scholarly journals Measure of CINE - A relevant parameter for forecasting pre-monsoon thunderstorms over GWB

MAUSAM ◽  
2022 ◽  
Vol 52 (4) ◽  
pp. 679-684
Author(s):  
SUTAPA CHAUDHURI ◽  
SURAJIT CHATTOPADHYAY
Keyword(s):  
Potential Energy ◽  
Great Plains ◽  
Negative Correlation ◽  
West Bengal ◽  
Convective Available Potential Energy ◽  
Relevant Parameter ◽  
Frequency Of Occurrence ◽  
Severe Thunderstorms ◽  
Convective Inhibition

A method of testing the significance of Z- Statistic is introduced in this paper to discern the role of Convective Available Potential Energy (CAPE) and Convective Inhibition Energy (CINE) in forecasting the occurrence of pre-monsoon thunderstorms over Gangetic West Bengal (GWB). The result reveals that a negative correlation exists between CAPE and CINE. It further indicates that a range for the lower values of CINE can be fixed where the frequency of occurrence of such storms will be maximum, but such range, either for lower or for higher values of CAPE, is not possible. The paper, thus, ends with a very interesting finding that a measure of CINE is the only relevant parameter whereas CAPE has no significant role in forecasting the occurrence of pre-monsoon thunderstorms over GWB, which is in contrast to the concept of severe thunderstorms of Great Plains of America.

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 Analysis of Severe Elevated Thunderstorms over Frontal Surfaces Using DCIN and DCAPE

Atmosphere ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 449
Author(s):  
Patrick Market ◽  
Kevin Grempler ◽  
Paula Sumrall ◽  
Chasity Henson
Keyword(s):  
Weather Prediction ◽  
Convective Available Potential Energy ◽  
Numerical Weather Prediction Model ◽  
Surface Boundary ◽  
Storm Events ◽  
Cold Side ◽  
Severe Thunderstorms ◽  
Stable Surface Layer ◽  
Different Populations ◽  
Convective Inhibition

A 10-year study of elevated severe thunderstorms was performed using The National Centers for Environmental Information Storm Events Database. A total of 80 elevated thunderstorm cases were identified, verified, and divided into “Prolific” and “Marginal” classes. These severe cases occurred at least 80 km away from, and on the cold side of, a surface boundary. The downdraft convective available potential energy (DCAPE), downdraft convective inhibition (DCIN), and their ratio are tools to help estimate the potential for a downdraft to penetrate through the depth of a stable surface layer. The hypothesis is that as the DCIN/DCAPE ratio decreases, there exists enhanced possibility of severe surface winds. Using the initial fields from the Rapid Refresh numerical weather prediction model, datasets of DCIN, DCAPE, and their ratio were created. Mann-Whitney U tests on the Prolific versus Marginal case sets were undertaken to determine if the DCAPE and DCIN values come from different populations for the two different case sets. Results show that the Prolific cases have values of DCIN closer to zero, suggesting the downdraft is able to penetrate to the surface causing severe winds. Thus, comparing DCIN and DCAPE is a viable tool in determining if downdrafts will reach the surface from elevated thunderstorms.

CHAOTIC GRAPH THEORY APPROACH FOR IDENTIFICATION OF CONVECTIVE AVAILABLE POTENTIAL ENERGY (CAPE) PATTERNS REQUIRED FOR THE GENESIS OF SEVERE THUNDERSTORMS

2007 ◽  
Vol 10 (03) ◽  
pp. 413-422 ◽  
Author(s):  
SUTAPA CHAUDHURI
Keyword(s):  
Graph Theory ◽  
Potential Energy ◽  
Deep Convection ◽  
Convective Available Potential Energy ◽  
Pressure Level ◽  
Theory Approach ◽  
Severe Thunderstorm ◽  
Available Potential Energy ◽  
Severe Thunderstorms ◽  
Conditional Instability

Severe thunderstorms are a manifestation of deep convection. Conditional instability is known to be the mechanism by which thunderstorms are formed. The energy that drives conditional instability is convective available potential energy (CAPE), which is computed with radio sonde data at each pressure level. The purpose of the present paper is to identify the pattern or shape of CAPE required for the genesis of severe thunderstorms over Kolkata (22°32′N, 88°20′E) confined within the northeastern part (20°N to 24°N latitude, 85°E to 93°E longitude) of India. The method of chaotic graph theory is adopted for this purpose. Chaotic graphs of pressure levels and CAPE are formed for thunderstorm and non-thunderstorm days. Ranks of the adjacency matrices constituted with the union of chaotic graphs of pressure levels and CAPE are computed for thunderstorm and non-thunderstorm days. The results reveal that the rank of the adjacency matrix is maximum for non-thunderstorm days and a column with all zeros occurs very quickly on severe thunderstorms days. This indicates that CAPE loses connectivity with pressure levels very early on severe thunderstorm days, showing that for the genesis of severe thunderstorms over Kolkata short, and therefore broad, CAPE is preferred.

scholarly journals WRF Forecasts of Great Plains Nocturnal Low-Level Jet-Driven MCSs. Part II: Differences between Strongly and Weakly Forced Low-Level Jet Environments

2016 ◽  
Vol 31 (5) ◽  
pp. 1491-1510 ◽  
Author(s):  
Brian J. Squitieri ◽  
William A. Gallus
Keyword(s):  
Great Plains ◽  
Convective Available Potential Energy ◽  
Initiation Time ◽  
Mixing Ratio ◽  
Atmospheric Water ◽  
Low Level ◽  
The North ◽  
Low Level Jet ◽  
Convective Inhibition ◽  
Water Vapor Mixing Ratio

Abstract The classic Great Plains southerly low-level jet (LLJ) is a primary factor in sustaining nocturnal convection. This study compares convection-allowing WRF forecasts of LLJ events associated with MCSs in strongly and weakly forced synoptic environments. The depth of the LLJs and magnitude, altitude, and times of the LLJ peak wind were evaluated in observations and WRF forecasts for 31 cases as well as for case subsets of strongly and weakly forced synoptic regimes. LLJs in strongly forced regimes were stronger, deeper, and peaked at higher altitudes and at earlier times compared to weakly forced cases. Mean error MCS-centered composites of WRF forecasts versus RUC analyses were derived at MCS initiation time for the LLJ atmospheric water vapor mixing ratio, LLJ total wind magnitude, convergence, most unstable convective available potential energy (MUCAPE), and most unstable convective inhibition (MUCIN). In most configurations, simulated MCSs in strongly and weakly forced regimes initiated to the north and east of observations, generally in a region where LLJ moisture, MUCAPE, and MUCIN fields were forecast well, with larger errors outside this region. However, WSM6 simulations for strongly forced cases showed a southward displacement in MCS initiation, where a combination of ambient environmental factors and microphysics impacts may simultaneously play a role in the location of forecast MCS initiation. Strongly forced observed and simulated MCSs initiated west of the LLJ axis and moved eastward into the LLJ, while observed and simulated MCSs in weakly forced environments traversed the termini of the LLJ. A northward bias existed for simulated MCS initiation and LLJ termini for weakly forced regimes.

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 A Statistical Investigation of Mesoscale Precursors of Significant Tornadoes: The Italian Case Study

Atmosphere ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 301
Author(s):  
Roberto Ingrosso ◽  
Piero Lionello ◽  
Mario Marcello Miglietta ◽  
Gianfausto Salvadori
Keyword(s):  
Potential Energy ◽  
Wind Shear ◽  
Deep Level ◽  
Convective Available Potential Energy ◽  
Vertical Wind Shear ◽  
Statistical Investigation ◽  
Italian Case ◽  
Large Wind

In this study, mesoscale environments associated with 57 significant tornadoes occurring over Italy in the period 2000–2018 are analyzed. The role of the vertical Wind Shear in the lower and middle troposphere, in terms of low-level shear (LLS) and deep-level shear (DLS), and of the convective available potential energy (CAPE) as possible precursors of significant tornadoes is statistically investigated. Wind shear and CAPE data are extracted from the ERA-5 and ERA-Interim reanalyses. Overall, the study indicates that: (a) values of these variables in the two uppermost quartiles of their statistical distribution significantly increases the probability of tornado occurrences; (b) the probability increases for increasing values of LLS and DLS, and (c) is maximum when either wind shear or CAPE are large. These conclusions hold for both the reanalysis datasets and do not depend upon the season and/or the considered area. With the possible exception of weak tornadoes, which are not included in our study, our results show that large wind shear, in the presence of medium-to-high values of CAPE, are reliable precursors of tornadoes.

scholarly journals Dynamic Ensemble Analysis of Frontal Placement Impacts in the Presence of Elevated Thunderstorms during PRECIP Events

Atmosphere ◽  
2018 ◽  
Vol 9 (9) ◽  
pp. 339 ◽  
Author(s):  
Joshua Kastman ◽  
Patrick Market ◽  
Neil Fox
Keyword(s):  
Potential Energy ◽  
Convective Available Potential Energy ◽  
Wrf Model ◽  
Weather Research And Forecasting ◽  
Model Ensemble ◽  
Field Campaign ◽  
Cold Pools ◽  
Frontal Zones ◽  
Convective Inhibition ◽  
Ensemble Analysis

The Program for Research on Elevated Convection with Intense Precipitation (PRECIP) field campaign sampled 10 cases of elevated convection during 2014 and 2015. These intense observing periods (IOP) mostly featured well-defined stationary or warm frontal zones, over whose inversion elevated convection would form. However, not all frontal zones translated as expected, with some poleward motions being arrested and even returning equatorward. Prior analyses of the observed data highlighted the downdrafts in these events, especially diagnostics for their behavior: the downdraft convective available potential energy (DCAPE) and the downdraft convective inhibition (DCIN). With the current study, the DCAPE and DCIN are examined for four cases: two where frontal motion proceeded poleward, as expected, and two where the frontal motions were slowed significantly or stalled altogether. Using the Weather Research and Forecasting (WRF) model, a multi-model ensemble was created for each of the four cases, and the best performing members were selected for additional deterministic examination. Analyses of frontal motions and surface cold pools are explored in the context of DCAPE and DCIN. These analyses further establish the DCAPE and DCIN, not only as a means to classify elevated convection, but also to aid in explaining frontal motions in the presence of elevated convection.

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.   

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