Mukunda M. Gogoi

Vikram Sarabhai Space Centre · ISRO

In this study, we assess the response of ambient aerosol black carbon (BC) mass concentrations and spectral absorption properties across Indian mainland during the nationwide lockdown (LD) in connection with the Coronavirus Disease 19 (COVID-19) pandemic. The LD had brought near to total cutoff of emissions from industrial, traffic (road, railways,...

Continuous long-term monitoring of black carbon (BC) mass concentrations and aerosol scattering coefficients (σSCA), supplemented by number size distribution and chemical composition, are utilized in this study to understand the temporal changes in the aerosol properties, associated source processes and radiative impacts at Ny-Ålesund (79oN) in the...

The plausible impact of light-absorbing aerosols on snow darkening and subsequent retreating of glaciers is a global climatic concern. In this study, we present the characteristics of multi-layer distribution and effects of Black Carbon (BC) and inorganic ions in the snowpacks of Khardung (KG) and Phuche (PG) glaciers (>5 km a.s.l.) in the western...

The rapid changes in the pattern of atmospheric warming as well as the degradation of glaciers in the Himalayas point to the inevitability of accurate source characterization and quantification of the impact of aerosols. In this regard, optical and chemical properties of aerosols, and their role in radiative effects are examined over a remote high-...

The dust plume tracks from the Middle East and Eastern Africa to the Indian subcontinent have an impact on the atmospheric and ocean biogeochemistry of the Arabian Sea (AS). Here, we present the impact of dust on net primary productivity (NPP) over the AS using satellite-based observation and model simulation. Seasonal episodes and long-term trends...

Scientific research on the concentration and size distribution of bioaerosols in diverse environmental conditions is recently being prioritized. Exposure to bioaerosols, especially through inhalation, is linked to many severe health complications. The inhalation of the bioaerosols is directly linked with the size as well as the nature of the bioaer...

Fog is a common atmospheric event in northern India. Frequently, dense and prolonged fog envelops the entire Indo-Gangetic Plain (IGP), especially in the winter season. During winter, conducive atmospheric conditions also facilitate the accumulation of airborne particulates near the earth surface, significantly reducing atmospheric visibility in th...

Spatial and temporal shifts in rainfall patterns over South Asia and the adjoining Seas during the pre-monsoon season have been observed over the past 2 decades from 2000 to 2019. Aerosol particles suspended above the boundary layer are a contributing factor to these changes. These particles not only alter cloud characteristics, but also diminish t...

This study investigates the light absorption properties of organic aerosols in PM10 collected at a high-altitude location (2700 m a.s.l.) in the eastern Himalayas from March 2019 to February 2020. The analysis reveals an enhanced light-absorbing signature of methanol-soluble brown carbon (MeS-BrC) extracts compared to water-soluble brown carbon (WS...

The winter period is most ideal for studying near-surface aerosols in the Indo-Gangetic plains (IGP) of India, since this period is inundated with significantly higher concentrations of aerosols across the unique geographical domain because of shallow atmospheric boundary layer. This study focuses on analysing the concentration of the biotic compon...

Light-absorbing black carbon (BC) aerosols strongly affect Earth's radiation budget and climate. This paper presents satellite retrieval of BC over India based on observations from the Cloud and Aerosol Imager-2 (CAI-2) on board the Greenhouse gases Observing Satellite-2 (GOSAT-2). To evaluate and validate the satellite retrievals, near-surface BC...

The decadal variability of direct radiative effects of aerosols is investigated at Dibrugarh, a site in northeast India (NEI) at the eastern Himalayan foothills, primarily using multi-wavelength solar radiometer measurements spanning from October 2001 to February 2020. The ground-based aerosol observations are combined with satellite remote sensing...

Chemical properties of the continental outflow to the northern Indian Ocean are investigated using shipborne measurements carried out as a part of the Integrated Campaign for Aerosols, gases and Radiation Budget (ICARB-2018) experiment during winter 2018. The organic carbon (OC) and elemental carbon (EC) showed high values (OC = 4.8 ± 2.1 μg m⁻³ an...

The light-absorbing Black Carbon (BC) aerosols have very sensitive role in affecting the Earth’s radiation budget and climate. In this study, satellite-based retrieval of BC over India is presented based on observations from the Cloud and Aerosol-Imager-2 (CAI-2) on-board the Greenhouse gases Observing Satellite-2 (GOSAT-2). To evaluate and validat...

Continuous measurements of Aerosol Optical Depth (AOD), columnar water vapor (WV) and Ozone (O3) concentrations were made over a semi-arid urban location Rajkot (22.29°N, 70.74°E, and 142m AMSL) in the western India. The annual mean values of AOD, WV and O3 were 0.37 ± 0.15, 1.44 ± 0.6 gm cm⁻² and 243 ± 18 DU during 2016-2019. AOD showed large seas...

Continuous ground-based observations of aerosols over the Himalayan region are highly beneficial in studying aerosol trends over the complex geographic terrain. This study presents the results from continuous long-term observations (2004–2016) of aerosols over a high-altitude site in the central Himalayas – Nainital, quantifying multihued aspects o...

Multi-year measurements of surface-reaching solar (shortwave) radiation fluxes across a network of aerosol observatories (ARFINET) are combined with concurrent satellite (CERES)-based top of the atmosphere (TOA) fluxes to estimate regional aerosol direct radiative forcing (ARF) over the Indian region. The synergistic approach improves the accuracy...

Regional climatic implications of aerosol black carbon (BC), which has a wide variety of anthropogenic sources in large abundance, are well recognized over South Asia. Significant uncertainties remain in its quantification due to a lack of sufficient information on the microphysical properties (its concentration, size, and mixing state with other a...

Continuous and multi-year (2008–2012) measurements of black carbon (BC) mass concentrations (MBC), carried out from the semiarid tropical site Udaipur (24.6° N, 74° E, 580 m a.s.l.) near the western Indian desert, are analyzed for their region-specific features. MBC varied over a wide range during the period of study, with the hourly mean values oc...

The serene environment of the Himalayas is experiencing adverse impact of air pollution, rising critically with the advent of rapid industrialization and urbanization. However, systematic longterm ground-based measurements are almost nonexistent in this region due to the prevailing extreme conditions and complex terrain. In this context, we present...

Accurate estimation of black carbon (BC) from the widely used optical attenuation technique is important for the reliable assessment of their climatic impact. The optical instruments use Mass Absorption Cross-section (MAC) for converting light attenuation records to BC mass concentrations and Aethalometer is a widely used optical instrument for BC...

Particle morphology and elemental compositions are among the crucial parameters of aerosols required for accurate understanding of the climatic effect of aerosols in the earth-atmosphere system; yet their vertical distributions and region specific properties are poorly characterised due to sparse in-situ measurements. This is the first study to cla...

Regional climatic implications of aerosol black carbon (BC) are well recognized over South Asia, which has a wide variety of anthropogenic sources in a large abundance. Significant uncertainties remain in its quantification due to lack of sufficient information on the microphysical properties (its concentration, size, and mixing state with other ae...

The particle number concentrations, size distributions, and new particle formation (NPF) events were investigated in the South Asian outflow over South-eastern Arabian Sea (SEAS), northern (NIO) and the equatorial Indian Ocean (EIO) during the winter of 2018 based on the extensive measurements of particle number size distributions in size range 10–...

Multimode PNSDs over the northern Indian Ocean. � New particle formation (NPF) events in coastal and remote ocean. � NPF events associated with subsidence of free-tropospheric air masses to the MABL. � Enhanced organics mass concentrations during the NPF events. A R T I C L E I N F O Keywords: New particle formation Marine aerosols Indian Ocean aer...

During the combined South-West Asian Aerosol–Monsoon Interactions and Regional Aerosol Warming Experiment (SWAAMI–RAWEX), collocated airborne measurements of aerosol number–size distributions in the size (diameter) regime 0.5 to 20 µm and black carbon (BC) mass concentrations were made across the Indo-Gangetic Plain (IGP), for the first time, from...

Global distribution of aerosol direct radiative forcing (DRF) is estimated using Clouds and Earth's Radiant Energy System (CERES) synoptic (SYN) 1° datasets. During 2001–2017, a statistically significant change of global DRFs is revealed with a general decreasing trend (i.e., a reduced cooling effect) at the top of the atmosphere (DRFTOA ~ 0.017 W⋅...

Extensive measurements of cloud condensation nuclei (CCN) and condensation nuclei (CN) concentrations in the South Asian outflow to the northern Indian Ocean were carried out on board an instrumented research vessel, as part of the Integrated Campaign for Aerosols, gases and Radiation Budget (ICARB) during the winter season (January–February 2018)....

Abstract. During the South-West Asian Aerosol Monsoon Interaction (SWAAMI) experiment, collocated air-borne measurements of aerosol number-size distributions in the size (diameter) regime 0.5 to 20 µm and black carbon (BC) mass concentrations were made across the Indo-Gangetic Plains (IGP), for the first time, from three distinct locations, just pr...

Concurrent measurements of the altitude profiles of the concentration of cloud condensation nuclei (CCN), as a function of supersaturation (ranging from 0.2 % to 1.0 %), and aerosol optical properties (scattering and absorption coefficients) were carried out aboard an instrumented aircraft across the Indo-Gangetic Plain (IGP) just prior to the onse...

The absorption characteristics and source processes of aerosols are investigated at two nearby distinct altitude sites: Nainital, located over the central Himalayas (~1958 m amsl) and Pantnagar, in the adjacent foothill region (~231 m amsl) in the Indo-Gangetic Plain region (IGP); based on in-situ measurements and model (GEOS-Chem) simulations. The...

ID: A209 26 to 28 November, 2018 IASTA 2018 Indian Institue of Technology, Delhi  Black carbon is the most strongly light-absorbing component of particulate matter (PM).  BC is a solid form of mostly pure carbon that absorbs solar radiation (light) at all wavelengths.  BC is formed by incomplete combustion of fossil fuels, biofuels, and biomass....

Extensive measurements of cloud condensation nuclei (CCN) and condensation nuclei (CN) concentrations in the South Asian outflow to the northern Indian Ocean were carried out on board an instrumented research vessel, as part of the Integrated Campaign for Aerosols, gases and Radiation Budget (ICARB) during winter season (January–February 2018). Mea...

This paper presents first of its kind results on the aerosol mass concentrations and size distributions, their chemical properties and columnar aerosol optical depth (AOD) over a high-altitude background site of Lahaul and Spiti valley (32.4°N, 77.6°E, 4080 m a.s.l.) in the western Himalayas, obtained from collocated and concurrent measurements mad...

Aircraft measurements of the vertical profiles of aerosol total number concentrations and size distributions (in the size range of 0.5–20 μm) were made over seven geographically diverse locations of the Indian mainland during two contrasting seasons, winter (December 2012) and spring (April–May 2013), as a part of the regional aerosol warming exper...

Concurrent measurements of the altitude profiles of cloud condensation nuclei (CCN) concentration, as a function of supersaturation (ranging from 0.2 % to 1.0 %), and aerosol optical properties (scattering and absorption coefficients) were carried out aboard an instrumented aircraft across the Indo-Gangetic Plain (IGP) covering coastal, urban and a...

We examine long-term trends in the near-surface black carbon mass concentration, using multiyear primary data obtained from a dense network (ARFINET) of observatories over the Indian region. We report for the first time the statistically significant decreasing trend in black carbon mass concentration, based on primary data from this region, at an a...

Measurements of the vertical profiles of the optical properties (namely the extinction coefficient and scattering and absorption coefficients respectively σext / σscat / σabs) of aerosols have been made across the Indo-Gangetic Plain (IGP) using an instrumented aircraft operated from three base stations – Jodhpur (JDR), representing the semi-arid w...

Carbonaceous aerosols are very important due to their direct effects on health, radiation budget and their indirect effect in altering cloud properties, thus acting as short term climate forcers. Simultaneous measurements of BC, CO, CH4 and CO2 have particular importance in terms of radiation budget, constraining emission sources and tropospheric c...

Measurements of the vertical profiles of the optical properties (namely the extinction/scattering and absorption coefficients; respectively σext/σscat/σabs) of aerosols have been made across the Indo-Gangetic Plain (IGP) using an instrumented aircraft operated from three base stations (Jodhpur (JDR) representing the semiarid western IGP; Varanasi (...

The spectral estimates of Aerosol Optical Depth (AOD, τ) were made by operating a Microtops-II sun photometer in the spectral range 0.380–0.870 μm over Tripura in north-eastern India and analyzed to infer the aerosol types and source characteristics in different seasons. The Ångström exponent (α) derived from spectral AOD in different wavelength (λ...

Ground reaching solar radiation flux was simulated using a 1-dimensional radiative transfer (SBDART) and a 3-dimensional regional climate (RegCM 4.4) model and their seasonality against simultaneous surface measurements carried out using a CNR4 net Radiometer over a sub-Himalayan foothill site of south-east Asia was assessed for the period from Mar...

Long-term monitoring of atmospheric aerosols and their interaction with radiation, cloud, and cryosphere over the Arctic and the Antarctic are very important for the global climate change related issues. In this regard, for conducting aerosol measurements, India has extended the concerted efforts to the Indian stations at the Svalbard region of the...

In order to understand the climatic implications of atmospheric aerosols, top of atmosphere (TOA) shortwave (SW, 0.3–5 µm) fluxes and aerosol optical depth (AOD) at 550 nm retrieved simultaneously by clouds and the earth's radiant energy system (CERES) and moderate resolution imaging spectroradiometer (MODIS) instruments, respectively, are analysed...

Multiyear measurements of spectral properties of aerosol absorption are examined over four geographically distinct locations of northeastern India. Results indicated significant spatiotemporal variation in aerosol absorption coefficients (σabs) with highest values in winter and lowest in monsoon. The western parts of the region, close to the outflo...

Multiyear measurements of spectral properties of aerosol absorption are examined over four geographically distinct locations of northeastern India. Results indicated significant spatiotemporal variation in aerosol absorption coefficients (σ abs) with highest values in winter and lowest in monsoon. The western parts of the region, close to the outfl...

Northeast India (NEI) is located within the boundary of the great Himalayas in the north and the Bay of Bengal (BoB) in the southwest, experiences the mixed influence of the westerly dust advection from the Indian desert, anthropogenic aerosols from the highly polluted Indo-Gangetic Plains (IGP) and marine aerosols from BoB. The present study deals...

Northeast India (NEI) is located within the boundary of the great Himalayas in the north and the Bay of Bengal (BoB) in the southwest, experiences the mixed influence of the westerly dust advection from the Indian desert, anthropogenic aerosols from the highly polluted Indo-Gangetic Plains (IGP) and marine aerosols from BoB. The present study deals...

Aerosol absorption in the lower troposphere over continental India was assessed using extensive measurements of the vertical distribution of absorption coefficients aboard an instrumented aircraft. Measurements were made from seven base stations during winter (November-December 2012) and spring (April-May 2013), supplemented by the data from the ne...