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 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.

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 Retrieval of convective available potential energy from INSAT-3D measurements: comparison with radiosonde data and its spatial-temporal variations

2018 ◽  
Author(s):  
Uriya Veerendra Murali Krishna ◽  
Subrata Kumar Das ◽  
Kizhathur Narasimhan Uma ◽  
Govindan Pandithurai
Keyword(s):  
Potential Energy ◽  
Convective Available Potential Energy ◽  
Atmospheric Stability ◽  
Temporal Variations ◽  
Indian Region ◽  
Radiosonde Data ◽  
Available Potential Energy ◽  
Different Seasons ◽  
First Time ◽  
Derived Data

Abstract. Convective available potential energy (CAPE) is a measure of the amount of energy available for convection in the atmosphere. The satellite-derived data over the ocean and land is used for a better understanding of the atmospheric stability indices. In this work, an attempt is made for the first time to estimate CAPE from high spatial and temporal resolution measurements of the INSAT-3D over the Indian region. The estimated CAPE from the INSAT-3D is comprehensively evaluated using radiosonde derived CAPE and ERA-Interim CAPE. The evaluation shows that the INSAT-3D CAPE reasonably correlated with the radiosonde derived CAPE; however, the magnitude of CAPE shows higher values. Further, the distribution of CAPE is studied for different instability conditions (different range of CAPE values) during different seasons over the Indian region. In addition, the diurnal and seasonal variability in CAPE is also investigated at different geographical locations to understand the spatial variability with respect to different terrains.

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