Pre-monsoon Season Research Articles

Assessment of seasonal water quality and land use land cover change in Subarnarekha watershed of Ranchi stretch in Jharkhand.

In this paper, the assessment of seasonal water quality and land use land cover change in the Subarnarekha watershed in Ranchi stretch was analysed. Agricultural runoff along with climate change adds to the pollution risk to the Subarnarekha River of Ranchi stretch in Jharkhand. Water quality indicators, like acidity alkalinity (ALK), total dissolved solids (TDS), hardness (H), dissolved oxygen (DO), biochemical oxygen demand (BOD), chlorides (CL-), electrical conductivity (EC), salinity (SAL), resistivity (RES) and pH, were assessed as per the standard method. During monsoon season, acidity, alkalinity, hardness, chlorides, salinity, pH and DO decreased, whereas EC, TDS, BOD and resistivity increased in comparison to pre-monsoon season. In post-monsoon, chloride problem was observed very high. Hardness was least in monsoon and maximum in post-monsoon season. EC and BOD increased in monsoon season in comparison to other seasons. Statistical analysis like HCA (hierarchical cluster analysis) and PCA (principal component analysis) also confirmed the problem of TDS, EC, chloride and hardness in the area. WQI (water quality index) analysis showed that the water quality was poor to unsuitable on all the sampling points throughout the study area in all seasons. LULC (land use land cover) and NDWI (normalized difference water index) analysis had also concluded that due to high rate of urbanization, the area has undergone a massive change in terms of forest cover and water bodies. The need for afforestation, forest protection and wetland protection can be clearly seen from the result of this study.

Marine heatwaves during the pre-monsoon season and their impact on Chlorophyll-a in the north Indian Ocean in 1982–2021

Indian Ocean has been undergoing rapid warming in recent years, which increases the likelihood of Marine heatwave (MHW). MHWs are extreme warm ocean surface conditions in which temperature exceeds the 95th percentile for three or more consecutive days. We investigate MHW events occurred in Arabian Sea (AS) and Bay of Bengal (BoB) during pre-monsoon for 1982–2021 period, their impact on Chlorophyll-a (Chl-a) and net primary productivity (NPP). There were 42 (68) MHW events with a significant trend of 8.1 (6.3) MHW days dec−1 in AS (BoB). There is a distinct decrease in Chl-a concentration associated with MHW, especially in medium and long duration events. In general, AS and BoB have witnessed more frequent and long-lasting MHWs in the 2002–2021 period, which reduce NPP of north Indian Ocean. A decrease in Chl-a and NPP, 10 % in AS and 2 % in BoB, is estimated, but only severe MHWs inflict a notable reduction.

Seasonal variation of the quality of groundwater resources for human consumption and industrial purposes in the central plain zone of Punjab, India.

Due to environmental pollution, climate change, and anthropogenic activities, the judicious use and regular assessment of the quality of groundwater for industrial, agricultural, and drinking purposes had gained a lot of attention across the globe. To assess the seasonal suitability of groundwater based on hydrochemistry and different quality indices, groundwater samples were collected and analyzed for different physicochemical parameters. Our findings indicated that the pH, electrical conductivity (EC), total dissolved solids (TDS), total hardness (TH), and calcium ion (Ca2+) content of groundwater were within acceptable limits of WHO and Bureau of Indian Standards (BIS) guidelines for drinking water. However, chloride content exceeded the acceptable levels, accounting for about 29.1% during the pre-monsoon and 15.3% during the post-monsoon period. Based on the water quality index (WQI), none of the water samples were deemed unsuitable for drinking purposes. However, when considering the synthetic pollution index (SPI), 100% of the samples were categorized as moderately polluted during both the pre-monsoon and post-monsoon periods. For industrial purpose suitability, 39.8 and 30.6% of the water samples had high corrosion tendency for pre-monsoon and post-monsoon seasons, respectively. Additionally, 77.5-93.4% of the total water samples were slightly affected by salinization on the basis of Revelle index. Generally, the groundwater quality for drinking purposes meets the WHO and BIS guidelines, with high corrosion potential for industrial use and slight salinization concerns in the area.

Quantifying climate variation and associated regional air pollution in southern India using Google Earth Engine

Climate change and regional air pollution have had significant proportional coherence and are collectively hazardous for the regional ecosystem. To conduct this present investigation, we obtained high-resolution remotely sensed datasets from 2001 to 2022. To estimate climate variation, we utilized Climate Hazard Group InfraRed Precipitation with Station Data Version 2.0 (CHIRPS) and Moderate Imaging Spectroradiometer (MODIS) Land Surface Temperature (LST). Additionally, we used Sentinel-5P datasets to collect spatio-temporal information for regional CO (Carbon Monoxide), NO2 (Nitrogen Dioxide), SO2 (Sulfur Dioxide), and UV Aerosol index for Coimbatore city. Numerous non-parametric and descriptive statistical applications were then employed to check the spatial integrity of satellite data products and spatio-temporal trends using Google Earth Engine algorithms. The study reveals most of the southern parts of Coimbatore city witnessed increased LST (0.10 °C/year) together with decreased rainfall (21.5 mm/year). Moreover, regional concentration of air pollutants exhibits spatio-temporal variability at annual and seasonal scales, where maximum engrossment is occupied by CO during the pre-monsoon and monsoon season. However, other pollutants are also dominant in the northern parts of the city, whereas NO2 and absorbing Aerosol during pre-monsoon season experienced significant increase throughout the years. Understanding the fluctuations in air pollution levels across different weather situations might help in developing targeted pollution reduction methods.

Assessing Groundwater Quality for Sustainable Drinking and Irrigation: A GIS-Based Hydro-Chemical and Health Risk Study in Kovilpatti Taluk, Tamil Nadu

The continuous investigation of water resources is essential to assess pollution risks. This study investigated a groundwater assessment in the coastal belt of Tamil Nadu’s Kovilpatti Taluk, Thoothukudi district. Twenty-one groundwater samples were collected during the pre-monsoon and post-monsoon seasons, analyzing water quality parameters, namely pH, EC, Cl−, SO42−, Ca2+, Mg2+, HCO3−, TH, Na2+, and K+. The Water Quality Index (WQI) was computed and it is observed that 5% of pre-monsoon and 9% of post-monsoon samples were unsuitable for drinking. SAR, MHR, RSC, %Na and Kelley’s index were used to determine irrigation suitability. Pre-monsoon shows 29% (MHR) and 71% (RSC) unsuitable, and post-monsoon shows 59% (MHR) and 9% (RSC) unsuitable. Coastal activity, urbanization, and industrialization in Kovilpatti resulted in the degradation of groundwater quality. Solving this coastal issue requires sustainable wastewater treatment and strict industrial discharge guidelines. Spatial distribution plots, Box plots, Gibbs plots, Piper plots, Wilcox plots and Correlation Matrices had similar results to the computed WQI and its physical–chemical parameters. According to the human health risk assessment, the Mooppanpatti, Illuppaiurani, and Vijayapuri regions show high health risks due to the nitrate and fluoride concentration in the groundwater. Kadambu, Melparaipatti, Therkuilandhaikulam, and Vadakku Vandanam have low levels, posing a minimal health risk.

Comparative Study of Water Quality from Two Major Dam Reservoirs of Thiruvananthapuram District, Kerala

Neyyar Dam and Aruvikkara Dam are two major dam reservoirs located at Thiruvananthapuram District of Kerala State. Physicochemical parameters of water from these two dam reservoirs were studied and compared during pre-monsoon and monsoon period from April 2018 to July2018.Water samples were collected from different sampling stations of the reservoirs and analyzed as per standard methods of APHA (2012). Water from Neyyar dam shows maximum value of all physicochemical parameters compared to water from Aruvikkara dam in the present study period. Water temperature, Total Dissolved Solids, Total Suspended Solids, pH, free CO2, Biological Oxygen Demand and Total hardness were maximumin pre monsoon season and Turbidity, Productivity and Dissolved Oxygen were maximum in monsoon season at both sites. Present study reveal that water from Neyyar dam is more polluted than water from Aruvikkara.

Contribution of tropical cyclone induced waves to the mean and extreme wave climatology in the Bay of Bengal

This paper examines the contribution of tropical cyclones (TCs) to the mean wave and the extreme wave climatology in the Bay of Bengal (BoB). To assess the impact of TCs on the wave activity in the BoB, we compare 40-years long WAVEWATCH III (WW3) numerical simulation with a twin experiment, where TC signatures are filtered out from the wind forcing dataset. Our experimental strategy of twin simulations, with and without TCs, allow us to separate the TC-induced waves from the background wave activity and therefore allow us to quantify their contribution. The simulation samples more than 200 TCs in the BoB and is extensively validated against the available buoy observations that measure 39 TCs in the BoB. Results show that TCs contribute up to ∼80 % and ∼40 % to the extreme significant wave height (SWH) climatology defined as the maximum SWH and highest 1 % SWH and up to ∼9 % to the mean SWH climatology during the post-monsoon season with slightly lesser contributions during the pre-monsoon season. This contribution is largest in the northern BoB and along the east coast of India during the post-monsoon season and in the eastern BoB and along the Bangladesh and Myanmar coast during the pre-monsoon season.

Impact of southern annular mode on the Indian Ocean surface waves

AbstractInterannual climate modes, especially the southern annular mode (SAM), significantly influence the wave climate modulation of the Indian Ocean (IO). The present study, aligned with previous research, identifies two crucial swell generation regions in the IO: the extratropical southern Indian Ocean (ETSI) and the tropical southern Indian Ocean (TSIO). The SAM, governing Southern Ocean surface winds, significantly shapes wave generation in these zones, thereby dominantly regulating IO wave conditions. Positive SAM phases shifts the westerlies poleward creating significant negative anomalies in the northern ETSI, reducing wave generation and swell propagation into the northern IO (NIO) basins, while the positive wind anomalies in the western TSIO creates a new swell generation area that directs swells towards the Arabian Sea, elevating wave heights there during monsoons. Conversely, negative SAM phases enhance TSIO easterlies, making it the primary IO swell source, increasing swell activity in the Bay of Bengal, notably during premonsoon and monsoon seasons. SAM impact expands beyond swells, influencing NIO wave climate by altering wind seas through Hadley cell (HC) circulation shifts. Positive SAM phases trigger NIO and midlatitude anomalous warming, intensifying HC and NIO surface winds in the next season, thereby affecting convection and subsequent sea surface temperature (SST) anomaly changes. The “SAM positive anomaly wind‐SST oscillations (SPAWSO)” pattern emerges, where warm SST anomalies in DJF and JJA precede increased surface winds in MAM and SON, thus increasing the wind‐sea conditions in the NIO. SPAWSO, hence, acts as a delayed mode, season‐dependent positive air–sea interaction cycle linked to positive SAM phases, significantly impacting NIO's wind‐sea dynamics. Thus the present study provides better insights into the long‐term wave prediction accuracy in the IO by considering the direct swell influence and SPAWSO‐driven wind‐sea changes, aiding preparations for changing wave dynamics and their impacts.

An integrated approach for evaluating freshwater ecosystems under the influence of high salinity: a case study of Manchar Lake in Pakistan.

Manchar Lake, Pakistan's biggest lake in the arid zone, faces human-induced salinity issues. This study investigated its effects on the multifaceted ecosystem services, including serving as a source of drinking and irrigation water and aquatic health through assessing fish diversity and characteristics. Analyses of 189 water samples from 21 sites revealed spatiotemporal variations in major ions contributing to lake water salinity. The study assessed water suitability for drinking and agriculture using the water quality index (WQI), sodium adsorption ratio (SAR), magnesium hazard (MH), sodium percent (Na%), and Kelly's ratio (KR). The WQI, ranging from 141 to 408, indicated that the lake water was unfit for drinking. In some seasons, such as the pre-monsoon period, the lake water was deemed unsuitable for irrigation due to high SAR values (18 ± 4 g/L, average ± standard deviation), consistently rising MH values exceeding 66 in all seasons and elevated sodium percentages surpassing 66% in both the pre-monsoon and monsoon seasons. The KR remained acceptable (averaging 0.8 to 2.5) in all seasons. Fish health in highly saline conditions was assessed using data from interviews, focus group discussions, and fish sampling (1684 fish from 10 sites). Results depicted that high salt contamination severely impacted fish length and weight. The study found low richness (Simpson's biodiversity: 0.697 and Shannon Weaver: 1.51) and evenness (Pielou's index: 0.48) among the fish populations. Since 1998, Manchar Lake has seen a decline in fish varieties from 32 to 23, with changes in fish species' feeding habits. To improve lake water quality, the study recommends diverting saline water to the sea before and after the monsoon season while utilizing freshwater from alternative sources to fill any water deficit.

Enhanced surface temperature over India during 1980–2020 and future projections: causal links of the drivers and trends

The Earth’s surface temperatures have increased significantly since the beginning of industrialisation. The high emissions of greenhouse gases have contributed to global warming and climate change, which is expected to continue. Here, we investigate the long-term trends of surface temperature in India using surface, satellite and reanalysis data for the period of 1980–2020, and assess the influence of geophysical drivers on temperature change using the causal discovery. The highest mean surface temperatures are observed in the southern India and the lowest in Himalaya in accordance with the incidence of solar radiation. Causal discovery reveals the relative influence of atmospheric processes, aerosols and specific humidity on surface temperature. We observe a positive trend in temperature during pre-monsoon (0.1–0.3 °C dec−1) and post-monsoon (0.2–0.4 °C dec−1) seasons in the northwest, northeast and north-central India. The analysis exposes high annual (0.22 ± 0.14 °C dec−1) and monsoon (0.24 ± 0.08 °C dec−1) warming in the northeast India. Post-monsoon season shows a positive trend in the entire India, where the highest value is estimated for the western Himalaya (0.2–0.5 °C dec−1) and northeast India (0.1–0.4 °C dec−1). Analyses with the Coupled Model Intercomparison Project 6 (CMIP6) results show that temperature can increase up to 1.1–5.1 °C by year 2100 under the Shared Socioeconomic Pathways (SSP5)–8.5 scenario. The increasing trend of temperature in India is a big concern, which calls for adaption and mitigation measures to alleviate adverse effects of accelerated warming and regional climate change.

Long-term quantification of pre and post-monsoon surface water area of Bangladesh

Since the 1990s, about 70 percent of the world's wetland ecosystem have been lost, despite the acknowledged contribution of surface waters to human well-being. Surface water is a prerequisite for agriculture, fisheries, and other human activities. It also significantly impacts the groundwater reserve, soil conditions, the environment, and the surrounding area's ecology. Bangladesh's population and economic expansion have increased the need for water resources. Therefore, monitoring the spatial and temporal distribution of surface water resources is essential. The present study used more than 2700 Landsat scenes from 1990 to 2020 to quantify the total surface water area utilizing the strength of cloud computing in the Google Earth Engine platform. Mann-Kendall trend analysis was performed to understand the trend of the surface water area. In 1990 the total pre-monsoon and post-monsoon surface water areas were 7994.91 km2 and 11453.43 km2 which is 5.38% and 7.71% of the total countries area, respectively. In 2010 and 2020, the water area was 10748.61 km2 (7.24%) and 10313.49 km2 (6.94%), respectively, in the pre-monsoon; and 10794.05 km2 (7.27%) and 15570.36 km2 (10.48%) respectively in the post-monsoon season. The overall change between 2020 and 1990 is 7994.91 km2 (1.89%) in the pre-monsoon season and 4116.93 (2.77%) in the post-monsoon season. The maximum average surface water area in the post-monsoon season was found in Sylhet (22.68%), followed by Khulna (14.52%). Rangpur was found to have the least average surface water area in both seasons (2.85% and 3.57%). Coastal regions showed a significant increasing trend in the surface water area in the pre-monsoon and post-monsoon seasons. These findings have significant implications for sustainable surface water management decisions, priority interventions, legal frameworks, and public policies to conserve valuable surface water resources in Bangladesh.

Understanding the soil water dynamics during excess and deficit rainfall conditions over the core monsoon zone of India

Observations of soil moisture (SM) during excess and deficit monsoon seasons between 2000 to 2021 present a unique opportunity to understand the soil water dynamics (SWD) over core monsoon zone (CMZ) of India. This study aims to analyse SWD by investigating the SM variability, SM memory (SMM), and the coupling between surface and subsurface SM levels. Particularly intriguing are instances of concurrent monsoonal extremes, which give rise to complex SWD patterns. Usually, it is noted that a depleted convective activity and persistence of higher temperatures during the pre-monsoon season leads to lower SM, while monsoon rains and post-monsoon showers support the prevalence of higher SM conditions. The long persistent dry spells during deficit monsoon years enhances the Bowen ratio (BR) due to the high sensible heat fluxes. On the other hand, the availability of large latent heat flux during excess monsoon and post-monsoon seasons tend to decrease the BR. This enhancement or reduction in BR is due to evapotranspiration (ET), which influences the SWD by modulating the surface—subsurface SM coupling. The surface and subsurface SM coupling analysis for CMZ exhibits significant distinction in the evolution of wet and dry extremes. SM variations and persistence time scale is used as an indicator of SMM, and analysed for both surface and subsurface SM observation levels. Evidently, subsurface SM exhibits remarkably prolonged memory timescales, approximately twice that of surface SM. Furthermore, we dissect SWD linked to wet and dry extremes by analysing annual soil water balance at a local site in Pune, India. Our findings reveal that ET and deep drainage on annual scale are modulated largely by number of break events during the monsoon season. In essence, our study underscores the significance of surface–subsurface SM observations in unravelling the intricate tapestry of SWD.

Variations of Pre-monsoon season related atmospheric parameters over Kakinada region

Pre-monsoon showers occur before the beginning of the rainy season. From the months of March to May, they take place, and can be anything from little drizzles to powerful thunderstorms. March, April and May are known as the pre-monsoon season (PRMS). The precipitation patterns recorded in PRMS are critical because they have an impact on a wide range of crop-related operations across the country. During PRMS, the maximum temperature (TMAX), minimum temperature (TMIN), soil moisture, relative humidity, latent heat, convective available potential energy (CAPE), and total precipitable water (TPW) were analysed at Kakinada region. These variables were collected using daily ERA5 reanalysis data for the PRMS from 1981 to 2021. Studying the convection-related characteristics over the Kakinada station during the PRMS was our goal. During the study period, the five years with the highest PRMS rainfall were 1990, 1995, 2008, 2010 and 2016 and the five years with the lowest rainfall were 1990, 1995, 2008, 2010 and 2016. In the months leading up to the monsoon, the Kakinada station experiences CAPE values between 1000 and 6000 J/kg, while TPW values are between 25 and 60 mm. The PRMS values for CAPE and TPW both show that the prerequisites for moderate to severe convection activity have been fulfilled. TPW, soil moisture, relative humidity, and CAPE parameters during PRMS were well estimated using the ARMA and ARIMA models.

Otolith microchemistry of freshwater indigenous minor carp (Bangana dero) as a biomonitoring tool to trace heavy metals in River Sutlej, Ropar Wetland (Ramsar site), Punjab, India.

The elemental composition of the fish otolith may represent a permanent record of the environmental condition the fish inhabited. Fish otolith grows incrementally from the core to a marginal region that acts as a repository of trace metal signatures. The present study explores the potential application of otolith microchemistry of the benthopelagic indigenous minor carp Bangana dero sampled from the Ropar wetland on River Sutlej, Punjab. The concentration of sixteen metals was evaluated in the otolith (n = 42) and water (n = 48) for the post-monsoon and pre-monsoon season from 2020 to 2022 using inductively coupled plasma mass spectrometry (ICP-MS) followed by element detection in the core and marginal region of whole otolith, using energy-dispersive mass spectroscopy (EDS). All the heavy metals exhibited an increase in metal concentrations in fish otolith than water during the post-monsoon season. By indices approach, the otolith was found to have a high bioaccumulation factor for Se in the post-monsoon and Hg in the pre-monsoon. Certain trace metals like As and Hg exhibited fluctuations in their core and marginal region. Thus, trace metal patterns in the otolith could act as a potential tool for monitoring the seasonal changes of metals in water bodies. The EFHg, EFSe and EFAs in the fish otolith predicted its anthropogenic source, while the remaining studied elements showed ambient water origin. Thus, using the otoliths of Bangana dero as a long-term monitoring tool in the future may be helpful for environmental assessments and the reconstruction of historical exposure for safeguarding of water bodies.

Diurnal variations in lightning over India and three lightning hotspots: A climatological study

Advancements have been made in the field of lightning research. A study on lightning frequency in India, a tropical hotspot, has not been conducted despite the existence of a global climatology on mean flash rate lightning. Lightning climatology in India is determined using high-resolution datasets from MicroLab-1 and Tropical Rainfall Measuring Mission (TRMM) satellites and Lightning Imaging Sensor (LIS) diurnal datasets spanning from 1996 to 2013. The study analyzed the difference in density of lightning flashes during two time periods, 1996–2001 and 2008–2013, on a daily, monthly, and seasonal level. Three regions with high lightning activity have been selected: East Khasi Hills in the northeast with 101.25 flashes/Km2/yr, Rajouri in Jammu & Kashmir with 121.40 flashes/Km2/yr, and Kottayam with 92.94 flashes/Km2/yr. The study focuses on the rainfall, convective available potential energy (CAPE), and lightning density. Due to localized climatological factors, lightning events vary in diurnal and seasonal patterns across the three hotspots.Lightning strikes are predominantly distributed in certain regions of India, including Jammu, Kashmir, the foothills of the Himalayan belt, and the North-Eastern region, encompassing Bangladesh, Bihar, Jharkhand, and Orissa. The frequency of lightning strikes ranges from 0.2 to 0.45 flashes/Km2/day. Lightning activity experienced a slight rise between 2008 and 2013. There was a rise in lightning activity (0.04 flashes/Km2/day) in India and its three hotspots in 2010. The study aims to investigate the daily changes in lightning activity. A significant portion of daily lightning activity occurs at approximately 1000 UTC and generally decreases in the afternoon across all seasons. The study examines the seasonal variation in lightning activity across India, specifically during pre-monsoon, monsoon, post-monsoon, and winter. The results are significant for developing lightning climatology in the region. Lightning density in India experiences a slight increase during both pre-monsoon and monsoon seasons, with a noticeable variation observed across India and three hotspot locations.

Evaluation of water hyacinth utility through geospatial mapping and in situ biomass estimation approach: a case study of Deepor beel (wetland), Assam, India.

As an invasive species, water hyacinths (Eichhornia crassipes) are known to progressively proliferate and cause the ecological invasions of the aquatic environment. The incursions of the water hyacinths not only cause the disappearance of native species but gradually degrade the natural habitats of freshwater regimes. The control and management of these species are laborious task; however, transforming weed into wealth can substantially serve a sustainable approach to reduce the efforts. Therefore, the present study intends to utilize the application of geospatial techniques for mapping the water hyacinths growth in the Deepor beel (wetland) of Assam, India. Sentinel based image analysis has shown that pre-monsoon seasons has encountered massive productivity and area coverage of water hyacinth, whereas in post-monsoon seasons, productivity of water hyacinths reduces to half. Furthermore, in situ biomass estimation of the water hyacinth samples, same around the productive season has been collected and was analyzed as 6kg (green biomass) and 1kg (dry biomass after sun-dried). Finally, this hybrid approach evaluated the production and revenue generation from Moorhen yoga mat (handicraft item) made from the dried water hyacinths. After assuming the actual availability of 50% of total mass yield of water hyacinths, around ~ 0.8 million (8.8 lakhs) yoga mats can be commercially produced within the most productive seasons. The revenue generation from the yoga mat in the domestic and international markets evaluated around US $12.79 million (Rs. 105.85 crore) and US $15.99 million (Rs. 132.31 crore), respectively, from a single productive season. Thus, applicative intent of this study can boost potential market in Assam, renovate the weed waste of water hyacinth into wealth generation, and sustainably support the livelihoods of the local communities.

Convective weather event monitoring with multispectral image analysis of INSAT-3D/3DR over Indian domain

Pre-monsoon season (March to May) is very challenging as convective activities prevails almost throughout the country. Most of the Rabi crops harvesting affected and sometimes suffer great losses due to sudden rain or high winds. INSAT-3D/3DR satellite images and derived products provides continuous support to the forecasters and end users in monitoring such events and thereafter significant value addition improves the prediction. This information was found to be very useful where actual ground based or upper air observations are limited or especially over data sparse or difficult terrain regions. In this work, we have examined three weather events at different Geographical locations (i) Rainfall over Bihar-24-26 June, 2020 (ii) Delhi & NCR region on 17 June, 2022 (iii) NE region activity in 16-18 June, 2022. The Real Time Analysis of Products and Information Dissemination (RAPID) web based tool was utilized in monitoring and diagnosing the convective weather events based on the brightness temperature & derived products like Outgoing longwave radiation, upper tropospheric humidity, insolation etc & RGB imagery composite in terms of day & night time microphysics daily operational products. The time series of the wind derived products for Delhi NCR rainfall and NE rainfall products also generated through RAPID. The synoptic model analysis provides valuable inputs for these mesoscale convective weather events. The southerly wind flow (at 925 hPa) and velocity convergence (at 500 hPa) analysis of European Centre for Medium Range Weather Forecasting (ECMWF) supports the severity of NE event occurred on 16-18 June, 2022. Therefore, utilization of near real time INSAT-3D/3DR products along with appropriate synoptic model analysis can help the forecasters to understand better about such mesoscale convective events & accurate forecast with sufficient lead time can save the life and property.

Severe dust storm/thunderstorm activity over Uttar Pradesh on 13th May, 2018 - A case study

Premonsoon season over Uttar Pradesh is characterized withthunderstorm accompanied with rain, dust storm, gale winds and hail storms etc. These storms generally develop locally in association with convection and moisture convergence and seen as single cells in Doppler Weather Radar, but sometime these thunderstorms are associated with synoptic scale systems viz. Western Disturbance as cyclonic circulation/trough, induced low/ cyclonic circulation or northwest-southeast oriented trough, thereby increasing the spatial extent and severity of these thunderstorms significantly. In the present study, Duststorm/Thunderstorm activity that occurred over the state on large scale on 13th May 2018 and which claimed more than 49 human lives and large number of livestock in Uttar Pradesh has been analyzed. The purpose of this study wasto find out probable dynamic and thermodynamic aspects of this activity. The study indicates that the environment was highly favourable thermodynamically for severe thunderstorm activity with high maximum temperatures (>40C), high CAPE(>1000), high Total Total Index(>50) and high negative Lifted Index values (<-5) over most parts of the northwest Indian plains. The moisture discontinuity line was clearly noticed over south Uttar Pradesh with high moisture contents towards its north. Also 00UTC GFS wind analysis of the day at 925hPa indicated strong southeasterlies of the order of 30-35Kts over Uttar Pradesh resulting high moisture incursion in the lower levels over this region. The Low level wind shear was also high and was about 25-30Kt as evident from Skew-T gram of Lucknow for 12UTC of the day taken from Wyoming site as well as 12UTC wind shear analysis using ERA Interim daily data of ECMWF on 13 May, 2018. These features together with synoptic conditions viz; Western Disturbance (WD) in mid and upper levels and a Cyclonic Circulation (cycir) over south Haryana & neighbourhood as well as an east-west trough extending from this cycir in the lower levels made the environment highly favourable for severe thunderstorm activity over the region.

Rainfall trend and variability analysis of the past 119 (1901-2019) years using statistical techniques: A case study of Kolkata, India

The core purpose of this study is to investigate the spatial variation in monthly, seasonally, and yearly rainfall patterns in the Kolkata district of West Bengal, India, between 1901 and 2019. (Around 119 years). The trend's reliability and intensity were assessed non-parametrically by applying monthly rainfall data series and the Mann–Kendall and Sen's slope estimators. The data showed a considerable increase in pre-monsoon, monsoon, post-monsoon, and also annual rainfall while decreasing in winter rainfall across the district of Kolkata. The positive trend is identified in the data series of pre-monsoon, monsoon, post-monsoon, and annual rainfall, however, winter rainfall exhibited negative trends. The highest increase in rainfall was observed during the post-monsoon season (0.365091 mm year-1), with the smallest increase (0.232591 mm year-1) occurring during the pre-monsoon season. In the winter season, there was a notable rain that has declined substantially(-0.01356 mm year-1). The coefficient CV, %, was used to determine the pattern of rainfall variability. The winter rainfall exhibited the highest CV rating (72.89%), but annual rainfall showed a minimum CV value (17.68%). Generally speaking, a high variance in CV was discovered, indicating that the whole area is very sensitive to droughts and floods. For future forecasts, there is a considerable difference in monthly rainfall data between linear regression and SMOreg, while the annual rainfall is little difference between linear regression, SMOreg, and CA-ANN analysis.

A study on seasonal dynamics of heavy mineral distribution and surface micro-textures of Beach sediment from Govindampalli – Durgarajupatnam Coast, East Coast of India

The main objective of this research is to investigate the distribution, concentration, and surface micro-textures of heavy minerals in beach sediments from four micro-environments: dune, backshore, berm, and foreshore. A total of forty-eight samples (twenty-four samples in each season) were collected along the Govindampalli (GP) to Durgarajupatnam (DP) Coast on the east coast of India, covering the pre-monsoon and post-monsoon periods from June 2016 to December 2016. The study revealed significant heterogeneity in beach sediment properties, heavy mineral distribution, and concentrations. Heavy mineral analysis was conducted on the coarse (+60), medium (+120), and fine (+230) fractions of the beach sediment. The analysis of weight percentage (wt%) demonstrated that a higher proportion of heavy minerals was associated with the fine fraction (+230) compared to the coarse and medium fractions at all stations. Opaque minerals, garnets, zircons, and monazites were found in promising quantities along the coast. The total concentrations of heavy minerals were higher during the pre-monsoon season compared to the post-monsoon season. The surface micro-textures of heavy mineral grains from various stations in the study area were primarily influenced by mechanical and chemical processes occurring on the grain surfaces. These micro-textures indicated significant mechanical influences at the estuary point and moderate to high wave energy in the beach deposits.