scholarly journals Influence of Temperature, Relative Humidity and Seasonal Variability on Ambient Air Quality in a Coastal Urban Area

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Ramasamy Jayamurugan ◽  
B. Kumaravel ◽  
S. Palanivelraja ◽  
M. P. Chockalingam
Keyword(s):  
Relative Humidity ◽  
Monsoon Season ◽  
Coastal Region ◽  
Ambient Air ◽  
Influence Of Temperature ◽  
Post Monsoon ◽  
Four Seasons ◽  
Post Monsoon Season ◽  
Influence Of Temperature On ◽  
Higher Temperature

The concentration of air pollutants in ambient air is governed by the meteorological parameters such as atmospheric wind speed, wind direction, relative humidity, and temperature. This study analyses the influence of temperature and relative humidity on ambient SO2, NOx, RSPM, and SPM concentrations at North Chennai, a coastal city in India, during monsoon, post-monsoon, summer, and pre-monsoon seasons for 2010-11 using regression analysis. The results of the study show that both SO2 and NOx were negatively correlated in summer (r2=0.25 for SO2 and r2=0.15 for NOx) and moderately and positively correlated (r2=0.32 for SO2 and r2=0.51 for NOx) during post-monsoon season with temperature. RSPM and SPM had positive correlation with temperature in all the seasons except post-monsoon one. These findings indicate that the influence of temperature on gaseous pollutant (SO2 & NOx) is much more effective in summer than other seasons, due to higher temperature range, but in case of particulate, the correlation was found contradictory. The very weak to moderate correlations existing between the temperature and ambient pollutant concentration during all seasons indicate the influence of inconstant thermal variation in the coastal region. Statistically significant negative correlations were found between humidity and particulates (RSPM and SPM) in all the four seasons, but level of correlation was found moderate only during monsoon (r2=0.51 and r2=0.41) in comparison with other three seasons and no significant correlation was found between humidity and SO2, NOx in all the seasons. It is suggested from this study that the influence of humidity is effective on subsiding particulates in the coastal region.

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 Seasonal Variation of Tropical Cyclone Genesis and the Related Large-Scale Environments: Comparison between the Bay of Bengal and Arabian Sea Sub-Basins

Atmosphere ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1593
Author(s):  
Wei Duan ◽  
Junpeng Yuan ◽  
Xu Duan ◽  
Dian Feng
Keyword(s):  
Tropical Cyclone ◽  
Relative Humidity ◽  
Wind Shear ◽  
Monsoon Season ◽  
Vertical Wind Shear ◽  
Vertical Wind ◽  
Tropical Cyclone Genesis ◽  
Positive Contribution ◽  
Post Monsoon ◽  
Post Monsoon Season

Using tropical cyclone data along with sea surface temperature data (SST) and atmospheric circulation reanalysis data during the period of 1980–2019, the seasonal variation of tropical cyclone genesis (TCG), and the related oceanic and atmospheric environments over the Arabian Sea (AS) and Bay of Bengal (BOB) are compared and analyzed in detail. The results show that TCG in both the BOB and AS present bimodal seasonal variations, with two peak periods in the pre-monsoon and post-monsoon season, respectively. The frequencies of TCG in the BOB and AS are comparatively similar in the pre-monsoon season but significantly different in the post-monsoon season. During the post-monsoon season of October–November, the TCG frequency in the BOB is approximately 2.3 times higher than that of the AS. The vertical wind shear and relative humidity in the low- and middle-level troposphere are the two major contributing factors for TCG, and the combination of these two factors determines the bimodal seasonal cycle of TCG in both the AS and BOB. In the pre-monsoon season, an increase in the positive contribution of vertical wind shear and a decrease in the negative contribution of relative humidity are collaboratively favorable for TCG in the AS and BOB. During the monsoon season, the relative humidity factor shows a significant and positive contribution to TCG, but its positive effect is offset by the strong negative effect of vertical wind shear and potential intensity, thus resulting in very low TCG in the AS and BOB. However, the specific relative contributions of each environmental factor to the TCG variations in the AS and BOB basins are quite different, especially in the post-monsoon season. In the post-monsoon season, the primary positive contributor to TCG in the AS basin is vertical wind shear, while the combined effect of vertical wind shear and relative humidity dominates in the BOB TCG. From the analysis of environmental factors, atmospheric circulations, and genesis potential index (GPI), the BOB is found to have more favorable TCG conditions than the AS, especially in the post-monsoon season.

scholarly journals Recent trends in climate of Bangalore

MAUSAM ◽  
2022 ◽  
Vol 53 (4) ◽  
pp. 425-438
Author(s):  
M. MOHAPATRA
Keyword(s):  
Relative Humidity ◽  
Monsoon Season ◽  
Winter Season ◽  
Maximum Temperature ◽  
Average Temperature ◽  
Bangalore City ◽  
Post Monsoon ◽  
Diurnal Range ◽  
Rate Of Increase ◽  
Post Monsoon Season

The linear trends in the monthly, seasonal and annual mean maximum temperature, minimum temperature, average temperature, diurnal range of temperature, rainfall, relative humidities at 0830 & 1730 hr IST of Bangalore city and airport have been analysed based on the data for the period from 1960-95. The variation in surface wind over Bangalore during above period has also been studied to find out impact of urbanisation on weather parameters. It is found that Bangalore city is becoming warmer in terms of mean maximum & mean minimum temperatures. Rate of increase is significantly higher over Bangalore city (central observatory) than that over airport during winter months. Similarly the rising trend of average temperature of Bangalore city is higher than of Bangalore airport during October to April being significantly so during winter season. Also the diurnal range of temperature of Bangalore is becoming larger in winter months with the rising trend being higher over Bangalore city than over airport. Even though rainfall does not show any significant trend, the rising trend during monsoon & falling trend during post monsoon season over Bangalore city are higher than that of Bangalore airport. Also though both Bangalore city & airport show maximum rising trend in mean relative humidity at 0830 hr IST during winter, the rate of rise is less over Bangalore city. Similarly though the relative humidity at 1730 hr IST shows decreasing trend during all the seasons, the rate of decrease is less over Bangalore city for all seasons except post monsoon season. The mean maximum, minimum and average temperatures and relative humidities show cyclic variation of their monthly trend coefficients during the year.

scholarly journals Intensification and movement of cyclonic storm in the Bay of Bengal during post monsoon season

MAUSAM ◽  
2021 ◽  
Vol 59 (1) ◽  
pp. 51-68
Author(s):  
A. MUTHUCHAMI ◽  
S. SRIDHARAN
Keyword(s):  
Relative Humidity ◽  
Bay Of Bengal ◽  
Wind Shear ◽  
Monsoon Season ◽  
India Meteorological Department ◽  
Reanalysis Data ◽  
Cyclonic Storm ◽  
Post Monsoon ◽  
Post Monsoon Season ◽  
Cyclonic Storms

Using NCEP/NCAR reanalysis data and from the available data on tracks of the storms from India Meteorological Department for the period 1981-2005 an attempt is made to understand the intensification of storms and their movements in the Bay of Bengal during post-monsoon season. It is noticed that in the month of October only 12 % of the cyclonic storms weakened whereas in November and December it is 28 % and 41 % respectively. Cyclonic storms moving in a northeast direction weaken in all the months of post-monsoon season. Most of the westward moving storms do not undergo weakening. In the Bay of Bengal, SST and relative humidity are not responsible for weakening of the storms except in December but wind shear is responsible for weakening. The orientation of isotherms of SST of Bay of Bengal influences the direction of motion.  During the years when the storms are predominantly moving west/northwest the SST over the Bay of Bengal is about 1.0° C warmer than the years when the storms are predominantly moving in north/northeastward. If the isotherms of SST are oriented southwest-northeast with higher value in the east then system may move in north or northeastward and on such occasions east Bay of Bengal is warmer than west Bay of Bengal.

scholarly journals Characteristics of near-surface air pollutants at an urban station in the central Indo-Gangetic Basin

MAUSAM ◽  
2021 ◽  
Vol 71 (2) ◽  
pp. 245-254
Author(s):  
KUMAR SUNIL ◽  
SRIVASTAVA A K ◽  
PATHAK V
Keyword(s):  
Air Pollutants ◽  
Monsoon Season ◽  
Ambient Air ◽  
Industrial Site ◽  
Urban Station ◽  
Near Surface ◽  
Residential Site ◽  
Post Monsoon ◽  
Post Monsoon Season ◽  
Mass Concentrations

Measurements of near-surface air pollutants at an urban station, Lucknow have been studied at two contrasting sites as residential and industrial during three-year period from 2015 to 2017 to understand their variability on different temporal scales. The annual mean mass concentrations of sulphur dioxide (SO2), nitrogen dioxide (NO2), nitric oxide (NO) and particulate matter of size less than 2.5 µm (PM2.5) at an industrial site were about 10 ± 5, 28 ± 17, 10 ± 11 and 128 ± 99 µg m-3 and at the residential site were about 8 ± 5, 30 ± 21, 9 ± 7 and 102 ± 81 µg m-3 respectively. It was observed that the annual mean mass concentration of PM2.5 was about 3 times higher than its annual National Ambient Air Quality Standards (NAAQS) level. However, SO2 and NO2 were about 5 and 1.5 times lower to their annual NAAQS levels, respectively. The seasonal mean mass concentrations of all the pollutants were found to be highest during the winter/post-monsoon season at both the sites, which are more pronounced at industrial site compared to residential site. The observed high pollutants over the station during the winter/post-monsoon season were found to be largely associated with the air mass back-trajectories from N-NW direction.

scholarly journals Assessment of Trophic Responses of a Reservoir to Seasonal and Annual Variations in Monsoon

Water ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2117
Author(s):  
Su-mi Kim ◽  
Hyun-su Kim
Keyword(s):  
Water Quality ◽  
Trophic State ◽  
Monsoon Season ◽  
Phytoplankton Growth ◽  
Phosphorus Loading ◽  
Nutrient Concentrations ◽  
Trophic State Index ◽  
Post Monsoon ◽  
Post Monsoon Season ◽  
State Index

The variations in water quality parameters and trophic status of a multipurpose reservoir in response to changing intensity of monsoon rain was investigated by applying a trophic state index deviation (TSID) analysis and an empirical regression model to the data collected in two periods from 2014 to 2017. The reservoir in general maintained mesotrophic conditions, and Carlson’s trophic state index (TSIc) was affected most by TSITP. Nutrient concentrations, particularly phosphorus, did not show strong correlations with precipitation, particularly in the period with weak monsoon, and a significant increase in total phosphorus (TP) was observed in Spring 2015, indicating the possibility of internal phosphorus loading under decreased depth and stability of water body due to a lack of precipitation. TSIChl was higher than TSISD in most data in period 1 when a negligible increase in precipitation was observed in the monsoon season while a significant fraction in period 2 showed the opposite trend. Phytoplankton growth was not limited by nutrient limitation although nutrient ratios (N/P) of most samples were significantly higher than 20, indicating phosphorus-limited condition. TSID and regression analysis indicated that phytoplankton growth was limited by zooplankton grazing in the Spring, and that cell concentrations and community structure in the monsoon and post-monsoon season were controlled by the changing intensity of the monsoon, as evidenced by the positive and negative relationships between community size and cyanobacterial population with the amount of precipitation in the Summer, respectively. The possibility of contribution from internal loading and an increase in cyanobacterial population associated with weak monsoon, in addition to potential for nutrient enrichment in the post-monsoon season, implies a need for the application of more stringent water quality management in the reservoir that can handle all potential scenarios of eutrophication.

A Study on Prevalence and Seasonal Distribution of Dengue at a Tertiary Care Centre of North India

Healthline ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 100-107
Author(s):  
Arti Agrawal ◽  
Vikas Kumar ◽  
Sanjeev Kumar ◽  
Neha K Mani
Keyword(s):  
Monsoon Season ◽  
Dengue Infection ◽  
Tertiary Care ◽  
Seasonal Distribution ◽  
North India ◽  
Care Centre ◽  
Tertiary Care Centre ◽  
Post Monsoon ◽  
Post Monsoon Season ◽  
Male Preponderance

Introduction: Dengue virus infection is a major public health issue prevalent in tropical and sub-tropical countries all over the world mostly in urban and semi-urban areas. WHO estimates about 50-100 million dengue infections worldwide every year. The present study is aimed to assess the prevalence and seasonal distribution of dengue disease during three consecutive years from 2016-2018 at a tertiary care centre of North India. Method: This is an observational retrospective study conducted on total 6,481 clinical suspected cases referred from indoor and outdoor departments of Medicine and Pediatrics of one of the medical colleges of Agra during the period from 1st January 2016 to 31st December 2018. Results: The maximum positivity was recorded in the year 2016 (16.66%), followed by 2017 (14.07%) and 2018(13.56%).Our study shows male preponderance with maximum cases in the year 2018 was recorded in the month of October (22.75%) whereas the lowest in the month of May (1.96%). Most of the cases were in the age group 0-30 years with a male preponderance. The outbreak occurred during the months of August to November indicating vector transmission in the monsoon and post-monsoon season. Conclusion: From the analysis, this study reflects that the numbers of dengue cases in 2016 were maximum and outnumbered the dengue cases among three consecutive years from 2016 to 2018. The peak in dengue positivity was observed during September to October. As this disease affects the population in the monsoon and post monsoon months therefore continuous monitoring of dengue infection is important during the post-monsoon season.

scholarly journals Seasonal Nature and Trends of Tropical Cyclone Frequency and Intensity over the North Indian Ocean

2020 ◽  
Vol 15 (3) ◽  
pp. 526-534
Author(s):  
Abhisek Pal ◽  
Soumendu Chatterjee
Keyword(s):  
Time Series ◽  
Tropical Cyclone ◽  
Indian Ocean ◽  
Monsoon Season ◽  
North Indian Ocean ◽  
Post Monsoon ◽  
The North ◽  
Increasing Trend ◽  
Post Monsoon Season ◽  
Cyclone Frequency

Tropical cyclone (TC) genesis over the North Indian Ocean (NIO) region showed significant amount of both spatial and temporal variability.It was observed that the TC genesis was significantly suppressed during the monsoon (June-September) compared to pre-monsoon (March-May) and post-monsoon (October-December) season specifically in terms of severe cyclonic storms (SCS) frequency. The Bay of Bengal (BoB) was characterized by higher TC frequency but lower intensity compared to the Arabian Sea (AS). It was also observed that the TC genesis locations were shifted significantly seasonally.The movement of the TCs also portrayed some significant seasonal differences. The pre-monsoon and post-monsoon season was responsible for generating TCs with higher values of accumulated cyclone energy (ACE) compared to the monsoon. The time series of TC frequency showed a statistically significant decreasing trend whereas the time series of ACE showed astatistically significant increasing trend over the NIO.

scholarly journals Dragonflies and damselflies (Insecta: Odonata) of the Kole Wetlands, central Kerala, India

2021 ◽  
Vol 13 (3) ◽  
pp. 17963-17971
Author(s):  
A. Vivek Chandran ◽  
Subin K. Jose ◽  
Sujith V. Gopalan
Keyword(s):  
Species Richness ◽  
Monsoon Season ◽  
Survey Method ◽  
Ramsar Site ◽  
Post Monsoon ◽  
Post Monsoon Season

A year-long study was conducted at the Kole Wetlands, a Ramsar site in central Kerala to document the diversity of dragonflies and damselflies and understand their seasonality.  Checklist survey method was used to sample adult odonates in 30 randomly chosen locations.  A total of 44 species (30 dragonflies and 14 damselflies) belonging to 33 genera and eight families were recorded in the study area.  Species richness showed a peak in the post-monsoon season and a dip in the summer.  The observations support the value of the Kole Wetlands in providing valuable resources for Odonata.

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