scholarly journals Some climatological aspects of thunderstorms and squalls over Guwahati Airport

MAUSAM ◽  
2021 ◽  
Vol 57 (2) ◽  
pp. 231-240
Author(s):  
GAJENDRA KUMAR ◽  
M. MOHAPATRA
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Frequency Distribution ◽  
Environmental Temperature ◽  
Environmental Changes ◽  
Monsoon Season ◽  
Early Morning ◽  
Maximum Wind ◽  
The Past ◽  
Average Maximum

Lkkj & xqokgkVh gokbZ vM~Ms ij vk, paMokr ls tqM+s okf"kZd vkSj ekfld ckjEckjrk dk forj.k] xtZ ds lkFk vk, rwQkuksa  vkSj paMokrksa ds vkjEHk gksus dk le; vkSj mudh vof/k rFkk i;kZoj.kh; ifjorZuksa dk fo’ys"k.k fd;k x;k gSA rwQku vkSj paMokr lcls T;knk ebZ ds eghusa esa vkrs gSa vkSj mlds ckn viSzy ds eghus esa vkrs gSaA rwQkuksa vkSj paMokrksa dh vko`fr;k¡ lcls T;knk ebZ ds eghusa esa gksrh gSa vkSj mlds ckn vizSy ds eghus esa gksrh gSaA vf/kdk¡’k rwQku ekulwu _rq ls iwoZ vkSj ekulwu _rq ds nkSjku vkrs gSa rFkk paMokr Qjojh ls ebZ ds eghuksa ds nkSjku vkrs gSaA ekulwu _rq ls iwoZ vkus okys vf/kdk¡’k rwQku e/; jkf= ls ysdj rM+ds lqcg ds le; esa vkrs gSa tcfd ekulwu _rq ds nkSjku vkus okys rwQku 0600&1200 ;w- Vh- lh- ds chp vk;k djrs gSa  vf/kdk¡’k rwQkuksa dh vof/k rhu ?kaVksa ls Hkh de dh gksrh gSA vf/kdk¡’k paMokrksa dh vof/k pkj feuVksa ls Hkh de dh gksrh gS] fn’kk mÙkj if’pe vkSj ;s 0900&2100 ;w- Vh- lh- ds le; vkrs gSaA xqokgkVh gokbZ vM~Ms ij paMokr ds vkus ls i;kZoj.kh; rkieku vkSlru 2-2° lsa- rd fxj tkrk gS] lkisf{kd vknzZrk 8-5 izfr’kr rd c<+ tkrh gS vkSj nkc 1-6 gSDVkikLdy rd c<+ tkrk gSA xqokgkVh gokbZ vM~Ms ij paMokr ds vkus ls vf/kdre iou xfr vkSlru yxHkx 39 ukWV~l gksrh gSA fiNys v/;;uksa ls rqyuk djus ij ;g irk pyrk gS fd fiNys dqN o"kksZa esa rQkuksa vkSj paMokrksa ds y{k.kksa esa fo’ks"k ifjorZu ugha vk;k gSA  The annual and monthly frequency distribution, time of commencement and duration of thunderstorms & squalls and environmental changes associated with occurrence of squall at Guwahati Airport have been analyzed. The frequencies of thunderstorms and squalls are maximum in the month of May followed by April. Most of the thunderstorms occur during premonsoon and monsoon season and squalls occur during Feb-May. Most of the premonsoon thunderstorms commence during midnight to early morning while the thunderstorms during monsoon season have preference to commence between 0600-1200 UTC. Majority of thunderstorms is of the duration of less than three hours. Majority of squalls have the duration of less than four minutes, direction as northwesterly and occur during 0900-2100 UTC. On the average, environmental temperature falls by 2.2° C, the relative humidity rises by 8.5%, and the pressure increases by 1.6 hPa due to squall over Guwahati Airport. The average maximum wind speed associated with a squall over Guwahati Airport is about 39 knots. Comparison with the past studies indicates that characteristics of thunderstorms and squalls have not changed significantly over the years.

scholarly journals Characteristics of thunderstorms and squalls over Indira Gandhi International (IGI) airport, New Delhi - Impact on environment especially on summer’s day temperatures and use in forecasting

MAUSAM ◽  
2021 ◽  
Vol 60 (4) ◽  
pp. 461-474
Author(s):  
R. K. JENAMANI ◽  
R. C. VASHISTH ◽  
S. C. BHAN
Keyword(s):  
Wind Speed ◽  
Environmental Changes ◽  
Maximum Wind Speed ◽  
Maximum Temperature ◽  
Daily Maximum Temperature ◽  
Daily Maximum ◽  
Peak Time ◽  
New Delhi ◽  
Maximum Wind ◽  
Average Maximum

In the present study, commencement timings and duration of thunderstorms (TS) and squalls at IGI airport, Palam, New Delhi have been analysed critically based on most recent eleven years data of 1995-2005 to find their favourable time of occurrences. Then utility of such data base in the aviation warning has been demonstrated. Environmental changes associated with these squalls have also been further analysed to understand their impact. Being recent May 2007 a very cool month over Delhi, the role of TS on controlling the day’s soaring temperature has also been studied from their data.  Results show TS are maximum in June followed by July whereas squalls are maximum in May followed by June. It shows more than 80% of TS in each season are of duration less than 3 hours with remaining are mostly 3 to 6 hours. The peak time period of commencement of both TS and squalls in the day differ with the progress of the months. For pre monsoon months, the most favourable timing of TS and squalls are 1200-1500 UTC while for monsoon, it starts earlier. Around 37% of the total TS during the period were associated with squalls. The average maximum wind speed in squall at IGI airport is about 68 kmph with highest maximum wind speed 139 kmph. On an average the environmental temperature falls by 5.6° C, humidity levels rises by 17.8% and mean sea level pressure rises by 1.6 hPa due to the occurrences of squalls. Study also shows daily maximum temperature rise is highly controlled by TS occurrences and May 2007, being a month of highest TS occurrences at the airport since 1995, became one of the coolest month in May over Delhi. The comparison of TS frequencies shows 12% increase in their annual activities since 1950-1980 with very high unusual increase of 51% in June and 26% in May. Since analysis of data from 1995 shows occurrences of TS are reversely but strongly correlated with summer temperatures and longer period temperature data since 1975 also confirms absence of significant trend in maximum temperature and higher temperature days in peak summer months of May and June till recent as expected due to high pollution, global warming and fast urbanization in the city, so it is the higher number of TS occurrences over the region from time to time which might have been main factor for controlling its significant rise.

Assessment of Weather and Climate-Related Risks to Human Health in Different Areas of the Krasnoyarsk Region

2021 ◽  
pp. 61-66
Author(s):  
DA Narutdinov ◽  
RS Rakhmanov ◽  
ES Bogomolova ◽  
SA Razgulin
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Human Health ◽  
Minimum Temperature ◽  
Temperate Climate ◽  
Maximum Wind ◽  
Average Wind ◽  
Weather And Climate ◽  
Effective Temperatures ◽  
Temperate Climates

Introduction: Extreme climate conditions have a negative impact on human health. Purpose: The study aimed to assess weather and climate-related risks to human health in different areas of the Krasnoyarsk Region by effective temperatures estimated during two long-term observation periods. Materials and methods: We analyzed ambient temperatures (average monthly and minimum), wind speed (average and maximum), and relative humidity in the subarctic and temperate continental zones estimated during the periods of determining climatic norms in 1961–1990 and 1991–2020. The health risk was assessed on the basis of effective temperatures. Results: In the subarctic zone, the wind strength (average and maximum values) decreased, the duration of such periods increased just like the ambient temperature while the relative humidity did not change. In temperate climates, all indicators have changed. In the subarctic zone, in the second observation period, frostbite was possible within 20–30 minutes during two months (versus 3 in the first). In the temperate climate, there was no such risk to humans. At the minimum temperature and maximum wind speed in the subarctic zone, the risk of frostbite is possible during 5 months (versus 6): after 10–15 minutes during two months and after 20–30 minutes – during three months of the year. In temperate climates, frostbite is possible within 20–30 minutes during two months (versus 3 in the first period). Conclusions: In the interval of establishing climatic norms (1991–2020), a significant increase in effective temperatures was determined: in the subarctic zone with the average wind strength and temperature in February–April and June, with maximum wind and minimum temperature – in March–July; in temperate climates, in April and June, respectively. The duration of periods of health risks posed by cold temperature exposures in the subarctic climate with average wind and temperature values equaled two months (I–II), with maximum wind speed and minimum temperatures – five months (XI–III); in the temperate climate, it was null and 2 (3) months (I, II, and XII), respectively.

DETERMINATION OF THE CORRELATION BETWEEN INDIVIDUAL METEOROLOGICAL VALUES AT THE BEGINNING OF THE DEPOSITION OF ICE ON THE TERRITORY OF UKRAINE BY THE MONTHS OF THE COLD PERIOD OF THE YEAR DURING 2001-2013 AND THEIR SPATIAL DISTRIBUTION

2019 ◽  
pp. 140-151
Author(s):  
S.I. Pyasetska ◽  
N.P. Grebenyuk ◽  
S.V. Savchuk
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Sea Level ◽  
Meteorological Parameters ◽  
Cold Period ◽  
Sea Level Pressure ◽  
Average Maximum ◽  
Average Relative Humidity ◽  
Maximum Minimum

The article presents the results of the study of the determination of the correlation connection between a number of meteorological values at the beginning of the deposition of ice on the wires of a standard ice-cream machine in certain months of the cold period of the year on the territory of Ukraine during 2001-2013. The research was conducted for 3 winter months, as well as for March and November. The pair of meteorological parameters have been determined at the beginning of the deposition of ice that have a statistically significant correlation coefficient and a spatial-temporal distribution of the distribution in certain months across the territory of Ukraine has been obtained. The most common variant of the statistically significant connection between individual meteorological parameters was the connection between the temperature of the water column (average, maximum, minimum) and relative humidity of air (average, maximum). Thus, for almost all months studied, a statistically significant correlation between the temperature of the vapor (average, maximum, minimum) and relative humidity of air (average, maximum) was established. For the winter months, the correlation coefficient of this connection was positive, and for March and November, it was negative. A widespread version of a statistically significant connection was the relationship between the air temperature (average, maximum, minimum) and the height of the snow cover. This connection for the months studied turned out to be negative. The variants of negative statistically significant connection between average wind speed and average relative humidity of air (January-February, December), average and maximum wind speed and sea-level pressure (November), and also between daily amount precipitation and snow (March), daily rainfall and wind speed (average, maximum), and pressure at sea level (November). During the months of the cold period of the year, statistically significant connections between the air temperature (average, maximum) and pressure at sea level (November), wind speed (average, maximum) and average humidity (January, December), pressure on sea levels and average relative humidity (March). Also, there were isolated cases of statistically significant correlation between snow and sea level pressure (December). The most frequently statistically significant connections between meteorological values at the dates of deposition of ice on the wires of a standard icing machine were observed at stations in the central, northeastern, eastern and separate southern regions.

scholarly journals Nor’wester over West Bengal and comfortability

MAUSAM ◽  
2021 ◽  
Vol 58 (2) ◽  
pp. 177-188
Author(s):  
K. K. CHAKRABARTY ◽  
A. K. NATH ◽  
S. SENGUPTA
Keyword(s):  
Relative Humidity ◽  
West Bengal ◽  
Monsoon Season ◽  
Early Morning ◽  
Positive Aspect ◽  
Weather Factors ◽  
Thermal Index ◽  
The People ◽  
Tropical Areas ◽  
Weather Parameters

During the pre-monsoon months of March, April and May the weather over Kolkata is generally very uncomfortable due to high temperature and relative humidity. During this season Kolkata is affected by the nor’wester activity. Generally the nor’wester activity is defined as a disastrous weather activity and is locally called as ‘Kaalbaisakhi’ as it is ‘kaal’ or destruction during Bengali Baishakh (April-May) month over Bengal. However the downdraft associated with the nor’wester brings cool air and temperature sometimes drops by as much as 8 to 9 degree Celsius and the atmosphere becomes comfortable for some period. This is an entirely different and positive aspect of nor’wester.The human comfortability depends upon many weather parameters apart from human physiological parameters. However the primary weather factors are air temperature and relative humidity especially for tropical areas. Many authors have worked on this and the well accepted formula for thermal index THI or Discomfort Index DI is taken from Thom (1957,1958) which is a function of dry bulb and wet bulb temperature i.e., THI or DI = 0.4 (Ta + Tw) + 15 where temperature is in ºF and is 0.72 (Ta + Tw) + 40.6 where temperature is in ºC. Various stages of comfortability are classified viz., (i) Discomfortable (ii) Partial discomfortable and (iii) Comfortable. Neglecting the effect of wind and further simplifying the equation for DI as a function of (Ta + Tw) the range varies from 27 to 55 in increasing order of temperature.During the pre-monsoon months when the climate over Kolkata is very sultry and uncomfortable, people generally desire the onset of nor’wester for some temporary relief although it results into destruction. The nor’wester makes the weather comfortable after its occurrence and remains comfortable for 10 to 12 hours and some time even for a day. The present study is made taking six years data over Kolkata, both Alipore and Dum Dum. It is seen that except early morning of March the remaining period of pre-monsoon season is found to be uncomfortable climatologically. In the present study there were 91 occasions of squalls and it is found that most of the squalls occurred during the month of April and May and on most of the occasions nor’wester made the weather comfortable for a large part of the day in the month of April. By the end of May nor’wester activity also brought relief but not to that extent as in March and April to the people of Kolkata and neighbourhood.

Evapotranspiration Distribution and Variation of Pakistan (1931-2015)

2017 ◽  
Vol 17 (2) ◽  
pp. 184-197 ◽  
Author(s):  
Saifullah Khan ◽  
Mahmood Ul Hasan
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Surface Pressure ◽  
Sunshine Duration ◽  
Monsoon Season ◽  
Winter Season ◽  
Main Element ◽  
Mountainous Region ◽  
Post Monsoon ◽  
Post Monsoon Season

AbstractEvapotranspiration is the main element of aridity and desertification and to balance the natural hydrological processes. Pakistan has a high degree of evapotranspiration, as it is in subtropical belt, with long sunshine duration and low cloudiness in summers. June is the warmest month, when the evapotranspiration exceeds 7mm (0.28inches), whereas, January is the coldest month, when evapotranspiration of the country falls to 1mm (0.04inches). The maximum evapotranspiration has been recorded at the southern latitudes of the country (Hyderabad and Jacobabad), while it decreases towards northwest (mountainous region) and Gilgit-Baltistan (Astore and Skardu). This variation in evapotranspiration is due to fluctuation in temperature, precipitation, sunshine duration, wind speed, relative humidity, physical relief and latitudinal as well as altitudinal extend of the country. The average evapotranspiration of Pakistan is 4.5mm with an increase of 1.0mm during 1931-2015. In winter and summer season, the lower Indus basin, has recorded high evapotranspiration as compared to the northern mountainous region. The average evapotranspiration of Pakistan during winter season is 2.7mm, while in summer it is 6.3mm. This variation is due to the variation in the length of day and night, humidity, precipitation, surface pressure, wind speed, and topography of the land. During cold season the average evapotranspiration of the country is 13.7mm, pre-monsoon season 17.1mm, monsoon season 15.8mm and post monsoon season 8mm. Obviously, the highest evapotranspiration of Pakistan has recorded during pre-monsoon season with extreme temperature, scarce precipitation, long sunshine duration, lowest relative humidity, low pressure, and calm winds and chilly condition. Furthermore, during cold (0.1mm), pre-monsoon (3.5mm), and monsoon season (2.2mm) the evapotranspiration shows an increase, where as it reveals a negative deviation of -5.6mm in post monsoon season due to increase in the precipitation from reversible monsoon lows at the southern latitudes of the country. Generally, the evapotranspiration of Pakistan increases from northwest to southeast and a main agent of delimitation of the arid region of the country. The main factors that cause variation in the evapotranspiration of the country from south towards north are temperature, precipitation, sunshine duration, relative humidity, surface pressure, wind speed, fogs, cloudiness, topography, latitudinal and altitudinal extend of the country that required further research.

scholarly journals Modelling Agro-Met Station Observations Using Genetic Algorithm

2014 ◽  
Vol 2014 ◽  
pp. 1-8
Author(s):  
Prashant Kumar ◽  
Bimal K. Bhattacharya ◽  
C. M. Kishtawal ◽  
Sujit Basu
Keyword(s):  
Genetic Algorithm ◽  
Wind Speed ◽  
Relative Humidity ◽  
Data Fitting ◽  
Prediction Methods ◽  
Training Algorithm ◽  
Near Surface ◽  
The Past ◽  
Forecast Models ◽  
Weather Parameters

The present work discusses the development of a nonlinear data-fitting technique based on genetic algorithm (GA) for the prediction of routine weather parameters using observations from Agro-Met Stations (AMS). The algorithm produces the equations that best describe the temporal evolutions of daily minimum and maximum near-surface (at 2.5-meter height) air temperature and relative humidity and daily averaged wind speed (at 10-meter height) at selected AMS locations. These enable the forecasts of these weather parameters, which could have possible use in crop forecast models. The forecast equations developed in the present study use only the past observations of the above-mentioned parameters. This approach, unlike other prediction methods, provides explicit analytical forecast equation for each parameter. The predictions up to 3 days in advance have been validated using independent datasets, unknown to the training algorithm, with impressive results. The power of the algorithm has also been demonstrated by its superiority over persistence forecast used as a benchmark.

scholarly journals EVALUATION OF HIGH RESOLUTION URBAN LULC FOR SEASONAL FORECASTS OF URBAN CLIMATE USING WRF MODEL

2018 ◽  
Vol IV-5 ◽  
pp. 303-310 ◽  
Author(s):  
M. Bhavana ◽  
K. Gupta ◽  
P. K. Pal ◽  
A. S. Kumar ◽  
J. Gummapu
Keyword(s):  
High Resolution ◽  
Wind Speed ◽  
Relative Humidity ◽  
Urban Area ◽  
Monsoon Season ◽  
Urban Climate ◽  
Urban Morphology ◽  
Climatic Variables ◽  
Seasonal Forecasts ◽  
Post Monsoon

<p><strong>Abstract.</strong> In all mesoscale models with urban parameterizations, urban area represented as a single entity to represent the influence of urban morphology. In the last few years, many Urban Canopy Models (UCM) have been developed by many researchers to model the urban energy fluxes, but their spatial resolution is too coarse. These models proves to be a hindrance in obtaining improved results for urban climatic studies due to their coarser resolution. So downscaling of climatic variables in an urban area is primary significance for urban climatic studies. Weather Research Forecasting Model (WRF) is the one of the models that has been used widely for downscaling the climatic variables at urban scale and it has been also integrated with UCM along with a number of urban sub physics options. In this study, modified high resolution Land Use Land Cover (LULC) representing three urban classes for the city of Chandigarh has been ingested into the model to examine and validate the model output with respect to ground observations. The model has been configured with two domains with a resolution of 3KM and 1KM and simulations were carried out for three days of the of four seasons of India, winter, summer, monsoon and post-monsoon for the analysis of seasonal variation. Improved values of Root Mean Square Error (RMSE) for surface temperature, relative humidity and wind speed was observed with modified high resolution LULC with BEM option as compared to single urban built up class. In terms of temperature, summer season showed very less RMSE than other seasons, i.e, 0.76<span class="thinspace"></span>&amp;deg;C and . In terms of relative humidity, monsoon season showed very less RMSE than other seasons, i.e., 2.63% and in terms of wind speed, post monsoon season is giving less RMSE i.e., 1.01<span class="thinspace"></span>m/s.</p>

The diurnal activity of the chicken-biting black fly, Simulium griseicolle Becker (Diptera, Simuliidae) in Northern Sudan

1976 ◽  
Vol 66 (3) ◽  
pp. 481-487 ◽  
Author(s):  
S. El Bashir ◽  
M. H. El Jack ◽  
H. M. El Hadi
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Light Intensity ◽  
Early Morning ◽  
The Other ◽  
Diurnal Activity ◽  
Black Fly ◽  
Early Afternoon ◽  
Trapping Methods ◽  
Two Peaks

AbstractThe diurnal flight activity of Simulium griseicolle Becker was determined at Shambat, Khartoum, by means of a suction trap and a vehicle-mounted trap; and the biting activity by means of a chicken-baited trap. Only incidental observations of mammal-biting activity were made. The three trapping methods indicated two peaks of activity, one in the morning and the other late in the afternoon. Fly activity was lowest in the early afternoon when temperature and light intensity were highest, wind speed was moderate and relative humidity was least. Females outnumbered males in all the catches, except in the early morning when more males were sometimes recorded.

scholarly journals The radiative impact of out-of-cloud aerosol hygroscopic growth during the summer monsoon in southernWest Africa

2018 ◽  
Author(s):  
Sophie L. Haslett ◽  
Jonathan W. Taylor ◽  
Konrad Deetz ◽  
Bernhard Vogel ◽  
Karmen Babić ◽  
...  
Keyword(s):  
Optical Properties ◽  
Chemical Composition ◽  
Relative Humidity ◽  
West Africa ◽  
Frequency Distribution ◽  
Monsoon Season ◽  
Hygroscopic Growth ◽  
Aerosol Direct Effect ◽  
Humidity Measurements ◽  
Original Size

Abstract. Water in the atmosphere exists as both vapour and liquid water contained in particles. At high humidities, more water vapour condenses onto particles and causes them to swell, sometimes up to several times their original size. This significant change in size and chemical composition is termed hygroscopic growth and alters a particle's optical properties. Even in unsaturated conditions, this can change the aerosol direct effect, for example by increasing the extinction of incoming sunlight. This can have an impact on a region's energy balance and affect visibility. Here, aerosol and relative humidity measurements collected from aircraft and radiosondes during the Dynamics-Aerosol-Chemistry-Cloud Interactions in West Africa (DACCIWA) campaign were used to estimate the effect of highly humid layers of air on aerosol optical properties during the monsoon season in southern West Africa. The effects of hygroscopic growth in this region are of particular interest due to the regular occurrence of high humidity and the high levels of pollution in the region. The Zdanovskii, Stokes and Robinson (ZSR) mixing rule is used to estimate the hygroscopic growth of particles under different conditions based on chemical composition. These results are used to estimate the aerosol optical depth (AOD) for 63 relative humidity profiles. A static aerosol profile was assumed. Therefore, these results show the extent of the AOD frequency distribution that can be explained by humidity alone, rather than predicting actual AOD values. The median AOD in the region from these calculations was 0.46, which compares to a median of 0.36 measured by sun photometers. The shape of the AOD frequency distribution was largely comparable to that of the sun photometer measurements, demonstrating that relative humidity is able to account for a large part of the region's AOD variability. Humid layers are found to have the most significant impact on AOD when they reach relative humidities greater than 98 %, which can result in a wet AOD up to seven times larger than the dry AOD. Unsaturated humid layers were found to reach these high levels of relative humidity in 37 % of observed cases. Aerosol concentrations in southern West Africa are projected to increase substantially in the coming years; results presented here show that the presence of highly humid layers in the region is likely to enhance the consequent effect on AOD significantly.

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