Analysis of the Aerosol-radiation-cloud Interactions Through the Use of Regional Climate/chemistry Coupled Models

Analysis of the Aerosol-radiation-cloud Interactions Through the Use of Regional Climate/chemistry Coupled Models PDF Author: Rocío Baró Esteban
Publisher:
ISBN:
Category :
Languages : en
Pages : 208

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Book Description
The response of the climate systems to aerosols and their effect on the radiative budget of the Earth is the most uncertain climate feedback and one of the key topics in climate change mitigation. Air quality-climate studies (AQCI) are a key, but uncertain contributor to the anthropogenic forcing that remains poorly understood. To build confidence in the AQCI studies, regional-scale integrated meteorology-atmospheric chemistry models are in demand. The main objective of the present Thesis is the characterization of the uncertainties in the climate-chemistry-aerosol-cloud-radiation system associated to the aerosol direct and indirect radiative effects caused by aerosols over Europe, employing an ensemble of fully-coupled climate and chemistry model simulations. The first topic covered deals with the microphysics parameterization configuration of an online-coupled model. The differences when using two microphysics schemes within the Weather Research and Forecasting coupled with Chemistry (WRF-Chem) model are analyzed. The evaluated simulations come from the Air quality Model Evaluation International Initiative (AQMEII) Phase 2. The impact on several variables is estimated when selecting Morrison vs. Lin microphysics. The results showed smaller and more numerous cloud droplets simulated with the Morrison and therefore this scheme is more effective in scattering shortwave radiation. Also, the impact of biomass burning (BB) aerosols on surface winds during the Russian heat wave and wildfires episode is studied. The methodology consists of three WRF-Chem simulations over Europe, run under the context of EuMetChem COST Action ES1004, differing in the inclusion (or not) of aerosol-radiation (ARI) and aerosol-cloud interactions (ACI). These aerosols can affect surface winds where emission sources are located and further from the release areas. Local winds decrease due to a reduction of shortwave radiation at the ground, which leads to decreases in 2-m temperature. Atmospheric stability increases when considering aerosol feedbacks, inducing a lower planetary boundary layer height. This Dissertation also investigates the ability of an ensemble of simulations to elucidate the aerosol-radiation-cloud interactions. An assessment of whether the inclusion of atmospheric aerosol radiative feedbacks during two aerosol case studies of an ensemble of on-line coupled models improves the simulation results for maximum, mean and minimum 2-m temperature is done. The simulations (COST Action ES1004) are evaluated against observational data from E-OBS database. In both episodes, a general underestimation of the studied variables is found, being most noticeable in maximum temperature. The biases are improved when including ARI or ARI+ACI in the dust case. Although the ensemble does not outperform the individual models (in general), its improvements when including ARI+ARI are more remarkable. Last, an improvement of the spatio-temporal variability and correlation coefficients when aerosol radiative effects are included is found. Finally, the representation of the ACI in regional-scale integrated models when simulating the climate-chemistry-cloud-radiation system is analyzed. It complements the temperature analyses. The evaluated simulations are run in the context of AQMEII Phase 2 and include the ARI+ACI interactions. Simulations are evaluated against the (ESA) Cloud_cci data. Results show an underestimation(overestimation) of cloud fraction (CFR) over land(ocean) areas, which could be related to satellite retrieval missing thin clouds. Lower bias and mean absolute error (MAE) are found in the ensemble Cloud optical depth (COD) and cloud liquid ice path (CIP) are generally underestimated. The differences are related to microphysics. The development of this Thesis has contributed to the state of the art in AQCI studies. Although including aerosol feedbacks does not modify the bias, the spatio-temporal variability and correlation coefficients are improved.

Analysis of the Aerosol-radiation-cloud Interactions Through the Use of Regional Climate/chemistry Coupled Models

Analysis of the Aerosol-radiation-cloud Interactions Through the Use of Regional Climate/chemistry Coupled Models PDF Author: Rocío Baró Esteban
Publisher:
ISBN:
Category :
Languages : en
Pages : 208

Get Book Here

Book Description
The response of the climate systems to aerosols and their effect on the radiative budget of the Earth is the most uncertain climate feedback and one of the key topics in climate change mitigation. Air quality-climate studies (AQCI) are a key, but uncertain contributor to the anthropogenic forcing that remains poorly understood. To build confidence in the AQCI studies, regional-scale integrated meteorology-atmospheric chemistry models are in demand. The main objective of the present Thesis is the characterization of the uncertainties in the climate-chemistry-aerosol-cloud-radiation system associated to the aerosol direct and indirect radiative effects caused by aerosols over Europe, employing an ensemble of fully-coupled climate and chemistry model simulations. The first topic covered deals with the microphysics parameterization configuration of an online-coupled model. The differences when using two microphysics schemes within the Weather Research and Forecasting coupled with Chemistry (WRF-Chem) model are analyzed. The evaluated simulations come from the Air quality Model Evaluation International Initiative (AQMEII) Phase 2. The impact on several variables is estimated when selecting Morrison vs. Lin microphysics. The results showed smaller and more numerous cloud droplets simulated with the Morrison and therefore this scheme is more effective in scattering shortwave radiation. Also, the impact of biomass burning (BB) aerosols on surface winds during the Russian heat wave and wildfires episode is studied. The methodology consists of three WRF-Chem simulations over Europe, run under the context of EuMetChem COST Action ES1004, differing in the inclusion (or not) of aerosol-radiation (ARI) and aerosol-cloud interactions (ACI). These aerosols can affect surface winds where emission sources are located and further from the release areas. Local winds decrease due to a reduction of shortwave radiation at the ground, which leads to decreases in 2-m temperature. Atmospheric stability increases when considering aerosol feedbacks, inducing a lower planetary boundary layer height. This Dissertation also investigates the ability of an ensemble of simulations to elucidate the aerosol-radiation-cloud interactions. An assessment of whether the inclusion of atmospheric aerosol radiative feedbacks during two aerosol case studies of an ensemble of on-line coupled models improves the simulation results for maximum, mean and minimum 2-m temperature is done. The simulations (COST Action ES1004) are evaluated against observational data from E-OBS database. In both episodes, a general underestimation of the studied variables is found, being most noticeable in maximum temperature. The biases are improved when including ARI or ARI+ACI in the dust case. Although the ensemble does not outperform the individual models (in general), its improvements when including ARI+ARI are more remarkable. Last, an improvement of the spatio-temporal variability and correlation coefficients when aerosol radiative effects are included is found. Finally, the representation of the ACI in regional-scale integrated models when simulating the climate-chemistry-cloud-radiation system is analyzed. It complements the temperature analyses. The evaluated simulations are run in the context of AQMEII Phase 2 and include the ARI+ACI interactions. Simulations are evaluated against the (ESA) Cloud_cci data. Results show an underestimation(overestimation) of cloud fraction (CFR) over land(ocean) areas, which could be related to satellite retrieval missing thin clouds. Lower bias and mean absolute error (MAE) are found in the ensemble Cloud optical depth (COD) and cloud liquid ice path (CIP) are generally underestimated. The differences are related to microphysics. The development of this Thesis has contributed to the state of the art in AQCI studies. Although including aerosol feedbacks does not modify the bias, the spatio-temporal variability and correlation coefficients are improved.

Aerosol-Cloud Interactions from Urban, Regional, to Global Scales

Aerosol-Cloud Interactions from Urban, Regional, to Global Scales PDF Author: Yuan Wang
Publisher: Springer
ISBN: 3662471752
Category : Science
Languages : en
Pages : 100

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Book Description
The studies in this dissertation aim at advancing our scientific understandings about physical processes involved in the aerosol-cloud-precipitation interaction and quantitatively assessing the impacts of aerosols on the cloud systems with diverse scales over the globe on the basis of the observational data analysis and various modeling studies. As recognized in the Fifth Assessment Report by the Inter-government Panel on Climate Change, the magnitude of radiative forcing by atmospheric aerosols is highly uncertain, representing the largest uncertainty in projections of future climate by anthropogenic activities. By using a newly implemented cloud microphysical scheme in the cloud-resolving model, the thesis assesses aerosol-cloud interaction for distinct weather systems, ranging from individual cumulus to mesoscale convective systems. This thesis also introduces a novel hierarchical modeling approach that solves a long outstanding mismatch between simulations by regional weather models and global climate models in the climate modeling community. More importantly, the thesis provides key scientific solutions to several challenging questions in climate science, including the global impacts of the Asian pollution. As scientists wrestle with the complexities of climate change in response to varied anthropogenic forcing, perhaps no problem is more challenging than the understanding of the impacts of atmospheric aerosols from air pollution on clouds and the global circulation.

Air Pollution Modeling and its Application XX

Air Pollution Modeling and its Application XX PDF Author: Douw G. Steyn
Publisher: Springer
ISBN: 9048138124
Category : Science
Languages : en
Pages : 608

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Book Description
Recent developments in air pollution modelling are explored as a series of contributions from researchers at the forefront of their field. This book on air pollution modelling and its application is focused on local, urban, regional and intercontinental modelling; data assimilation and air quality forecasting; model assessment and evaluation; aerosol transformation; the relationship between air quality and human health and the effects of climate change on air quality. It consists of a series of papers that were presented at the 30th NATO/SPS International Technical Meeting on Air Pollution Modelling and its Application held in San Francisco, U.S.A., May 18-22, 2009. It is intended as reference material for students and professors interested in air pollution modelling at the graduate level as well as researchers and professionals involved in developing and utilizing air pollution models.

Aerosol-Cloud-Climate Interactions

Aerosol-Cloud-Climate Interactions PDF Author: Peter V. Hobbs
Publisher: Academic Press
ISBN: 0080959962
Category : Science
Languages : en
Pages : 259

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Book Description
Aerosol and clouds play important roles in determining the earth's climate, in ways that we are only beginning to comprehend. In conjunction with molecular scattering from gases, aerosol and clouds determine in part what fraction of solar radiation reaches the earth's surface, and what fraction of the longwave radiation from the earth escapes to space. This book provides an overview of the latest research on atmospheric aerosol and clouds and their effects on global climate. Subjects reviewed include the direct and indirect effects of aerosol on climate, the radiative properties of clouds and their effects on the Earth's radiation balance, the incorporation of cloud effects in numerical weather prediction models, and stratospheric aerosol and clouds.

Study of Aerosol/Cloud/Radiation Interactions Over the ARM SGP Site

Study of Aerosol/Cloud/Radiation Interactions Over the ARM SGP Site PDF Author: C. Chuang
Publisher:
ISBN:
Category :
Languages : en
Pages : 9

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Book Description
While considerable advances in the understanding of atmospheric processes and feedbacks in the climate system have led to a better representation of these mechanisms in general circulation models (GCMs), the greatest uncertainty in predictability of future climate arises from clouds and their interactions with radiation. To explore this uncertainty, cloud resolving model has been evolved as one of the main tools for understanding and testing cloud feedback processes in climate models, whereas the indirect effects of aerosols are closely linked with cloud feedback processes. In this study we incorporated an existing parameterization of cloud drop concentration (Chuang et al., 2002a) together with aerosol prediction from a global chemistry/aerosol model (IMPACT) (Rotman et al., 2004; Chuang et al., 2002b; Chuang et al., 2005) into LLNL cloud resolving model (Chin, 1994; Chin et al., 1995; Chin and Wilhelmson, 1998) to investigate the effects of aerosols on cloud/precipitation properties and the resulting radiation fields over the Southern Great Plains.

Clouds and Their Climatic Impact

Clouds and Their Climatic Impact PDF Author: Sylvia Sullivan
Publisher: John Wiley & Sons
ISBN: 1119700310
Category : Science
Languages : en
Pages : 371

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Book Description
Clouds and Their Climatic Impacts Clouds are an influential and complex element of Earth’s climate system. They evolve rapidly in time and exist over small spatial scales, but also affect global radiative balance and large-scale circulations. With more powerful models and extensive observations now at our disposal, the climate impact of clouds is receiving ever more research attention. Clouds and Their Climatic Impacts: Radiation, Circulation, and Precipitation presents an overview of our current understanding on various types of clouds and cloud systems and their multifaceted role in the radiative budget, circulation patterns, and rainfall. Volume highlights include: Interactions of aerosol with both liquid and ice clouds Surface and atmospheric cloud radiative feedbacks and effects Arctic, extratropical, and tropical clouds Cloud-circulation coupling at global, meso, and micro scales Precipitation efficiency, phase, and measurements The role of machine learning in understanding clouds and climate The American Geophysical Union promotes discovery in Earth and space science for the benefit of humanity. Its publications disseminate scientific knowledge and provide resources for researchers, students, and professionals.

Opportunities to Improve Representation of Clouds and Aerosols in Climate Models with Classified Observing Systems

Opportunities to Improve Representation of Clouds and Aerosols in Climate Models with Classified Observing Systems PDF Author: National Academies of Sciences, Engineering, and Medicine
Publisher: National Academies Press
ISBN: 0309443458
Category : Science
Languages : en
Pages : 53

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Book Description
One of the most significant and uncertain aspects of climate change projections is the impact of aerosols on the climate system. Aerosols influence the climate indirectly by interacting with nearby clouds leading to small changes in cloud cover, thickness, and altitude, which significantly affect Earth's radiative balance. Advancements have been made in recent years on understanding the complex processes and atmospheric interactions involved when aerosols interact with surrounding clouds, but further progress has been hindered by limited observations. The National Academies of Sciences, Engineering, and Medicine organized a workshop to discuss the usefulness of the classified observing systems in advancing understanding of cloud and aerosol interactions. Because these systems were not developed with weather and climate modeling as a primary mission objective, many participants said it is necessary for scientists to find creative ways to utilize the data. The data from these systems have the potential to be useful in advancing understanding of cloud and aerosol interactions. This publication summarizes the presentations and discussions from the workshop.

Clouds, Chemistry and Climate

Clouds, Chemistry and Climate PDF Author: Paul J. Crutzen
Publisher: Springer Science & Business Media
ISBN: 364261051X
Category : Science
Languages : en
Pages : 337

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Book Description
The objective of this NATO Advanced Research Workshop was to discuss our current understanding of the role of clouds in climate and chemistry. The range of topics dis cussed during the workshop included: modeling of clouds in GCMs; observations of the cloud micro physical properties; the water vapor cycle; troposphere-stratosphere exchange; role of in-cloud transport in tropospheric ozone; regulation of current and paleo climate by clouds; and anthropogenic sulfate aerosols and modification of cloud properties. The essence of the discussions is captured in the accompanying summary by the rapporteurs and the chapters by some of the speakers. The underlying message is that significant progress has been made, resulting in exciting new developments in our perception of the role of clouds in the global system . .. The tropical convective-cirrus cloud systems emerge as a major influence on the climate system. Micro physical processes, such as the rate of precipitation and re evaporation of ice particles, seem to regulate the large scale vertical distribution of water vapor which is the dominant greenhouse gas. Water vapor data collected during the Central Equatorial Pacific Experiment (CEPEX), document the large moistening effect of deep convection on scales of thousands of kilometers. A major chemical finding in the same region was the observation of extremely low ozone 8 volume mixing ratios of less than 10- in the entire troposphere of the central equatorial Pacific extending over a distance of about 2000 km. This finding establishes the Pacific as a major chemical sink region for tropospheric ozone.

A Plan for a Research Program on Aerosol Radiative Forcing and Climate Change

A Plan for a Research Program on Aerosol Radiative Forcing and Climate Change PDF Author: Panel on Aerosol Radiative Forcing and Climate Change
Publisher: National Academies Press
ISBN: 0309588871
Category : Science
Languages : en
Pages : 180

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Book Description
This book recommends the initiation of an "integrated" research program to study the role of aerosols in the predicted global climate change. Current understanding suggest that, even now, aerosols, primarily from anthropogenic sources, may be reducing the rate of warming caused by greenhouse gas emissions. In addition to specific research recommendations, this book forcefully argues for two kinds of research program integration: integration of the individual laboratory, field, and theoretical research activities and an integrated management structure that involves all of the concerned federal agencies.

Impacts of Aerosol-cloud Interactions on Past and Future Changes in Tropospheric Composition

Impacts of Aerosol-cloud Interactions on Past and Future Changes in Tropospheric Composition PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
The development of effective emissions control policies that are beneficial to both climate and air quality requires a detailed understanding of all the feedbacks in the atmospheric composition and climate system. We perform sensitivity studies with a global atmospheric composition-climate model to assess the impact of aerosols on tropospheric chemistry through their modification on clouds, aerosol-cloud interactions (ACI). The model includes coupling between both tropospheric gas-phase and aerosol chemistry and aerosols and liquid-phase clouds. We investigate past impacts from preindustrial (PI) to present day (PD) and future impacts from PD to 2050 (for the moderate IPCC A1B scenario) that embrace a wide spectrum of precursor emission changes and consequential ACI. The aerosol indirect effect (AIE) is estimated to be -2.0 Wm−2 for PD-PI and -0.6 Wm−2 for 2050-PD, at the high end of current estimates. Inclusion of ACI substantially impacts changes in global mean methane lifetime across both time periods, enhancing the past and future increases by 10% and 30%, respectively. In regions where pollution emissions increase, inclusion of ACI leads to 20% enhancements in in-cloud sulfate production and (almost equal to)10% enhancements in sulfate wet deposition that is displaced away from the immediate source regions. The enhanced in-cloud sulfate formation leads to larger increases in surface sulfate across polluted regions ((almost equal to)10-30%). Nitric acid wet deposition is dampened by 15-20% across the industrialized regions due to ACI allowing additional re-release of reactive nitrogen that contributes to 1-2 ppbv increases in surface ozone in outflow regions. Our model findings indicate that ACI must be considered in studies of methane trends and projections of future changes to particulate matter air quality.