer is skillfully forecast, but the impact of midlatitude drivers enhancing the rainfall in later summer is not captured. This case study demonstrates both the utility of probabilistic seasonal forecasts for the Yangtze region and the potential limitations in anticipating complex extreme events driven by a combination of coincident factors.

scholarly journals Skilful predictions of the Asian summer monsoon one year ahead

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yuhei Takaya ◽  
Yu Kosaka ◽  
Masahiro Watanabe ◽  
Shuhei Maeda
Keyword(s):  
Long Range ◽  
Summer Monsoon ◽  
Southern Oscillation ◽  
Asian Summer Monsoon ◽  
Boreal Summer ◽  
Climate Modelling ◽  
Large Ensemble ◽  
Asian Society ◽  
Asian Summer ◽  
One Year

AbstractThe interannual variability of the Asian summer monsoon has significant impacts on Asian society. Advances in climate modelling have enabled us to make useful predictions of the seasonal Asian summer monsoon up to approximately half a year ahead, but long-range predictions remain challenging. Here, using a 52-member large ensemble hindcast experiment spanning 1980–2016, we show that a state-of-the-art climate model can predict the Asian summer monsoon and associated summer tropical cyclone activity more than one year ahead. The key to this long-range prediction is successfully simulating El Niño-Southern Oscillation evolution and realistically representing the subsequent atmosphere–ocean response in the Indian Ocean–western North Pacific in the second boreal summer of the prediction. A large ensemble size is also important for achieving a useful prediction skill, with a margin for further improvement by an even larger ensemble.

Tropospheric ozone variability over Hong Kong based on recent 20‐year (2000–2019) ozonesonde observation

2020 ◽  
Author(s):  
Zhiheng Liao ◽  
Zhenhao Ling ◽  
Meng Gao ◽  
Jiaren Sun ◽  
Wei Zhao ◽  
...  
Keyword(s):  
Hong Kong ◽  
Tropospheric Ozone ◽  
Year 2000

Exploring the Asian Economic Miracle: Politics, Economics, Society, Culture, and History — A Review Article

1994 ◽  
Vol 53 (1) ◽  
pp. 124-131 ◽  
Author(s):  
Terutomo Ozawa
Keyword(s):  
Hong Kong ◽  
South Korea ◽  
The Philippines ◽  
Review Article ◽  
The Political ◽  
Political Systems ◽  
Industrial Activities ◽  
Economic Miracle ◽  
The Pacific ◽  
Pacific Asia

Structural upgrading and industrial dynamismin Pacific Asia—initially Japan, then the Asian NIEs (Newly Industrializing Economies: South Korea, Taiwan, Hong Kong, and Singapore) following closely behind, and most recently, ASEAN 4 (Thailand, Malaysia, Indonesia, and the Philippines)—have been unprecedentedly phenomenal. This regional supergrowth in industrial activities has become the center of attention, but the evolving changes in the political systems and societal structures of the Pacific Asian nations have been, no doubt, equally important, although rather subtle and not so dramatic in appearance.

scholarly journals Analysis of the latitudinal variability of tropospheric ozone in the Arctic using the large number of aircraft and ozonesonde observations in early summer 2008

2016 ◽  
Author(s):  
Gerard Ancellet ◽  
Nikos Daskalakis ◽  
Jean Christophe Raut ◽  
Boris Quennehen ◽  
François Ravetta ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Tropospheric Ozone ◽  
Lower Troposphere ◽  
Early Summer ◽  
Ozone Production ◽  
The Arctic ◽  
Integrated Analysis ◽  
International Polar Year ◽  
Latitude Range ◽  
Vertical Variability

Abstract. The goal of the paper are to: (1) present tropospheric ozone (O3) climatologies in summer 2008 based on a large amount of measurements, during the International Polar Year when the Polar Study using Aircraft, Remote Sensing, Surface Measurements, and Models of Climate Chemistry, Aerosols, and Transport (POLARCAT) campaigns were conducted (2) investigate the processes that determine O3 concentrations in two different regions (Canada and Greenland) that were thoroughly studied using measurements from 3 aircraft and 7 ozonesonde stations. This paper provides an integrated analysis of these observations and the discussion of the latitudinal and vertical variability of tropospheric ozone north of 55° N during this period is performed using a regional model (WFR-Chem). Ozone, CO and potential vorticity (PV) distributions are extracted from the simulation at the measurement locations. The model is able to reproduce the O3 latitudinal and vertical variability but a negative O3 bias of 6–15 ppbv is found in the free troposphere over 4 km, especially over Canada. Ozone average concentrations are of the order of 65 ppbv at altitudes above 4 km both over Canada and Greenland, while they are less than 50 ppbv in the lower troposphere. The relative influence of stratosphere-troposphere exchange (STE) and of ozone production related to the local biomass burning (BB) emissions is discussed using differences between average values of O3, CO and PV for Southern and Northern Canada or Greenland and two vertical ranges in the troposphere: 0–4 km and 4–8 km. For Canada, the model CO distribution and the weak correlation (< 30 %) of O3 and PV suggests that stratosphere-troposphere exchange (STE) is not the major contribution to average tropospheric ozone at latitudes less than 70° N, due to the fact that local biomass burning (BB) emissions were significant during the 2008 summer period. Conversely over Greenland, significant STE is found according to the better O3 versus PV correlation (> 40 %) and the higher 75th PV percentile. A weak negative latitudinal summer ozone gradient −6 to −8 ppbv is found over Canada in the mid troposphere between 4 and 8 km. This is attributed to an efficient O3 photochemical production due to the BB emissions at latitudes less than 65° N, while STE contribution is more homogeneous in the latitude range 55° N to 70° N. A positive ozone latitudinal gradient of 12 ppbv is observed in the same altitude range over Greenland not because of an increasing latitudinal influence of STE, but because of different long range transport from multiple mid-latitude sources (North America, Europe and even Asia for latitudes higher than 77° N).

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