Abstracts – Session E2
iLEAPS Asia: Land-atmosphere research in Asia: From air pollution to climate change
E201 - ORAL-0320: Impacts of aerosol-boundary layer interactions on weather and haze pollution in East Asia
Aijun Ding1, Xin Huang1, Wei Nie1, Xuguang Chi1, Markku Kulmala2, Congbin Fu1
1JirLATEST, School of Atmospheric Sciences, Nanjing University, Nanjing, China 2Division of Atmospheric Sciences, Department of Physics, University of Helsinki,, Helsinki, Finland
Air pollution is one of the grand environmental challenges in East Asia. Synoptic weather is one of the important conditions influencing day-to-day air quality, however intense air pollution, especially high concentration of aerosols, can substantially influence meteorological parameters through the aerosol-radiation-boundary layer interactions. Such kind of two-way feedback will not only influence weather and regional climate but also crucial for the enhancement of haze pollution in regions with strong emission of air pollutants. Based on measurements results at the Station for Observation Regional Processes of the Earth System (SORPES) in East China and numerical modeling, we will present some latest observational evidences to show how the complex air pollutants from anthropogenic fossil fuel combustion sources and biomass burning activities could substantially modify weather, including air temperature, precipitation and clouds in East Asia. We will also show how the air pollutants influence the boundary layer dynamics, the most important condition for air pollution dispersion and accumulation, and to show how the aerosol-radiation-PBL interaction, especially through its impact on increasing relative humidity, is important for secondary aerosol formation in Asia. The roles of strong-absorption aerosols, like black carbon, in modifying boundary layer dynamics and enhancement of haze pollution in megacities (i.e. the so-called “dome effect”) will be discussed based on modeling of meteorology-chemistry coupled model WRF-Chem. Some future field campaigns and modeling efforts for this region will also be introduced.
E202 - ORAL-0382: Air quality improvements and health benefits from China’s clean air action since 2013
Yixuan Zheng1, Tao Xue1, Qiang Zhang1, Guannan Geng1, 2, Dan Tong1, Xin Li1, Kebin He3
1Ministry of Education Key Laboratory for Earth System Modeling, Department of Earth System Science, Tsinghua University, Beijing, China 2Rollins School of Public Health, Emory University, Atlanta, The United States of America 3State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, China
Aggressive emission control measures were taken by Chinese government after the promulgation of the “Air Pollution Prevention and Control Action Plan” in 2013. Here we evaluated the air quality and health benefits associated with this stringent policy during 2013-2015 by using surface PM2.5 concentrations estimated from a three-stage data fusion model and cause-specific integrated exposure-response functions. The population-weighted annual mean PM2.5 concentrations decreased by 21.5% over China during 2013-2015, reducing from 60.5 in 2013 to 47.5 µg/m3 in 2015. Subsequently, the national PM2.5-attributable mortality decreased from 1.22 million (95% CI: 1.05, 1.37) in 2013 to 1.10 million (95% CI: 0.95, 1.25) in 2015, which reduced by 9.1%. The limited health benefits compared to air quality improvements are mainly due to the supralinear responses of mortality to PM2.5 over the high concentration end of the concentration-response functions. Our study affirms the effectiveness of China’s recent air quality policy; however, due to the nonlinear responses of mortality to PM2.5 variations, current policies should remain in place and more stringent measures should be implemented to protect public health.
E203 - ORAL-0321: Micrometeorological flux measurements of pollutant emissions above Beijing
Eiko Nemitz1, Ben Langford1, Neil Mullinger1, Nicholas Cowan1, Mhairi Coyle1, Chiara Di Marco1, Joe Acton2, Brian Davison2, C. Nicholas Hewitt2, James Lee3, Freya Squires3, Rutambhara Joshi4, Dantong Liu4, James Allan4, Xinmin Wang5, Pingqing Fu6
1NERC Centre for Ecology and Hydrology (CEH), Penicuik, United Kingdom 2Lancaster University, Lancaster, United Kingdom 3WACL, University of York, York, United Kingdom 4School of Earth and Environmental Sciences, University of Manchester, Manchester, United Kingdom 5CAS Guangzhou Institute of Geochemistry, Guangzhou, China 6Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China
Air pollution is estimated to cause 1.6 million premature deaths in China every year and in the winter 2016/17 Beijing had to issue health alerts and put in place ad hoc limitations on industrial and vehicular activity. Much of this pollution is attributed to emissions from industrial processes and in particular coal combustion. By contrast, the diffuse pollutant sources within the city are less well understood. This includes, e.g., emissions from the Beijing traffic fleet, the sewage system, food preparation, solid fuel combustion in the streets and small industrial processes.
Within the framework of a major UK-Chinese collaboration to study air pollution and its impact on human health in Beijing, we therefore measured fluxes of a large range of pollutants from a height of 102 m on the meteorological tower at the Institute of Atmospheric Physics during two contrasting periods (Nov/Dec 2016 and May/Jun 2017). We mounted some instruments on the tower and housed others in a measurement container at its base. Fluxes were quantified by eddy-covariance for the gases CO2, CO, NOx, O3, a large number of VOCs and, for the first time above an urban area, NH3. In addition, we measured aerosol fluxes in terms of total particle number, size-segregated particle number (0.06 to 20 µm) and chemically resolved, using an eddy-covariance flux system based on an Aerosol Mass Spectrometer (non-refractory PM1 NH4+, NO3-, SO42-, Cl- organic aerosol) and trialling a single particle soot spectrometer (SP2, DMT) for black carbon.
Fluxes were similar in magnitude to Western city centre locations, but with important differences: (a) aerosol emissions included SO2- and Cl- not previously observed; (b) NH3 fluxes were larger than estimated for, e.g., UK cities; (c) NOx fluxes were lower than predicted by the emission inventories, whilst the opposite has been found in the UK and Austria.
E204 - ORAL-0034: Flood management by the stakeholders along Mayurakshi Basin: A New perspective
1Asutosh College, Kolkata, India
Water has always been an essential resource for survival. Integrated Natural Resource Management (INRM) is the driving force for sustainability of resources and focuses to incorporate all possible stakeholders from the planning level itself, reducing possible future conflicts. There is a great spatial and temporal inequality in the distribution of precipitation in India which is generated by the south-west monsoon. India experiences disastrous floods every year which threaten regions and the people living there and the basis of their existence. Flood Risk Management (FRM) is the latest approach which has shifted its paradigms from technical oriented flood protection measures of focus on defending against floods towards flood risk management, a focus on managing flood risks. Human perceptions of flood risk of the stakeholders provide the necessary information and integration of these perceptions in decision-making process may help in developing a holistic flood management policy. Our study aims to analyse the perception of flood damage and its causes by the inhabitants of Mayurakshi River basin in Jharkhand and West Bengal. The river Mayurakshi, one of the major right bank tributaries of the river Bhagirathi flows down through a large part of eastern India and has structural measures like Massanjore dam and Tilpara barrage. The river has become infamous for its widespread flooding and long duration water logging in the lower reaches of its basin, the worst of which happened in the year 2000. A questionnaire survey was carried out in 21 villages covering a wide range of flood- related issues was prepared to examine the perception of the bank-dwellers. People’s perception suggests that apart from natural causes like very high rainfall, improper management of the reservoirs and dams, as well as lack of adequate coordination in releasing water from dams and barrages, are the root causes of recent flood in the basin.
E205 - ORAL-0176: Aircraft Observations of Land-Atmosphere Interactions in Northern India
Emma Barton1, Christopher Taylor2, Phil Harris2, Douglas Parker3, Steef Boeing3, Andrew Turner4, Ashis Mitra5, Jennifer Brooke6, Chawn Harlow6
1Centre for Ecology and Hydrology, Wallingford, United Kingdom 2Centre for Ecology & Hydrology, Wallingford, United Kingdom 3School of Earth and Environment, University of Leeds, Leeds, United Kingdom 4University of Reading, Reading, United Kingdom 5NCMRWF, Noida, India 6Met Office, Exeter, United Kingdom
India is a region of the world where the influence of land surface fluxes of sensible and latent heat plays an important role in weather and climate. Indian rainfall simulations in GCMs are known to be particularly sensitive to soil moisture. However, in a monsoon region where seasonal convective rainfall dominates, it is a big challenge for GCMs to capture, on the one hand, a realistic depiction of surface fluxes during wetting up and drying down at seasonal and sub-seasonal scales, and on the other, the sensitivity of convective rainfall and regional circulations to space-time fluctuations in land surface fluxes. On top of this, most GCMs and operational atmospheric forecast models don’t explicitly consider irrigation. In the Indo-Gangetic plains of the Indian sub-continent, irrigated agriculture has become the dominant land use. Irrigation suppresses temporal flux variability for much of the year, and at the same time enhances spatial heterogeneity.
As part of the Anglo-Indian Interaction of Convective Organization and Monsoon Precipitation, Atmosphere, Surface and Sea (INCOMPASS) project, a series of research flights was performed during June and July 2016 across the sub-continent using the NERC/Met Office BAe146 aircraft. Here we present results for a case study from a flight on 30th June which sampled the Planetary Boundary Layer (PBL) on a 700 km low level transect, from semi-arid Rajasthan eastwards into the extensively irrigated state of Uttar Pradesh. As well as crossing different land uses, the flight also sampled mesoscale regions with contrasting recent rainfall conditions. We show how variations in surface hydrology, driven by both irrigation and rainfall, influence properties of the PBL and moist convective processes. These unique observations will provide a powerful tool for understanding the dominant land-atmosphere coupling mechanisms operating on a range of multiple length scales, and which help to shape the Indian monsoon.
E206 - ORAL-0358: Impact of Brick Kiln emission on air pollution tolerance index of surrounding vegetations in Faisalabad-Pakistan
1Department of Environmental Sciences & Engineering, Government College University, Faisalabad, Faisalabad, Pakistan
In any contaminated environment, the sensitive plant species can serve as bio-indicator of air pollution while tolerant plant species can act as a sink for air pollutants. The present study was aimed to identify the sensitive and tolerant plant species in the vicinity of brick kilns in the Faisalabad city. Keeping in view the importance of different vegetation’s around Brick kilns, we conducted a research to study the impact of brick kiln gases on the vegetation. Random samples of Khajor (Phoenix dactylitera. L), kekar (Prosopic juliflora), Neem (Azadirachta Indica), and Bary (Melia azedarach) are collected from distance 100m, 250m, 400m, and 500m from two sites (Jhang road and Ismail road) in Faisalabad. To determine the susceptibility level of the selected plant species, four biochemical parameters, ascorbic acid, total chlorophyll content, relative water content and pH of leaf extract, were assessed and APTI was calculated. The results of the study revealed that among four studied plant species, Phoenix dactylitera. L (Khajoor) and Azadirachta Indica (Neem) were found to be the most tolerant species, whereas Melia azedarach. L (Berry) was found to be the most sensitive species. The present study suggested that the most tolerant species, Phoenix dactylitera. L. and Azadirachta Indica, could be grown in the vicinity of such pollution sources as a remedial measure of brick kiln pollution. The results also showed an inverse relation in APTI and distance of pollution source.
E207 - ORAL-0500: Large unexplained suite of chemically reactive compounds present in ambient air due to biomass fires
Vinayak Sinha1, Vinod Kumar1, B.P. Chandra1
1 Department of Earth and Environmental Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, S. A. S. Nagar, Manauli PO, Punjab, India 140306
Agricultural burning is a widespread practice globally, which impacts atmospheric chemistry, air quality and climate. A key process that is still poorly understood concerns the quanta of extra chemical reactivity that emissions from biomass fires introduce directly and indirectly (through secondary processes) into ambient atmospheric environments.
Here, we investigated the impact of summertime agricultural biomass fires by measuring the total ambient OH reactivity of air and a suite of major known OH reactants at a regionally representative suburban site located downwind of agricultural fields in the north-west Indo Gangetic Plain from March-May 2013, during pre-harvest and the post-harvest periods. It was found that from virtually no missing OH reactivity in pre-harvest summertime air, the missing OH reactivity fraction increased to ~40 % in the post-harvest summertime period influenced by large scale biomass fires. The increase in the missing OH reactivity was accompanied by greater than two-fold increase in absolute total OH reactivity from 28 s-1 to 64 s-1. Thus, a large suite of chemically reactive compounds resulting from the biomass fires remain unknown. Strong photochemical formation of rarely measured nitrogenous volatile organic compounds having high OH reactivity and/or significant health effects, which are not included in current atmospheric chemistry models, correlated with the increased missing OH reactivity. The findings reveal that for more accurate understanding of atmospheric chemistry-air-quality-climate feedbacks in fire impacted atmospheric environments, measurement of organic nitrogenous gases are a key requirement.
E208 - ORAL-0502: Overview of Ground Measurements during the KORUS-AQ/MAPS-Seoul 2016 Campaign
Meehye Lee1, Joon Young Ahn, Gangwoong Lee, You Deok Hong, Jeonghoo Park, Limseok Chang, Huijeong Kim
1Korea University, Seoul, South Korea
As a part of the KORUS-AQ campaign, ground measurements were conducted at the Olympic Park in Seoul during May 12 ~ June 15 2016. For the entire experiment period, high O3 events of hourly mean over 100 ppbv occurred on May 20, 24, 29, and 30 and June 10 and 14. Except for the first and last days, O3 was enhanced with fine aerosols, when air masses came from the southern and northern part of China. These high concentration episodes were distinguished by meteorological conditions, precursor strengths, and chemical characteristics. The preliminary results highlight the role of local circulation and aromatics in controlling the air quality of Seoul Metropolitan Areas. In addition, further studies need to be done to understand oxidant cycle, daytime HONO, missing OH reactivity, nighttime chemistry, and active particle formation.
E209 - POSTER-0128: Impacts of urban air conditioning on regional climate change
Chang-eui Park1, Su-Jong Jeong1
1Southern University of Science and Technology (SUSTech), Shenzhen, China
Anthropogenic heat flux from air conditioning, which is one of major reasons of the urban heat island (UHI) in summer season, influences on local climate, further regional climate. As the climate warms, cooling degree days are projected to increase explosively over the mid-latitude. In particular, cooling demands over urban area are increased explosively over China and India due to rapid urbanization and economic growth in recent decades. However, the impacts of increasing cooling demands on local and regional climate change are remained unknown despite numerous people might be influenced by urban climate changes. This study aims to examine the potential impacts of air conditioning on urban and regional climate using coupled global atmosphere-land model with urban parameterizations. Enlarged UHI due to the increase in air conditioning heat flux is signified over the China, Mediterranean, Central America, India, and Southeast Asia. Especially, India shows significant increase in the surface temperature due to both high urban fractions and efficiency of thermal conduction. In addition, the surface heating changes the monsoon circulation in summer season over the northern India. Results informs that increasing demands of urban cooling should be quantified for exact projection of future climate.
E210 - POSTER-0281: New particle formation at SORPES station
Wei Nie1, Aijun Ding1, Ximeng Qi1, Xuguang Chi1, Zheng Xu1, Xin Huang1, Yuning Xie1, Veli-Matti Kerminen2, Tuukka Petaja2, Markku Kulmala2
1Joint International Research Laboratory of Atmospheric and Earth System Sciences, School of Atmospheric Sciences, Nanjing University, Nanjing, China 2Division of Atmospheric Sciences, Department of Physics, University of Helsinki,, Helsinki, Finland
Atmospheric new particle formation (NPF) and growth have been demonstrated to be an important source of atmospheric aerosols and play important roles in climate. We conducted a long term measurement from 2011 focusing on particle size distribution and related parameters at SORPES station. A high frequency of NPF events, up to 44% of the sampling days, have been observed. Many of these events occurred on the days with heavy aerosol pollution. Dust and biomass burning particles was demonstrated to have the potential to enhance atmospheric oxidation capacity via heterogeneous or heterogeneous photochemical reactions, and in turn promote NPF. Sulfuric acid was major precursors of particle nucleation and the initial growth, but highly oxygenated molecules (HOMs) also played important roles. A certain class of early-morning NPF, which occurred only a few minutes after sunrise, were observed during summer time. Monoterpene oxidation was confirmed as the major driver to induce this kind of NPF events.
E211 - POSTER-0293: Simulation on the radiative effects of aerosols and their influence on regional meteorology in East Asia
Xin Huang1, Aijun Ding1
1Nanjing University, Nanjing, China
China has been experiencing an economic boom featuring fast urbanization, growing industrial production, tremendous energy consumption in recent decades, which lead to increasingly severe air pollution, especially for aerosols. Intense precursor emissions and high concentrations of aerosols make the chemical interactions much more complex in China. In addition, such concentrated aerosols would exert substantial impacts on radiation transfer through their extinction effects, thereby influencing regional climate.
Almost all the regional and global chemical transport models underestimate sulfate aerosol concentration in East Asia, particularly in winter. Based on one-year field observations and WRF-Chem simulation, we found the enhancement role of existing mineral aerosols on sulfate formation, which includes enhanced aqueous oxidation due to increasing alkalinity of cloud water and transition metal-catalyzed oxidation, and heterogeneous reactions on aerosol surface. The improved WRF-Chem model does well reproduce aerosol components including sulfate. To quantify the direct radiative effect of multicomponent aerosol over china, a diagnostic iteration method is developed and applied. Among all the chemical compositions, light-absorbing black carbon (BC) has the largest positive radiative effect on long-term scale. For the biomass-burning case, this radiative effect due to BC could modify regional weather significantly. Intensive emission of BC from straw burning in mid-June 2012 trapped a considerable part of solar radiation in the atmosphere and reduced incident radiation reaching the surface on a regional scale. The energy re-allocation gave rise to substantial adjustments in vertical temperature stratification and led to precipitation redistribution.
E212 - POSTER-0294: Identification of high concentration episodes with an influence of continental outflow over the Yellow Sea
Inae Kwon, Meehye Lee, Hyunjin Ahn, Beomcheol Shin, Inae Kwon, Jinsang Jung, Sangwoo Kim
Black Carbon (BC), scattering coefficient and gaseous species concentration (Peroxyacetyl nitrate (PAN), O3, CO, SO2, NO2 and PM10) were measured onboard the RV Gisang 1 over the Yellow Sea (covering 124°~127°E, 31°~38°N) during May 2~12, May 17~30, and June 2~12, 2016. PAN and NO2 were determined every 2 minutes by a fast GC coupled with luminol chemiluminescence detection. CO, O3 and SO2 were measured by use of ultra violet absorption, non-dispersive infrared and ultraviolet fluorescence method. During the experiment, several high concentration episodes were identified by characteristic enhancement of aerosol species and reactive gases. An influence of continental outflow was dominant and under different meteorological condition. Chinese outflow came from the east of China continent was distinguished by elevated CO and SO2 concentration. A plume through Gobi desert was considered to increase PM10 concentration. O3 was highly elevated in outflow which passed through the west coast of Korea. Also, a mixed plume which originated from nearby continents, are characterized by high O3 and scattering coefficient. As an effect of plume aged over the east coast of China, BC, O3 and scattering coefficient were highly elevated. In the middle of the Yellow sea, a rapid increase of NO2, SO2 and BC for a short period were considered as influence of ship emission rather than continental outflow.
E213 - POSTER-0306: Evaluation and projection of climate extremes in China by RMIP models
Under the framework of the Regional Model Intercomparision Project (RMIP III), the simulation results from six regional climate models (RCMs) and two global models (GCMs) are used to generate the climate extreme indices for present and future over China using the performance-based ensemble averaging (PEA) method. During the control climate (1981-2000), PEA can reasonably reproduce the spatial and temporal variations of the climate extremes, and demonstrates more skill in representing temperature extremes than in precipitation extremes. Noticeable deficiencies in temperature extreme are found over the areas with complex topography, and too frequent heavy precipitation at smaller intensity is simulated by PEA. For the interannual variability, PEA shows higher skill in reproducing the temperature intense indices than the frequency and duration indices, and simulates more reasonable precipitation frequency and duration indices than intense indices. Under the scenario A1B for 2041-2060, widespread increases in Tmax90p, Tmin10p and WSDI are projected by PEA, associated with a decrease in FD and CSDI. Changes in Tmin10p are more pronounced than in Tmax90p, and more severe changes in CSDI and WSDI are found over western China. More intense and more frequent extreme precipitation events are projected over most China. The heavy precipitation generally increases faster than the average precipitation over the Yangtze River Basin, in which the most dramatic increases in the magnitude of precipitation events are found. The consecutive dry days are projected to increase over South China, which indicates future intensification of dry conditions over there.