scholarly journals Should Reversible Convective Inhibition be Used when Determining the Inflow Layer of a Convective Storm?

2021 ◽  
Vol 78 (10) ◽  
pp. 3047-3067
Author(s):  
Shawn S. Murdzek ◽  
Paul M. Markowski ◽  
Yvette P. Richardson ◽  
Matthew R. Kumjian
Keyword(s):  
Potential Energy ◽  
Convective Available Potential Energy ◽  
Adiabatic Process ◽  
Convective Storm ◽  
Available Potential Energy ◽  
Convective Inhibition

AbstractConvective inhibition (CIN) is one of the parameters used by forecasters to determine the inflow layer of a convective storm, but little work has examined the best way to compute CIN. One decision that must be made is whether to lift parcels following a pseudoadiabat (removing hydrometeors as the parcel ascends) or reversible moist adiabat (retaining hydrometeors). To determine which option is best, idealized simulations of ordinary convection are examined using a variety of base states with different reversible CIN values for parcels originating in the lowest 500 m. Parcel trajectories suggest that ascent over the lowest few kilometers, where CIN is typically accumulated, is best conceptualized as a reversible moist adiabatic process instead of a pseudoadiabatic process. Most inflow layers do not contain parcels with substantial reversible CIN, despite these parcels possessing ample convective available potential energy and minimal pseudoadiabatic CIN. If a stronger initiation method is used, or hydrometeor loading is ignored, simulations can ingest more parcels with large amounts of reversible CIN. These results suggest that reversible CIN, not pseudoadiabatic CIN, is the physically relevant way to compute CIN and that forecasters may benefit from examining reversible CIN instead of pseudoadiabatic CIN when determining the inflow layer.

scholarly journals Study of Pre-Monsoon Thunderstorms and Associated Thermodynamic Features Over Bangladesh Using WRF-ARW Model

2019 ◽  
Vol 67 (2) ◽  
pp. 151-156
Author(s):  
Pappu Paul ◽  
Ashik Imran ◽  
Md Jafrul Islam ◽  
Alamgir Kabir ◽  
Sahadat Jaman ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Potential Energy ◽  
Convective Available Potential Energy ◽  
Severe Thunderstorm ◽  
Available Potential Energy ◽  
K Index ◽  
Mesoscale System ◽  
Arw Model ◽  
Convective Inhibition ◽  
Wind Distribution

Thunderstorm is a mesoscale system (from a km to below thousands of km and sustaining less than one hour). Two pre-monsoon thunderstorms events are analyzed in this study which are named as event-1 (0030-0150 UTC of 19 April 2018 over Chattogram) and event-2 (0600-1000 UTC of 4 May 2018 over Dhaka). To predict these events Mean Convective Available Potential Energy (mCAPE), Mean Convective Inhibition Energy (mCINE), K Index (KI), Total totals Index (TTI), wind distribution, and relative humidity (RH) are investigated.The model simulated mCAPE and mCINE values, 18 hours before the events, are found greater than 1700 J/Kg and less than 100 J/Kg respectively which satisfies the conditions for thunderstorms to occur.The KI values are close to 400C and TTI values are greater or equal to 450C for both events. The wind patterns and the high value of mid –tropospheric RH also favors the formation of severe thunderstorm. Dhaka Univ. J. Sci. 67(2): 151-156, 2019 (July)

scholarly journals Role of Hamiltonian energy in thunderstorms

MAUSAM ◽  
2021 ◽  
Vol 68 (3) ◽  
pp. 519-528
Author(s):  
G. K. SAWAISARJE ◽  
SOMENATH DUTTA ◽  
S. JAGTAP
Keyword(s):  
Free Convection ◽  
Potential Energy ◽  
Convective Available Potential Energy ◽  
Lower Troposphere ◽  
Air Mass ◽  
Available Potential Energy ◽  
Special Cases ◽  
Meteorological Observatory ◽  
Synoptic Conditions ◽  
Convective Inhibition

In the present study, we propose a hypothesis that “Hamiltonian energy of thunder storm is contributing towards the energy that overcomes convective inhibition energy to lift the parcel to the level of free convection and releases convective available potential energy in the environment”. We attempt to substantiate the hypothesis. We have applied Hamiltonian structure to a thundercloud which has occurred vertically above the meteorological observatory station. Further, a total of 62 cases of thunderstorms are selected for both stations Palam and Dumdum. Hamiltonian energy is computed and investigated the cases having significant large convective inhibition energy as compared to that of convective available potential energy. We attempt to show that Hamiltonian is the energy that overcomes convective inhibition energy to lift the parcel to the level of free convection and plays a major role in thunderstorms for giving rain.     Results reveal that Hamiltonian energy is seen to be maximum at the surface and contributes to both convective inhibition energy and convective available potential energy. At the lower troposphere, it overcomes the convective inhibition energy and provides necessary trigger for air mass to move from surface to the level of free convection. While in the upper troposphere, it is contributing to the convective available potential energy such that the part of potential energy converted into kinetic energy & warm and moist air mass (unstable) acceleration is enhanced by pressure energy.                          Further, in all the six special cases stability indices had indicated possibility of thunderstorm. In addition, synoptic conditions were also favorable for the same.   

Changes in Convective Available Potential Energy and Convective Inhibition under Global Warming

2020 ◽  
Vol 33 (6) ◽  
pp. 2025-2050 ◽  
Author(s):  
Jiao Chen ◽  
Aiguo Dai ◽  
Yaocun Zhang ◽  
Kristen L. Rasmussen
Keyword(s):  
Global Warming ◽  
Potential Energy ◽  
Climate Model ◽  
Convective Available Potential Energy ◽  
The United States ◽  
Specific Humidity ◽  
Low Level ◽  
Available Potential Energy ◽  
Convective Inhibition ◽  
The Impact

AbstractAtmospheric convective available potential energy (CAPE) is expected to increase under greenhouse gas–induced global warming, but a recent regional study also suggests enhanced convective inhibition (CIN) over land although its cause is not well understood. In this study, a global climate model is first evaluated by comparing its CAPE and CIN with reanalysis data, and then their future changes and the underlying causes are examined. The climate model reasonably captures the present-day CAPE and CIN patterns seen in the reanalysis, and projects increased CAPE almost everywhere and stronger CIN over most land under global warming. Over land, the cases or times with medium to strong CAPE or CIN would increase while cases with weak CAPE or CIN would decrease, leading to an overall strengthening in their mean values. These projected changes are confirmed by convection-permitting 4-km model simulations over the United States. The CAPE increase results mainly from increased low-level specific humidity, which leads to more latent heating and buoyancy for a lifted parcel above the level of free convection (LFC) and also a higher level of neutral buoyancy. The enhanced CIN over most land results mainly from reduced low-level relative humidity (RH), which leads to a higher lifting condensation level and a higher LFC and thus more negative buoyancy. Over tropical oceans, the near-surface RH increases slightly, leading to slight weakening of CIN. Over the subtropical eastern Pacific and Atlantic Ocean, the impact of reduced low-level atmospheric lapse rates overshadows the effect of increased specific humidity, leading to decreased CAPE.

scholarly journals Role of CAPE and CINE in modulating the convective activities during April over India

MAUSAM ◽  
2021 ◽  
Vol 50 (3) ◽  
pp. 257-262
Author(s):  
A. K. SRIVASTAVA ◽  
K. C. SINHA RAY
Keyword(s):  
Potential Energy ◽  
Convective Available Potential Energy ◽  
Available Potential Energy ◽  
Western Disturbances ◽  
Convective Inhibition ◽  
Northwest India

During the month of April, except over northwest India, where rain is normally associated with the intrusion of midlatitudinal westerly systems in the form of western disturbances, other parts of the country receive rain due to enhancement of convective activities in the form of thundershowers, occurring over many parts of the country. The role of Convective Available Potential Energy (CAPE) and Convective Inhibition Energy (CINE) were studied for the occurrence of more convective activities in the month of April 1997 compared to other years. The results reveal that larger values of CAPE and smaller values of CINE in April 1997 over various parts of India compared to other years were responsible for more convective activities and consequently appreciable fall in temperature in April 1997.

scholarly journals Ocean Convective Available Potential Energy. Part II: Energetics of Thermobaric Convection and Thermobaric Cabbeling

2016 ◽  
Vol 46 (4) ◽  
pp. 1097-1115 ◽  
Author(s):  
Zhan Su ◽  
Andrew P. Ingersoll ◽  
Andrew L. Stewart ◽  
Andrew F. Thompson
Keyword(s):  
Potential Energy ◽  
Deep Convection ◽  
Center Of Mass ◽  
Convective Available Potential Energy ◽  
Vertical Mixing ◽  
Available Potential Energy ◽  
Energy Part ◽  
Different Temperatures ◽  
Simplifying Assumptions ◽  
Diabatic Processes

AbstractThe energetics of thermobaricity- and cabbeling-powered deep convection occurring in oceans with cold freshwater overlying warm salty water are investigated here. These quasi-two-layer profiles are widely observed in wintertime polar oceans. The key diagnostic is the ocean convective available potential energy (OCAPE), a concept introduced in a companion piece to this paper (Part I). For an isolated ocean column, OCAPE arises from thermobaricity and is the maximum potential energy (PE) that can be converted into kinetic energy (KE) under adiabatic vertical parcel rearrangements. This study explores the KE budget of convection using two-dimensional numerical simulations and analytical estimates. The authors find that OCAPE is a principal source for KE. However, the complete conversion of OCAPE to KE is inhibited by diabatic processes. Further, this study finds that diabatic processes produce three other distinct contributions to the KE budget: (i) a sink of KE due to the reduction of stratification by vertical mixing, which raises water column’s center of mass and thus acts to convert KE to PE; (ii) a source of KE due to cabbeling-induced shrinking of the water column’s volume when water masses with different temperatures are mixed, which lowers the water column’s center of mass and thus acts to convert PE into KE; and (iii) a reduced production of KE due to diabatic energy conversion of the KE convertible part of the PE to the KE inconvertible part of the PE. Under some simplifying assumptions, the authors also propose a theory to estimate the maximum depth of convection from an energetic perspective. This study provides a potential basis for improving the convection parameterization in ocean models.

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