Arun Chakraborty

Indian Institute of Technology Kharagpur | IIT KGP · Centre of Oceans, Rivers, Atmosphere and Land Sciences

Anomalous increase in sea surface temperature and its impact on natural ecosystems greatly interests the research community. Here we investigate the causes, impacts, and trends of marine heat wave (MHW) events in the Bay of Bengal (BoB) from 1982 to 2021. A total of 107 MHW events have been isolated (> 90th percentile threshold) in this Indian Ocea...

Alarmed at increasing level of carbon dioxide in the atmosphere, and persuaded that this contributes to climate change, policy makers and researchers are looking for ways to slow down or even reverse its accumulation. Trees and other vegetation of the producer community naturally remove carbon dioxide from the air during photosynthesis and store-se...

Marine heatwaves (MHWs) are abnormal Sea Surface Temperature (SST) conditions in which temperature exceeds the 90th percentile threshold limit. It has significant impacts on marine biodiversity causing large-scale coral bleaching, fish deaths or migration, and local weather changes. Analyzing MHWs and their causative mechanism can help to understan...

The Bay of Bengal (BOB) is known for prominent seasonal and annual climatic variability. The bay is locked from three directions, north, east, and west, and open to the Indian Ocean from the southern direction. BOB experiences local and remote effects in its thermohaline features. The BOB always has a higher surface temperature (SST) compared to th...

The Bay of Bengal (BoB) region experienced three sequentially strong tropical cyclones named Helen, Lehar, and Madi during the month of November-December 2013. These cyclones passed over the same region and Lehar formed immediately after Helen dissipated, while the Madi began eight days after Lehar made landfall. The genesis, progression, and subse...

In the ocean, temperature extremes have adverse effects on precipitation patterns, sea level change, and migration/damage of ecosystems. It has been found that most species are more sensitive to extreme events like marine heatwaves (MHWs), implying the severe impacts of MHWs on ecology. These events are driven by various atmospheric and oceanic pro...

In the ocean, temperature extremes have adverse effects on precipitation patterns, sea level change, and migration/damage of ecosystems. It has been found that most species are more sensitive to extreme events like marine heatwaves (MHWs), implying the severe impacts of MHWs on ecology. These events are driven by various atmospheric and oceanic pro...

An investigation is conducted to study the uncertainty in the cyclonic ocean wind speed (CWS) of Cyclone Global Navigation Satellite System (CYGNSS) satellites over the North Indian Ocean (NIO). For the completion of the assessment, the comparison of CYGNSS wind speed during normal ocean conditions is also carried out with respect to buoy and advan...

The Mixed Layer Depth (MLD) of an ocean acts as a storage of the incoming heat and releases via air-sea exchange processes. The present study tries to understand the decadal variability of MLD over the Bay of Bengal (BoB) and its association with local as well as external forcing. The time series and wavelet analysis confirm the significant decadal...

Arabian Sea (AS) witnessed two very severe cyclones Maha and Kyarr simultaneously in October–November 2019. Here, we analyse the factors that influenced the genesis and simultaneous occurrences of these cyclones. Kyarr (24 October–3 November 2019) is the second super cyclone formed in AS after Gonu in 2007. The path of Maha (30 October–7 November 2...

The Bay of Bengal (BoB) exhibits a complex upper ocean dynamics owing to its semi-open basin shape, monsoon winds, equatorial remote influence, huge fresh water influx and tidal forcing. The river fresh water plays a significant role in the BoB on defining the upper ocean characteristics like mixed layer, stratification and density distribution. Ag...

We present a detailed long-term (1982–2020) analysis of cyclone-induced surface cooling (i.e., cold wake) in the northeast Indian Ocean, which hosts about 6% of the annual tropical cyclones in the world. Here, the analysis is performed for 92 cyclones that triggered significant cooling at the sea surface in two different seasons: the post and pre-m...

Global energy consumption is increasing, highlighting the need for renewable energy sources for power generation. Nonrenewable energy sources, as they are currently employed, are quite likely to go extinct very soon. Pressure retarded osmosis (PRO) and reverse electrodialysis (RED) are two methods of harvesting renewable energy using salinity gradi...

The changing climate may adversely affect crop production unless appropriate adaptation strategies are used. The appropriate level of fertilization and sowing dates are some of the simple and most economic but effective strategies which can be developed and applied for specific climatic regions. Keeping the aforesaid fact in mind, varying sowing da...

Surface energy balance largely depends on the state of atmospheric variables and a change in their interrelation propagates a change in the balance. Other than the meteorological factors, land use land cover (LULC) also plays a major role deciding the proportional participation of different heat fluxes in the heat balance of an area. Delineating th...

The Bay of Bengal (BoB) is cyclone prone region where most of the storms occur during spring-summer/pre-monsoon (April-May) and fall-winter/post-monsoon (October-December) transition periods every year. Annually 4% of the global cyclones occur in the BoB region. One pre-monsoon cyclone (Viyaru, 10-17 May) and four post-monsoon cyclones. (Phailin, 8...

A superior cost-effective cation exchange membrane based on polyvinylidene fluoride (PVDF), cellulose acetate (CA), and reduced graphene oxide (rGO) work as a superior cost-effective cation exchange membrane for the energy extraction application employing microbial fuel cells (MFCs). In this work, waste sugarcane bagasse was used to make CA, and th...

Cities are becoming hotter day-by-day because heat is trapped near the earth's surface due to a decrease in green cover, rapid urbanization, energy-intensity activities, and concrete structures. The four major metropolitan cities of India, i.e. Kolkata, Chennai, Delhi and Mumbai, have experienced heat waves and heat stress frequently during the sum...

Polyvinylidene fluoride (PVDF) based, Cellulose acetate (CA), and Graphene oxide (GO) doped membrane acts as a superior cost-effective cation exchange membrane (CEM) for the energy extraction application using microbial fuel cells (MFCs). In this study, the waste sugarcane bagasse was used to prepare CA, and the Tour method was used to prepare to G...

The northern Indian Ocean, comprising of two marginal seas, the Arabian Sea (AS) and the Bay of Bengal (BoB), is known for the occurrence of tropical cyclones. The simultaneous occurrence of the cyclones Luban in the AS and Titli in the BoB is a rare phenomenon, and, in the present study, we examined their contrasting upper ocean responses and what...

In the present work, we have operationally implemented a data assimilation (DA) scheme in the wave forecasting system at the Indian operational agency, Indian National Centre for Ocean Information Services (INCOIS). Significant Wave Height (SWH) measurements from the SARAL/AltiKa, Jason-2 and Jason-3 altimeters were assimilated using the Optimal In...

We examine the influence of Madden Julian Oscillation (MJO) on tropical cyclones (TCs) in the north Indian Ocean (NIO). To analyse cyclogenesis, we have used the Genesis Potential Index (GPI) and Accumulated Cyclonic Energy (ACE) in the active years (AYs) and the non-active years (NAYs) of MJO during the period 1979–2019. The GPI anomaly shows enha...

This study illustrates the preparation of graphene oxide (GO) impregnated cellulose acetate (CA) ion exchange membrane (IEM). The compositional ratio of GO/CA/polyethylene glycol for preparing cation exchange membranes was optimised for ion exchange capacity (IEC), fixed charged density, water uptake, swelling degree and proton conductivity. Proton...

COrona VIrus Disease (COVID) 2019 pandemic forced most countries to go into complete lockdown and India went on complete lockdown from 24th March 2020 to 8th June 2020. To understand the possible implications of lockdown, we analyze the long-term distribution of Net Primary Productivity (NPP) in the North Indian Ocean (NIO) and the factors that inf...

This study investigates the role of driving atmospheric forces [winds, net heat flux, and evaporation–precipitation (E–P)] and the possible mechanisms on the mixed layer depth (MLD) spatiotemporal variability in the Bay of Bengal (BoB) using a finer-resolution (~ 9 km) Regional Ocean Modeling System (ROMS). The model simulation is configured for 20...

The destruction created by cyclones depends upon their intensity. Ocean wind is the crucial parameter to understand and forecast the intensity of cyclones. During cyclones, due to dynamic ocean conditions and the limited data availability, a neural network with the regulari- zation approach is used to retrieve cyclonic wind (CW) speed. Several opti...

This study addresses the air–sea interaction processes and mixed layer variability, which cause the intraseasonal oscillations in the sea surface temperature (SST) during January 2013–December 2014 using the Regional Ocean Modeling System (ROMS). We have analyzed the SST variability at three locations—northern Bay of Bengal (BoB)/15°N, 90°E (R15),...

This study explores the potential of atmospheric moisture content, its transport and its divergence over the ocean and land as proxies for the variability of Indian summer monsoon rainfall (ISMR) for the period 1950–2019. The analyses using multiple linear regression reveal that the interannual and intraseasonal variability of ISMR and the mean ISM...

The monsoon reversal winds in different seasons and high influx of freshwater from various rivers make the Bay of Bengal (BoB) a unique region. Thus, the knowledge of the dynamics of the mixed layer over this region is very important to assess the climatic variation of the Indian subcontinent. A comprehensive study of the role of external forcing o...

Global climate change can harm the food production globally by varying intensity and frequency of rainfall, occurrence of extreme weather and increment in greenhouse gases. Increased occurrence of extreme climate events results in greater variability of agricultural production. In this study, the climate change impact evaluation was done by using C...

Atmospheric Rivers (AR) are long plumes of intense water vapor transport in the lower atmosphere that carry most of the atmospheric water vapor fluxes from the lower latitudes to the higher latitudes. Landfalling ARs are a major source of heavy precipitation and often cause major weather and/or hydro-meteorological extremes. An AR detection algorit...

This study investigates the seasonal transport variability of the North Indian Ocean (NIO) boundary currents, in particular, the East India Coastal Current (EICC) in the Bay of Bengal (BoB), West India Coastal Current (WICC) in the Arabian Sea (AS) and Somali Current (SC) in the Equatorial Indian Ocean (EIO) using a high-resolution Regional Ocean M...

This study attempts to investigate the simulation of heavy precipitation events (HPEs) over the West Coast of India associated with atmospheric rivers (ARs) using the Advanced Research Weather Research and Forecasting (ARW-WRF) model. The study evaluates the sensitivity of five microphysical (Lin, WSM6, Goddard, Thompson, and Morrison) and cumulus...

Heavy precipitation events (HPEs) associated with the occurrence of atmospheric rivers (ARs) are identified during summer monsoon season in the previous studies over the Indian region. Numerical prediction of HPEs associated with ARs in west coast region of India (WCI) was analyzed and compared to observations. The main aim of the present study is...

East India Coastal Current (EICC), the Western Boundary Current (WBC) in the Bay of Bengal (BOB), is continuous and well–directed during pre– and post–Monsoon, but discontinuous during monsoon (June–September). This study examines the individual and combined effects of river discharge and tidal forcing on the EICC discontinuity using high resolutio...

Madi was a category-2 cyclonic storm formed over the south-western Bay of Bengal (BoB) in December 2013. It formed on 6th December as a depression, and by 8th December it became a very severe cyclonic storm. Some unique features of Madi were: (a) an unexpected reduction in the intensity during its north-westward movement, (b) sudden change in track...

In the Arabian Sea, two extremely severe cyclonic storms occurred back to back during October–November 2015. Using a suite of ocean and atmospheric data, we examined the upper ocean responses of tropical cyclones Chapala and Megh, the latter originated immediately after the dissipation of the former. Cyclones Chapala and Megh cooled the sea surface...

In this article, a nutrient‐autotroph‐herbivore model with nutrient recycling is constructed. Holling type‐II functional response for the relation between nutrient and autotroph while Beddington‐DeAngelis‐type functional response for autotroph and herbivore relation are considered here. It is plausible that the conversion of nutrient from dead biom...

The study of climatic variables that govern the Indian summer monsoon has been widely explored. In this work, we use a non-linear deep learning-based feature reduction scheme for the discovery of skilful predictors for monsoon rainfall with climatic variables from various regions of the globe. We use a stacked autoencoder network along with two adv...

Nitrogen (N) plays an important role in agriculture crop production but the increasing application of nitrogen increases the possibilities of groundwater contamination through nitrate leaching. Nitrate leaching is the inevitable part of agriculture production which occurs during nitrogen fertilization. Hence, the quantification of nitrogen fertiliz...

This study evaluates the impact of coupled model in simulating the ocean state conditions of Bay of Bengal by comparing standalone and coupled numerical model simulations. The oceanic model is the Regional Ocean Modelling System (ROMS) and the coupled model comprises of ROMS and Weather Research and Forecast modelling system to simulate the oceanic...

Water is a key driver of agricultural production, the scarcity of which the production is adversely affected; hence, it is critical for the agriculture system and global food security. Water use efficiency (WUE) can be an effective measure to reduce water demand against crop yield as it depends upon water consumption. Thus, the purpose of this rese...

North Indian Ocean witnesses varied dynamical response due to independent climate modes such as Indian Ocean Dipole (IOD)/El Niño Southern Oscillations (ENSO) and their co-occurrences. These modes have a significant impact on ocean productivity, which in turn shows feedback for the strengthening of these patterns. Keeping this in view, the present...

Nitrate ( NO3−) leaching is a leading process of nitrogen (N) loss in agricultural ecosystems. The present research focused on NO3− leaching and transport in soil from the packed soil columns at different depths (0–20, 0–40, 0–60 and 0–90 cm) under saturated or unsaturated conditions for a lateritic soil. The leached NO3− collected from the bottom...

This study investigates the interannual variability of the EICC discontinuity in connection to the Indian Ocean Dipole (IOD) event using a high resolution (1/12°) Regional Ocean Modeling System (ROMS) simulation. The ROMS simulation for the period 2007–2014 includes the river discharge from the major rivers and dominant tidal components in the regi...

Landfalling atmospheric rivers (ARs) along the west coast (WC) of India during summer monsoon (SM) frequently lead to heavy precipitation events (HPEs). In the present study, a simulation of an AR event associated HPE that occurred on 28 July 2015 was examined. The simulations were performed using WRF-ARW numerical model with five different microph...

The Bay of Bengal (BOB) region of Indian Ocean is affected by numerous tropical cyclones during pre- and post-monsoon seasons when various eddies are generated in the central and western bay. Here, numerical simulations of few tropical cyclones (Aila, Laila, Phailin, Hudhud and Madi) that occurred in different seasons are carried out using an ocean...

Urban heat island (UHI) phenomena is among the major consequences of the alteration of earth's surface due to human activities. The relatively warmer temperatures in urban areas compared to suburban areas (i.e. UHI) has potential health hazards, such as mortality due to high temperatures and heat waves. In addition, UHI situation demands more energ...

The Northern Bay of Bengal is one of the most prominent bays for receiving large influxes of sediments and freshwater. Most of the sediment transport is from the Great Himalaya and carried by the rivers Ganga, Brahmaputra, Brahmani, and Mahanadi, along with freshwater influx. The present study has been carried out on the coastal zone of the norther...

A stage structure prey–predator model that consists of a system of three nonlinear ordinary differential equations in the presence of discrete time delay is proposed and analysed in this paper. The prey population is divided into two categories: immature and mature prey. The predator population depends on mature prey only and that followed by Crowl...

The Western Boundary Current in the Bay of Bengal (BOB), also known as East India Coastal Current (EICC), is northward (southward) and continuous during pre– (post–) Indian Summer Monsoon (ISM), but discontinuous during ISM (June–September). This study investigates the features of this discontinuity and role of eddies, local winds and southern open...

The ocean plays a major role in climate change, and its impact has an extreme effect on the process of coastal and other activities around the globe. The comprehensive analysis of long-term wave climate is carried out at selected locations in the western Bay of Bengal (BoB), by observing the distribution of significant wave height (SWH) using month...

Integrated water vapor transport (IVT) detection algorithm is implemented over the Arabian Sea basin for the identification of strong moisture transport events (SMTs) over Indian subcontinent during 1979-2013. Attempt has been made through the spatiotemporal characteristics whether SMTs are responsible for the occurrence of heavy precipitation even...

The urban heat island (UHI), the phenomena by which the urbanized areas experience relatively warmer temperatures compared to suburban areas, is a major evidence of anthropogenic impact on urban climate. It has potential health effects such as mortality due to high temperatures and heat waves. Additionally, UHI demands more energy, required for run...

The life cycle of the tropical cyclone Madi in the southwestern Bay of Bengal (BoB) during 6th to 12th December 2013 was studied using a suite of ocean and atmospheric data. Madi formed as a depression on 6th December and intensified into a very severe cyclonic storm by 8th December. What was distinct about Madi was its (1) swift weakening from ver...

The Bay of Bengal region of Indian Ocean is affected by tropical cyclones every year predominantly during pre-monsoon and post-monsoon season. Also the bay is well known for its eddy formation for most part of the year. When a tropical cyclone moves over an eddy, it can intensify both positively and negatively based on the conditions of the oceanic...