scholarly journals Structure and properties of summer monsoon stationary B,"Operational use of Ozone over .southern Asia: an observational study

MAUSAM ◽  
2021 ◽  
Vol 47 (2) ◽  
pp. 133-144
Author(s):  
SURANJANA SARA ◽  
K.R. SAHA
Keyword(s):  
Phase Difference ◽  
Stationary Wave ◽  
Direct Conversion ◽  
Temperature Fields ◽  
Physical Factors ◽  
The West ◽  
Meridional Component ◽  
Cold Air ◽  
Thermal Advection ◽  
Southern Asia

A study of ten-year (1976-1985) mean July climatology of southern Asia and adjoining ocean areas confirms the presence of a well-defined stationary wave, believed to be due mainly to land-sea thermal contrast over the region, in the fields of several meteorological variables. The wave extends laterally over about 10 degrees of latitude with maximum intensity along about 20° N and vertically from surface to about 300 hPa. Its zonal wavelength is about 2000-2500 km and its amplitude in the field of zonal anomaly of temperature and meridional component of wind is 1 oC and 4ms-l respectively. The trough-ridge system of the wave appears to tilt eastward with height from surface to about 700 hPa and westward aloft up to about 300 hPa, while the warmest-coldest anomaly system appears to tilt eastward all the way from surface to about 300 hPa. A phase difference appears to exist between the geopotential and the temperature fields in both the lower and the upper tropospheres. The aforesaid zonal-vertical tilt of the monsoon trough and phase difference between the geopotential and the temperature fields appears to be compatible, through thermal advection, With a direct conversion of eddy available potential energy into eddy kinetic energy via a west-east (clockwise) overturning with warm air rising in the west and cold air sinking in the east in the case of the eastward-tilting lower-tropospheric trough and an east-west (anti-clockwise) overturning with warm air rising in the east and cold air sinking in the west in the case of the westward-tilting middle and upper-tropospheric trough, An enhancement of the thermal advection and hence the vertical circulation may occasionally lead to development of the trough into a I(JW or depression. However, the question of development of the trough and physical factors, which may contribute to such development, needs to be examined by further study.

Observed mesoscale patterns in the irrigated Eastern Ebro basin

2021 ◽  
Author(s):  
Antoni Grau Ferrer ◽  
Mª Antònia Jiménez Cortés ◽  
Daniel Martínez Villagrasa ◽  
Joan Cuxart Rodamilans
Keyword(s):  
Sea Breeze ◽  
Research Data ◽  
Ebro Basin ◽  
The West ◽  
Cold Air ◽  
Late Afternoon ◽  
Mountain Ranges ◽  
The North ◽  
Marine Air ◽  
Filtering Procedure

<p>The Eastern Ebro basin is composed of an extensive lower irrigated area, surrounded by dry-fed slopes and wooden mountain ranges to the North, East and South, while to the West is open to the agricultural Western Ebro basin. Previous studies, based on research data or on statistics for one station, indicate that these features determine the local circulations in the area. A network of stations is used here to analyze a period of 15 years, taking representative data for the different units of landscape. A filtering procedure is developed which selects the events with predominance of local circulations, based on detecting stably stratified nights.</p><p>The analysis of the filtered data indicates the presence of a valley circulation between the lower plain and the slopes and mountains that reverses its sense of circulation between day and night, which intensity varies in summer due to an increasing thermal contrast between irrigated and rain-fed areas. The presence of sea-breeze in the late afternoon in the warm months is common, bringing cooler and wetter marine air to the area after crossing the mountain range at the South. At night in the centre of the basin, cold air pools are formed, which evolve to persistent fog events in winter, causing the statistics to be very different in that season compared to the rest of the year.</p>

scholarly journals Effect of heater size on heat transfer in a falling liquid film

2021 ◽  
pp. 50-55
Author(s):  
В.В. Кузнецов
Keyword(s):  
Heat Transfer ◽  
Three Dimensional ◽  
Analytical Formula ◽  
Temperature Fields ◽  
Maximum Temperature ◽  
Physical Factors ◽  
Thermocapillary Effect ◽  
Average Value ◽  
Surface Deformations ◽  
Falling Liquid Film

Проведены расчеты полей скорости и температуры, а также положение границы раздела жидкость-газ при стекании тонкой пленки жидкости по плоской подложке, наклоненной к горизонту. На подложке расположен нагреватель квадратной формы, мощность которого фиксирована, а размеры варьировались в ходе расчетов:- одним из перспективных методов отвода высоких тепловых потоков от электронного оборудования являются технологии, использующие тонкие пленки жидкости, движущиеся по охлаждаемой поверхности. Целью работы было исследование зависимости динамики и теплообмена в пленки от размера нагревателя;- на основе разработанной трехмерной нестационарной модели движения проведены расчеты теплообмена в движущейся поенке. При этом учитывалось действие всех основных физческих факторов при их взаимодействии: диффузионный и конвективный теплопереносы, зависимость вязкости от температуры, термокапиллярный эффект, появление и эволюция поверхностных деформаций;- установлено, что размер нагревателя существенно влияет на поля температуры и поверхностные деформации, а также на значение температурных экстремумов. Выведена аналитическая формула для расчета наибольшего достигаемого на подложке превышения температуры её среднего значения;- результаты могут применяться при проектировании систем охлаждения электронного оборудования. On the basis of the developed three-dimensional non-stationary model of motion, calculations of heat transfer in a moving roll were carried out. In this case, the action of all the main physical factors during their interaction was taken into account: diffusion and convective heat transfer, the dependence of viscosity on temperature, the thermocapillary effect, the appearance and evolution of surface deformations.  it was found that the size of the heater significantly affects the temperature fields and surface deformations, as well as the value of temperature extremes. An analytical formula is derived for calculating the maximum temperature rise attainable on the substrate of its average value.

scholarly journals Cold-Air Pool Processes in the Inn Valley During Föhn: A Comparison of Four Cases During the PIANO Campaign

2021 ◽  
Author(s):  
Maren Haid ◽  
Alexander Gohm ◽  
Lukas Umek ◽  
Helen C. Ward ◽  
Mathias W. Rotach
Keyword(s):  
Temporal Variability ◽  
Flow Instability ◽  
Heat Budget ◽  
Comprehensive Analysis ◽  
City Centre ◽  
The West ◽  
Cold Air ◽  
Spatio Temporal ◽  
Shear Flow Instability ◽  
The City

AbstractWe present a comprehensive analysis of four south föhn events observed during the Penetration and Interruption of Alpine Foehn (PIANO) field campaign in the Inn Valley, Austria, in the vicinity of Innsbruck. The goal is to detect and quantify processes of cold-air pool (CAP) erosion by föhn as well as processes of föhn breakdown. Despite differences in föhn breakthrough and strength, the four cases exhibit similarities in CAP evolution: initially, the CAP experienced strongest warming in the centre of Innsbruck, where the föhn jet from the Wipp Valley interacted with the CAP in the Inn Valley. The resulting shear-flow instability at the föhn–CAP interface caused turbulent CAP erosion and, together with vertical warm-air advection, led to CAP depression over the city centre. This depression drove pre-föhn westerlies near the surface that caused cold-air advection inside the CAP west of the city centre and warm-air advection in the east. Ultimately, the latter contributed to stronger CAP erosion in the east than in the west. This stronger heating also explains the preferential initial föhn breakthrough at the valley floor east of Innsbruck. In two of the cases, subsequent westward propagation of the föhn–CAP boundary across the city accompanied by northerly (deflected) föhn winds led to a complete föhn breakthrough. Föhn breakdown occurred either by a backflow of the CAP remnant or by a cold-frontal passage. This study emphasizes the importance of both turbulence and advection in the CAP heat budget and reveal their large spatio–temporal variability.

A brief account of the hibiscus mealybug Maconellicoccus hirsutus (Hemiptera: Pseudococcidae), a pest of agriculture and horticulture, with descriptions of two related species from southern Asia

1996 ◽  
Vol 86 (5) ◽  
pp. 617-628 ◽  
Author(s):  
D.J. Williams
Keyword(s):  
South America ◽  
Related Species ◽  
West Indies ◽  
Food Crops ◽  
The West ◽  
Maconellicoccus Hirsutus ◽  
Southern Asia ◽  
The Usa ◽  
Plant Produce ◽  
Extensive Damage

AbstractThe mealybug Maconellicoccus hirsutus (Green) occurs in many tropical and subtropical parts of the Old World and extends into some temperate areas. It has now reached the West Indies where it is causing extensive damage to plants. There is concern that it may be introduced to the southern USA and to Central and South America. A brief account is given of reported damage caused by M. hirsutus to some commercial and food crops in Asia and Africa and the species is redescribed. M. multipori (Takahashi), now known from a wide area in southern Asia, is redescribed, and M. ramchensissp. n. from Nepal, is described as new. These two species are closely related to M. hirsutus and can easily be mistaken for it. M. hirsutus and M. multipori are sometimes intercepted at quarantine inspection of plants and plant produce in the USA and Europe. In order to aid identification, a key is provided to the eight species presently included in the genus Maconellicoccus Ezzat.

scholarly journals The Cold Avoidance of Typhoons in Their North Turning Over the South China Sea

2021 ◽  
Vol 9 ◽  
Author(s):  
Shaojun Lai ◽  
Ying Li ◽  
Fen He ◽  
Yufei Wang ◽  
Yan Chen
Keyword(s):  
South China Sea ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
South China ◽  
The South China Sea ◽  
Sea Surface ◽  
The South ◽  
The West ◽  
Cold Air ◽  
Westerly Trough

Based on the typhoon best tracks of the China Meteorological Administration (CMA), ERA5 reanalysis data of ECMWF at 0.25 degrees horizontal resolution, and NOAA optimal interpolated sea surface temperature (OISST V2) data, the dynamical compositing analysis is used to study the north turning at nearly 90 degrees of 4 westward typhoons over the South China Sea (SCS). The composite analysis results show that: (1) As the typhoon goes westward into the SCS, the upper-level westerly trough moves eastward to the vicinity of 110°E in the mainland of China, and the western North Pacific subtropical high (SH) retreats eastward at the same time, which weakens the steering flow of typhoon and slowes down its movement. (2) The cold air guided by the westerly trough invades southwardly into the western part of SCS from the mainland leading to a descending and divergent airflow in the lower-to-middle atmospheric layers and enhancing the eastward pressure gradient force (PGF) in the west quadrant of the typhoon, which blocks and repesl the typhoon from moving any further westward. (3) Due to the cold air intrusion, the vertical atmospheric stratification in the west quadrant of the typhoon becomes static and stable, which may suppress the convection, impeding a typhoon’s westward motion. (4) With the cold air involving to the south of the typhoon, the direction of the PGF on the typhoon switches from eastward to northward, and the SH falling southward enhances the southwesterly airflow on the south of the typhoon at the same time. The remarkable increase of the northward steering airflows of the typhoon results in an abrupt northward turn. (5) In addition, the sea surface temperature (SST) and the ocean heat content (OHC) on the western part of the SCS is also reduced, attributed to the cold air cooling, and the typhoon is likely to avoid the cold ocean and approach a relatively warmer region. This study suggests that cold avoidance during the westward movement of typhoons is worthy of consideration in the operational forecast of typhoon tracks.

The rate of stationary wave of filtration combustion of gases in the same fields of temperature and concentration

2017 ◽  
Vol 12 (1) ◽  
pp. 27-32
Author(s):  
M.M. Kabilov ◽  
P.B. Sadriddinov ◽  
B.J. Gulboev ◽  
O.A. Kholov
Keyword(s):  
Wave Velocity ◽  
Stationary Wave ◽  
Equilibrium Temperature ◽  
Characteristic Size ◽  
Injection Rate ◽  
Temperature Fields ◽  
Inert Porous Medium ◽  
Combustion Of Gases ◽  
The Relationship ◽  
Combustion Of Hydrogen

Combustion of hydrogen-methane-air mixtures of gases in an inert porous medium is considered when the temperature fields of the medium end the concentration of the missing component of the mixture are similar. The relationship between the functions of temperature and concentration, as well as the equation for the numerical calculation of the temperature distribution, are obtained. Numerical calculations were made for different compositions of the hydrogen-methane-air mixture of gases and their effects on the wave velocity were determined. Dependences of the wave velocity, the equilibrium temperature, the characteristic size of the combustion zone, and the diffusion coefficient of the missing component on the gas injection rate are studied.

scholarly journals Low-Frequency Variability and Evolution of North American Cold Air Outbreaks

2006 ◽  
Vol 134 (2) ◽  
pp. 579-597 ◽  
Author(s):  
Diane H. Portis ◽  
Michael P. Cellitti ◽  
William L. Chapman ◽  
John E. Walsh
Keyword(s):  
Rocky Mountains ◽  
Low Frequency ◽  
The West ◽  
Air Mass ◽  
Cold Air ◽  
Air Masses ◽  
Horizontal Advection ◽  
Vertical Advection ◽  
Low Frequency Variability ◽  
Diabatic Processes

Abstract Hourly data from 17 relatively evenly distributed stations east of the Rocky Mountains during 54 winter seasons (1948/49 through 2001/02) are used to evaluate the low-frequency variability of extreme cold air outbreaks (CAOs). The results show no overall trend in CAO frequency, despite an increase in mean temperature over the Midwest and especially upstream into the CAO formation regions of high-latitude North America. However, there are regionally based trends in the intensity of long-duration (5 day) CAOs. Daily heat budgets from reanalysis data are also used to investigate the thermodynamic and dynamic processes involved in the evolution of a subset of the major CAOs. The cooling of the air masses can be generally traced in the heat budget analysis as the air masses track southward along the Rocky Mountains into the Midwest. The earliest cooling begins in northwestern Canada more than a week before the cold air mass reaches the Midwest. Downstream in southwestern Canada, both diabatic and advective processes contribute to the cumulative cooling of the air mass. At peak intensity over the Midwest, diabatic processes and horizontal advection cool the air mass, but warming by subsidence offsets this cooling. By contrast, to the west of the CAO track into the Midwestern United States, vertical advection by orographic lifting cumulatively cools the air in the upslope flow regime associated with the low-level airflow around a cold air mass, and this cooling is offset by diabatic warming. Diabatic processes have strong positive correlations with temperature change over all regions (especially in central Canada) except for the mountainous regions in the United States that are to the west of the track of the cold air mass. Correlations of vertical advection with horizontal advection and diabatic processes are physically consistent and give credibility to the vertical advection field.

The Role of Savings and Wealth in Southern Asia and the West.

1965 ◽  
Vol 30 (2) ◽  
pp. 311
Author(s):  
Cyril S. Belshaw ◽  
Richard D. Lambert ◽  
Bert F. Hoselitz
Keyword(s):  
The West ◽  
Southern Asia

Heat Transfer Augmentation in an Oscillating Flow

2002 ◽  
Author(s):  
A. Holst ◽  
E. Lundgren ◽  
U. Marksten
Keyword(s):  
Heat Transfer ◽  
Phase Difference ◽  
Temperature Fields ◽  
Oscillating Flow ◽  
Parallel Plates ◽  
Governing Equations ◽  
Special Flow ◽  
Heat Transfer Augmentation ◽  
Pulse Combustor ◽  
Temperature Oscillations

For combustors a heat transfer augmentation of two to five times higher than expected has been reported. Experiments, where the temperature profile in the tail pipe of the pulse combustor has been measured, give no indication why the heat transfer should be augmented. The objective is to study the heat transfer of an oscillating flow between two parallel plates. A set of governing equations is formulated from first principles. Analytical solutions can then be obtained for both the velocity and temperature fields for the special flow considered. The heat conduction vector can so be determined and the heat transfer at the plates over one cycle is found to be dependent of the frequency of the oscillations as well as the phase difference between the pressure and temperature oscillations. From the analysis it is found that for certain intervals of the phase difference and the frequency of the oscillations an augmented heat transfer can be found. This means that an augmented heating (or cooling) process can be arranged in a steady flow by superimposing oscillations.

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