Sachin Ghude

• Indian Institute of Tropical Meteorology

Air quality in India faces significant risk from agricultural residue burning, especially in Punjab and Haryana, which are pivotal to the world's second‐largest agrarian economy. This study quantifies emissions from post‐monsoon biomass burning (10 October–30 November 2022) in these states using VIIRS fire detection data and Sentinel‐2‐derived burn...

Rapid urbanization has subjected the megacities of developing countries to various environmental stresses. Delhi, a major Indian megacity, faces increasing urban stress leading to reduction in air quality, and visibility. These challenges necessitate an integrated modeling framework to mitigate adverse environmental impacts on public health. Theref...

Volatile organic compounds (VOCs) significantly impact the atmospheric chemistry of polluted megacities. Delhi is a dynamically changing megacity, and yet our knowledge of its ambient VOC composition and chemistry is limited to few studies conducted mainly in winter before 2020 (all pre-COVID-19). Here, using a new extended volatility range high-ma...

Air pollution poses a significant environmental risk to large cities worldwide, including New Delhi, India's capital. Occurrence of frequent episodes of elevated levels of air pollution during October to March in Delhi and National Capital Tertiary (Delhi-NCT) chokes its ∼32 million residents every year. Current air quality models lack the ability...

Accurate fog prediction in densely urbanized cities poses a challenge due to the complex influence of urban morphology on meteorological conditions in the urban roughness sublayer. This study implemented a coupled WRF‐Urban Asymmetric Convective Model (WRF‐UACM) for Delhi, India, integrating explicit urban physics with Sentinel‐updated USGS land‐us...

This study presents an innovative approach to creating a dynamic, AI based emission inventory system for use with the Weather Research and Forecasting model coupled with Chemistry (WRF Chem), designed to simulate vehicular and other anthropogenic emissions at satellite detectable resolution. The methodology leverages state of the art deep learning...

Volatile organic compounds (VOCs) and particulate matter (PM) are major constituents of smog. Delhi experiences severe smog during the post-monsoon season, but a quantitative understanding of VOCs and PM sources is still lacking. Here, we conduct a source apportionment study for VOCs and PM using a recent (2022), high-quality dataset of 111 VOCs, P...

Several major Indian cities experience elevated PM2.5 concentrations, particularly during the winter season. Effective air quality management in these densely populated urban areas necessitates a comprehensive understanding of the diverse emission sources contributing to air pollution. This study investigates PM2.5 pollution in 53 million-plus popu...

With the changing climate, the study of fog formation is essential due to the impact of the complexity of natural and anthropogenic aerosols. The evolution of the droplet size distribution in the presence of different aerosol species remains poorly understood. To make progress towards reducing the uncertainty of fog forecasts, the Eulerian–Lagrangi...

Winter fog and severe aerosol loading in the boundary layer over northern India, particularly in the Indo-Gangetic Plain (IGP), disrupt the daily lives of millions of people in the region. To better understand the role of aerosol–radiation (AR) feedback on the occurrence, spatial extent, and persistence of winter fog, as well as the associated aque...

Predicting fog with present numerical weather prediction models is challenging due to the complex processes involved in its formation. In addition, the performance of the models varies depending on the specific types of fog. To understand better, we first designed an objective-based algorithm to classify different prevailing dense fog types in the...

This paper discusses the newly developed Decision Support System version 1.0 (DSS v1.0) for air quality management activities in Delhi, India. In addition to standard air quality forecasts, DSS provides the contribution of Delhi, its surrounding districts, and stubble-burning fires in the neighboring states of Punjab and Haryana to the PM2.5 load i...

Accurately predicting fog is challenging due to interplay of myriad processes in its formation and high spatiotemporal variability. This study compares the performance of the Weather Research and Forecasting model with control (CNTL‐WRF) and assimilated fine‐grid (HRLDAS‐WRF) soil fields in the Ingo‐Gangetic Plain (IGP) over a 2‐years winter period...

Dense wintertime fog regularly impacts Delhi, severely affecting road and rail transport, aviation and human health. Recent decades have seen an unexplained increase in fog events over northern India, coincident with a steep rise in wintertime irrigation associated with the introduction of double-cropping. Accurate fog forecasting is challenging du...

Volatile organic compounds significantly impact the atmospheric chemistry of polluted megacities. Delhi is a dynamically changing megacity and yet our knowledge of its ambient VOC composition and chemistry is limited to few studies conducted mainly in winter before 2020 (all pre-covid). Here, using a new extended volatility range high mass resoluti...

Volatile organic compounds (VOCs) and particulate matter (PM) are major constituents of smog. Delhi experiences severe smog during post-monsoon season, but a quantitative understanding of VOCs and PM sources is still lacking. Here, we source-apportioned VOCs and PM, using a high-quality recent (2022) dataset of 111 VOCs, PM2.5, and PM10 using posit...

Non-technical summary Greenhouse gas emissions and land use change – from deforestation, forest degradation, and agricultural intensification – are contributing to climate change and biodiversity loss. Important land-based strategies such as planting trees or growing bioenergy crops (with carbon capture and storage) are needed to achieve the goals...

Accurate fog prediction in densely urbanized cities poses a challenge due to the complex influence of urban morphology on meteorological conditions in the urban roughness sublayer. This study implemented a coupled WRF-Urban Asymmetric Convective Model (WRF-UACM) for Delhi, India, integrating explicit urban physics with Sentinel-updated USGS land-us...

Winter fog and severe aerosol loading in the boundary layer over north India, especially in the Indo-Gangetic Plain (IGP), cause disruption in the daily lives of millions of people in the region. To understand better the role of atmospheric aerosols on the occurrence, spatial extent, and persistence of winter fog in the IGP, several model simulatio...

The Indo-Gangetic Plain (IGP) experiences severe air pollution every winter, with ammonium chloride and ammonium nitrate as the major inorganic fractions of fine aerosols. Many past attempts to tackle air pollution in the IGP were inadequate, as they targeted a subset of the primary pollutants in an environment where the majority of the particulate...

Climate change and human activity have increased fires in India. Fine particulate matter (\(\hbox {PM}_{2.5}\)) is released into the atmosphere by stubble burning in Punjab and Haryana and forest fires in the north-eastern and central areas of the country. Accurate short-term \(\hbox {PM}_{2.5}\) estimates are essential to protect human health and...

Stubble-burning in northern India is an important source of atmospheric particulate matter (PM) and trace gases, which significantly impact local and regional climate, in addition to causing severe health risks. Scientific research on assessing the impact of these burnings on the air quality over Delhi is still relatively sparse. The present study...

The ability of a chemical transport model to simulate accurate meteorological and chemical processes depends upon the physical parametrizations and quality of meteorological input data such as initial/boundary conditions. In this study, weather research and forecasting model coupled with chemistry (WRF-Chem) is used to test the sensitivity of PM2.5...

This paper discusses the newly developed Decision Support System version 1.0 (DSS v1.0) for air quality management activities in Delhi, India. In addition to standard air quality forecasts, DSS provides the contribution of Delhi, its surrounding districts, and stubble-burning fires in the neighboring states of Punjab and Haryana to the PM2.5 load i...

The presence of persistent heavy fog in northern India during winter creates hazardous situations for transportation systems and disrupts the lives of about 400 million people. The meteorological factors responsible for its genesis and predictability are not yet completely understood in this region. Given its high potential for socio-economic impac...

The Indo-Gangetic plains (IGP) region spreading across the northern parts of India is prone to fog formations during the winter season. The increasing dense fog episodes over the past few decades due to dipping temperatures and negative anomalies in the region are creating concern for the aviation and transportation sectors, particularly at the Ind...

The Winter Fog Experiment (WiFEX) was an intensive field campaign conducted at Indira Gandhi International Airport (IGIA) Delhi, India, in the Indo-Gangetic Plain (IGP) during the winter of 2017–2018. Here, we report the first comparison in South Asia of high-temporal-resolution simulation of ammonia (NH3) along with ammonium (NH4+) and total NHx (...

Increasing concentrations of air pollutant are directly affecting human health and crop production and shown to have negative impact on economic sector of India. Similarly, wintertime fog in India severely hinders the flight operations and causes significant financial losses to the aviation industry. It is therefore important to undertake a quantit...

The current study highlights the importance of a detailed representation of urban processes in numerical weather prediction models and emphasizes the need for accurate urban morphology data for improving the near‐surface weather prediction over Delhi, a tropical Indian city. The Met Office Reading Urban Surface Exchange Scheme (MORUSES), a two‐tile...

The Indo-Gangetic Plain (IGP) experiences severe air pollution every winter, with ammonium chloride and ammonium nitrate as the major inorganic fractions of fine aerosols. Many past attempts to tackle air pollution in the IGP were inadequate, as they targeted a subset of the primary pollutants in an environment where the majority of the particulate...

The spread of the COVID-19 pandemic forced the administration to lock down in many countries globally to stop the spread. As the lockdown phase had only the emergency use of transportation and most of the industries were shut down, there was an apparent reduction in pollution. With the end of the lockdown period, pollution is returning to its regul...

One of the well-known challenges of fog forecasting is the high spatio-temporal variability of fog. An ensemble forecast aims to capture this variability by representing the uncertainty in the initial/lateral boundary conditions (ICs/BCs) and model physics. The present study highlights a new operational Ensemble Forecast System (EFS) developed by t...

Many recent studies have highlighted a decreasing trend in the pre-monsoon dust loading over the Indian subcontinent, which has motivated us to investigate and quantify the effect of reduced dust emissions on the ISMR. Our analyses show that reducing dust emissions significantly alters the spatial distribution of seasonal mean monsoon rainfall. The...

The Indo-Gangetic Plain experiences significant air pollution during the winter, affecting hundreds of millions of people. During the WiFEX (Winter Fog Experiment) campaign in the winter of 2016-2017, we conducted unprecedented measurements and source studies of 52 NMHCs (25 alkanes, 16 aromatics, 10 alkenes, and one alkyne) in the cities of Delhi...

The campaign mode observational program 'Winter Fog Experiment' (WiFEX) was set up at the Indira Gandhi International Airport (IGIA), New Delhi, during the winter months of 2016–17 and 2017–18. Using the WiFEX data, in this study, we examine the microphysical structure of fog formed in a polluted environment and attempt to predict visibility (Vis)...

To improve ambient air quality, India has laid out strict action plans to reduce the increment in emissions over regional to urban scale by the year 2030. This study evaluates policy-induced improvement in air quality and associated health benefits achievable due to reduction in PM2.5 exposure under the adoption of promulgated (S2) and ambitious pr...

The present study aims to understand the three-dimensional structure of a dense fog event during the Winter Fog Experiment (WiFEX) 2016–2017 carried out at the Indira Gandhi International Airport (IGIA). The event is analysed with the help of ground-based measurements and the Weather Research and Forecasting (WRF) model. Sensitivity experiments wer...

The present study highlights the role of high-resolution land data assimilation in improving the prediction of the radiation fog and near-surface meteorological variables. The performance of the Weather Research and Forecasting (WRF) model coupled with the High-Resolution Land Data Assimilation System (HRLDAS) is evaluated for a dense fog event tha...

A suitable parameterization of heterogeneous ice nucleation (HIN) is essential for the effective simulation of ice processes in climate models and comprehending their interactions with aerosols. In this study, the influence of HIN formulations in Morrison two-moment bulk cloud microphysical scheme of the Weather Research and Forecasting (WRF-ARW) m...

Three major sequential widespread dust events were experienced in the northern parts of India in May 2018. A significant impact of these pre-monsoon dust storms on the aerosol characteristics over the Indian National capital region (NCR) has been studied using remotely sensed ceilometer and ground-based measurements at Indira Gandhi International a...

The Winter Fog Experiment (WiFEX) was an intensive field campaign conducted at Indira Gandhi International Airport (IGIA) Delhi, India, in the Indo-Gangetic Plain during the winter of 2017–2018. Here, we report the first comparison in South Asia of the high temporal resolution measurements of NH3 along with water-soluble inorganic ions in PM2.5 (Cl...

The Indian Institute of Tropical Meteorology (IITM), in partnership with the National Center for Atmospheric Research (NCAR), has developed a high resolution (400 m) air-quality Early Warning System (EWS) for Delhi using an advanced approach of assimilating aerosol optical depth, fire emissions from a space-borne platform, and real-time aerosol obs...

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 Mahar...

Stubble-burning in northern India is an important source of atmospheric particulate matter (PM) and trace gases, which significantly impact local and regional climate, in addition to causing severe health risks. Scientific research on assessing the impact of these burnings on the air quality over Delhi is still relatively sparse. The present study...

The association between aerosol and lightning has been investigated with long-term decadal data (2005-2014) for lightning, aerosol optical depth (AOD), relative humidity, and effective cloud droplet size. To understand the complex relationship between aerosol and lightning, two different regions with different climatic and weather conditions, a hum...

The Indo-Gangetic Plain (IGP) has high wintertime fine aerosol loadings that significantly modulate the widespread fog formation and sustenance. Here, we investigate the potential formation of secondary inorganic aerosol driven by excess ammonia during winter fog. Physicochemical properties of fine aerosols (PM1 and PM2.5) and trace gases (HCl, HON...

This research aims to understand the role of the initial hygroscopicity of aerosol particles, scavenging mechanisms and of aqueous chemistry in the evolution of the aerosol size distribution. A box model with a size resolving moving bin scheme is used to simulate the fog events over Budapest (Hungary) and Delhi (India). The results from the study a...

Accurate representations of soil state (soil moisture and soil temperature) in numerical weather prediction (NWP) model is crucial for better prediction of large-scale (synoptic) to small-scale (eddies) weather activities. In this sense, land data assimilation has been performed by direct improvisation in the initial fields of soil state in recent...

The Indian subcontinent is a major hotspot of enhanced aerosol loading and emission of various chemical compounds due to extensive anthropogenic activities that profoundly impact the hydrological cycle of this region. Using coupled regional atmospheric chemistry transport model, WRF-Chem (Weather Research and Forecasting model coupled with chemistr...

Poster Code: MANGO-6C

Dense fog events and their micrometeorological characteristics and structural evolution at Indira Gandhi International Airport (IGIA), New Delhi, during the Winter Fog Experiment (WiFEX) are illustrated in this study. Four dense fog events that occurred in January 2016 for which visibility dropped below 200 m have been selected. Depending on the vi...

Widespread catastrophic fog episodes in polluted northern India have been attributed to tropical cyclone activity in the Bay of Bengal & Arabian Sea; however, limited studies have been conducted on the effect of tropical cyclone intensity (‘T’ Numbers) on different fog characteristics in Indo Gangetic Basin, Northern India. In this study, different...

During wintertime, the Indo-Gangetic Plain suffers from severe air pollution affecting several hundred million people. Here we present unprecedented measurements and source analyses of 52 NMHCs (25 alkanes, 16 aromatics, 10 alkenes and one alkyne) in the cities of Delhi and Mohali (300 km north of Delhi) during wintertime (Dec 2016–Jan 2017). NMHCs...

Global urban population is projected to double by 2050. This rapid urbanization is the driver of economic growth but has environmental challenges. To that end, there is an urgent need to understand, simulate and disseminate information about extreme events, routine city operations and long term planning decisions. This paper describes an effort un...

This paper presents a relationship of lightning activity with maximum air temperature, Bowen ratio, rainfall, cloud ice contents and Aerosol Optical Depth (AOD) over India during transition period from dry to wet seasons. Lightning flash count data and weather parameters are retrieved from the Tropical Rainfall Measuring Mission (Lightning Imaging...

Ice nucleating particles (INPs) concentration in deposition mode was measured and reported for a polluted urban site in New Delhi, India. The measurements were carried out during the winter period from December 2016 to January 2017. The INPs data, sampled under different meteorological conditions, were analysed using a thermal gradient static diffu...

Limited availability of atmospheric ammonia (NH3) observations limits our understanding of controls on its spatial and temporal variability and its interactions with the ecosystem. Here we used the Model for Ozone and Related chemical Tracers version 4 (MOZART-4) global chemistry transport model and the Hemispheric Transport of Air Pollution versio...

Comprehensive measurements were conducted to simultaneously monitor the trace gases (HCl, HONO, HNO3, SO2, and NH3) and inorganic chemical constituents (Cl-, NO3 -, SO42-, Na+, NH4+, K+, Ca2+, and Mg2+) of fine particulates (PM1 and PM2.5) at hourly resolution during the Winter Fog Experiment (WIFEX) field campaign, Delhi, India, for the winter per...

Comprehensive measurements were conducted to simultaneously monitor the trace gases (HCl, HONO, HNO3, SO2, and NH3) and inorganic chemical constituents (Cl-, NO3 -, SO42-, Na+, NH4+, K+, Ca2+, and Mg2+) of fine particulates (PM1 and PM2.5) at hourly resolution during the Winter Fog Experiment (WIFEX) field campaign, Delhi, India, for the winter per...

This paper presents the lightning activity, aerosol optical depth (AOD) and climatic parameters (Bowen ratio, relative humidity, rainfall, maximum surface temperature and maximum updraft speed) over wet (Northeast India—NEI) and dry (Northwest India—NWI) land surfaces in a comparative analysis. The analyses are performed on flash counts and weather...

This study reports a very high-resolution (400 m grid-spacing) operational air quality forecasting system developed to alert residents of Delhi and the National Capital Region (NCR) about forthcoming acute air pollution episodes. Such a high-resolution system has been developed for the first time and is evaluated during October 2019-February 2020....

Three major sequential widespread dust events were experienced in the northern parts of India in May 2018. A significant impact of these pre-monsoon dust storms on the aerosol characteristics over the Indian National capital region (NCR) has been studied using remotely sensed ceilometer and ground-based measurements at Indira Gandhi International (...

In the last six decades, the consumption of reactive nitrogen (Nr) in the form of fertilizer in India has been growing rapidly, whilst the nitrogen use efficiency (NUE) of cropping systems has been decreasing. These trends have led to increasing environmental losses of Nr, threatening the quality of air, soils, and fresh waters, and thereby endange...

Thunderstorms source of lightning discharge is a major hazard to humans. In India, the loss of human life due to thunderstorms is high because of frequent lightning during pre-monsoon season (March-May). Therefore, simulation of lightning flash counts based on various lightning parameterization schemes and Lightning Potential Index (LPI) in Weather...

Measurement of boundary-layer carbon monoxide (CO) concentration at Maitri (70.46S, 11.44E, 140 masl), Schirmacher region of east Antarctica was conducted over a 6-week period during February 1–March 14, 2003 (austral summer). A systematical diurnal cycle of CO concentration coinciding with the diurnal cycle of solar actinic radiation at a snow-cov...

The occurrence of thick fog for longer duration in the northern regions of India disturbs the aviation, road transportation and other day to day activities. To understand the turbulence properties during fog period, we measured the atmospheric turbulent parameters along with carbon dioxide concentrations in the atmospheric boundary layer using eddy...

Elevated levels of fine particulate matter (PM2.5) during winter-time have become one of the most important environmental concerns over the Indo-Gangetic Plain (IGP) region of India, and particularly for Delhi. Accurate reconstruction of PM2.5, its optical properties, and dominant chemical components over this region is essential to evaluate the pe...

This paper examines the accuracy of Weather Research and Forecasting model coupled with Chemistry (WRF‐Chem) generated 72 hr fine particulate matter (PM2.5) forecasts in Delhi during the crop residue burning season of October‐November 2017 with respect to assimilation of the Moderate Resolution Imaging Spectroradiometer (MODIS) aerosol optical dept...

Limited availability of atmospheric ammonia (NH3) observations, limits our understanding of controls on its spatial and temporal variability and its interactions with ecosystems. Here we used the Model for Ozone and Related chemical Tracers (MOZART-4) global chemistry transport model and the Hemispheric Transport of Air Pollution version-2 (HTAP-v2...

Air quality has become one of the most important environmental concerns for Delhi, India. In this perspective , we have developed a high-resolution air quality prediction system for Delhi based on chemical data assimilation in the chemical transport model-Weather Research and Forecasting with Chemistry (WRF-Chem). The data assimilation system was a...

The impact of aerosols on cloud microphysical properties, as well as precipitation during a wintertime hot weather event, occurred in February 2016 is analyzed. The chemistry module embedded within Weather Research and Forecasting model (WRF-Chem) is primarily used for this study. During the pre-mature and mature phases of the event, hot and dry we...

The impact of aerosols on cloud microphysical properties, as well as precipitation during a wintertime hot weather event, occurred in February 2016 is analyzed. The chemistry module embedded within Weather Research and Forecasting model (WRF-Chem) is primarily used for this study. During the pre-mature and mature phases of the event, hot and dry we...

The effect of relative humidity and temperature on the submicron aerosol variability and its ageing process was studied over a high altitude site, Mahabaleshwar in south-west India. The mass composition of non-refractory particulate matter of 1 μm (NR-PM1) size was obtained using Time of Flight Aerosol Chemical Speciation Monitor (ToF-ACSM) along w...

The occurrence of thick fog for longer duration in the northern regions of India disturbs the aviation, road transportation and other day to day activities. To understand the turbulence properties during fog period, we measured the atmospheric turbulent parameters along with carbon dioxide concentrations in the atmospheric boundary layer using eddy...

Editorial: Human perception on climate change as a natural disaster demands management solutions of remediation, mitigation, and resilience in sustainable, eco-friendly, and economic manner. A better solution however always demands more detailed examination. Hence, any detailed study or team effort at a given time remains inadequate or incomplete f...

Numerical simulations of a thunderstorm event that occurred in the pre‐monsoon season over the North‐Eastern region of India (NEI) and Bangladesh are performed using Weather Research and Forecasting (WRF) Advanced Research Weather Research and Forecasting Model (ARW, version 3.8.1). Doppler weather radar indicates severe convective activity lasted...