scholarly journals A forecasting aspect of thundersquall over Calcutta and its parameterisation during pre-monsoon season

MAUSAM ◽  
2022 ◽  
Vol 53 (3) ◽  
pp. 271-280
Author(s):  
G. C. BASU ◽  
D. K. MONDAL

Severe thunderstorms accompanied by squalls are the most hazardous weather phenomena during pre-monsoon season in north-eastern region of India. An attempt has been made in this paper to study some parameters for forecasting thundersqualls over Calcutta (Airport) during pre-monsoon season. Parameterisation of thermodynamic components alongwith the synoptic support during thundersqualls over Calcutta has been discussed here. A forecasting aspect for propagation speed of thunderstorm cell at Calcutta in pre-monsoon season has been examined with respect to radar-echo positions, mid-level winds and convective available potential energy (CAPE). Occurrences of multiple thundersqualls over Calcutta Airport within a few hours’ interval have been discussed and examined through hodograph analysis, radar observations and synoptic situations.

2007 ◽  
Vol 10 (03) ◽  
pp. 413-422 ◽  
Author(s):  
SUTAPA CHAUDHURI

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.


MAUSAM ◽  
2021 ◽  
Vol 57 (2) ◽  
pp. 249-254
Author(s):  
SUTAPA CHAUDHURI ◽  
SUCHANDRA AICH BHOWMICK

Lkkj & bl 'kks/k&i= dk mÌs’; dksydkrk ¼22°32¢] 88°20¢½ esa ekulwu iwoZ _rq ¼vizSy&ebZ½ ds nkSjku xtZ ds lkFk vkus okys Hkh"k.k rwQkuksa dh mRifÙk vkSj fodkl esa lgk;d es?k dh lw{e HkkSfrdh; izfØ;kvksa dh tk¡p djuk gSA bl v/;;u ls ;g irk pyk gS fd dksydkrk esa ekulwu&iwoZ _rq ds nkSjku xtZ ds lkFk vkus okys Hkh"k.k rwQkuksa ds nkSjku rkixfrdh;] xfrdh;] es?k dh lw{e HkkSfrdh vkSj fctyh pdeus dks J`a[kykc) djus esa laoguh; miyC/k foHko ÅtkZ ¼lh- ,- ih- bZ-½ lgk;d gSA bl v/;;u ls izkIr gq, ifj.kkeksa ls ;g irk pyk gS fd dksydkrk esa laoguh; miyC/k foHko ÅtkZ 1000 twYl izfr fd- xzk- ds Hkhrj izcy ikbZ xbZ tks eqDr laogu Lrj ¼,y- ,Q- lh-½ ls Åij fu/kkZfjr nkc Lrjksa ds Hkhrj ikbZ xbZ vkSj ok;q dh viMªk¶V xfr ds ln`’k eku fu"izHkkoh mRIykodrk Lrj ¼,y- ,u- ch-½ esa yxHkx 30 - 50 eh-@ lsdsaM ik, x,A bl v/;;u ls ;g Hkh irk pyk gS fd 5 fe- eh- rd ds O;kl ds vkdkj dh c¡wns fLFkj jg ldrh gS ftlds ckn vkdkj c<+us ds dkj.k cw¡nsa VwV tkrh gSaA tc cw¡n dh f=T;k 2-5 fe- eh- ls 3 fe- eh- dh ifjf/k esa gksrh gS rc cw¡nksa dk VwVuk  'kq: gks tkrk gS vkSj 3 fe- eh- ls 5 fe- eh- dh ifjf/k esa cw¡nksa ds VwVus dh laHkkouk vf/kd gksrh gS D;ksfd bl fLFkfr esa cw¡nksa ds yxkrkj VwVus dh dkj.k mudk thoudky cgqr NksVk gks tkrk gSA  The aim of the present paper is to view the cloud microphysical processes entailed in the genesis and the development of the severe thunderstorms of pre-monsoon season (April - May) over Kolkata (22°32', 88°20'). The study shows that Convective Available Potential Energy (CAPE) is instrumental in establishing a linkage among thermodynamics, dynamics, cloud microphysics, and lightning during severe thunderstorm of pre monsoon season over Kolkata. The results of the present study reveal that for the thunderstorms reported over Kolkata, CAPE are found to be predominantly within 1000 joules per kgs within the prescribed pressure levels above the Level of Free Convection (LFC) and the corresponding values of the updraft speeds of the air are found to be nearly 30 - 50 m/s at the Level of Neutral Buoyancy (LNB). The study also depicts that the drops may grow up to the size of 5mm in diameter stably, beyond which, they tend to breakup due to the large drop instability. The breakup or splitting is observed to initiate when the drop radius is within the range of 2.5mm to 3mm and the breakup is most likely within the range of 3mm to 5mm because at this stage the lifetime of the drops are short due to the spontaneous breakup.  


Author(s):  
Saurav Dey Shuvo ◽  
Md Rabiul Awal

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


2006 ◽  
Vol 21 (3) ◽  
pp. 325-335 ◽  
Author(s):  
Max L. Dupilka ◽  
Gerhard W. Reuter

Abstract This study investigates, for Alberta, Canada, whether observed sounding parameters such as wind shear and buoyant energy can be used to help distinguish between thunderstorms with significant (F2–F5) tornadoes, thunderstorms with weak (F0–F1) tornadoes, and nontornadic severe thunderstorms. The observational dataset contains 87 severe convective storms, all of which occurred within 200 km of the upper-air site at Stony Plain, Alberta, Canada. Of these storms, 13 spawned significant (F2–F5) tornadoes, 61 spawned weak (F0–F1) tornadoes, and 13 had no reported tornadoes yet produced 3 cm or larger hailstones. The observations suggest that bulk shear contained information about the probability of tornado formation and the intensity of the tornado. Significant tornadic storms tended to have stronger shear values than weak tornadic or nontornadic severe storms. All significant tornado cases had a wind shear magnitude in the 900–500-mb layer exceeding 3 m s−1 km−1. Combining the 900–500-mb shear with the 900–800-mb shear increased the probabilistic guidance for the likelihood of significant tornado occurrence. The data suggest that buoyant energy alone (quantified by the most unstable convective available potential energy) provided no skill in discriminating between tornadic and nontornadic severe storms, or between significant and weak tornadoes.


MAUSAM ◽  
2022 ◽  
Vol 52 (4) ◽  
pp. 679-684
Author(s):  
SUTAPA CHAUDHURI ◽  
SURAJIT CHATTOPADHYAY

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.


2017 ◽  
Vol 32 (2) ◽  
pp. 361-375 ◽  
Author(s):  
Lee B. Carlaw ◽  
Ariel E. Cohen ◽  
Jaret W. Rogers

Abstract This paper comprehensively analyzes the synoptic and mesoscale environment associated with North American monsoon–related thunderstorms affecting central and southern Arizona. Analyses of thunderstorm environments are presented using reanalysis data, severe thunderstorm reports, and cloud-to-ground lightning information from 2003 to 2013, which serves as a springboard for lightning-prediction models provided in a companion paper. Spatial and temporal analyses of lightning strikes indicate thunderstorm frequencies maximize between 2100 and 0000 UTC, when the greatest frequencies are concentrated over higher terrain. Severe thunderstorm reports typically occur later in the day (between 2300 and 0100 UTC), while reports are maximized in the Tucson and Phoenix metropolitan areas. Composite analyses of the synoptic-scale patterns associated with severe thunderstorm days and nonthunderstorm days during the summer using the North American Regional Reanalysis dataset are presented. Severe thunderstorm cases tend to be associated with a stronger midlevel anticyclone and deep-layer moisture over portions of the southwestern United States. By September, severe weather patterns tend to associate with a midlevel trough along the Pacific coast. Specific parameters associated with severe thunderstorms are analyzed across the Tucson and Phoenix areas, where severe weather reporting is more consistent. Greater convective available potential energy, low-level lapse rates, and downdraft convective available potential energy are associated with severe thunderstorm (especially severe wind) environments compared to those with nonsevere thunderstorms, while stronger effective bulk wind differences (at least 15–20 kt, where 1 kt = 0.51 m s−1) can be used to distinguish severe hail environments.


Author(s):  
MELAKYRKHU NIANGMIH ◽  
SAMIRAN CHUTIA ◽  
DAS BANYASHREE ◽  
SARKAR BAPI ROY ◽  
DEY BIPLAB KUMAR ◽  
...  

Think India ◽  
2019 ◽  
Vol 22 (3) ◽  
pp. 186-192
Author(s):  
Dr. Oinam Ranjit Singh ◽  
Dr. Nushar Bargayary

The Bodo of the North Eastern region of India have their own kinship system to maintain social relationship since ancient periods. Kinship is the expression of social relationship. Kinship may be defined as connection or relationships between persons based on marriage or blood. In each and every society of the world, social relationship is considered to be the more important than the biological bond. The relationship is not socially recognized, it fall outside the realm of kinship. Since kinship is considered as universal, it plays a vital role in the socialization of individuals and the maintenance of social cohesion of the group. Thus, kinship is considered to be the study of the sum total of these relations. The kinship of the Bodo is bilateral. The kin related through the father is known as Bahagi in Bodo whereas the kin to the mother is called Kurma. The nature of social relationships, the kinship terms, kinship behaviours and prescriptive and proscriptive rules are the important themes of the present study.


2020 ◽  
Vol 15 (3) ◽  
pp. 264-273
Author(s):  
Syeda Sabiha Salam ◽  
Pankaj Chetia ◽  
Devid Kardong

Background: Malaria is endemic in various parts of India particularly in the North- Eastern states with Plasmodium falciparum-the most prevalent human malaria parasite. Plantderived compounds have always received tremendous importance in the area of drug discovery and development and scientific study of traditional medicinal plants are of great importance to mankind. Objective: The present work deals with the computational study of some antimalarial compounds obtained from a few medicinal plants used by the tribal inhabitants of the North-Eastern region of India for treating malaria. Methods: In silico methodologies were performed to study the ligand-receptor interactions. Target was identified based on the pharmacophore mapping approach. A total of 18 plant-derived compounds were investigated in order to estimate the binding energies of the compounds with their drug target through molecular docking using Autodock 4.2. ADMET filtering for determining the pharmacokinetic properties of the compounds was done using Mobyle@RPBS server. Subsequent Quantitative-Structure Activity Relationship analysis for bioactivity prediction (IC50) of the compounds was done using Easy QSAR 1.0. Results: The docking result identified Salannin to be the most potent Plasmepsin II inhibitor while the QSAR analysis identified Lupeol to have the least IC50 value. Most of the compounds have passed the ADME/Tox filtration. Conclusion: Salannin and Lupeol were found to be the most potent antimalarial compounds that can act as successful inhibitors against Plasmepsin II of P. falciparum. The compounds Salannin and Lupeol are found in Azadirachta indica and Swertia chirata plants respectively, abundantly available in the North-Eastern region of India and used by many inhabiting tribes for the treatment of malaria and its symptoms.


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