scholarly journals Some aspects of squall over Indira Gandhi International airport, New Delhi

MAUSAM ◽  
2021 ◽  
Vol 63 (4) ◽  
pp. 623-638
Author(s):  
SURESH RAM ◽  
M. MOHAPATRA
Keyword(s):  
Meteorological Parameters ◽  
Environmental Changes ◽  
Lower Troposphere ◽  
India Meteorological Department ◽  
Dew Point ◽  
New Delhi ◽  
Dry Air ◽  
Intensity Duration Frequency ◽  
Level Inversion ◽  
Period Of Occurrence

A study is undertaken to analyse the characteristics of squall over Delhi and to find out the potential precursors for its prediction. For this purpose, the squall data of Indira Gandhi International (IGI) airport along with the surface and upper air meteorological parameters recorded by India Meteorological Department have been considered for all individual months over the period of 2001-2010. Apart from the characteristics like period of occurrence, intensity, duration, frequency and nature of squall, the environmental changes due to squall and thermodynamic features and indices leading to squall have been analysed. Higher than normal warming of lower troposphere upto 700 hPa level in March, April & June and at 925 hPa in May accompanied with cold dry air advection leading to lower than normal dew point in middle and upper levels (500-300 hPa in March, May and June, 400-300 hPa in April) are favourable for occurrence of the squall over Delhi. The lower level inversion in March and April only also helps in the occurrence of squall. In monsoon months of July- September, cold and dry air advection in middle and upper tropospheric levels (8- 15° C below normal dew point at 400-300 hPa in July, about 15° C below normal dew point at 300-200 hPa in August and 17- 24° C below normal dew point at 500-300 hPa in September) favours occurrence of squall over Delhi. Unlike pre-monsoon months lower level moisture does not play any role for the occurrence of squall over Delhi in monsoon months. Significantly higher than normal SWEAT index in March to September at 0000 UTC can be used as predictor of squall over Delhi on that day. Total totals index is the next suitable precursor for all the months except June.

scholarly journals Identification allergen Cladosporium spores concentration in the ambient of Ahvaz wastewater treatment plant and their relationship with meteorological variables, Ahvaz, Iran

2020 ◽  
Author(s):  
Nastaran Talepour ◽  
Mohammad Sadegh Hassanvand ◽  
Effat Abbasi-Montazeri ◽  
Seyed Mahmoud Latifi ◽  
Neamat Jaafarzadeh Haghighi Fard
Keyword(s):  
Wastewater Treatment ◽  
Wind Speed ◽  
Meteorological Parameters ◽  
Treatment Plant ◽  
Allergic Diseases ◽  
Airborne Fungi ◽  
Air Pressure ◽  
Dew Point ◽  
Uv Index ◽  
Ultraviolet Index

Introduction: Airborne Cladosporium spores in different regions of the world are known as the main cause of allergic diseases. This study aimed to identify the Cladosporium species airborne fungi in Ahvaz wastewater treat- ment plant area and its adjacent places and check the effect of some meteoro- logical parameters on their emissions. Materials and methods: Cladosporium spores were cultured on Sabouraud`s dextrose agar (SDA) medium in both cold and warm seasons. The passive sampling method was performed and after incubation, colonies were counted as CFU/Plate/h. Then, according to the macroscopic and microscopic charac- teristics of the genus, the fungal was studied. The meteorological parameters including temperature, humidity, air pressure, dew point, wind speed, and ultraviolet index were measured. Results: At least, 3358 colonies were counted. 1433 colonies were related  to the Cladosporium species. The amount of Cladosporium in indoor air was 46% of the total Cladosporium. The average of meteorological parameters includes temperature, humidity, air pressure, dew point, wind speed and UV index during the study were 27.8 °C, 32.9%, 548.7 °Kpa, 3.6°, 9.1 km / h and 3.9 respectively. 42.6% of the total number of colonies was related to the Cladosporium species. Cladospiromes had a direct correlation with the dew point, temperature, humidity, air pressure, wind speed, and ultraviolet index (Pvalue<0.05). Primary sludge dewatering has the greatest role in the Cladospo- rium spores emission. Conclusion: Considering the importance of Cladosporium spores in the ap- pearance of allergic diseases, and given that wastewater treatment workers spend most of their time outside, observing health and preventive measures is necessary in this regard.

scholarly journals Estimating Daily Dew Point Temperature Using Machine Learning Algorithms

Water ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 582 ◽  
Author(s):  
Sultan Noman Qasem ◽  
Saeed Samadianfard ◽  
Hamed Sadri Nahand ◽  
Amir Mosavi ◽  
Shahaboddin Shamshirband ◽  
...  
Keyword(s):  
Meteorological Parameters ◽  
Gene Expression Programming ◽  
Machine Learning Algorithms ◽  
Dew Point ◽  
Coefficient Of Determination ◽  
Support Vector ◽  
M5 Model Tree ◽  
Point Temperature ◽  
Dew Point Temperature ◽  
Input Parameters

In the current study, the ability of three data-driven methods of Gene Expression Programming (GEP), M5 model tree (M5), and Support Vector Regression (SVR) were investigated in order to model and estimate the dew point temperature (DPT) at Tabriz station, Iran. For this purpose, meteorological parameters of daily average temperature (T), relative humidity (RH), actual vapor pressure (Vp), wind speed (W), and sunshine hours (S) were obtained from the meteorological organization of East Azerbaijan province, Iran for the period 1998 to 2016. Following this, the methods mentioned above were examined by defining 15 different input combinations of meteorological parameters. Additionally, root mean square error (RMSE) and the coefficient of determination (R2) were implemented to analyze the accuracy of the proposed methods. The results showed that the GEP-10 method, using three input parameters of T, RH, and S, with RMSE of 0.96°, the SVR-5, using two input parameters of T and RH, with RMSE of 0.44, and M5-15, using five input parameters of T, RH, Vp, W, and S with RMSE of 0.37 present better performance in the estimation of the DPT. As a conclusion, the M5-15 is recommended as the most precise model in the estimation of DPT in comparison with other considered models. As a conclusion, the obtained results proved the high capability of proposed M5 models in DPT estimation.

Life of a Six-Hour Hurricane

2009 ◽  
Vol 137 (1) ◽  
pp. 51-67 ◽  
Author(s):  
Kay L. Shelton ◽  
John Molinari
Keyword(s):  
Deep Convection ◽  
Potential Temperature ◽  
Vertical Wind Shear ◽  
Lower Troposphere ◽  
Vertical Shear ◽  
Vortex Center ◽  
Dry Air ◽  
Sheared Flow ◽  
The Core ◽  
Equivalent Potential

Abstract Hurricane Claudette developed from a weak vortex in 6 h as deep convection shifted from downshear into the vortex center, despite ambient vertical wind shear exceeding 10 m s−1. Six hours later it weakened to a tropical storm, and 12 h after the hurricane stage a circulation center could not be found at 850 hPa by aircraft reconnaissance. At hurricane strength the vortex contained classic structure seen in intensifying hurricanes, with the exception of 7°–12°C dewpoint depressions in the lower troposphere upshear of the center. These extended from the 100-km radius to immediately adjacent to the eyewall, where equivalent potential temperature gradients reached 6 K km−1. The dry air was not present prior to intensification, suggesting that it was associated with vertical shear–induced subsidence upshear of the developing storm. It is argued that weakening of the vortex was driven by cooling associated with the mixing of dry air into the core, and subsequent evaporation and cold downdrafts. Evidence suggests that this mixing might have been enhanced by eyewall instabilities after the period of rapid deepening. The existence of a fragile, small, but genuinely hurricane-strength vortex at the surface for 6 h presents difficult problems for forecasters. Such a “temporary hurricane” in strongly sheared flow might require a different warning protocol than longer-lasting hurricane vortices in weaker shear.

scholarly journals Prediction on the Seasonal Behavior of Hydrogen Sulfide Using a Neural Network Model

2011 ◽  
Vol 11 ◽  
pp. 992-1004 ◽  
Author(s):  
Byungwhan Kim ◽  
Joogong Lee ◽  
Jungyoung Jang ◽  
Dongil Han ◽  
Ki-Hyun Kim
Keyword(s):  
Neural Networks ◽  
Hydrogen Sulfide ◽  
Wind Speed ◽  
Meteorological Parameters ◽  
Dew Point ◽  
Industrial Complex ◽  
Seasonal Behavior ◽  
Generalized Regression Neural Networks ◽  
Main Effect ◽  
Optimized Model

Models to predict seasonal hydrogen sulfide (H2S) concentrations were constructed using neural networks. To this end, two types of generalized regression neural networks and radial basis function networks are considered and optimized. The input data for H2S were collected from August 2005 to Fall 2006 from a huge industrial complex located in Ansan City, Korea. Three types of seasonal groupings were prepared and one optimized model is built for each dataset. These optimized models were then used for the analysis of the sensitivity and main effect of the parameters. H2S was noted to be very sensitive to rainfall during the spring and summer. In the autumn, its sensitivity showed a strong dependency on wind speed and pressure. Pressure was identified as the most influential parameter during the spring and summer. In the autumn, relative humidity overwhelmingly affected H2S. It was noted that H2S maintained an inverse relationship with a number of parameters (e.g., radiation, wind speed, or dew-point temperature). In contrast, it exhibited a declining trend with a decrease in pressure. An increase in radiation was likely to decrease during spring and summer, but the opposite trend was predicted for the autumn. The overall results of this study thus suggest that the behavior of H2S can be accounted for by a diverse combination of meteorological parameters across seasons.

scholarly journals Statistical Analysis of SO2 and NO2 with Respect to Meteorological Parameters (Gwalior, India)

2021 ◽  
Vol 22 (2) ◽  
pp. 280-287
Author(s):  
Mehraj ud din Bhat ◽  
Anish C Pandey
Keyword(s):  
Statistical Analysis ◽  
Meteorological Parameters ◽  
Sodium Hydroxide Solution ◽  
Stable Solution ◽  
Ambient Air ◽  
New Delhi ◽  
Air Stream ◽  
Different Seasons ◽  
Indian Meteorological Department

The present study is carried out in Gwalior to know the level of pollutants viz sulphur dioxide (SO2) and nitrogen dioxide (NO2). In this study, both NO2 and SO2 were collected during different seasons, and estimation was done using chemical methods. The methods used for the determination of SO2 and NO2 in the ambient air of Gwalior was (Modified West and Geake method) and (Modified Jacob and Hochheisier). The SO2 from the air stream was absorbed in a sodium tetramer curate solution. NO2 was collected by bubbling air through a sodium hydroxide solution to form a stable solution of sodium nitrate. Meteorological parameters like temperature, relative humidity were recorded by thermometers and hygrometry during the sampling. Rainfall data was taken from Indian Meteorological Department, New Delhi, for four sampling years. The statistical analysis was carried out between the level of pollutants SO2 and NO2 measured and meteorological parameters recorded during the sampling. This study observed that pollutants were very high in winter and summer compared to monsoon and post-monsoon periods due to the heavy transport movement and favourable meteorological conditions like temperature, humidity, rainfall, and wind speed and directions.

scholarly journals Air quality improvement during triple-lockdown in the coastal city of Kannur, Kerala to combat Covid-19 transmission

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9642 ◽  
Author(s):  
C.T. Resmi ◽  
T. Nishanth ◽  
M.K. Satheesh Kumar ◽  
M.G. Manoj ◽  
M. Balachandramohan ◽  
...  
Keyword(s):  
Air Quality ◽  
South India ◽  
Meteorological Parameters ◽  
Virus Transmission ◽  
Lower Troposphere ◽  
The Novel ◽  
Observational Site ◽  
Air Quality Improvement ◽  
The Government ◽  
The City

The novel SARS-CoV-2 coronavirus that emerged in the city of Wuhan, China, last year has since become the COVID-19 pandemic across all continents. To restrict the spread of the virus pandemic, the Government of India imposed a lockdown from 25 March 2020. In India, Kannur district was identified as the first “hotspot” of virus transmission and a “triple-lockdown” was implemented for a span of twenty days from 20 April 2020. This article highlights the variations of surface O3, NO, NO2, CO, SO2, NH3, VOC’s, PM10, PM2.5 and meteorological parameters at the time of pre-lockdown, lockdown and triple-lockdown days at Kannur town in south India using ground-based analyzers. From pre-lockdown days to triple-lockdown days, surface O3 concentration was found to increase by 22% in this VOC limited environment. NO and NO2 concentrations were decreased by 61% and 71% respectively. The concentration of PM10 and PM2.5 were observed to decline significantly by 61% and 53% respectively. Reduction in PM10 during lockdown and triple-lockdown days enhanced the intensity of solar radiation reaching the lower troposphere, and increased air temperature and reduced the relative humidity. Owing to this, surface O3 production over Kannur was found to have increased during triple-lockdown days. The concentration of CO (67%), VOCs (61%), SO2 (62%) and NH3 (16%) were found to decrease significantly from pre-lockdown days to triple-lockdown days. The air quality index revealed that the air quality at the observational site was clean during the lockdown.

scholarly journals Meteorological observations in tall masts for the mapping of atmospheric flow in Norwegian fjords

2020 ◽  
Vol 12 (4) ◽  
pp. 3621-3640
Author(s):  
Birgitte Rugaard Furevik ◽  
Hálfdán Ágústsson ◽  
Anette Lauen Borg ◽  
Zakari Midjiyawa ◽  
Finn Nyhammer ◽  
...  
Keyword(s):  
Atmospheric Pressure ◽  
Complex Terrain ◽  
Meteorological Parameters ◽  
Temporal Frequency ◽  
Three Dimensional ◽  
Dew Point ◽  
The Arctic ◽  
Atmospheric Flow ◽  
Climatological Data ◽  
Meteorological Observations

Abstract. Since 2014, 11 tall meteorological masts have been erected in coastal areas of mid-Norway in order to provide observational data for a detailed description of the wind conditions at several potential fjord crossing sites. The planned fjord crossings are part of the Norwegian Public Roads Administration (NPRA) Coastal Highway E39 project. The meteorological masts are 50–100 m high and located in complex terrain near the shoreline in Halsafjorden, Julsundet and Storfjorden in the Møre og Romsdal county of Norway. Observations of the three-dimensional wind vector are made at 2–4 levels of each mast with a temporal frequency of 10 Hz. The dataset is corroborated with observed profiles of temperature at two masts, as well as observations of precipitation, atmospheric pressure, relative humidity and dew point at one site. The first masts were erected in 2014, and the measurement campaign will continue until at least 2024. The current paper describes the observational setup, and observations of key atmospheric parameters are presented and put in context with observations and climatological data from a nearby reference weather station. The 10 min and 10 Hz wind data, as well as other meteorological parameters, are publicly available through the Arctic Data Centre (https://doi.org/10.21343/z9n1-qw63; Furevik et al., 2019).

scholarly journals Application of aerological radar to determine the wind profile in the lower troposphere

2021 ◽  
Vol 5 (1) ◽  
pp. 32-48
Author(s):  
I. V. Bukrin ◽  
◽  
A. V. Gusev ◽  
S. I. Kudinov ◽  
V. E. Ivanov ◽  
...  
Keyword(s):  
Wind Profile ◽  
Meteorological Parameters ◽  
Operation Mode ◽  
Lower Troposphere ◽  
Vertical Wind ◽  
Doppler Spectrum ◽  
Free Atmosphere ◽  
Climate Forecasts ◽  
Angular Coordinates ◽  
Sky Conditions

Currently, radar and radionavigation systems for aerological sounding of the atmosphere with the help of aerological radiosondes launched into the atmosphere are widely used to provide operational weather and climate forecasts. Meteorological radar systems for various purposes have been developed to obtain operational data on the free atmosphere. The systems are operated, providing measurement of meteorological parameters by noncontact methods. One of the most important meteorological parameters is the vertical wind profile. Specialized radars have been created to determine the distribution of wind direction and speed by altitude. They allow measuring the dynamic parameters of the wind in real time. The article considers the possibility of creating a radar for the wind parameters measuring the lower troposphere based on the modernization of a serial domestic aerological radar. Technical characteristics of the radar such as the pulse transmitting power, the sensitivity of the receiver, the ability to control the antenna radiation pattern accurately by angular coordinates make it possible to provide fundamental wind measurement in the lower troposphere. The main issues of modernization are related to the need of implementation of the coherent operation mode into the radar receiver and transmitter and ensuring the coherent energy storage of the reflected signal during the interval of statistical stability of the atmosphere. The information about the wind at the measured altitude is estimated from the Doppler spectrum of the signal reflected from meteorological inhomogeneities. The ability to accurately point the antenna during the sounding session allows determination of the vertical wind profile in the altitude range, even in clear sky conditions.

scholarly journals Wildfire Pyroconvection and CAPE: Buoyancy’s Drying and Atmospheric Intensification—Fort McMurray

Atmosphere ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 763
Author(s):  
Atoossa Bakhshaii ◽  
Edward A. Johnson ◽  
Kiana Nayebi
Keyword(s):  
Weather Prediction ◽  
Convective Available Potential Energy ◽  
Cumulus Cell ◽  
Leading Edge ◽  
Dew Point ◽  
Fire Plume ◽  
Fort Mcmurray ◽  
Dry Air ◽  
Short Period ◽  
Upper Level

The accurate prediction of wildfire behavior and spread is possible only when fire and atmosphere simulations are coupled. In this work, we present a mechanism that causes a small fire to intensify by altering the atmosphere. These alterations are caused by fire-related fluxes at the surface. The fire plume and fluxes increase the convective available potential energy (CAPE) and the chance of the development of a strong pyroconvection system. To study this possible mechanism, we used WRF-Fire to capture fire line propagation as the result of interactions between heat and moisture fluxes, pressure perturbations, wind shear development and dry air downdraft. The wind patterns and dynamics of the pyroconvection system are simulated for the Horse River wildfire at Fort McMurray, Canada. The results revealed that the updraft speed reached up to 12 m/s. The entrainment mixed the mid and upper-level dry air and lowered the atmospheric moisture. The mid-level and upper-level dew point temperature changed by 5–10 ∘ C in a short period of time. The buoyant air strengthened the ascent as soon as the nocturnal inversion was eliminated by daytime heating. The 887 J/kg total increase of CAPE in less than 5 h and the high bulk Richardson number (BRN) of 93 were indicators of the growing pyro-cumulus cell. The presented simulation has not improved the original model or supported leading-edge numerical weather prediction (NWP) achievements, except for adapting WRF-Fire for Canadian biomass fuel. However, we were able to present a great deal of improvements in wildfire nowcasting and short-term forecasting to save lives and costs associated with wildfires. The simulation is sufficiently fast and efficient to be considered for a real-time operational model. While the project was designed and succeeded as an NWP application, we are still searching for a solution for the intractable problems associated with political borders and the current liable authorities for the further development of a new generation of national atmosphere–wildfire forecasting systems.

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