نتایج جستجو برای: cumulonimbus (cb) thunderstorm cloud. often low

تعداد نتایج: 1707458  

Journal: :فیزیک زمین و فضا 0
سحر تاج بخش سازمان هواشناسی کشور- دکتری پروین غفاریان دانشگاه آزاد اسلامی ، واحد علوم و تحقیقات- دانشجوی دکتری ابراهیم میرزایی سازمان هواشناسی کشور- کارشناس ارشد

thunderstorm is one of the most dangerous phenomena in aviation because the greatest number weather hazards such as icing, turbulence, wind shear, lightning hail are combined in one single source, the thunderstorm. spatial characteristics of thunderstorms which can be associated with irreparable outcomes are known by most of the forecasters. tornadoes, microbursts, very strong winds and flash f...

1965
Tetsuya Fujita

An attempt is made to explain the mechanism of a hook-echo formation on the southwestern cdgc of an eastward-moving cumulonimbus cell. The conditions necessary for originating a hook-echo circulation through this proposed mechanism are: significant absolute vorticity within the subcloud layer, intcn,se updraft to bring the low-level moist air into the cloud, and a vertical wind shear which stee...

2007
D. Rosenfeld M. Fromm J. Trentmann G. Luderer M. O. Andreae

A fire storm that occurred on 28 May 2001 and devastated the town of Chisholm, ∼150 km north of Edmonton, Alberta, induced a violent fire-invigorated cumulonimbus cloud. This pyro-cumulonimbus (pyro-Cb) had overshooting tops of 2.5–3 km above the tropopause, and injected massive amounts of smoke into the lower stratosphere. Fortunately, this event occurred under good coverage of radar, rain gau...

2014
Yu Liu Zhao-Liang Li

Although cumulonimbus (Cb) clouds are the main source of precipitation in south China, the relationship between Cb cloud characteristics and precipitation remains unclear. Accordingly, the primary objective of this study was to thoroughly analyze the relationship between Cb cloud features and precipitation both at the pixel and cloud patch scale, and then to apply it in precipitation estimation...

2012

As a thunderstorm approaches a fixed asset (90% of the time) where people are located, VHF cloud lightning mapping provides 10s of minutes of lead time before the first cloud-to-ground strokes reach this asset. At times when a thunderstorm develops directly over the fixed asset (~10% of the time), the cloud flash detection efficiency exceeding 90% maximizes lead time during thunderstorm growth ...

2010
R. Vishnu Murali Das S. Sampath Mohan Kumar

In India, Kerala state is known to have relatively high lightning incidence. The nature of spatial and temporal distribution of past incidents, type of thunderclouds which cause lightning, the topography, proximity to a mountain range and sea point to the possibility of the mountain weather aiding in Cb formation. For investigating the role of mountain weather in convective Cb formation a field...

Journal: :جغرافیا و مخاطرات محیطی 0
علی اکبر رسولی علی محمد خورشید دوست مجتبی فخاری واحد

1. introduction thunderstorms or lightning storms are kinds of storms that generally are associated with the convective clouds and usually are resulted in hailing, strong winds, and flash floods. clouds of convective storms are observed in most regions, but a small percentage of the convective storms can produce severe weather conditions and flash floods that cause damages. a flash flood is a d...

2002
Steven C. Sherwood Steven Platnick G. T. Arnold

It is of considerable importance to understand the impacts (if any) of aerosols and other atmospheric constituents on clouds. These impacts may include modification of the optical properties, coverage, dynamical behavior, and/or hydrological role of clouds. The most basic variables that must be measured in order to make progress are cloud coverage, optical thicknesses, and size distributions of...

1997
Robert A. Houze

It was once generally thought that stratiform precipitation was something occurring primarily, if not exclusively, in middle latitudes—in baroclinic cyclones and fronts. Early radar observations in the Tropics, however, showed large radar echoes composed of convective rain alongside stratiform precipitation, with the stratiform echoes covering great areas and accounting for a large portion of t...

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