scholarly journals Downstream and In Situ: Two Perspectives on the Initiation of Monsoon Low‐Pressure Systems Over the Bay of Bengal

2019 ◽  
Vol 46 (21) ◽  
pp. 12303-12310 ◽  
Author(s):  
M. Meera ◽  
E. Suhas ◽  
S. Sandeep
Keyword(s):  
Bay Of Bengal ◽  
Low Pressure ◽  
Low Pressure Systems

scholarly journals Excess and deficient summer monsoon rainfall over Orissa in relation to low pressure systems

MAUSAM ◽  
2021 ◽  
Vol 60 (1) ◽  
pp. 25-38
Author(s):  
M. MOHAPATRA ◽  
U. C. MOHANTY
Keyword(s):  
Bay Of Bengal ◽  
Andhra Pradesh ◽  
West Bengal ◽  
Monsoon Rainfall ◽  
Low Pressure ◽  
Summer Monsoon Rainfall ◽  
Cyclonic Storm ◽  
Normal Number ◽  
Different Characteristics ◽  
Low Pressure Systems

A study has been undertaken to find out different characteristics like frequency, intensity, movement, region of occurrence etc. of low pressure systems (LPS) including low, depression and cyclonic storm etc. developing over Orissa and neighbouring sea and land regions during excess and deficient monsoon  rainfall months (June – September) over Orissa. The study is based on data of 20 years (1980-1999). The principal objective of this study is to find out the contribution of LPS to extreme monsoon rainfall activity over Orissa.   The number of LPS days rather than frequency of formation of LPS over different regions better explain the excess and deficient rainfall over Orissa. The excess rainfall over Orissa during June is not significantly related with the number of LPS days. Significantly less than normal number of LPS days over northwest (NW) Bay of Bengal and Gangetic West Bengal (GWB) and higher number of LPS days over west central (WC) Bay off north coastal Andhra Pradesh (NCAP) cause deficient rainfall over Orissa during June. While significantly higher than normal number of LPS days over NW Bay and Orissa leads to excess rainfall during July, less than normal number of LPS days over WC Bay off NCAP is associated with excess rainfall during August. The less number of LPS days over Orissa due to less frequent movement of LPS across Orissa from the Bay of Bengal leads to deficient rainfall over Orissa during both July and August. Significantly higher/less than normal number of LPS days over NW Bay leads to excess/deficient rainfall over Orissa during September.

scholarly journals Synoptic study of extremely heavy rainfall events over lower Yamuna catchment : Some cases

MAUSAM ◽  
2021 ◽  
Vol 64 (2) ◽  
pp. 265-280
Author(s):  
MEHFOOZ ALI MEHFOOZALI ◽  
U.P. SINGH ◽  
D. JOARDAR ◽  
NIZAMUDDIN NIZAMUDDIN
Keyword(s):  
Bay Of Bengal ◽  
Heavy Rainfall ◽  
Extreme Rainfall ◽  
Low Pressure ◽  
Crop Damage ◽  
Local Conditions ◽  
Rainfall Events ◽  
Synoptic Conditions ◽  
Heavy Rainfall Events ◽  
Low Pressure Systems

vR;f/kd o"kkZ gksus ds dkj.k HkwL[kyu gksrk gS vDlekr ck<+ vk tkrh gS vkSj Qly dks {kfr igq¡prh gSA lekt] vFkZO;oLFkk vkSj i;kZoj.k ij bldk cgqr nq"izHkko iM+rk gSA i;kZoj.kh; vkSj flukWfIVd fLFkfr;ksa ds mRiUu gksus ls  vR;f/kd vFkok cgqr Hkkjh o"kkZ gksus ds dkj.k Hkkjr esa nf{k.k if’peh ekulwu _rq ds nkSjku vf/kdk¡’kr% ck<+ vkrh gSA bl 'kks/k i= esa izeq[k flukWfIVd dkj.kksa dk irk yxkus dk iz;kl fd;k x;k gS tks y?kq vof/k iwokZuqeku ds {ks= esa fodflr iwokZuqeku rduhd vkSj vk/kqfud izs{k.kkRed izkS|ksfxdh ij vk/kkfjr o"kZ 1998&2010 dh vof/k dh bl o"kkZ  vkSj ok;qeaMyh; iz.kkfy;ksa ds e/; laca/kksa ds fo’ys"k.k ds ek/;e ls ;equk ds fupys tyxzg.k {ks= ¼,y-okbZ-lh-½ esa vR;f/kd Hkkjh o"kkZ dh ?kVukvksa ds fy, mRrjnk;h gSA bl v/;;u ls ;g irk pyk gS fd  bl {ks= esa caxky dh [kkM+h esa fuEu nkc iz.kkfy;ksa dk cuuk izeq[k dkjd gS fuLlansg ;fn LFkkuh; fLFkfr;k¡ izHkkoh gks tSlsa fd xehZ dk c<+uk rks ogk¡ ij Hkkjh o"kkZ gksrh gSA lkekU;r% caxky dh [kkM+h esa fuEu vcnkc iz.kkfy;k¡ ¼pØokr] vonkc] fuEu vonkc {ks= vkfn tSls ¼,y-ih-,l-½ fodflr gqbZ tks if’pe ls mRrjh  if’peh fn’kk dh vksj c<+h rFkk ;equk ds fupys tyxzg.k ¼,y-okbZ-lh-½ {ks= esa igq¡phA ,slh ?kVukvksa ds fy, mRrjnk;h mifjru  ok;q pØokrh ifjlapj.k ¼lkblj½ ds izHkko ls ogha ij ,y- ih- ,l- Hkh cu ldrk gSA ,slh iz.kkyh ls bDds&nwDds LFkkuksa ij vR;f/kd Hkkjh o"kkZ dh ?kVuk,¡ ¼lkekU;r% iz.kkyh ds nf{k.k if’pe {ks= esa½ vkSj dqN LFkkuksa ij Hkkjh ls cgqr Hkkjh o"kkZ gqbZ ftlds dkj.k ck<+ vkbZA ;fn ;equk ds fupys tyxzg.k ¼,y-okbZ-lh-½ {ks= esa ,y-ih-,l- fuf"Ø; ;k /khek iM+ tkrk gS rks bl izdkj dh o"kkZ dh ?kVukvksa dh laHkkouk c<+ ldrh gSA ,y-ih-,l- ds vkxs c<+us dk lgh iwokZuqeku nsus ds fy, vkj-,l-,e-lh- ¼Hkkjr ekSle foKku foHkkx½ ubZ fnYYkh ds iwoZuqeku :i js[kk ds ,u-MCY;w-ih- mRikn@72] 48 vkSj 24 ?kaVksa ds iou pkVZ lgh lk/ku ik, x, gSaA vR;f/kd o"kkZ dh ?kVukvksa ds iwokZuqeku esa bl izdkj dh lwpuk nsus ls iwokZuqekudrkvksa dks fuf’pr :i ls lgh iwokZuqeku feysxk rkfd ftyk izkf/kdkjh le; jgrs vkink dh rS;kjh ds fy, vko’;d ewyHkwr lqfo/kk,¡ miyC/k djk ldsaA  Extreme rainfall results in landslides, flash flood and crop damage that have major impact on society, the economy and the environment. During southwest monsoon season, flood mostly occurs in India due to extremely or very heavy rain that originates from environmental and   synoptic conditions. An attempt has been made to identify the main synoptic reasons, which are responsible for extremely heavy rainfall events over Lower Yamuna catchment (LYC) through the analysis of the relationship between this rainfall and atmospheric systems for the period 1998-2010 based on modern observational technology and developed forecasting technique in the field of short range prediction. The finding of this study show that the major factor have is the arrival of Bay of Bengal low pressure systems in this region, of course if the ascent local conditions such as heat occur, causing the heaviest rains there. The low pressure systems (LPS like, Cyclone, depression, low pressure area etc.) developed generally over Bay of Bengal moved in west to north-westwards direction and reached over the LYC region. Also LPS may be formed in situ under the influence of upper air cyclonic circulation (cycir) responsible for such events. Such system yield extremely heavy rainfall events (generally in the south-west sector of the system) at isolated places and heavy to very heavy rainfall at a few places and there by caused flood situation. The possibility of occurrence of such type of rainfall would be higher if the LPS is either stagnate or slow over LYC region. The NWP products of RSMC (IMD) New Delhi forecast contours / wind charts for 72, 48 & 24 hrs were found good tool for accurate forecast position of the movement of the LPS. Such information certainly facilitate to forecaster in prediction of extreme rainfall events more accurately so that district authorities may set up necessary infrastructures for disaster preparedness in time.

scholarly journals Downstream and In Situ Genesis of Monsoon Low‐Pressure Systems in Climate Models

2021 ◽  
Vol 8 (9) ◽  
Author(s):  
K. S. S. Sai Srujan ◽  
S. Sandeep ◽  
E. Suhas
Keyword(s):  
Climate Models ◽  
Low Pressure ◽  
Low Pressure Systems

scholarly journals In-Situ Synchrotron X-ray Diffraction Investigation of Microstructural Evolutions During Low-Pressure Carburizing

2021 ◽  
Author(s):  
Ogün Baris Tapar ◽  
Jérémy Epp ◽  
Matthias Steinbacher ◽  
Jens Gibmeier
Keyword(s):  
Carbon Content ◽  
Carbon Diffusion ◽  
Low Pressure ◽  
Carbon Accumulation ◽  
Experimental Chamber ◽  
Carbide Formation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Carbon Supply

AbstractAn experimental heat treatment chamber and control system were developed to perform in-situ X-ray diffraction experiments during low-pressure carburizing (LPC) processes. Results from the experimental chamber and industrial furnace were compared, and it was proven that the built system is reliable for LPC experiments. In-situ X-ray diffraction investigations during LPC treatment were conducted at the German Electron Synchrotron Facility in Hamburg Germany. During the boost steps, carbon accumulation and carbide formation was observed at the surface. These accumulation and carbide formation decelerated the further carbon diffusion from atmosphere to the sample. In the early minutes of the diffusion steps, it is observed that cementite content continue to increase although there is no presence of gas. This effect is attributed to the high carbon accumulation at the surface during boost steps which acts as a carbon supply. During quenching, martensite at higher temperature had a lower c/a ratio than later formed ones. This difference is credited to the early transformation of austenite regions having lower carbon content. Also, it was noticed that the final carbon content dissolved in martensite reduced compared to carbon in austenite before quenching. This reduction was attributed to the auto-tempering effect.

In Situ Phosphorus-Doped Poly-Si by Low Pressure Chemical Vapor Deposition for Passivating Contacts

2020 ◽  
Author(s):  
Meric Firat ◽  
Hariharsudan Sivaramakrishnan Radhakrishnan ◽  
Maria Recaman Payo ◽  
Filip Duerinckx ◽  
Rajiv Sharma ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Low Pressure ◽  
Pressure Chemical ◽  
Phosphorus Doped

scholarly journals Springtime daily variations in lower-tropospheric ozone over east Asia: the role of cyclonic activity and pollution as observed from space with IASI

2015 ◽  
Vol 15 (18) ◽  
pp. 10839-10856 ◽  
Author(s):  
G. Dufour ◽  
M. Eremenko ◽  
J. Cuesta ◽  
C. Doche ◽  
G. Foret ◽  
...  
Keyword(s):  
Carbon Monoxide ◽  
East Asia ◽  
Tropospheric Ozone ◽  
North China Plain ◽  
North China ◽  
Low Pressure ◽  
The North ◽  
The North China Plain ◽  
Co Observations ◽  
Low Pressure Systems

Abstract. We use satellite observations from IASI (Infrared Atmospheric Sounding Interferometer) on board the MetOp-A satellite to evaluate the springtime daily variations in lower-tropospheric ozone over east Asia. The availability of semi-independent columns of ozone from the surface up to 12 km simultaneously with CO columns provides a powerful observational data set to diagnose the processes controlling tropospheric ozone enhancement on synoptic scales. By combining IASI observations with meteorological reanalyses from ERA-Interim, we develop an analysis method based only on IASI ozone and CO observations to identify the respective roles of the stratospheric source and the photochemical source in ozone distribution and variations over east Asia. The succession of low- and high-pressure systems drives the day-to-day variations in lower-tropospheric ozone. A case study analysis of one frontal system and one cut-off low system in May 2008 shows that reversible subsiding and ascending ozone transfers in the upper-troposphere–lower-stratosphere (UTLS) region, due to the tropopause perturbations occurring in the vicinity of low-pressure systems, impact free and lower-tropospheric ozone over large regions, especially north of 40° N, and largely explain the ozone enhancement observed with IASI for these latitudes. Irreversible stratosphere–troposphere exchanges of ozone-rich air masses occur more locally in the southern and southeastern flanks of the trough. The contribution to the lower-tropospheric ozone column is difficult to dissociate from the tropopause perturbations generated by weather systems. For regions south of 40° N, a significant correlation has been found between lower-tropospheric ozone and carbon monoxide (CO) observations from IASI, especially over the North China Plain (NCP). Considering carbon monoxide observations as a pollutant tracer, the O3–CO correlation indicates that the photochemical production of ozone from primary pollutants emitted over such large polluted regions significantly contributes to the ozone enhancements observed in the lower troposphere via IASI. When low-pressure systems circulate over the NCP, stratospheric and pollution sources play a concomitant role in the ozone enhancement. IASI's 3-D observational capability allows the areas in which each source dominates to be determined. Moreover, the studied cut-off low system has enough potential convective capacity to uplift pollutants (ozone and CO) and to transport them to Japan. The increase in the enhancement ratio of ozone to CO from 0.16 on 12 May over the North China Plain to 0.28 over the Sea of Japan on 14 May indicates photochemical processing during the plume transport.

scholarly journals Indian Monsoon Low-Pressure Systems Feed Up-and-Over Moisture Transport to the Southwestern Tibetan Plateau

2017 ◽  
Vol 122 (22) ◽  
pp. 12,140-12,151 ◽  
Author(s):  
Wenhao Dong ◽  
Yanluan Lin ◽  
Jonathon S. Wright ◽  
Yuanyu Xie ◽  
Fanghua Xu ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Moisture Transport ◽  
Indian Monsoon ◽  
Low Pressure ◽  
Low Pressure Systems
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