Connecting Subseasonal Movements of the Winter Mean Ridge in Western North America to Inversion Climatology in Cache Valley, Utah

Wang, Shih-Yu; Gillies, Robert R.; Martin, Randy S.; Davies, R. E.; Booth, Marty R.

doi:10.1175/jamc-d-11-0101.1

Cited by 14 publications

(11 citation statements)

References 30 publications

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“…In some mountainous areas of Upstate New York, 1-2 μg/m 3 higher PM 2.5 accumulated in valleys in winter was found. This phenomenon is consistent with the findings of previous studies suggesting that the stagnant weather conditions in valleys caused by strong temperature inversions could lead to the increase in PM 2.5 levels (Gillies et al 2010;Silcox et al 2012;Wang et al 2012).…”

Section: Discussionsupporting

confidence: 93%

Impacts of snow and cloud covers on satellite-derived PM2.5 levels

Belle

Wang

et al. 2019

Remote Sensing of Environment

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Satellite aerosol optical depth (AOD) has been widely employed to evaluate ground fine particle (PM 2.5 ) levels, whereas snow/cloud covers often lead to a large proportion of non-random missing AOD values. As a result, the fully covered and unbiased PM 2.5 estimates will be hard to generate. Among the current approaches to deal with the data gap issue, few have considered the cloud-AOD relationship and none of them have considered the snow-AOD relationship. This study examined the impacts of snow and cloud covers on AOD and PM 2.5 and made full-coverage PM 2.5 predictions by considering these impacts. To estimate missing AOD values, daily gap-filling models with snow/cloud fractions and meteorological covariates were developed using the random forest algorithm. By using these models in New York State, a daily AOD data set with a 1-km resolution was generated with a complete coverage. The "out-of-bag" R 2 of the gap-filling models averaged 0.93 with an interquartile range from 0.90 to 0.95. Subsequently, a random forest-based PM 2.5 prediction model with the gap-filled AOD and covariates was built to predict fully covered PM 2.5 estimates. A ten-fold cross-validation for the prediction model showed a good performance with an R 2 of 0.82. In the gap-filling models, the snow fraction was of higher significance to the snow season compared with the rest of the year. The prediction models fitted with/without the snow fraction also suggested the discernible changes in PM 2.5 patterns, further confirming the significance of this parameter. Compared with the methods without considering snow and cloud covers, our PM 2.5 prediction surfaces showed more spatial details and reflected small-scale terrain-driven PM 2.5 patterns. The proposed methods can be generalized to the areas with extensive snow/cloud covers and large proportions of missing satellite AOD data for predicting PM 2.5 levels with high resolutions and complete coverage.

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Section: Discussionsupporting

confidence: 93%

Impacts of snow and cloud covers on satellite-derived PM2.5 levels

Belle

Wang

et al. 2019

Remote Sensing of Environment

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“…For example, Gillies et al (, ) linked persistent inversions in Utah's Salt Lake Valley to the two key modes, the synoptic (6‐day) mode and the intraseasonal (30‐day) mode, of the mid‐latitude winter circulation, with the synoptic mode having a particularly strong impact on persistent inversions that often lead to heavy pollution episodes. Wang et al (, ) showed a correlation between the subseasonal variability of the persistent inversion events in Utah's Cashe Valley with the North Atlantic Oscillation (NAO).…”

Section: Introductionmentioning

confidence: 99%

Multi‐day valley cold‐air pools in the western United States as derived from NARR

Zhong

Bian

2016

Intl Journal of Climatology

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Valleys can trap cold air to form Valley Cold Pools (VCPs). Characterized by stable stratification and weak winds, VCPs, especially those that last over multiple days, can produce adverse effects such as poor visibility and severe air pollution. Using the gridded data set of the North American Regional Reanalysis (NARR) for the period of 1979 through 2012, this study examines the climatology of VCPs in the western United States with a focus on spatial and temporal variability. The results reveal a widespread occurrence of short‐lived (1–2 days) VCPs over both the mountainous areas of the West and the Northern Plains. Longer VCP episodes, however, tend to be limited to large basins/valleys in the Northwest and the Intermountain West. The leading mode of variability in the annual number of cold‐season multi‐day VCP event anomalies appears to be linked to a sea‐surface temperature anomaly pattern typically found during the warm phase of Pacific Decadal Oscillation. Corresponding to the positive phase of the leading mode of variability is an anomalous 500‐hPa ridge over the western United States induced by a Rossby wave train, which, by blocking cold‐air intrusions and producing mid‐level subsidence warming, leads to more persistent VCP episodes in the western United States. In addition to large‐scale wintertime circulation anomalies, local surface temperature anomalies also contribute to the variability.

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“…High pressure and ridge systems and their associated subsidence and inversion layers have been related to poor air quality in some regions (e.g., Lee et al, 2012a;Wang et al, 2012). This is in part because the air is stagnant, trapping emitted pollutants, but it is also partly due to the lack of precipitation.…”

Section: Number Of Eventsmentioning

confidence: 99%

Changes in weather and climate extremes: State of knowledge relevant to air and water quality in the United States

Peterson

Karl

Kossin

et al. 2013

Journal of the Air & Waste Management Association

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Air and water quality are impacted by extreme weather and climate events on time scales ranging from minutes to many months. This review paper discusses the state of knowledge of how and why extreme events are changing and are projected to change in the future. These events include heat waves, cold waves, floods, droughts, hurricanes, strong extratropical cyclones such as nor'easters, heavy rain, and major snowfalls. Some of these events, such as heat waves, are projected to increase, while others, with cold waves being a good example, will decrease in intensity in our warming world. Each extreme's impact on air or water quality can be complex and can even vary over the course of the event.Implications: Because extreme weather and climate events impact air and water quality, understanding how the various extremes are changing and are projected to change in the future has ramifications on air and water quality management.

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Connecting Subseasonal Movements of the Winter Mean Ridge in Western North America to Inversion Climatology in Cache Valley, Utah

Cited by 14 publications

References 30 publications

Impacts of snow and cloud covers on satellite-derived PM2.5 levels

Impacts of snow and cloud covers on satellite-derived PM2.5 levels

Multi‐day valley cold‐air pools in the western United States as derived from NARR

Changes in weather and climate extremes: State of knowledge relevant to air and water quality in the United States

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