Analyze and Comparison of the Atmospheric Instability Using K-Index, Lifted Index Total Totals Index Convective Availability Potential Energy (CAPE) and Convective Inhibition (CIN) in Development of Thunderstorms in Sri Lanka During Second Inter-Monsoon

2021 ◽  
pp. 603-614
Author(s):  
Malith Fernando ◽  
Malinda Millangoda ◽  
Sarath Premalal
Keyword(s):  
Sri Lanka ◽  
Potential Energy ◽  
K Index ◽  
Atmospheric Instability ◽  
Convective Inhibition

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 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 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 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.   

scholarly journals Assessing Atmospheric Instability over the Bay of Bengal during October and November Months between 2007 – 2018

2021 ◽  
Vol 9 (2) ◽  
pp. 45-54
Author(s):  
Saurav Dey Shuvo ◽  
Md Rabiul Awal
Keyword(s):  
Potential Energy ◽  
Bay Of Bengal ◽  
Convective Available Potential Energy ◽  
Environmental Sciences ◽  
Available Potential Energy ◽  
Average Temperature ◽  
Monthly Average ◽  
Atmospheric Instability ◽  
Over Time ◽  
Made In

An attempt has been made in this research to delineate a pattern for atmospheric instability during the months of October and November from 2007 to 2018. The results show an alarming trend of increasing instability throughout the study period. The average temperature at 2-meters height around the Bay of Bengal has changed significantly over time. Most notably, the gap between monthly average highest and monthly average lowest temperatures (at 2-meters height) is more or less increasing from 2007 to 2018 – ranging from 3.0 degrees to 11.0 degrees Celsius. Similar tendencies are observed for CAPE (Convective Available Potential Energy) as well – with the highest value of more than 3000 J/Kg. The findings of this research will help in understanding the prevailing conditions over the Bay, and also enable better preparedness for any potential severe convective activities. The Dhaka University Journal of Earth and Environmental Sciences, Vol. 9(2), 2020, P 45-54

scholarly journals Changes in the simulation of atmospheric instability over the Iberian Peninsula due to the use of 3DVAR data assimilation

2021 ◽  
Vol 25 (6) ◽  
pp. 3471-3492
Author(s):  
Santos J. González-Rojí ◽  
Sheila Carreno-Madinabeitia ◽  
Jon Sáenz ◽  
Gabriel Ibarra-Berastegi
Keyword(s):  
Data Assimilation ◽  
Iberian Peninsula ◽  
Mean Squared Error ◽  
Initial Conditions ◽  
Atlantic Coast ◽  
Convective Available Potential Energy ◽  
Mediterranean Coast ◽  
Dew Point ◽  
Atmospheric Instability ◽  
Convective Inhibition

Abstract. The ability of two downscaling experiments to correctly simulate thermodynamic conditions over the Iberian Peninsula (IP) is compared in this paper. To do so, three parameters used to evaluate the unstable conditions in the atmosphere are evaluated: the total totals index (TT), convective available potential energy (CAPE), and convective inhibition (CIN). The Weather and Research Forecasting (WRF) model is used for the simulations. The N experiment is driven by ERA-Interim's initial and boundary conditions. The D experiment has the same configuration as N, but the 3DVAR data assimilation step is additionally run at 00:00, 06:00, 12:00, and 18:00 UTC. Eight radiosondes are available over the IP, and the vertical temperature and moisture profiles from the radiosondes provided by the University of Wyoming and the Integrated Global Radiosonde Archive (IGRA) were used to calculate three parameters commonly used to represent atmospheric instability by our own methodology using the R package aiRthermo. According to the validation, the correlation, standard deviation (SD), and root mean squared error (RMSE) obtained by the D experiment for all the variables at most of the stations are better than those for N. The different methods produce small discrepancies between the values for TT, but these are larger for CAPE and CIN due to the dependency of these quantities on the initial conditions assumed for the calculation of a lifted air parcel. Similar results arise from the seasonal analysis concerning both WRF experiments: N tends to overestimate or underestimate (depending on the parameter) the variability of the reference values of the parameters, but D is able to capture it in most of the seasons. In general, D is able to produce more reliable results due to the more realistic values of dew point temperature and virtual temperature profiles over the IP. The heterogeneity of the studied variables is highlighted in the mean maps over the IP. According to those for D, the unstable air masses are found along the entire Atlantic coast during winter, but in summer they are located particularly over the Mediterranean coast. The convective inhibition is more extended towards inland at 00:00 UTC in those areas. However, high values are also observed near the southeastern corner of the IP (near Murcia) at 12:00 UTC. Finally, no linear relationship between TT, CAPE, or CIN was found, and consequently, CAPE and CIN should be preferred for the study of the instability of the atmosphere as more atmospheric layers are employed during their calculation than for the TT index.

scholarly journals A statistical analysis of sounding derived indices and parameters for extreme and non-extreme thunderstorm events over Cyprus

2010 ◽  
Vol 23 ◽  
pp. 79-85 ◽  
Author(s):  
K. Savvidou ◽  
A. Orphanou ◽  
D. Charalambous ◽  
P. Lingis ◽  
S. Michaelides
Keyword(s):  
Statistical Analysis ◽  
Potential Energy ◽  
Convective Available Potential Energy ◽  
Radiosonde Data ◽  
Available Potential Energy ◽  
K Index ◽  
Upper Limits ◽  
The Stability ◽  
Simple Statistical Analysis ◽  
Stability Indices

Abstract. The main purpose of this study is to provide a simple statistical analysis of several stability indices and parameters for extreme and non-extreme thunderstorm events during the period 1997 to 2001 in Cyprus. For this study, radiosonde data from Athalassa station (35°1´ N, 33°4´ E) were analyzed during the aforementioned period. The stability indices and parameters set under study are the K index, the Total Totals (TT) index, the Convective Available Potential Energy related parameters such as Convective Available Potential Energy (CAPE), Downdraft CAPE (DCAPE) and the Convective Inhibition (CIN), the Vorticity Generator Parameter (VGP), the Bulk Richardson Number (BRN), the BRN Shear and the Storm Relative Helicity (SRH). An event is categorized as extreme, if primarily, CAPE was non zero and secondary, if values of both the K and the TotalTotals (TT) indices exceeded 26.9 and 50, respectively. The cases with positive CAPE but lower values of the other indices, were identified as non-extreme. By calculating the median, the lower and upper limits, as well as the lower and upper quartiles of the values of these indices, the main characteristics of their distribution were determined.

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.

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