Atmospheric composite sounding analysis as a forecasting tool for ozone accumulation in a semiarid metropolitan area during the North America monsoon: Phoenix, Arizona

Jonny William Malloy, Randall S. Cerveny

Research output: Contribution to journalArticle

Abstract

Phoenix, Arizona, observes a high summertime frequency for daily maximum 8-h ozone averages (DMO8) exceeding 70 parts per billion, resulting in nonattainment status by the U.S. Environmental Protection Agency. This study discusses the use of composite atmospheric sounding analysis (con-structing average sounding conditions for specific recurring events) to forecast different air quality index daily ozone classifications, including ‘‘good,’’ ‘‘moderate,’’ and collectively categories exceeding the 2015 ozone standard. Composite sounding analysis, using the Phoenix 1200 UTC (0500 LST) rawinsonde data (2006–17), identifies ‘‘pollutant dispersion windows’’ for ozone accumulation or dispersal for Phoenix during the North American monsoon (July and August period). A favorable ozone exceedance atmosphere is associated with a ‘‘Four Corners high’’ synoptic pattern bringing relatively light winds at and below 700 hPa (≤4.5 ms21) and higher easterly winds above (≤12.3 ms21). Healthy ozone days (good category) are common when Pacific low pressure troughing over the western United States creates deep and faster westerly flow above the surface reaching speeds of 6.7 (19.5) m s21 by 700 (200) hPa. Surprisingly, large standard deviations over 108C for dewpoint temperature at midlevels (500–400 hPa) were determined for all three daily ozone classification ranges used in this study. Additionally, modest temperature deviations and mean differences are noted at significant pressure levels. Consequently, wind speed and direction are better indicators when forecasting ozone accumulation potential. These results are pertinent to air quality meteorologists responsible for disseminating ozone forecasts for heavily urbanized areas of the U.S. Southwest.

Original languageEnglish (US)
Pages (from-to)887-904
Number of pages18
JournalWeather and Forecasting
Volume34
Issue number4
DOIs
StatePublished - Aug 2019
Externally publishedYes

Fingerprint

metropolitan area
monsoon
ozone
air quality
analysis
North America
westerly
wind direction
low pressure
wind velocity
temperature
atmosphere

ASJC Scopus subject areas

  • Atmospheric Science

Cite this

@article{860f841c9f6f45f196cc152ad62f11ce,
title = "Atmospheric composite sounding analysis as a forecasting tool for ozone accumulation in a semiarid metropolitan area during the North America monsoon: Phoenix, Arizona",
abstract = "Phoenix, Arizona, observes a high summertime frequency for daily maximum 8-h ozone averages (DMO8) exceeding 70 parts per billion, resulting in nonattainment status by the U.S. Environmental Protection Agency. This study discusses the use of composite atmospheric sounding analysis (con-structing average sounding conditions for specific recurring events) to forecast different air quality index daily ozone classifications, including ‘‘good,’’ ‘‘moderate,’’ and collectively categories exceeding the 2015 ozone standard. Composite sounding analysis, using the Phoenix 1200 UTC (0500 LST) rawinsonde data (2006–17), identifies ‘‘pollutant dispersion windows’’ for ozone accumulation or dispersal for Phoenix during the North American monsoon (July and August period). A favorable ozone exceedance atmosphere is associated with a ‘‘Four Corners high’’ synoptic pattern bringing relatively light winds at and below 700 hPa (≤4.5 ms21) and higher easterly winds above (≤12.3 ms21). Healthy ozone days (good category) are common when Pacific low pressure troughing over the western United States creates deep and faster westerly flow above the surface reaching speeds of 6.7 (19.5) m s21 by 700 (200) hPa. Surprisingly, large standard deviations over 108C for dewpoint temperature at midlevels (500–400 hPa) were determined for all three daily ozone classification ranges used in this study. Additionally, modest temperature deviations and mean differences are noted at significant pressure levels. Consequently, wind speed and direction are better indicators when forecasting ozone accumulation potential. These results are pertinent to air quality meteorologists responsible for disseminating ozone forecasts for heavily urbanized areas of the U.S. Southwest.",
author = "Malloy, {Jonny William} and Cerveny, {Randall S.}",
year = "2019",
month = "8",
doi = "10.1175/WAF-D-18-0204.1",
language = "English (US)",
volume = "34",
pages = "887--904",
journal = "Weather and Forecasting",
issn = "0882-8156",
publisher = "American Meteorological Society",
number = "4",

}

TY - JOUR

T1 - Atmospheric composite sounding analysis as a forecasting tool for ozone accumulation in a semiarid metropolitan area during the North America monsoon

T2 - Phoenix, Arizona

AU - Malloy, Jonny William

AU - Cerveny, Randall S.

PY - 2019/8

Y1 - 2019/8

N2 - Phoenix, Arizona, observes a high summertime frequency for daily maximum 8-h ozone averages (DMO8) exceeding 70 parts per billion, resulting in nonattainment status by the U.S. Environmental Protection Agency. This study discusses the use of composite atmospheric sounding analysis (con-structing average sounding conditions for specific recurring events) to forecast different air quality index daily ozone classifications, including ‘‘good,’’ ‘‘moderate,’’ and collectively categories exceeding the 2015 ozone standard. Composite sounding analysis, using the Phoenix 1200 UTC (0500 LST) rawinsonde data (2006–17), identifies ‘‘pollutant dispersion windows’’ for ozone accumulation or dispersal for Phoenix during the North American monsoon (July and August period). A favorable ozone exceedance atmosphere is associated with a ‘‘Four Corners high’’ synoptic pattern bringing relatively light winds at and below 700 hPa (≤4.5 ms21) and higher easterly winds above (≤12.3 ms21). Healthy ozone days (good category) are common when Pacific low pressure troughing over the western United States creates deep and faster westerly flow above the surface reaching speeds of 6.7 (19.5) m s21 by 700 (200) hPa. Surprisingly, large standard deviations over 108C for dewpoint temperature at midlevels (500–400 hPa) were determined for all three daily ozone classification ranges used in this study. Additionally, modest temperature deviations and mean differences are noted at significant pressure levels. Consequently, wind speed and direction are better indicators when forecasting ozone accumulation potential. These results are pertinent to air quality meteorologists responsible for disseminating ozone forecasts for heavily urbanized areas of the U.S. Southwest.

AB - Phoenix, Arizona, observes a high summertime frequency for daily maximum 8-h ozone averages (DMO8) exceeding 70 parts per billion, resulting in nonattainment status by the U.S. Environmental Protection Agency. This study discusses the use of composite atmospheric sounding analysis (con-structing average sounding conditions for specific recurring events) to forecast different air quality index daily ozone classifications, including ‘‘good,’’ ‘‘moderate,’’ and collectively categories exceeding the 2015 ozone standard. Composite sounding analysis, using the Phoenix 1200 UTC (0500 LST) rawinsonde data (2006–17), identifies ‘‘pollutant dispersion windows’’ for ozone accumulation or dispersal for Phoenix during the North American monsoon (July and August period). A favorable ozone exceedance atmosphere is associated with a ‘‘Four Corners high’’ synoptic pattern bringing relatively light winds at and below 700 hPa (≤4.5 ms21) and higher easterly winds above (≤12.3 ms21). Healthy ozone days (good category) are common when Pacific low pressure troughing over the western United States creates deep and faster westerly flow above the surface reaching speeds of 6.7 (19.5) m s21 by 700 (200) hPa. Surprisingly, large standard deviations over 108C for dewpoint temperature at midlevels (500–400 hPa) were determined for all three daily ozone classification ranges used in this study. Additionally, modest temperature deviations and mean differences are noted at significant pressure levels. Consequently, wind speed and direction are better indicators when forecasting ozone accumulation potential. These results are pertinent to air quality meteorologists responsible for disseminating ozone forecasts for heavily urbanized areas of the U.S. Southwest.

UR - http://www.scopus.com/inward/record.url?scp=85073330210&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85073330210&partnerID=8YFLogxK

U2 - 10.1175/WAF-D-18-0204.1

DO - 10.1175/WAF-D-18-0204.1

M3 - Article

AN - SCOPUS:85073330210

VL - 34

SP - 887

EP - 904

JO - Weather and Forecasting

JF - Weather and Forecasting

SN - 0882-8156

IS - 4

ER -