Upper-Level Structure of Oklahoma Tornadic Storms on 2 May 1979. II: Proposed Explanation of “V” Pattern and Internal Warm Region in Infrared Observations

Heymsfield, Gerald M.; Szejwach, G.; Schotz, Steven; Blackmer, Roy H.

doi:10.1175/1520-0469(1983)040<1756:ulsoot>2.0.co;2

Cited by 23 publications

(6 citation statements)

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“…Observations of such thermal structures have been reported repeatedly in the literature (e.g., Heymsfield et al, 1983;Heymsfield and Blackmer, Jr, 1988;Levizzani and Setvák, 1996;Setvák et al, 2007;Rosenfeld et al, 2007).…”

Section: Introductionmentioning

confidence: 58%

“…In a recent study based on analysis of brightness temperatures at various wavelengths, Setvák et al (2007) found that, for some storms, moisture plumes above the anvil level reach equilibrium with high stratospheric temperatures and mask the colder temperatures of the underlying cloud tops, thus giving rise to the observed warm center. Other studies suggested effects related to variations in radiative properties of cloud hydrometeors at the cloud top, with optically less opaque hydrometeors in the center allowing IR radiometers to see further down to a lower, hence warmer level of effective emission (Heymsfield et al, 1983). In this paper, we will demonstrate that both observations and simulations suggest that neither moisture masking nor effects related to the hydrometeors' radiative properties were relevant in our case study.…”

Section: Introductionmentioning

confidence: 58%

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Small-scale mixing processes enhancing troposphere-to-stratosphere transport by pyro-cumulonimbus storms

et al. 2007

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Abstract. Deep convection induced by large forest fires is an efficient mechanism for transport of aerosol particles and trace gases into the upper troposphere and lower stratosphere (UT/LS). For many pyro-cumulonimbus clouds (pyroCbs) as well as other cases of severe convection without fire forcing, radiometric observations of cloud tops in the thermal infrared (IR) reveal characteristic structures, featuring a region of relatively high brightness temperatures (warm center) surrounded by a U-shaped region of low brightness temperatures.We performed a numerical simulation of a specific case study of pyroCb using a non-hydrostatic cloud resolving model with a two-moment cloud microphysics parameterization and a prognostic turbulence scheme. The model is able to reproduce the thermal IR structure as observed from satellite radiometry. Our findings establish a close link between the observed temperature pattern and small-scale mixing processes atop and downwind of the overshooting dome of the pyroCb. Such small-scale mixing processes are strongly enhanced by the formation and breaking of a stationary gravity wave induced by the overshoot. They are found to increase the stratospheric penetration of the smoke by up to almost 30 K and thus are of major significance for irreversible transport of forest fire smoke into the lower stratosphere.

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Section: Introductionmentioning

confidence: 58%

Section: Introductionmentioning

confidence: 58%

Small-scale mixing processes enhancing troposphere-to-stratosphere transport by pyro-cumulonimbus storms

et al. 2007

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“…Typically, cold U brightness temperatures are lower than the tropopause minimum, while the temperatures in the warm center are higher than the temperatures of ambient air at the cloud top altitude. Observations of such thermal structures have been reported repeatedly in the literature (e.g., Heymsfield et al, 1983;Heymsfield and Blackmer, Jr, 1988;Levizzani and Setvák, 1996;Setvák et al, 2007;Rosenfeld et al, 2007).…”

Section: Introductionmentioning

confidence: 57%

Small-scale mixing processes enhancing troposphere-to-stratosphere transport by pyro-cumulonimbus storms

Luderer¹,

Trentmann²,

Hungershöfer³

et al. 2007

Preprint

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Deep convection induced by large forest fires is an efficient mechanism for transport of aerosol particles and trace gases into the upper troposphere and lower stratosphere (UT/LS). For many pyro-cumulonimbus clouds (pyroCbs) as well as other cases of severe convection without fire forcing, radiometric observations of cloud tops in the thermal infrared (IR) reveal characteristic structures, featuring a region of relatively high brightness temperatures (warm center) surrounded by a U-shaped region of low brightness temperatures.We performed a numerical simulation of a specific case study of pyroCb using a non-hydrostatic cloud resolving model with a two-moment cloud microphysics parameterization and a prognostic turbulence scheme. The model is able to reproduce the thermal IR structure as observed from satellite radiometry. Our findings establish a close link between the observed temperature pattern and small-scale mixing processes atop and downwind of the overshooting dome of the pyroCb. Such small-scale mixing processes are strongly enhanced by the formation and breaking of a stationary gravity wave induced by the overshoot. They are found to increase the stratospheric penetration of the smoke by up to almost 30 K and thus are of major significance for irreversible transport of forest fire smoke into the lower stratosphere.

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“…Thus, the greater the 0.8 µm albedo, the greater the probability of hail. According to Heymsfield et al (1983), hail areas are commonly associated with high OT, related to overshooting clouds or a V-shaped form. Bedka (2011) found that 53 % of cumulonimbus with overshooting clouds produce hail on the ground.…”

Section: Variables Input To the Modelmentioning

confidence: 99%

“…Another feature of severe storms (associated to severe weather according to Johns and Doswell, 1992) is that they often develop overshooting tops with a V-shape leeward of the cloud top, resembling a diverging plume above the anvil top (Heymsfield et al, 1983). This plume can have high reflectance in the NIR channels because it contains small ice particles (Levizzani and Setvák, 1996).…”

Section: Introductionmentioning

confidence: 99%

Daytime identification of summer hailstorm cells from MSG data

Merino¹,

López²,

Sánchez³

et al. 2014

Nat. Hazards Earth Syst. Sci.

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Abstract.Identifying deep convection is of paramount importance, as it may be associated with extreme weather phenomena that have significant impact on the environment, property and populations. A new method, the hail detection tool (HDT), is described for identifying hail-bearing storms using multispectral Meteosat Second Generation (MSG) data. HDT was conceived as a two-phase method, in which the first step is the convective mask (CM) algorithm devised for detection of deep convection, and the second a hail mask algorithm (HM) for the identification of hail-bearing clouds among cumulonimbus systems detected by CM. Both CM and HM are based on logistic regression models trained with multispectral MSG data sets comprised of summer convective events in the middle Ebro Valley (Spain) between 2006 and 2010, and detected by the RGB (red-green-blue) visualization technique (CM) or C-band weather radar system of the University of León. By means of the logistic regression approach, the probability of identifying a cumulonimbus event with CM or a hail event with HM are computed by exploiting a proper selection of MSG wavelengths or their combination. A number of cloud physical properties (liquid water path, optical thickness and effective cloud drop radius) were used to physically interpret results of statistical models from a meteorological perspective, using a method based on these "ingredients". Finally, the HDT was applied to a new validation sample consisting of events during summer 2011. The overall probability of detection was 76.9 % and the false alarm ratio 16.7 %.

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Upper-Level Structure of Oklahoma Tornadic Storms on 2 May 1979. II: Proposed Explanation of “V” Pattern and Internal Warm Region in Infrared Observations

Cited by 23 publications

References 0 publications

Small-scale mixing processes enhancing troposphere-to-stratosphere transport by pyro-cumulonimbus storms

Small-scale mixing processes enhancing troposphere-to-stratosphere transport by pyro-cumulonimbus storms

Small-scale mixing processes enhancing troposphere-to-stratosphere transport by pyro-cumulonimbus storms

Daytime identification of summer hailstorm cells from MSG data

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