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

Yu, Lejiang; Zhong, Shiyuan; Bian, Xindi

doi:10.1002/joc.4858

Cited by 14 publications

(27 citation statements)

References 47 publications

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“…By definition, it is a stagnant layer of air evidently colder than the air above (Whiteman et al., 2001). While a universal method to identify cold pools remains absent to date (McCaffrey et al., 2019; Reeves & Stensrud, 2009; Whiteman et al., 2001; Yu et al., 2017), most of the existing cold‐pool detection methods consider the lapse rate of the atmosphere (Reeves & Stensrud, 2009; Whiteman et al., 2001; Wolyn & McKee, 1989), which depicts a fundamental feature of a temperature inversion under the influence of cold pools. Hence, a cold pool is identified here as an area where the vertical gradient of virtual potential temperature (∂ θ v /∂ z ) exceeds 2.5 K km −1 in the lowest 1 km.…”

Section: Methodsmentioning

confidence: 99%

“…By definition, it is a stagnant layer of air evidently colder than the air above (Whiteman et al, 2001). While a universal method to identify cold pools remains absent to date (McCaffrey et al, 2019;Reeves & Stensrud, 2009;Whiteman et al, 2001;Yu et al, 2017), most of the existing cold-pool detection It is based on a 19-year MCS total since the 20th Late-winter occurred beyond our study period (see Table S1 in Supporting Information S1).…”

Section: Identification Of Cold Poolsmentioning

confidence: 99%

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A Dual Regime of Mesoscale Convective Systems in the East Asian Monsoon Annual Cycle

et al. 2022

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Eastern China is perennially hit by mesoscale convective systems (MCSs), yet it remains an open question as to whether and how their general properties change throughout the annual cycle. By leveraging high‐resolution satellite observations and a hybrid tracking algorithm, we present a 20‐year (2001–2020) climatology of MCSs over eastern China during eight subseasonal‐to‐seasonal (S2S) monsoon stages. MCSs contribute up to 50% of the stage‐total precipitation and over 60% of the rainband‐zone precipitation during the Pre‐Meiyu and Meiyu episodes, and their contributions remain non‐trivial during the transition seasons. We discover two contrasting regimes of MCSs that alternate immediately upon the Pre‐Meiyu and the Fall onsets. The wintertime regime features fast‐propagating shallow systems initiated at night in a strongly sheared and dry environment. The summertime regime, instead, features an outbreak of MCSs in the south, where the systems often initiate in the afternoon and propagate 2–3 times slower than the cold‐season ones. Based on multivariate clustering analysis, the nighttime MCSs that dictate the winter stages often initiate over a deep nocturnal boundary layer with moist rear inflows upgliding above it. In contrast, the afternoon‐initiated MCSs under the summertime regime feature a pronounced convective available potential energy (CAPE) "tongue" and upslope flows in their southeast quadrant. The southwesterly moist ascending flows are likely to shallow the convective inhibition at the tip of the CAPE tongue and facilitate the intense updrafts of the MCSs. Findings here may offer insights into S2S weather prediction and facilitate agricultural and water management throughout the year.

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Section: Methodsmentioning

confidence: 99%

Section: Identification Of Cold Poolsmentioning

confidence: 99%

A Dual Regime of Mesoscale Convective Systems in the East Asian Monsoon Annual Cycle

et al. 2022

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“…In such instances, disturbed weather, accompanied by humid air advections and cloudiness, ends the inversion sequence (Williams and Thorp, 2015). There is another type of inversion that is quite frequent in temperate latitudes (Barry, 2008;Mirocha and Branko, 2010;Dupont et al, 2016;Young, 2016;Yu et al, 2017). These are the subsidence inversions that occur under hot, high pressure conditions at high altitudes by adiabatic air compression.…”

Section: Topographic Descriptors and Thermal Inversions Amid The Platmentioning

confidence: 99%

Topographic descriptors and thermal inversions amid the plateaus and mountains of the Jura (France)

Joly

Richard

2018

Climatologie

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Sixteen temperature measurement sites under forest cover are distributed across the plateaus and mountains of the Jura (France). They are composed of pairs of stations located, one at the bottom of a topographic trough, the other at least 50 m higher in altitude. Three descriptors (station elevation, altitudinal difference (amplitude) between the two stations of each site, and topographical context) are used to explain how the frequency, intensity, and duration of inversions are spatially structured. Depending on whether one considers: 1) tn (minimum temperature) or tx (maximum temperature), 2) frequency or intensity, the sign of the correlation values changes. This reflects the fact that not all inversions can be explained in the same way. Elevation moderately explains the three characters of the inversions. Amplitude mainly explains their frequency (R =-0.83 for daily minima [tn]) and their intensity (R = 0.62 for daily maxima [tx]). The magnitude of the topographic depressions where the low stations are located mainly explains the tn inversions while the magnitude of the eminences where the high stations are located mainly explains the tx inversions. Finally, a multiple regression where the explanatory variables correspond to the topographic descriptors makes it possible to model the three inversion indicators.

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“…Later, Chachere and Pu (2016) also used this definition and referred to the DSL as CAP. Yu et al (2017) also used this method but considered the wind speed at 10 m, too.…”

Section: Introductionmentioning

confidence: 99%

Local identification of persistent cold air pool conditions in the Great Hungarian Plain

André¹,

Bartholy²,

Pongrácz³

et al. 2021

Időjárás

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Cold air pool (CAP) is a winter-time, anticyclonic weather event: a cold air layer confined by the topography and warm air aloft. If its duration is more than one day, then it is called persistent cold air pool (PCAP). CAPs are mainly examined in small basins and valleys. Fewer studies pay attention to PCAPs in much larger basins (with an area of more than 50 000 km2), and it is not evident how effective the existing numerical definitions are in cases of extensive PCAP events. A possible method of identifying PCAPs in a large basin is to identify PCAP weather conditions at different measuring sites across the basin. If there are PCAP weather conditions at most of the sites, then it is likely to be an extensive PCAP. In this work, we examine which of the documented CAP definitions can be used for reliable local detection of CAP conditions. Daily weather reports and meteorological data from two locations in the 52 000 km2 sized Great Hungarian Plain have been used to obtain a reference set of days with PCAP weather conditions during two consecutive winter months. Several numerical CAP definitions were compared for their performance in recognizing the presence of PCAP weather conditions using radiosonde measurements and reanalysis data. The lowest error was produced by using the heat deficit (HD) method. So this is considered the most suitable method for local identification of PCAPs in the Great Hungarian Plain.

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

Cited by 14 publications

References 47 publications

A Dual Regime of Mesoscale Convective Systems in the East Asian Monsoon Annual Cycle

A Dual Regime of Mesoscale Convective Systems in the East Asian Monsoon Annual Cycle

Topographic descriptors and thermal inversions amid the plateaus and mountains of the Jura (France)

Local identification of persistent cold air pool conditions in the Great Hungarian Plain

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