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Title: Probabilistic aspects of meteorological and ozone regional ensemble forecasts

Abstract

This study investigates whether probabilistic ozone forecasts from an ensemble can be made with skill; i.e., high verification resolution and reliability. Twenty-eight ozone forecasts were generated over the Lower Fraser Valley, British Columbia, Canada, for the 5-day period 11-15 August 2004, and compared with 1-hour averaged measurements of ozone concentrations at five stations. The forecasts were obtained by driving the CMAQ model with four meteorological forecasts and seven emission scenarios: a control run, {+-} 50% NO{sub x}, {+-} 50% VOC, and {+-} 50% NO{sub x} combined with VOC. Probabilistic forecast quality is verified using relative operating characteristic curves, Talagrand diagrams, and a new reliability index. Results show that both meteorology and emission perturbations are needed to have a skillful probabilistic forecast system--the meteorology perturbation is important to capture the ozone temporal and spatial distribution, and the emission perturbation is needed to span the range of ozone-concentration magnitudes. Emission perturbations are more important than meteorology perturbations for capturing the likelihood of high ozone concentrations. Perturbations involving NO{sub x} resulted in a more skillful probabilistic forecast for the episode analyzed, and therefore the 50% perturbation values appears to span much of the emission uncertainty for this case. All of the ensembles analyzedmore » show a high ozone concentration bias in the Talagrand diagrams, even when the biases from the unperturbed emissions forecasts are removed from all ensemble members. This result indicates nonlinearity in the ensemble, which arises from both ozone chemistry and its interaction with input from particular meteorological models.« less

Authors:
; ; ; ;
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
936476
Report Number(s):
UCRL-JRNL-219958
Journal ID: ISSN 0747-7309; TRN: US200818%%813
DOE Contract Number:
W-7405-ENG-48
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Geophysical Research - Atmospheres, vol. 111, D24307, December 29, 2006, doi:10.1029/2005JD006917; Journal Volume: 111
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; 54 ENVIRONMENTAL SCIENCES; BRITISH COLUMBIA; CANADA; CHEMISTRY; METEOROLOGY; ORGANIC COMPOUNDS; OZONE; RELIABILITY; RESOLUTION; SPATIAL DISTRIBUTION; VERIFICATION; VOLATILE MATTER

Citation Formats

Monache, L D, Hacker, J, Zhou, Y, Deng, X, and Stull, R. Probabilistic aspects of meteorological and ozone regional ensemble forecasts. United States: N. p., 2006. Web.
Monache, L D, Hacker, J, Zhou, Y, Deng, X, & Stull, R. Probabilistic aspects of meteorological and ozone regional ensemble forecasts. United States.
Monache, L D, Hacker, J, Zhou, Y, Deng, X, and Stull, R. Mon . "Probabilistic aspects of meteorological and ozone regional ensemble forecasts". United States. doi:. https://www.osti.gov/servlets/purl/936476.
@article{osti_936476,
title = {Probabilistic aspects of meteorological and ozone regional ensemble forecasts},
author = {Monache, L D and Hacker, J and Zhou, Y and Deng, X and Stull, R},
abstractNote = {This study investigates whether probabilistic ozone forecasts from an ensemble can be made with skill; i.e., high verification resolution and reliability. Twenty-eight ozone forecasts were generated over the Lower Fraser Valley, British Columbia, Canada, for the 5-day period 11-15 August 2004, and compared with 1-hour averaged measurements of ozone concentrations at five stations. The forecasts were obtained by driving the CMAQ model with four meteorological forecasts and seven emission scenarios: a control run, {+-} 50% NO{sub x}, {+-} 50% VOC, and {+-} 50% NO{sub x} combined with VOC. Probabilistic forecast quality is verified using relative operating characteristic curves, Talagrand diagrams, and a new reliability index. Results show that both meteorology and emission perturbations are needed to have a skillful probabilistic forecast system--the meteorology perturbation is important to capture the ozone temporal and spatial distribution, and the emission perturbation is needed to span the range of ozone-concentration magnitudes. Emission perturbations are more important than meteorology perturbations for capturing the likelihood of high ozone concentrations. Perturbations involving NO{sub x} resulted in a more skillful probabilistic forecast for the episode analyzed, and therefore the 50% perturbation values appears to span much of the emission uncertainty for this case. All of the ensembles analyzed show a high ozone concentration bias in the Talagrand diagrams, even when the biases from the unperturbed emissions forecasts are removed from all ensemble members. This result indicates nonlinearity in the ensemble, which arises from both ozone chemistry and its interaction with input from particular meteorological models.},
doi = {},
journal = {Journal of Geophysical Research - Atmospheres, vol. 111, D24307, December 29, 2006, doi:10.1029/2005JD006917},
number = ,
volume = 111,
place = {United States},
year = {Mon Mar 20 00:00:00 EST 2006},
month = {Mon Mar 20 00:00:00 EST 2006}
}
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