Jayanarayanan Kuttippurath

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

Methane (CH 4) is a prominent Greenhouse Gas (GHG) and its global atmospheric concentration has increased significantly since the year 2007. Anthropogenic CH 4 emissions are projected to be 9390 million metric tonnes by 2020. Here, we present the long-term changes in atmospheric methane over India and suggest possible alternatives to reduce soil em...

A comprehensive analysis of the temporal evolution of tropospheric ozone in Antarctica using more than 25 years of surface ozone and ozonesonde measurements reveals significant changes in tropospheric ozone there. It shows a positive trend in ozone at the surface and lower and mid-troposphere, but a negative trend in the upper troposphere. We also...

Continuous use of chemical fertilizers is detrimental to soil health and crop productivity. Therefore, we need to recycle the agroresidues in the valorized form (e.g., biochar or compost) to improve soil quality while maintaining crop yield. This study compares different nutrient management practices using varied dose combinations of biochar/compos...

Severe vortex-wide ozone loss in the Arctic would expose both ecosystems and several millions of people to unhealthy ultraviolet radiation. Adding to these worries, and extreme events as the harbingers of climate change, exceptionally low ozone with column values below 220 DU occurred over the Arctic in March and April 2020. Sporadic occurrences of...

The passive ozone method is used to estimate ozone loss from ground-based measurements in the Antarctic. A sensitivity study shows that the O₃ loss can be estimated within an accuracy of ~4%. The method is then applied to the observations from Amundsen-Scott/South Pole, Arrival Heights, Belgrano, Concordia, Dumont d'Urville, Faraday, Hal...

Atmospheric CO2 is the key Greenhouse Gas in terms of its global warming potential and anthropogenic sources. Therefore, it is important to analyse the changes in the concentration of atmospheric CO2 to monitor regional and global climate change. Here, we use ground-based and satellite measurements for the 2002–2020 period to assess CO2 over India....

Sudden stratospheric warmings (SSWs) are associated with rapid rise in temperature in a short period of time in the polar vortex and reversal of the zonal winds in major warming conditions. Although SSWs are primarily driven by the planetary waves emanating from the troposphere, the exact reasons and factors responsible for the wave forcing are sti...

India relies heavily on coal-based thermal power plants to meet its energy demands. Sulphur dioxide (SO2) emitted from these plants and industries is a major air pollutant. Analysis of spatial and temporal changes in SO2 using accurate and continuous observations is required to formulate mitigation strategies to curb the increasing air pollution in...

Agricultural practices contribute to greenhouse gas (GHG) emissions; therefore, it is essential to modify the production technologies. We analyzed decadal variation in CO 2 and CH 4 over a major rice cultivating area in subtropical India using GOSAT satellite data, which shows a sturdy increase. Furthermore, we carried out long-term field experimen...

A nationwide lockdown was imposed in India from 24 March 2020 to 31 May 2020 to contain the spread of COVID-19. The lockdown has changed the atmospheric pollution across the continents. Here, we analyze the changes in two most important air quality related trace gases, nitrogen dioxide (NO2) and tropospheric ozone (O3) from satellite and surface ob...

The increase in greenhouse gases (GHGs) due to anthropogenic activities enhances regional and global temperatures. The most abundant GHG, i.e., water vapour, has a vital positive feedback on the global warming and Earth's climate system. This study focuses on the spatial and temporal changes in water vapour in the troposphere over India and Indian...

Changes in rainfall patterns can have a profound impact on water availability, and therefore, examining the variability of rainfall is critical in addressing water resources and regional climate change. Tripura state of northeast India is known to have received a high amount of rainfall in the past few decades, but currently the region suffers from...

In this study, we analyse the dynamical evolution, and identify the major warming (MW) and minor warming events of the past 11 Arctic winters (2010/11–2020/21). During the period, MW is found in 4 winters and is in January for 2012/13, 2018/19 and 2020/21 and in February for 2017/18. A major final warming is observed in the year 2015/16. The most s...

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...

Atmospheric carbon dioxide (CO2) is an important greenhouse gas (GHG) due to its high contribution to global warming. The CO2 concentrations have increased significantly across the world after the industrialization. The anthropogenic provenance to the concentration of CO2 needs immediate mitigative interventions. India is a global agricultural powe...

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...

The estimate of changes in hydrological fluxes from a climate change perspective is inevitable for assessing the sustainability of watersheds and conserving water resources. Here, we quantify and assess the changes in different hydrological flux components for the Manu-Deo River Basin (MDRB) of northeast India using Soil and Water Assessment Tool (...

The discovery of causal structures behind a phenomenon under investigation has been at the heart of scientific inquiry since the beginning. Randomized control trials, the gold standard for causal analysis, may not always be feasible, such as in the domain of climate sciences. In the absence of interventional data, we are forced to depend only on ob...

Atmospheric formaldehyde (HCHO) has significant adverse health effects at higher concentrations. It is an unstable and inflammable organic compound, and is an index for atmospheric pollution. Although the ambient HCHO is due to methane oxidation, the localised enhancement in HCHO is mostly from the emissions of non-methane volatile organic compound...

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...

As the phytoplanktons consume carbon dioxide, they significantly influence the global carbon cycle and thus, the global temperature by modifying sea surface temperature. Studies on the changes in chlorophyll–a (Chl-a) amount are therefore, key for understanding the changes in ocean productivity, global carbon budget and climate. Here, we report the...

Well-known for their sporadic and abrupt blooms in the surface waters of warm oceans, Trichodesmium blooms occur during the pre-monsoon period (March to May), when the sea surface temperature is high with brilliant sunlight and stable high salinity. The present study deals with the unusual occurrence of Trichodesmium blooms along the Southeastern A...

The microphytoplankton community structure and composition were investigated along the South Eastern Arabian Sea (SEAS) during the late winter monsoon season (January 2020). A total of 186 species of phytoplankton were identified, with cyanobacteria Trichodesmium erythraeum (72%) being the most dominant, followed by diatoms (11%) and dinoflagellate...

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...

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...

We examine the projected changes in Indian summer monsoon rainfall (ISMR) and El Niño Southern Oscillation (ENSO) along with their changing relationships by the end of 21st century using Coupled Model Inter Comparison Project Phase5 (CMIP5) models. The historical (1951–2005) and future (2050–2099) projections of ISMR were assessed in addition to th...

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 discovery of causal structures behind a phenomenon under investigation has been at the heart of scientific inquiry since the beginning. Randomized control trials, the gold standard for causal analysis, may not always be feasible, such as in the domain of climate sciences. In the absence of interventional data, we are forced to depend only on ob...

Atmospheric formaldehyde (HCHO) is a potential pollutant and very harmful to public health at higher doses. There are different sources for HCHO in the atmosphere, in which fuel combustion and biomass burning is predominant. The oxidation of hydroxyl radicals (OH) and methane are the chemical production pathways of HCHO in the troposphere. Here, we...

We investigate the characteristics and causes of extreme rainfall event occurred in Kerala (south western regions of the peninsular India) in August 2018. The changes in large-scale circulations over the Indo-Pacific domain and their association with regional circulation features, which made the extreme rainfall in Kerala are analysed. During this...

To reduce the uncertainty in climatic impacts induced by black carbon (BC) from global and regional aerosol–climate model simulations, it is a foremost requirement to improve the prediction of modelled BC distribution, specifically over the regions where the atmosphere is loaded with a large amount of BC, e.g. the Indo-Gangetic Plain (IGP) in the I...

Atmospheric aerosols play key roles in radiation budget, ecosystem dynamics, air quality and cloud microphysics of a region and thus, they greatly influence the global climate, ecosystem and public health. We present the temporal variability of atmospheric aerosols over India and north Indian Ocean (NIO) for the past two decades (2000–2019). Here,...

The rapid increase in carbon dioxide (CO2) in the atmosphere due to anthropogenic activities aids global warming that demands immediate attention and policy actions. The changes in the weather patterns, such as winds, temperature and precipitation, leading to floods and droughts are linked to the increasing greenhouse gases including CO₂. This situ...

Stratospheric ozone is a trace gas of great importance as it filters harmful ultraviolet radiations reaching the earth surface. Since ozone influences temperature and dynamics of the stratosphere, it is also a climate-relevant gas by influencing tropospheric temperature. Significant changes in the stratospheric ozone are, therefore, a concern for h...

Severe vortex-wide ozone loss in the Arctic would expose nearly 650 million people and ecosystem to unhealthy ultra-violet radiation levels. Adding to these worries, and extreme weather events as the harbingers of climate change, clear signature of an ozone hole (ozone column values below 220 DU) appeared over the Arctic in March and April 2020. Sp...

Changes in rainfall affect drinking water, river and surface runoff, soil moisture, groundwater reserve, electricity generation, agriculture production and ultimately the economy of a country. Trends in rainfall, therefore, are important for examining the impact of climate change on water resources for its planning and management. Here, as analysed...

Atmospheric formaldehyde (HCHO) is a potential pollutant and very harmful to public health at higher doses. There are different sources for HCHO in the atmosphere, in which fuel combustion and biomass burning are predominant. The oxidation of hydroxyl radicals (OH) and methane are the chemical production pathways of HCHO in the troposphere. Here, w...

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...

To reduce the uncertainty in the black carbon (BC) induced climatic impacts from the global and regional aerosol-climate model simulations, it is a foremost requirement to improve the prediction of modelled BC distribution. And that specifically, over the regions where the atmosphere is loaded with a large amount of BC, e.g., the Indo-Gangetic plai...

Black carbon (BC) aerosols over the Indian subcontinent have been represented inadequately sofar in chemical transport models restricting the accurate assessment of BC-induced climate impacts. The divergence between simulated and measured BC concentration has specifically been reported to be large over the Indo-Gangetic Plain (IGP) during winter wh...

The El Niño Southern Oscillation (ENSO) is an important coupled ocean–atmosphere phenomenon in the tropical Pacific and an important modulator of the spatio-temporal variability of Indian summer monsoon rainfall (ISMR). Here, we explore the impact of ENSO during onset (June), peak (July–August) and withdrawal (September) phases of ISMR for the peri...

Atmospheric ammonia (NH3) is an alkaline gas and a prominent constituent of the nitrogen cycle that adversely affects ecosystems at higher concentrations. It is a pollutant, which influences all three spheres such as haze formation in the atmosphere, soil acidification in the lithosphere, and eutrophication in water bodies. Atmospheric NH3 reacts w...

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...

We observe significant changes in the ENSO–Indian summer monsoon rainfall (ISMR) relationship in past three multidecadal epochs (early epoch: 1931–1960, middle epoch: 1961–1990, and recent epoch: 1991–2015) based on consistent correlation. The rainfall during early epoch was above normal, however, in other two epochs it was relatively dry. The ENSO...

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...

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...

Methane is an important atmospheric trace gas involved in determining the radiative balance of Earth surface. The concentration of methane has increased significantly (approx 150%) after industrialization that attributable to intensive agricultural activities and urbanization. It is also a major driver of climate change in post industrialized era,...

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 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...

This study presents the contrasting trends of rainfall in the northern and southern Western Ghats (WG) and examines possible reasons for the phenomenon. The WG is one of the important mountain ranges that run parallel to the west coast of India. The mountain chain lies almost perpendicular to the low level jet stream (LLJ) and hence, receives about...

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...

The western region of Bay of Bengal (BoB) is of high importance because of its variability in Western Boundary Current (WBC) pattern, numerous eddy genesis and biogeochemical activities. The WBC is northward in pre-Indian Summer Monsoon (ISM) season and southward in post-ISM season with the presence of anticyclonic and cyclonic gyres respectively....

A well calibrated hydrological model is necessary for climate change impact analysis and land use land cover change studies. In addition, the time step of simulation alters the model performance to a greater extent. In this study, Soil and Water Assessment Tool (SWAT) is evaluated to simulate streamflow for both daily and monthly time steps. For th...

Industrial emissions of ozone depleting substances (ODSs) during the second half of the twentieth century have led to one of the most visible human impacts on the Earth: the Antarctic ozone hole. The ozone loss intensified in the 1980s and reached the level of saturation (i.e., complete loss of ozone) due to the high levels of ODSs in the atmospher...

Bay of Bengal (BoB) is one of the most cyclone prone regions in the world. Cyclones receive energy from warm ocean surface waters and the change in cyclone activity generally depends on the change in heat energy available in the upper ocean. Here, we use satellite‐based Modern Era Retrospective‐analysis for Research and Applications dataset, and re...