Stratospheric contribution to the summertime high surface ozone events over the western united states

<p>We present a research system for regional air quality forecasting over&#160; the contiguous United States (CONUS). This system has been developed at the National Center for Atmospheric Research (NCAR) to support community model development, allow early identification of model errors and biases, and support the atmospheric science community in their research. At the same time, it assists field campaign planning and air quality decision-making. The forecasts aim to complement the operational air quality forecasts produced by the National Oceanic and Atmospheric Administration (NOAA) and not to replace them. A publicly available information dissemination system has been established that displays various air quality products including a near-real-time evaluation of the model forecasts. Our forecasting system has been producing a 48-h forecast every day at 12 km x 12 km grid spacing over the entire CONUS since June 2019 and at 4 km x 4 km grid spacing in Colorado since June 2020. Here, we will report on the performance of our air quality forecasting system in simulating meteorology, PM2.5, ozone, and NOx for the period of 1 June 2019 to 31 December 2020. Our system showed excellent skill in capturing hourly to daily variations in temperature, surface pressure, relative humidity, water vapor mixing ratios, and wind direction but showed, in parts, relatively larger errors in wind speed. The model captured the seasonal cycle of surface PM2.5 and ozone very well in different regions of CONUS and at different types of sites (urban, suburban, and rural) but generally overestimates summertime surface ozone and fails to capture very high surface PM2.5 events. These shortcomings are being addressed in current work. The skill of the air quality forecasts remains fairly stable between the first and second days of the forecasts. Our air quality forecast products are publicly available at https://www.acom.ucar.edu/firex-aq/forecast.shtml and we invite the community to use our forecasting products for their research, as input for urban scale (< 4 km) air quality forecasts, or the co-development of customized products just to name a few applications.</p>

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Aerosol optical depth (AOD) retrieval using simultaneous GOES-East and GOES-West reflected radiances over the western United States

Atmospheric Measurement Techniques ◽

10.5194/amt-6-471-2013 ◽

2013 ◽

Vol 6 (2) ◽

pp. 471-486 ◽

Cited By ~ 12

Author(s):

H. Zhang ◽

R. M. Hoff ◽

S. Kondragunta ◽

I. Laszlo ◽

A. Lyapustin

Keyword(s):

United States ◽

Aerosol Optical Depth ◽

Optical Depth ◽

High Surface ◽

Atmospheric Correction ◽

Correlation Coefficients ◽

Western United States ◽

Retrieval Algorithm ◽

Hybrid Technique ◽

Single Observation

Abstract. Aerosol optical depth (AOD) in the western United States is observed independently by both the (Geostationary Operational Environmental Satellites) GOES-East and GOES-West imagers. The GASP (GOES Aerosol/Smoke Product) aerosol optical depth retrieval algorithm treats each satellite as a unique sensor and thus obtains two separate aerosol optical depth values at the same time for the same location. The TOA (the top of the atmosphere) radiances and the associated derived optical depths can be quite different due to the different viewing geometries with large difference in solar-scattering angles. In order to fully exploit the simultaneous observations and generate consistent AOD retrievals from the two satellites, the authors develop a new "hybrid" aerosol optical depth retrieval algorithm that uses data from both satellites. The algorithm uses both GOES-East and GOES-West visible channel TOA reflectance and daily average AOD from GOES Multi-Angle Implementation of Atmospheric Correction (GOES-MAIAC) on low AOD days (AOD less than 0.3), when diurnal variation of AOD is low, to retrieve surface BRDF (Bidirectional Reflectance Distribution Function). The known BRDF shape is applied on subsequent days to retrieve BRDF and AOD. The algorithm is validated at three AERONET sites over the western US. The AOD retrieval accuracy from the "hybrid" technique using the two satellites is similar to that from one satellite over UCSB (University of California Santa Barbara) and Railroad Valley, Nevada. Improvement of the accuracy is observed at Boulder, Colorado. The correlation coefficients between the GOES AOD and AERONET AOD are in the range of 0.67 to 0.81. More than 74% of AOD retrievals are within the error of ±(0.05 + 0.15 τ) compared to AERONET AOD. The hybrid algorithm has more data coverage compared to the single satellite retrievals over surfaces with high surface reflectance. For single observation areas the number of valid AOD data increases from the use of two-single satellite algorithms by 5–80% for the three sites. With the application of the new algorithm, consistent AOD retrievals and better retrieval coverages can be obtained using the data from the two GOES satellite imagers.

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Supplementary material to "Wildfire influences on the variability and trend of summer surface ozone in the mountainous western United States"

10.5194/acp-2016-646-supplement ◽

2016 ◽

Author(s):

Xiao Lu ◽

Lin Zhang ◽

Xu Yue ◽

Jiachen Zhang ◽

Daniel A. Jaffe ◽

...

Keyword(s):

United States ◽

Surface Ozone ◽

Western United States ◽

Supplementary Material

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Writing Time in Metaphors

10.3366/edinburgh/9781474423939.003.0004 ◽

2018 ◽

Author(s):

Jennifer J. Smith

Keyword(s):

United States ◽

The United States ◽

Western United States ◽

Entire System ◽

Language And Culture ◽

Space Race ◽

Do So

Coherence of place often exists alongside irregularities in time in cycles, and chapter three turns to cycles linked by temporal markers. Ray Bradbury’s The Martian Chronicles (1950) follows a linear chronology and describes the exploration, conquest, and repopulation of Mars by humans. Conversely, Louise Erdrich’s Love Medicine (1984) jumps back and forth across time to narrate the lives of interconnected families in the western United States. Bradbury’s cycle invokes a confluence of historical forces—time as value-laden, work as a calling, and travel as necessitating standardized time—and contextualizes them in relation to anxieties about the space race. Erdrich’s cycle invokes broader, oppositional conceptions of time—as recursive and arbitrary and as causal and meaningful—to depict time as implicated in an entire system of measurement that made possible the destruction and exploitation of the Chippewa people. Both volumes understand the United States to be preoccupied with imperialist impulses. Even as they critique such projects, they also point to the tenacity with which individuals encounter these systems, and they do so by creating “interstitial temporalities,” which allow them to navigate time at the crossroads of language and culture.

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