Implementation of a Brown Carbon Parameterization in the Community Earth System Model (CESM) PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Implementation of a Brown Carbon Parameterization in the Community Earth System Model (CESM) PDF full book. Access full book title Implementation of a Brown Carbon Parameterization in the Community Earth System Model (CESM) by Hunter Y. Brown. Download full books in PDF and EPUB format.
Author: Hunter Y. Brown
Publisher:
ISBN: 9780355324990
Category : Atmospheric aerosols
Languages : en
Pages : 61
Get Book Here
Book Description
A recent development in the representation of aerosols in climate models is the realization that some components of organic carbon (OC), emitted from biomass and biofuel burning, can have a significant contribution to short-wave radiation absorption in the atmosphere. The absorbing fraction of OC is referred to as brown carbon (BrC). This study introduces one of the first implementations of BrC into the Community Earth System Model (CESM), using a parameterization for BrC absorption described in Saleh et al. (2014). 9-year experiments are run (2003-2011) with prescribed emissions and sea surface temperatures to analyze the effect of BrC in the atmosphere. Model validation is conducted via model comparison to single-scatter albedo (SSA) and aerosol optical depth from the Aerosol Robotic Network (AERONET), as well as comparison with a laboratory derived parameterization for SSA dependent on the (black carbon (BC))/(BC+OC) ratio in biomass burning emissions. These comparisons reveal a model underestimation of SSA in biomass burning regions for both default and BrC model runs. Global annual average radiative effects are calculated due to aerosol-radiation interactions (REari; 0.13±0.021 W m−2), aerosol-cloud interactions (REaci; 0.07±0.056 W m -2), and surface albedo change (REsac; -0.06±0.035 W m−2). REari is similar to other studies’ estimations of BrC direct radiative effect, while REaci indicates a global reduction in low clouds due to the BrC semi-direct effect. REsac suggests increased surface albedo with BrC implementation due to modified snowfall, but does not take into account the warming effect of BrC on snow. Lastly, comparisons of BrC implementation approaches find that this implementation may do a better job of estimating BrC radiative effect in the Arctic regions than previous studies with CESM.
Author: Hunter Y. Brown
Publisher:
ISBN: 9780355324990
Category : Atmospheric aerosols
Languages : en
Pages : 61
Get Book Here
Book Description
A recent development in the representation of aerosols in climate models is the realization that some components of organic carbon (OC), emitted from biomass and biofuel burning, can have a significant contribution to short-wave radiation absorption in the atmosphere. The absorbing fraction of OC is referred to as brown carbon (BrC). This study introduces one of the first implementations of BrC into the Community Earth System Model (CESM), using a parameterization for BrC absorption described in Saleh et al. (2014). 9-year experiments are run (2003-2011) with prescribed emissions and sea surface temperatures to analyze the effect of BrC in the atmosphere. Model validation is conducted via model comparison to single-scatter albedo (SSA) and aerosol optical depth from the Aerosol Robotic Network (AERONET), as well as comparison with a laboratory derived parameterization for SSA dependent on the (black carbon (BC))/(BC+OC) ratio in biomass burning emissions. These comparisons reveal a model underestimation of SSA in biomass burning regions for both default and BrC model runs. Global annual average radiative effects are calculated due to aerosol-radiation interactions (REari; 0.13±0.021 W m−2), aerosol-cloud interactions (REaci; 0.07±0.056 W m -2), and surface albedo change (REsac; -0.06±0.035 W m−2). REari is similar to other studies’ estimations of BrC direct radiative effect, while REaci indicates a global reduction in low clouds due to the BrC semi-direct effect. REsac suggests increased surface albedo with BrC implementation due to modified snowfall, but does not take into account the warming effect of BrC on snow. Lastly, comparisons of BrC implementation approaches find that this implementation may do a better job of estimating BrC radiative effect in the Arctic regions than previous studies with CESM.
Author: William Christian Porter
Publisher:
ISBN:
Category : Atmospheric methane
Languages : en
Pages : 43
Get Book Here
Book Description
The Community Earth System Model (CESM) is a coupling of five different models which are combined to simulate the dynamic interactions between and within the Earth's atmosphere, ocean, land, land-ice, and sea-ice. In this work, the installation and testing of CESM on Portland State University's Cluster for Climate Change and Aerosol Research (CsAR) is described and documented, and two research applications of the model are performed. First, the improved treatment of cloud microphysics within recent versions of CESM's atmospheric module is applied to an examination of changes in shortwave cloud forcing (SWCF) and results are compared to output from older versions of the model. Second, the CESM model is applied to an examination of the effect that increased methane (CH4) concentrations have had on the catalytic destruction of stratospheric ozone (O3) by ozone depleting compounds (ODCs) such as chlorofluorocarbons (CFCs) and nitrous oxide (N2O).
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
Get Book Here
Book Description
The Community Earth System Model (CESM) is a fully-coupled, global climate model that provides state-of-the-art computer simulations of the Earth's past, present, and future climate states. This document provides the agenda and list of participants for the conference. Web materials for all lectures and practical sessions available from: http://www.cesm.ucar.edu/events/tutorials/073012.
Author:
Publisher:
ISBN:
Category : Air
Languages : en
Pages : 12
Get Book Here
Book Description
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 2
Get Book Here
Book Description
In this project we have been upgrading the Multiscale Modeling Framework (MMF) in the Community Atmosphere Model (CAM), also known as Super-Parameterized CAM (SP-CAM). This has included a major effort to update the coding standards and interface with CAM so that it can be placed on the main development trunk. It has also included development of a new software structure for CAM to be able to handle sub-grid column information. These efforts have formed the major thrust of the work.
Author: National Academies of Sciences, Engineering, and Medicine
Publisher: National Academies Press
ISBN: 0309388805
Category : Science
Languages : en
Pages : 351
Get Book Here
Book Description
As the nation's economic activities, security concerns, and stewardship of natural resources become increasingly complex and globally interrelated, they become ever more sensitive to adverse impacts from weather, climate, and other natural phenomena. For several decades, forecasts with lead times of a few days for weather and other environmental phenomena have yielded valuable information to improve decision-making across all sectors of society. Developing the capability to forecast environmental conditions and disruptive events several weeks and months in advance could dramatically increase the value and benefit of environmental predictions, saving lives, protecting property, increasing economic vitality, protecting the environment, and informing policy choices. Over the past decade, the ability to forecast weather and climate conditions on subseasonal to seasonal (S2S) timescales, i.e., two to fifty-two weeks in advance, has improved substantially. Although significant progress has been made, much work remains to make S2S predictions skillful enough, as well as optimally tailored and communicated, to enable widespread use. Next Generation Earth System Predictions presents a ten-year U.S. research agenda that increases the nation's S2S research and modeling capability, advances S2S forecasting, and aids in decision making at medium and extended lead times.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 17
Get Book Here
Book Description
Soil carbon (C) is a critical component of Earth system models (ESMs), and its diverse representations are a major source of the large spread across models in the terrestrial C sink from the third to fifth assessment reports of the Intergovernmental Panel on Climate Change (IPCC). Improving soil C projections is of a high priority for Earth system modeling in the future IPCC and other assessments. To achieve this goal, we suggest that (1) model structures should reflect real-world processes, (2) parameters should be calibrated to match model outputs with observations, and (3) external forcing variables should accurately prescribe the environmental conditions that soils experience. First, most soil C cycle models simulate C input from litter production and C release through decomposition. The latter process has traditionally been represented by first-order decay functions, regulated primarily by temperature, moisture, litter quality, and soil texture. While this formulation well captures macroscopic soil organic C (SOC) dynamics, better understanding is needed of their underlying mechanisms as related to microbial processes, depth-dependent environmental controls, and other processes that strongly affect soil C dynamics. Second, incomplete use of observations in model parameterization is a major cause of bias in soil C projections from ESMs. Optimal parameter calibration with both pool-and flux-based data sets through data assimilation is among the highest priorities for near-term research to reduce biases among ESMs. Third, external variables are represented inconsistently among ESMs, leading to differences in modeled soil C dynamics. Furthermore, we recommend the implementation of traceability analyses to identify how external variables and model parameterizations influence SOC dynamics in different ESMs. Overall, projections of the terrestrial C sink can be substantially improved when reliable data sets are available to select the most representative model structure, constrain parameters, and prescribe forcing fields.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
Get Book Here
Book Description
THE SAME REQUEST WILL BE SENT TO BOTH NSF AND DOE TO EACH SUPPORT $35K. The third annual Community Earth System Model (CESM) tutorial for students and early career scientists was held from 30 July to 3 August, 2012. This event was extremely successful and, as for the tutorials in previous years, there was a greater demand than could be met. This indicates a continuing need for a tutorial of this type and we anticipate that the 2013 tutorial will be well received. The tutorial will include lectures on simulating the climate system and practical sessions on running CESM, modifying components, and analyzing data. These will be targeted to the graduate student level. Attendance will be limited to a maximum of 80 students with financial support for up to 40 students. Attendees will be balanced across institutions.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
Get Book Here
Book Description
In fiscal year 2011, the Community Earth System Model (CESM) tutorial was taught at NCAR from 1-5 August 2011. This project hosted 79 full participants (1 accepted participant from China couldn't get a visa) selected from 180 applications. The tutorial was advertised through emails to CESM mailing lists. NCAR staff and long-term visitors (who were not eligible to attend) were also invited to 'audit' the climate and practical lectures and to work on the practical sessions on their own. 15 NCAR staff and long-term visitors took advantage of this opportunity. The majority of the students were graduate students, but several post-docs, faculty, and other research scientists also attended. Additionally, many people are using the on-line lessons and practical sessions. As of August 18, 2011, 407 people had registered to access and use the tutorial from 33 countries all over the world, but a majority from US universities. In fiscal year 2011, the Climate and Global Dynamics Division Information Systems Group (CGD/ISG) built and operated a temporary computer laboratory in a meeting room. This project was made possible through funding from the National Science Foundation Directorate of Geosciences, and the Department of Energy Office of Science.
Author: Panel on Aerosol Radiative Forcing and Climate Change
Publisher: National Academies Press
ISBN: 0309588871
Category : Science
Languages : en
Pages : 180
Get Book Here
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.
