An examination of the long-term CO records from MOPITT and IASI: comparison of retrieval methodology

International audienceCarbon monoxide (CO) is a key atmospheric compound that can be remotely sensed by satellite on the global scale. Fifteen years of continuous observations are now available from the MOPITT/Terra mission (2000 to present). Another fifteen and more years of observations will be provided by the IASI/MetOp instrument series (2007–2023>). In order to study long term variability and trends, a homogeneous record is required, which is not straightforward as the retrieved products are instrument and processing dependent. The present study aims at evaluating the consistency between the CO products derived from the MOPITT and IASI missions, both for total columns and vertical profiles, during a six year overlap period (2008–2013). The analysis is performed by first comparing the available 2013 versions of the retrieval algorithms, and second using a dedicated reprocessing of MOPITT CO profiles and columns based on the IASI a priori constraints. MOPITT v5T total columns are generally slightly higher over land (bias ranging from 0 to 13%) than IASI v20100815 data. When IASI and MOPITT data are retrieved with the same a priori constraints, correlation coefficients are slightly improved. Large discrepancies (total column bias over 15%) observed in the Northern Hemisphere during the winter months are reduced by a factor of 2 to 2.5. The detailed analysis of retrieved vertical profiles compared with collocated aircraft data from the MOZAIC-IAGOS network, illustrates the advantages and disadvantages of a constant vs. a variable a priori. On one hand, MOPITT agrees better with the aircraft profiles for observations with persisting high levels of CO throughout the year due to pollution or seasonal fire activity (because the climatology-based a priori is supposed to be closer to the real atmospheric state). On the other hand, IASI performs better when unexpected events leading to high levels of CO occur, due to the less constrained variance-covariance matrix

Radiative forcing of climate change from the Copernicus reanalysis of atmospheric composition

Radiative forcing provides an important basis for understanding and predicting global climate changes, but its quantification has historically been done independently for different forcing agents, involved observations to varying degrees, and studies have not always included a detailed analysis of uncertainties. The Copernicus Atmosphere Monitoring Service reanalysis is an optimal combination of modelling and observations of atmospheric composition. It provides a unique opportunity to rely on observations to quantify the monthly and spatially resolved global distributions of radiative forcing consistently for six of the largest forcing agents: carbon dioxide, methane, tropospheric ozone, stratospheric ozone, aerosol-radiation interactions, and aerosol-cloud interactions. These radiative forcing estimates account for adjustments in stratospheric temperatures, but do not account for rapid adjustments in the troposphere. On a global average and over the period 2003—2017, stratospherically adjusted radiative forcing of carbon dioxide has averaged +1.89 W m−2 (5-95% confidence interval: 1.50 to 2.29 W m−2) relative to 1750 and increased at a rate of 18% per decade. The corresponding values for methane are +0.46 (0.36 to 0.56) W m−2 and 4% per decade, but with a clear acceleration since 2007. Ozone radiative forcing averages +0.32 (0 to 0.64) W m−2, almost entirely contributed by tropospheric ozone since stratospheric ozone radiative forcing is only +0.003 W m−2. Aerosol radiative forcing averages −1.25 (−1.98 to −0.52) W m−2, with aerosol-radiation interactions contributing −0.56 W m−2 and aerosol-cloud interactions contributing −0.69 W m−2 to the global average. Both have been relatively stable since 2003. Taking the six forcing agents together, there no indication of a sustained slowdown or acceleration in the rate of increase in anthropogenic radiative forcing over the period. These ongoing radiative forcing estimates will monitor the impact on the Earth’s energy budget of the dramatic emission reductions towards net-zero that are needed to limit surface temperature warming to the Paris Agreement temperature targets. Indeed, such impacts should be clearly manifested in radiative forcing before being clear in the temperature record. In addition, this radiative forcing dataset can provide the input distributions needed by researchers involved in monitoring of climate change, detection and attribution, interannual to decadal prediction, and integrated assessment modelling. The data generated by this work are available at https://doi.org/10.24380/ads.1hj3y896 (Bellouin et al., 2020)

Intercomparison of air quality models in a megacity: Towards an operational ensemble forecasting system for São Paulo

An intercomparison of four air quality models is performed in the tropical megacity of Sao Paulo with the perspective of developing an air quality forecasting system based on a regional model ensemble. During three contrasting periods marked by different types of pollution events, we analyze the concentrations of the main regulated pollutants (Ozone, CO, SO2, NOx, PM2.5 and PM10) compared to observations of a dense air quality monitoring network. The modeled concentrations of CO, PM and NOx are in good agreement with the observations for the temporal variability and the range of variation. However, the transport of pollutants due to biomass burning pollution events can strongly affect the air quality in the metropolitan area of Sao Paulo with increases of CO, PM2.5 and PM10, and is associated with an important inter-model variability. Our results show that each model has periods and pollutants for which it has the best agreement. The observed day-to-day variability of ozone concentration is well reproduced by the models, as well as the average diurnal cycle in terms of timing. Overall the performance for ozone of the median of the regional model ensemble is the best in terms of time and magnitude because it takes advantage of the capabilities of each model. Therefore, an ensemble prediction of regional models is promising for an operational air quality forecasting system for the megacity of Sao Paulo.This article is a direct contribution to the research themes of the Klimapolis Lab-836 oratory (klimapolis.net), which is funded by the German Federal Ministry of Education837 and Research (BMBF)

Impact de la mousson africaine sur la composition chimique de l'atmosphère en Afrique équatoriale

Important amounts of reactive gases and particles are emitted over equatorial Africa by human activities and naturally by forests, lightning and soils. The different transport processes that characterize this region during the monsoon season (e.g. African and Tropical Easterly Jets, deep convection) can redistribute these emissions downwind out of Africa and, hence, have an impact on the regional as well as on the global ozone (O3) budget. The main objective of my thesis is to improve our knowledge of the impact of these emissions and transport processes on the chemical composition of the atmosphere over equatorial Africa. For this purpose, the in-situ data measured during the AMMA field campaign which took place over west Africa in summer 2006 together with MOZAIC data and satellite observations are analysed and compared with LMDz_INCA global model simulations. This allows evaluation of the model performance over equatorial Africa and, on the other hand, to analyse the influence of emissions and transport processes during the monsoon season on the regional ozone budget. A description and first validation of the LMDz_INCA results against satellite data are presented in the first part of this thesis. The second part is dedicated to the impact of deep convection and lightning nitric oxides (NOx) emissions on ozone and its precursors. The impact of biomass burning emissions over central Africa is then discussed. Finally, the last part is dedicated to anlysis of the contribution of African and Asian emissions to the regional ozone budget.Des quantités importantes de gaz réactifs et de particules sont émises en Afrique équatoriale par l'activité humaine et naturellement par les écosystèmes forestiers, les éclairs et les sols. Les différents processus de transport qui caractérisent cette région pendant la saison de la mousson (e.g. Jets d'Est Africain et Tropical, convection profonde) peuvent conduire à la redistribution de ces émissions en dehors du continent Africain et influencer ainsi aussi bien le bilan régional que global de l'ozone (O3). Le but de mes travaux de thèse est d'améliorer notre compréhension sur l'impact de ces émissions et de ces processus de transport sur la composition chimique de l'atmosphère en Afrique équatoriale. Les données mesurées pendant la campagne AMMA qui a eu lieu en été 2006 en Afrique de l'ouest ainsi que les données du programme MOZAIC sont analysées et confrontées aux résultats du modèle global LMDz_INCA. Cela permet d'évaluer les performances de ce modèle au dessus de l'Afrique équatoriale d'une part et, d'autre part, d'analyser l'influence des différentes émissions et des différents processus de transport qui caractérisent cette région pendant la saison de la mousson sur le bilan régional de l'ozone. Une description et une validation des résultats du modèle LMDz_INCA avec des observations satellitaires sont présentées dans la première partie de cette thèse. La deuxième partie est consacrée à l'impact du transport convectif et des oxydes d'azote (NOx) émis par les éclairs sur l'ozone et ses précurseurs. L'analyse de l'impact des émissions par les feux de biomasse depuis l'Afrique centrale est ensuite présentée. La dernière partie traite de la contribution des émissions africaines et asiatiques au bilan de l'ozone en Afrique équatoriale

Impact de la mousson africaine sur la composition chimique de l'atmosphère en Afrique équatoriale

PARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF

Air pollution in eastern Asia: an integrated perspective

This book, written by an international group of experts from China, Europe and the USA, presents a broad and comprehensive analysis of the chemical and meteorological processes responsible for the formation of air pollutants in eastern Asia, and in particular for the development of severe pollution episodes observed primarily during winter in the northeastern part of China. With the rapid population growth, economic development and urbanization occurring in Asia, air pollution has become a major environmental problem in this part of the world. The book is organized around six distinct parts. The first part of the volume offers a general perspective on issues related to air pollution including persistent haze events in eastern and southern Asia. The second part presents an overview of air pollution sources (i.e., anthropogenic and biomass burning sources). The third part analyzes in-situ observations of chemical species in China, while the fourth part focuses on space observations of gas-phase and aerosol species. The modeling aspects are treated in the fifth part of the volume, which includes a presentation of several air quality forecast systems and an assessment of the role of urbanization on air pollution levels. Finally, the effects of air pollution on health and crop productivity in China are discussed in the last part of the book. The book also presents an integrated view of past and present situations in Asia and provides the scientific basis from which mitigation policies can be established and air quality can be improved. Audience: This book is written for scientists, educators, students, environmental managers, policy-makers and leaders in public administration and private corporations who wish to use science-based information to mitigate air pollution. The book should help decision-makers to design effective policies for air quality improvement and to successfully manage short-term air pollution episodes that substantially affect people’s quality of life and strongly impact the economy. 

Towards an International Network for Monitoring, Analyzing and Forecasting Regional Air Quality.

International audienceUrbanization with its concentration of population, economic activities industrial development and business has generated an increase in the atmospheric level of air pollutants with adverse effects on human health, food production and well-being. Addressing this major problem, specifically in urban areas of Asia, Latin America and Africa, requires the development of coherent measurement, analysis modeling and dissemination tools with the highest possible standards. We propose to develop and implement a global interdisciplinary network of experts in different parts of the world who will work together and develop state-of-the-art regional air quality prediction systems with downscaling and evaluation capability from the global to the regional and local scales. We invite IGAC and other international programs to sponsor and support this worldwide initiative

Air Quality Forecating in latin America: the PAPILA project

International audienc

Predictions of Chemical Weather in Asia: The EU Panda Project

International audienceAir quality has become a pressing problem in Asia and specifically in China due to rapid economic development (i.e., rapidly expanding motor vehicle fleets, growing industrial and power generation activities, domestic and biomass burning). In spite of efforts to reduce chemical emissions, high levels of particle matter and ozone are observed and lead to severe health problems with a large number of premature deaths. To support efforts to reduce air pollution, the European Union is supporting the PANDA project whose objective is to use space and surface observations of chemical species as well as advanced meteorological and chemical models to analyze and predict air quality in China. The Project involves 7 European and 7 Chinese groups. The paper will describe the objectives of the project and present some first accomplishments. The project focuses on the improvement of methods for monitoring air quality from combined space and in-situ observations, the development of a comprehensive prediction system that makes use of these observations, the elaboration of indicators for air quality in support of policies, and the development of toolboxes for the dissemination of information