scholarly journals The severe thunderstorm of 5th April, 2010 at Guwahati airport : An observational study

MAUSAM ◽  
2021 ◽  
Vol 65 (1) ◽  
pp. 99-102
Author(s):  
SUNIT DAS ◽  
C.S. TOMAR ◽  
R.K. GIRI ◽  
K. BHATTACHARJEE ◽  
B. BARMAN

During the afternoon of 5th April, 2010, a thunderstorm swept across Guwahati Airport (Lat. 26º26´, Long 91º35´) and neighborhood from northwest direction. Strong squally winds (reaching up to 49 knots) and high intensity rain (11mm in 15 minutes) were registered accompanying the storm. One person was killed by the falling tree due to squally winds and several others were injured by the event. The observed evolution of temperature, humidity, wind and pressure at Guwahati Airport, as well as the sequence of satellite and radar images, revealed the presence and movement of convective cells. An observational analysis of the event has been given in this paper. The aim of the study is to contribute to the characterization of these events by analyzing the observational information available. The diagnosis is aimed at helping forecasters to identify this kind of organized deep convective events and being able to issue timely warnings. The synoptic scenario shows warm and moist advection from the Bay of Bengal in low levels over Northeastern region of India and an upper-level north-south trough running from Sub-Himalayan West Bengal to north Orissa. This situation is known to be favorable for development of severe convection over Northeastern region of India during pre-monsoon season.

2014 ◽  
Vol 142 (9) ◽  
pp. 3061-3080 ◽  
Author(s):  
Richard H. Johnson ◽  
Russ S. Schumacher ◽  
James H. Ruppert ◽  
Daniel T. Lindsey ◽  
Julia E. Ruthford ◽  
...  

The meteorological conditions associated with the rapid intensification and spread of the catastrophic Waldo Canyon fire on 26 June 2012 are studied. The fire caused two fatalities, destroyed 347 homes in Colorado Springs, and resulted in insurance losses of nearly $0.5 billion (U.S. dollars), making it the most economically destructive fire in Colorado’s history. While the fire was first discovered on 23 June, the paper focuses on 26 June, when it grew explosively and rapidly advanced eastward into a heavily populated area on the west side of Colorado Springs. Near-record hot and dry conditions prevailed over the Intermountain West prior to the fire, along with a persistent upper-level ridge. On 26 June, a narrow tongue of moist air aloft originating over the Southwest shifted from Utah into Colorado. Dry conditions at low levels and moisture aloft set the stage for strong microburst-producing thunderstorms to develop over Colorado. Convective cells first formed at midday over the San Juan Mountains, later consolidating into a thunderstorm complex that produced an organized convective outflow with strong, gusty winds at the surface. The leading gust front associated with the outflow moved past the Waldo Canyon fire at the hottest time of the day with recorded wind gusts up to 26 m s−1. The rapid eastward advance of the fire, as well as an onset of pyrocumulonimbus and lightning activity, was timed with the passage of the gust front. A numerical simulation, initiated one day earlier, produced mesoscale features closely resembling those observed, including the gust front passage at the fire and the vertical structure of the convective outflow.


Author(s):  
Juho Lehmusto ◽  
Anton V. Ievlev ◽  
Ercan Cakmak ◽  
James R. Keiser ◽  
Bruce A. Pint

AbstractSeveral modern power production systems utilize supercritical CO2 (sCO2), which can contain O2 and H2O as impurities. These impurities may degrade the compatibility of structural alloys through accelerated oxidation. However, it remains unclear which of these impurities plays a bigger role in high-temperature reactions taking place in sCO2. In this study, various model and commercial Fe‐ and Ni‐based alloys were exposed in 300 bar sCO2 at 750 °C to low levels (50 ppm) of O2 and H2O for 1,000 h. 18O-enriched water was used to enable the identification of the oxygen source in the post-exposure characterization of the samples. However, oxygen from the water did not accumulate in the scale, which consisted of Cr2O3 in the cases where a protective oxide formed. A 2wt.% Ti addition to a Ni-22%Cr model alloy resulted in the formation of thicker oxides in sCO2, while a 1wt.% Al addition reduced the scale thickness. A synergistic effect of both Al and Ti additions resulted in an even thicker oxide than what was formed solely by Ti, similar to observations for Ni-based alloy 282.


2011 ◽  
Vol 17 (5) ◽  
pp. 907-909 ◽  
Author(s):  
Vidya A. Arankalle ◽  
Bhaswati T. Bandyopadhyay ◽  
Ashwini Y. Ramdasi ◽  
Ramesh Jadi ◽  
Dilip R. Patil ◽  
...  

1988 ◽  
Vol 15 (2) ◽  
pp. 81-84 ◽  
Author(s):  
E. M. Ahmed ◽  
J. A. Applewhite

Abstract Florunner peanut seeds contained five trypsin isoinhibitors. Amino acid profiles of the trypsin inhibitors fraction showed high levels of aspartic acid, half-cystine and serine and low levels of histidine and tyrosine. The molecular weight of the inhibitor was 8.3 KDa. The presence of multiforms of this inhibitor, its low molecular weight and the high amount of half-cystine indicate that peanut trypsin inhibitor is of the Bowman-Birk type.


2013 ◽  
Vol 28 (5) ◽  
pp. 1241-1260 ◽  
Author(s):  
Clotilde Augros ◽  
Pierre Tabary ◽  
Adrien Anquez ◽  
Jean-Marc Moisselin ◽  
Pascal Brovelli ◽  
...  

Abstract An algorithm for the detection of horizontal wind shear at low levels was developed. The algorithm makes use of data collected by all radars from the Application Radar à la Météorologie Infra-Synoptique (ARAMIS) operational network, in order to build a complete mosaic of wind shear over metropolitan France. The product provides an estimation of the maximum horizontal wind shear detected in the low levels, between 0 and 2 km AGL. Examination of the wind shear mosaic for different cases shows that the product is able to retrieve small-scale wind shear signatures that can be linked to either convergence lines ahead of convective cells, which are indicative of gust fronts, or strong convergence areas inside intense cells. A statistical evaluation of the wind shear mosaic was performed, by comparing horizontal wind shear observed inside the area defined by convective objects with wind gusts recorded along their trajectory by weather stations. A link between those different observations was clearly established. Therefore, the use of wind shear for wind gust prediction was tested in combination with other parameters: an estimation of the energetic potential of density currents, the cell surface with reflectivity over 51 dBZ, relative helicity, and cell propagation speed. Different wind gust warning rules were tested on 468 convection nowcasting objects (CONOs). The results clearly highlighted the benefits of using wind shear for wind gust estimation, and also demonstrated the improvement in forecasting skill when combining different parameters. The wind shear mosaic will be produced operationally before the end of 2013 and will be used to improve wind gust warnings provided to end users.


Author(s):  
Mrityunjay Ghosh ◽  
S. Dolui ◽  
B. Das ◽  
K. Roy ◽  
D. MaryPyngrope ◽  
...  

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