Pre-monsoon Months Research Articles

Long-Term Seasonal and Annual Rainfall Trend Analysis of Giridih District, Jharkhand, India

District Giridih is primarily rain dependent on its 95 per cent net cultivable land under summer-monsoon crops. It is classified as a mono-cropping area as it lacks irrigation facilities, essential for winter crops. In the last few years, the district experienced water stress due to the shortage of monsoon rainfall. We study long term seasonal and annual rainfall trend analyses for the Giridih district of Jharkhand in India using linear regression modelling. The last 100 years of data were taken for the study and were divided into two-time phases of 50 years each to analyse the changing pattern of rainfall trends. We found a decreasing trend in monsoon rainfall from 1 mm y-1 to 3 mm y-1 between the initial (1921-1971) and final (1972-2021) phase of the study period. Similarly, the return period of droughts (rainfall deficit years) has also reduced from 11 years to 5 years. The study has shown that the rainfall pattern has changed, with the winter months showing a decrease and the pre-monsoon months an increase in their relative contributions to the annual rainfalls. The study may help in the formulation of water resource conservation-oriented decision-making to cope-up with the rainfall uncertainties and meet the future water demand.

Cloud-to-Ground Lightning in Cities: Seasonal Variability and Influential Factors

AbstractUrban-induced land use changes have a significant impact on local weather patterns, leading to increased hydro-meteorological hazards in cities. Despite substantial threats posed to humans, understanding atmospheric hazards related to urbanisation, such as thunderstorms, lightning, and convective precipitation, remains unclear. This study aims to analyse seasonal variability of cloud-to-ground (CG) lightning in the five large metropolitans in Bangladesh utilising six years (2015–2020) of Global Lightning Detection Network (popularly known as GLD360) data. It also investigates factors influencing CG strokes. The analysis revealed substantial seasonal fluctuations in CG strokes, with a noticeable increase in lightning activity during the pre-monsoon months from upwind to metropolitan areas across the five cities. Both season and location appear to impact the diurnal variability of CG strokes in these urban centres. Bivariate regression analysis indicated that precipitation and particulate matter (PM) significantly influence lightning generation, whilst population density, urban size, and mean surface temperature have negligible effects. A sensitivity test employing a random forest (RF) model underscored the pivotal role of PM in CG strokes in four of the five cities assessed, highlighting the enduring impact of extreme pollution on lightning activity. Despite low causalities from CG lightning, the risk of property damage remains high in urban environments. This study provides valuable insights for shaping public policies in Bangladesh, a globally recognised climate hotspot.

Soil moisture–temperature coupling over India through multi-scale observations

ABSTRACT Soil moisture–temperature coupling has been shown to affect the severity and occurrences of extreme temperature events like heatwaves and droughts. In this study, we quantify the soil moisture–temperature coupling over India at daily and climatological scales. Our results show maximum climatological coupling over north and central India during pre-monsoon months. The coupling strength is related to soil moisture content. Daily coupling is calculated for two heatwave events (2009 and 2015) to determine whether land–atmosphere coupling enhances the heatwave event. We observed strong soil moisture–temperature coupling during the 2009 heatwave, whereas weak coupling is observed in the 2015 heatwave. Our results suggest that soil moisture anomalies could enhance heat anomalies and temperature anomalies through the reduction in latent heat flux, leading to enhanced soil moisture–temperature coupling. Thus our study highlights the importance of soil moisture and associated coupling in understanding and predicting heatwave events.

The Diversity of Forensic Entomofauna Associated With Decaying Chicken Liver in the Tropical Region of Kerala, India.

Forensic entomology To elucidate the time of death based on insect evidence, there are several studies on forensic entomology on life cycles, environmental factors, and feeding habitats of insects. However, there have not been any comprehensive studies on forensic entomology and its usage in forensic inquiry specific to the region, especially Kerala, India. The insect succession on decomposed animal matter plays an important role in estimating minimum postmortem intervals (mPMI). Objective The purpose of the study was tounderstand forensically important insect groups and their role in the decomposition process of dead decayingmatter. The different decomposition stages of a corpse vary in attraction to necrophagous insects and the insect fauna depending on its prevailing conditions of decay. The decomposition is highly dependent on the exposition of animal matter and abiotic and biotic factors acting on it. The main objective of the present investigation was to identify the insect fauna associated with decaying chicken liver. The study also envisages comprising the diversity and abundance of insects between two different treatments of animal matter: in contact with soil and controlled conditions in a clean basin. Method The study was conducted for 45 days (until the total decomposition of the samples in both conditions) during the pre-monsoon months of April to May2022 at Chalikadavu, Muvattupuzha, in the Ernakulam district, Kerala, India. The samples were however kept away from direct sunlight and rain to avoid the direct impact on the orienting fauna. The entomofauna found to be associated with the decaying animal matter was carefully collected from the site and stored in 70% isopropyl alcohol for preservation. The total number of insects was recorded along with the hours of maximum incidence, and samples were stored in plastic vials for further identification. Result In this study, we analyzed the activities of ants, mites, wasps, cockroaches, moths, beetles, and flies during the decomposition of decaying chicken liver. Among these insects, flies and beetles are two important arthropod communities associated with animal matter decomposition. We collected these foraging organisms for morpho-taxonomic identification. The decomposition stages among the two treatments could help to understand the variable factors in the decomposition of decaying corpse with special reference to the insect fauna acting on it. Conclusion We got 100 specimens comprising 28 species in 17 families from Blattidae, Coleoptera, Diptera, Hymenoptera, and Lepidoptera. Besides this, we identified two parasitic wasps with their host (dipteran pupa), which is helpful in postmortem interval (PMI) estimation. Our analysis showed an association between decay and the activity of carrion insects. The decomposition stages among the two treatments could help to understand the variable factors in the decomposition of a decaying corpse with special reference to the insect fauna acting upon it.

Distribution and Abundance of Fry and Juveniles of A Few Cultivable Fishes in and Around Cochin Backwater, Kerala, India

The investigation was carried out at four selected stations in Cochin Backwater and intertidal water of the sea representing different ecological conditions at fortnightly intervals from February to September 1989. As per the observations, among the five species of fry recorded, the grey mullet Liza parsia was dominating throughout the study period with maximum abundance during the south-west monsoon. The fry of the milk fish Chanos chanos and the Indian tarpon Megalops cyprinoides were noted only during the pre-monsoon months when the salinity and temperature of water were considerably high, whereas the fry of the grey mullet Mugil cephalus were recorded during lower temperature and salinity conditions from June to August. Among the environmental parameters, salinity, temperature and distribution of phyto- and zooplankton were found to have profound influence on the distribution of different species directly or indirectly. Hydrogen ion concentration and dissolved oxygen were not found to influence the distribution. Among the eight species of juveniles recorded during the study, those of L. parsia were dominating followed by L. macrolepis. The juveniles of C. chanos, M. cyprinoides and Valamugil cunnesius were observed only after the onset of the monsoon indicating their preference of low salinity and temperature, and higher concentration of food materials.

Phytoplankton diversity in wastewater impacted Indian Ramsar site: a study from East Kolkata Wetland.

A seasonal study was undertaken to understand the influence of wastewater on phytoplankton distribution in a water body of East Kolkata Wetland (EKW), a designated Ramsar site in Kolkata, West Bengal, India. A total of 19 different genera of phytoplankton belonging to 5 phyla were recorded. Among all the groups, Chlorophyceae was found to be dominated by 8 genera followed by Bacillariophycaeae (4 genera), Cyanophyceae (4 genera), Euglenophyceae (2 genera), and Zygnematophyceae (1 genus). Seasonal variability showed maximum dominance of phytoplankton during post-monsoon and least during pre-monsoon months. Shannon-Wiener diversity (H') indices indicated Bacillariophyceae to be most species rich (1.059) while the most dominant group (D) was observed to be Chlorophyceae (0.507). Assessment of Palmer algal pollution index (PI) revealed the water body is impacted by high organic pollution during monsoon (22) compared to the pre-monsoon (19) and post-monsoon seasons (15). The results of canonical correspondence analysis (CCA) indicated water temperature, alkalinity, total dissolved solids, dissolved oxygen, and electrical conductivity as the major influencing parameters for growth and distribution of the phytoplankton in the water body. Therefore, it can be stated that hydrological alteration of a water body fed with wastewater plays a significant role in regulating the plankton density, richness, and diversity.

Comparative Assessment and Monitoring Changes in NDVI of Achanakmar Tiger Reserve (ATR) and its Buffer Zone, India

Achanakmar Tiger Reserve (ATR), endowed with rich biological diversity and lush green vegetation in and around, makes it more unique. It is also an integral part of the Achanakmar Amarkantak Biosphere Reserve (AABR) and has been identified as one of the important tiger reserves of the Central Indian landscape due to its connectivity with other protected areas and tiger reserves in neighboring landscapes. Vegetation mapping and monitoring are important to understand changes in ecosystem processes and associated temporal and spatial impacts. Pre- and post-monsoon IRS, LISS III, and AWiFS satellite data from 2000, 2004, 2008, 2010, and 2013 were used for the present study. This paper is an attempt to examine the variation in the normalized difference vegetation index (NDVI) of ATR and its buffer zone on a seasonal and temporal basis. Climate conditions such as temperature, precipitation, relative humidity, etc. play an important role in the growth and development of healthy vegetation. The NDVI value of ATR has shown fluctuation and recorded positive growth over the past 14 years with few exceptions. The post-monsoon season recorded a higher NDVI value as compared to the pre-monsoon months. The maximum NDVI value was recorded in 2004 (+0.539) for the entire ATR and its buffer zone.

Lightning Development over the Distinct Climate Regions of Uttarakhand, India

Objectives: Lightning activity and its connections with meteorology and aerosol loading over Uttarakhand, with varying topography and climates, is studied using ISS Lightning Imaging Sensor (LIS) aboard international space station (ISS) data during the period 2018–2021. Methods: To understand the variation of lightning activity with meteorology and aerosol loading the correlation of lightning activity with different meteorological parameters such as surface temperature, convective available potential energy (CAPE), aerosol optical depth (AOD), and convective precipitation is studied. Findings: Very poor correlation is observed between lightning flash counts with the meteorological parameters. Annual variation of lightning activity over Uttarakhand shows maximum during the monsoon season (June–September) with a peak during the pre–monsoon season (March–May) month April. The high frequency of western disturbances defined as warm low-pressure systems associated with moisture originated over Mediterranean Sea travelling from west to east across the northern states are responsible for peak lightning activity during pre–monsoon month April and maximum lightning activity in the monsoon season is attributed to the monsoon convection. Novelty: The study made the spatio – temporal variation of lightning over Uttarakhand and also reveals the connection between lightning and different meteorological parameters in different climatic conditions of Uttarakhand which is first defining the importance of large-scale meteorological processes in the development of lightning in Uttarakhand. Keywords: Lightning; Meteorological Parameters; Aerosol optical depth and Convective Available Potential energy (CAPE)

Quantifying the role of antecedent Southwestern Indian Ocean capacitance on the summer monsoon rainfall variability over homogeneous regions of India

The role of ocean variability is at a focal point in improving the weather and climate forecasts at different spatial and temporal scales. We study the effect of antecedent southwestern Indian Ocean mean sea level anomaly (MSLA) and sea surface temperature anomalies (SSTA) as a proxy to upper ocean heat capacitance on all India summer monsoon rainfall (AISMR) during 1993–2019. SSTA and MSLA over the southwestern Indian Ocean (SWIO) have been influenced by El Niño-Southern Oscillation (ENSO), the impact of ENSO-induced SWIO variability was low on rainfall variability over several homogeneous regions. Rainfall over northeast (NE) and North India (EI) has been modulated by ENSO-induced SSTA and MSLA over SWIO, thus effecting the total AISMR magnitude. The ENSO-induced changes in heat capacitance (SSTA and MSLA) over SWIO during antecedent months has less impact on west coast of India, central India and North India (NI) rainfall variability. The long-term trend in pre-monsoonal SSTA and MSLA over SWIO shows decreasing rainfall trend over NI, NE, and EI in the recent time. Furthermore, the cooler (warmer) anomaly over the western Indian Ocean affects rainfall variability adversely (favourably) due to the reversal of the wind pattern during the pre-monsoon period. While SSTA and MSLA are increasing in the SWIO, large-scale variability of these parameters during preceding winter and pre-monsoon months combined with surface winds could impact the inter-annual AISMR variability over homogeneous regions of India. Similarly, from an oceanic perspective, the antecedent heat capacitance over SWIO on an inter-annual time scale has been the key to the extreme monsoon rainfall variability.

Application of brown seaweed-derived agro biostimulant to the commercial farming of the red seaweed Kappaphycus alvarezii in India: Growth enhancement and production of quality raw material

Currently global seaweed industries are facing issue with availability of raw material for processing of carrageenan due to low growth of current planting material. Use of biostimulants in seaweed cultivation is recently paid more attention due to their proven biostimulatory effect, of which, Ascophyllum marine plant extract powder (AMPEP) is a well proven biostimulant to improve the growth and quality of Kappaphycus alvarezii biomass. Hence, 500 kg of AMPEP was purchased and studied its impact on the commercial farming of K. alvarezii from April 2018 to January 2022 in India. Vegetative propagule of K. alvarezii were dipped in an AMPEP with concentration range of: 0.025, 0.05, 0.10, 0.15, 0.20 and 0.25 % for 30, 60, 90 and 120 min. Before out-planting on rafts in shallow coastal water and found that K. alvarezii responded well to a 0.1 % solution with dipping time of 60 min. The percentage of average daily growth rate (ADGR%) of AMPEP-treated plant in a 45 d grow out period was 3.50 ± 0.50 % vs a control of 1.75 ± 0.25 % for the summer and pre-monsoon months (p < 0.05) but no statistically significant differences between the treated and control plants were found during the rainy and winter seasons. Treated plants were found with low incidence of epiphytes, and disease as compared to control plants. The general appearance and health of treated Kappaphycus was good with significant differences in the yield and quality of semi-refined carrageenan (SRC) and dry weed quality (p < 0.05). The cost of AMPEP for producing of additional 1 kg of dry Kappaphycus was 0.066USD. Results of the present study is very encouraging and AMPEP can be used for the production of K. alvarezii biomass for industrial and biorefinery processing as it has been witnessed that there was 16.66 % increase in biomass production in 2021in India.

Historical drought and its trend in South Asia: Spatial and temporal analysis 2000-2020

Every year, South Asian countries suffer from declining agricultural outputs due to climate extremes such as floods and droughts. Recurrent droughts have depressed rural economies and enhanced widespread hunger and human migration to South Asian cities (Miyan, 2015). Due to climatic changes, the region is projected to experience rising temperatures and more frequent extreme weather events in the long term (Trenberth et al., 2014). Accurate predictions of drought, its impact, and early detection facilities are not present in most South Asian countries due to a lack of sufficient hydro-meteorological datasets, poor access to satellite products, and shortages of well-trained staff. This study seeks to address these deficiencies scientifically by analysing historical drought conditions on a regional scale using open-access satellite products. The Drought Severity Index (DSI) has been employed to assess meteorological droughts from 2000 to 2020 and to prepare drought severity maps for the South Asian region. Results from DSI were further compared with the Standardised Precipitation Index (SPI) in Nepal and Bangladesh. The results identified pre-monsoon months as the driest period in South Asian countries experiencing severe to moderate drought.

Dynamic Characteristics of Aerosol Optical Properties over Dibrugarh City in the North-Eastern Indian Region during 2018–2021

Aerosols play an important role in the earth's environment across the globe through their involvement in various earth system cycles. The change in the aerosol properties may cause short and long-term impacts, the knowledge of such changes is useful in the estimation of the pollution sources of any region. We have carried out the analysis of the aerosols' optical and radiative properties using AERONET station data from 2018 to 2021 in Dibrugarh City. The higher Aerosol Optical Depth (AOD) values during winter and pre-monsoon months indicate high anthropogenic activities, and biomass burning in Dibrugarh. The impact of various sources and daily meteorological parameters help in understanding the diurnal variations of the AOD, Ångström Exponent (AE), and column water (CW). Fine aerosol fractions dominate the aerosol volume, but sometimes the long-range transport of dust affects aerosol properties during pre-monsoon months (MAM). MODIS-derived AOD and AERONET AOD values show a good correlation, with R2 = 0.68. The highest volume of the aerosols reaches up to 0.11 µm3 µm-2 during pre-monsoon months, whereas it lies below 0.05 µm3 µm-2 in other seasons. SSA values indicate the presence of scattering aerosols but in 2020, a sudden decline in the SSA values shows a strong rise in the absorbing aerosols. Throughout the study period (2018–2021), the positive radiative forcing indicates a rise in atmospheric heating.

Water quality index of springs in mid-hill of Nepal

Global population growth, rapid urbanization, and developmental activities have inflicted significant pressures on drinking water supplies, thus leading to severe water scarcity. Spring is the major source of water within the mid-hill and mountain region. However, studies carried out on water quality of spring in Nepal are quite limited. The objective of the study was to access the water quality index (WQI) of spring in April, and May (pre-monsoon months) and June (monsoon month) in Tanahun district of Nepal. Discharge of water from three springs was measured at 10 am and 4 pm in two months by bucket method. Water samples from the three springs were collected with plastic bottles (a bottle of sample for each month for each spring) and sent to the laboratory for analysis of various water quality parameters. The discharge of all the springs increased during the monsoon month than the pre-monsoon month. Water quality parameters i.e. turbidity, pH, ammonia, nitrate, total hardness calcium hardness, and alkalinity were approximately under the range of standard limits by World Health Organization (WHO), National Drinking Water Quality Standard of Nepal (NDWQS) and Bureau of Indian Standards (BIS). However, electrical conductivity (EC), total dissolved solids (TDS), and fecal coliform (E. coli) exceeded the WHO, and NDWQS permissible limit of drinking water. The presence of fecal coliform made the water unsuitable for drinking purposes without treatment. The WQI was good in Spring II (15.76) followed by Spring III (38.65) and Spring I (61.08). Spring II has the lowest WQI among the three springs due to the application of conservation measures like plastering the spring. The variation in WQI in three springs depends on both natural factor and management of springs. Overall, application of modern technology i.e. GIS and Remote Sensing will provide accurate information on the source of springs which can be beneficial for conservation of springs globally and contribute to reducing water scarcity especially in the mountain regions.

The behavior of cloud base height over a hilly remote station of North-East India using ground-based remote sensing technique

Impact of clouds and their vertical structures on the radiative budget, hydrological cycle, and climate is strong but still uncertain. There is a need to monitor and investigate cloud characteristics continuously to improve our knowledge and understanding. The behavior of the Cloud Base Height (CBH) is studied over Umiam, situated in a complex terrain of the Shillong Plateau. CBH measurements are obtained from a LIDAR Ceilometer and a comprehensive analysis of its characteristics covering from February 2019 to January 2022 has been presented here. Cloud occurrences showed distinct seasonality with maxima in wet months and minima in dry months. Multilayer cloud structures are found mostly in the monsoon season, although single-layer clouds dominated throughout the year. During the whole study period, the average frequency of occurrences of single, double, and triple layers of clouds are found at 38.5%, 11%, and 0.01% respectively against a total observation point of 78%. Near-ground cloud occurrences are ubiquitous with a maximum in July 2020 (18.08%) and a minimum in April 2021 (0.03%). CBH is found to vary with seasons too with higher bases during pre-monsoon months and lower during monsoon and post-monsoon months. Nighttime and early morning maxima in cloud occurrences are noted in some seasons. Cloud formation and occurrences are found to follow a pattern of existing circulation, dominated by local circulation during post-monsoon and winter and synoptic circulation during pre-monsoon and monsoon seasons. A comparison study of CBH with corresponding reanalysis datasets showed their inability to capture cloud representation over sloped terrain.

Nowcasting Severity of Thunderstorm Associated with Strong Wind Flow Over Indian Subcontinent: Resource Lightning Surges

Lightning Detection Systems (LDS) have a vital role in the real-time identification of the location of lightning strikes for the purpose of weather forecasting and issuing warning with sufficient lead time for safe operations. The spatial and temporal distribution of lightning, formulated using LDS observations, can be an objective input to infer and refine the climatology of Thunderstorm (TS) over a region. This study uses the data of Indian Air Force (IAF) LDS network to prepare climatological plots of lightning over India and to formulate location-specific TS guidance for a total of 12 Indian airports. The analysis of climatological plots reveals that there is a distinct warm-season preponderance of lightning strikes over Indian subcontinent, with pre-monsoon months receiving the maximum lightning. The most probable time of occurrence being 1200-1400 UTC during all the seasons across the country. Location-specific TS guidance not only signifies the most probable direction of occurrence of TS with respect to the airport, but also clearly brings out the favourable direction of movement. Hence, the same can be judiciously used as nowcasting aid coupled with actual LDS and Doppler Weather Radar (DWR) observations. Further, the characteristics features of lightning, like surges in flash rate, can be objectively used to define a predictor for nowcasting severe weather associated with a TS cloud. The study of these surges in lightning flash rate visa vis occurrence of Strong Surface Winds (SSW) &gt; 60 kmph over Delhi National Capital Region(NCR), indicated that there is an increase in the number of lightning flashes prior to the occurrence of SSW. 77.5 % occurrences are preceded by surges in flash rate within 45 minutes of the occurrence of SSW, however, the probability of detection of the event with a lead time of 15 to 45 minutes is around 71%.

Limited influence of irrigation on pre-monsoon heat stress in the Indo-Gangetic Plain

Hot extremes are anticipated to be more frequent and more intense under climate change, making the Indo-Gangetic Plain of India, with a 400 million population, vulnerable to heat stress. Recent studies suggest that irrigation has significant cooling and moistening effects over this region. While large-scale irrigation is prevalent in the Indo-Gangetic Plain during the two major cropping seasons, Kharif (Jun-Sep) and Rabi (Nov-Feb), hot extremes are reported in the pre-monsoon months (Apr-May) when irrigation activities are minimal. Here, using observed irrigation data and regional climate model simulations, we show that irrigation effects on heat stress during pre-monsoon are 4.9 times overestimated with model-simulated irrigation as prescribed in previous studies. We find that irrigation increases relative humidity by only 2.5%, indicating that irrigation is a non-crucial factor enhancing the moist heat stress. On the other hand, we detect causal effects of aerosol abundance on the daytime land surface temperature. Our study highlights the need to consider actual irrigation data in testing model-driven hypotheses related to the land-atmosphere feedback driven by human water management.

Spatial Pattern and Land Surface Features Associated with Cloud-to-Ground Lightning in Bangladesh: An Exploratory Study

Severe weather events such as lightning appear to be a significant threat to humans and property in South Asia, an area known for intense convective activity directly related to the tropical climate of these areas. The current study was conducted in Bangladesh and examined the association between cloud-to-ground (CG) lightning and ground surface properties, with the aim of improving existing knowledge regarding this phenomenon. GLD360 data from 2015 to 2020 were used to describe the seasonal lightning climatology. Elevation, land use and land cover, vegetation and surface heat flux data were used to examine all land surface features possibly associated with CG lightning occurrence. Hot and cold spot spatial patterning was calculated using local indicators of spatial association. Results indicated a strong CG lightning seasonality. CG stroke density varied considerably across seasons with the pre-monsoon exhibiting the highest density. This was followed by occurrences in the monsoon season. The March–June period experienced 73% of the total observed. Elevation appeared to influence the post-monsoon CG stroke, however, its role in the other seasons was more difficult to define. The land cover/lightning index indicated that waterbodies and herbaceous wetlands had more influence than other land cover types, both during the day and at night, and it appeared that latent heat flux played a major role. The CG stroke hot and cold spot locations varied diurnally. The findings suggest that large-scale irrigation practices, especially during the pre-monsoon months, can influence the observed spatiotemporal pattern. The production of hotspot maps could be an initial step in the development of a reliable lightning monitoring system and play a part in increasing public awareness of this issue.

Evaluation and Usefulness of Lightning Forecasts Made with Lightning Parameterization Schemes Coupled with the WRF Model

Abstract The evaluation and usefulness of lightning prediction for the Indian subcontinent are demonstrated. Implementation of the lightning parameterizations based on storm parameters, in the Weather Research and Forecasting (WRF) Model, with different microphysics schemes are carried out. With the availability of observed lightning measurements over Maharashtra from the lightning detection network (LDN), lightning cases have been identified during the pre-monsoon season of 2016–18. Lightning parameterization based on cloud top height defined by a reflectivity threshold factor of 20 dBZ is chosen. Initial analysis is carried out for 16 lightning events with four microphysical schemes for the usefulness in lightning prediction. Objective analysis is carried out and quantitative model performance (skill scores) is assessed based on observed data. The skills are evaluated for 10- and 50-km2 boxes from the 1-km domain. There is good POD of 0.86, 0.82, 0.85, and 0.84, and false alarm ratio (FAR) of 0.28, 0.25, 0.29, and 0.26 from WSM6, Thompson, Morrison, and WDM6, respectively. There is an overestimation in lightning flash with a spatial and temporal shift. The fractional skill score is evaluated as a function of spatial scale with neighborhoods from 25 to 250 km. These high skill scores and high degree of correlation between observations and model simulation gives us confidence to use the system for real-time operational forecast over India. The skill for 2019 and 2020 pre-monsoon are calculated to address the predictability of operational lightning prediction over India. Significance Statement A high-resolution model, namely, the Weather Research and Forecasting (WRF) Model, with multiple microphysics parameterization schemes and lightning parameterization is used here. The objective analysis is carried out for the lightning cases over India and the quantitative performance is assessed. The results highlight that there is fairly good probability of detection (POD) of 0.86, 0.82, 0.85, and 0.84 and false alarm ratio (FAR) of 0.28, 0.25, 0.29, and 0.26 from four different microphysical schemes (WSM6, Thompson, Morrison, and WDM6, respectively). These high skill scores and high degree of correlation between observations and model simulation gives us confidence to use the system for real-time operational forecast. The validation of lightning forecast system deployed over India for five pre-monsoon months in real time is carried out, which gives POD of 0.90, FAR of 0.64, hit rate of 0.57, and POFD of 0.50 for the whole Indian region.

Freshwater fish diversity in hill streams of Saberi River in Eastern Ghats of Odisha, India

Freshwater fish diversity of the hill streams of Saberi River (a major tributary of the Godavari River system) in Koraput district in Eastern Ghats of southern Odisha was studied from September 2017 to August 2019. Sites for the present study were located between Gupteswar Proposed Reserve Forest (PRF) of Odisha on the eastern side, and Kanger Valley National Park of Chhattisgarh on the western side. A total of 36 species of freshwater fish belonging to 24 genera, 13 families and six orders were recorded from the study sites, of which two species are exotic. Family Cyprinidae dominated with 14 species. Species richness and diversity is greater during the pre-monsoon months followed by post-monsoon and monsoon months respectively. The physico-chemical parameters of water in the study sites during all seasons are within prescribed limits for fish culture. Among the four major types of fish habitats identified in the study sites (riffles, runs, pools and logs), pools were the most preferred, and logs the least preferred habitat for the fishes. Habitat analysis indicated that deep pools and runs are the primary habitats contributing to the maximum species diversity, and therefore, protection of these particular habitats is recommended for conservation and management of ichthyodiversity.

Spatio-temporal variability of lightning climatology and its association with thunderstorm indices over India

Lightning is an electrical discharge — a ‘spark’ or ‘flash’ as charged regions in the atmosphere instantly balance themselves through this discharge. It is a beautiful and deadly naturally occurring phenomenon. In June 2020, more than a hundred people died in the state Bihar of India only in 3 days’ span due to lightning events. In this study, Lightning Imaging Sensor (LIS) from the Tropical Rainfall Measuring Mission (TRMM) satellite with a very high spatial resolution of 0.1° has been utilized to create the lightning climatology of India for 16 years during the period 1998 to 2013. Diurnal, monthly, and seasonal variations in the occurrence of lightning flash rate density have also been analyzed. TRMM satellite Low-Resolution Monthly Time Series (LRMTS) with 2.5° resolution datasets have been used for lightning trend analysis. The diurnal lightning event mainly occurs in the afternoon/evening time duration (1400–1900 h) around 0.001 flashes/km2/h. The highest lightning occurred in the month of May (0.04 flashes/km2/day) and the least in December (0.005 flashes/km2/day). The distribution of lightning flash counts by season over India landmass is mainly in pre-monsoon months (MAM) which ranges from 0.248 to 0.491 flashes/km2/day, and monsoon (JJA) ranges from 0.284 to 0.451 flashes/km2/day and decreases afterward. Spatially, the distribution of lightning flash density is seen over the North-Eastern region along with Bangladesh, Bihar, Jharkhand, Orissa, and Jammu and Kashmir region. The pre-monsoon (MAM) season shows a positive trend of lightning around 0.04 flashes in the North-Eastern region and the post-monsoon (SON) shows a negative trend of − 0.021 in central India. The CAPE and K-Index have positively correlated with the flash rate density seasonally but CAPE is more significantly correlated around 0.83 during pre-monsoon and monsoon season. This study also focused on finding out the district wise lightning hotspots regions of India. Rajouri and Reasi district in Jammu and Kashmir has the highest lightning with 121 and 115 flashes/km2/yr, respectively.