Current Science

Sachin D. Ghude ¹, C. K. Jena ¹, G. Beig ¹, Rajesh Kumar ², S. H. Kulkarni ³, D. M. Chate ¹

Affiliations
1 Indian Institute of Tropical Meteorology, Dr Homi Bhabha Road, Pune 411 008, IN
2 National Center for Atmospheric Research, Boulder Co, US
3 Centre for Development of Advance Computing, Pune 411 007,, IN

Abstract

In this study, we evaluate the potential impact of ground level ozone (O₃) on rice and wheat yield in top 10 states in India during 2005. This study is based on simulated hourly O₃ concentration from the Weather Research and Forecasting model coupled with Chemistry (WRF-Chem), district-wise seasonal crop production datasets and accumulated daytime hourly O₃ concentration over a threshold of 40 ppbv (AOT40) indices to estimate crop yield damage resulting from ambient O₃ exposure. The response of nitrogen oxides (NO_x) and volatile organic compounds (VOC) mitigation action is evaluated based on ground level O₃ simulations with individual reduction in anthropogenic NO_x and VOC emissions over the Indian domain. The total loss of wheat and rice from top 10 producing states in India is estimated to be 2.2 million tonnes (3.3%) and 2.05 million tonnes (2.5%) respectively. Sensitivity model study reveals relatively 93% decrease in O₃-induced crop yield losses in response to anthropogenic NO_x emission mitigation. The response of VOC mitigation action results in relatively small changes of about 24% decrease in O₃-induced crop yield losses, suggesting NO_x as a key pollutant for mitigation. VOC also contribute to crop yield reduction but their effects are a distant second compared to NO_x effects.

Keywords

AOT40, Chemical Transport Model, Crop Damage, Ozone, Yield Loss.

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Sachin D. Ghude ¹, G. S. Bhat ², Thara Prabhakaran ¹, R. K. Jenamani ³, D. M. Chate ¹, P. D. Safai ¹, A. K. Karipot ⁴, M. Konwar ¹, Prakash Pithani ¹, V. Sinha ⁵, P. S. P. Rao ¹, S. A. Dixit ¹, S. Tiwari ¹, K. Todekar ¹, S. Varpe ¹, A. K. Srivastava ¹, D. S. Bisht ¹, P. Murugavel ¹, Kaushar Ali ¹, Usha Mina ⁶, M. Dharua ¹, J. Rao ¹, B. Padmakumari ¹, A. Hazra ¹, N. Nigam ³, U. Shende ³, D. M. Lal ¹, B. P. Chandra ⁵, A. K. Mishra ⁵, A. Kumar ⁵, H. Hakkim ⁵, H. Pawar ⁵, P. Acharja ¹, Rachana Kulkarni ¹, C. Subharthi ¹, B. Balaji ¹, M. Varghese ¹, S. Bera ¹, M. Rajeevan ⁷

Affiliations
1 Indian Institute of Tropical Meteorology, Pashan, Pune 411 008, IN
2 Indian Institute of Science, Bengaluru 560 012, IN
3 India Meteorological Department, New Delhi 110 003, IN
4 Savitribai Phule Pune University, Pune 411 007, IN
5 Indian Institute of Science Education and Research Mohali, Mohali 140 306, IN
6 Indian Agricultural Research Institute, Pusa, New Delhi 110 012, IN
7 Ministry of Earth Sciences, Government of India, New Delhi 110 003, IN

Abstract

The objectives of the Winter Fog Experiment (WIFEX) over the Indo-Gangetic Plains of India are to develop better now-casting and forecasting of winter fog on various time- and spatial scales. Maximum fog occurrence over northwest India is about 48 days (visibility <1000 m) per year, and it occurs mostly during the December-February time-period. The physical and chemical characteristics of fog, meteorological factors responsible for its genesis, sustenance, intensity and dissipation are poorly understood. Improved understanding on the above aspects is required to develop reliable forecasting models and observational techniques for accurate prediction of the fog events. Extensive sets of comprehensive ground-based instrumentation were deployed at the Indira Gandhi International Airport, New Delhi. Major in situ sensors were deployed to measure surface micro-meteorological conditions, radiation balance, turbulence, thermodynamical structure of the surface layer, fog droplet and aerosol microphysics, aerosol optical properties, and aerosol and fog water chemistry to describe the complete environmental conditions under which fog develops. In addition, Weather Forecasting Model coupled with chemistry is planned for fog prediction at a spatial resolution of 2 km. The present study provides an introductory overview of the winter fog field campaign with its unique instrumentation.

Keywords

Aerosols, Atmospheric Profiles, Forecasting, Winter Fog.

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B. P. Chandra ¹, V. Sinha ¹, H. Hakkim ¹, A. Kumar ¹, H. Pawar ¹, A. K. Mishra ¹, G. Sharma ¹, Pallavi ¹, S. Garg ¹, Sachin D. Ghude ², D. M. Chate ², Prakash Pithani ², Rachana Kulkarni ², R. K. Jenamani ³, M. Rajeevan ⁴

Affiliations
1 Department of Earth and Environmental Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, S.A.S. Nagar, Manauli PO 140 306, IN
2 Indian Institute of Tropical Meteorology, Pashan, Pune 411 008, IN
3 India Meteorological Department, New Delhi 110 003, IN
4 Ministry of Earth Sciences, Government of India, New Delhi 110 003, IN

Abstract

We studied the impact of the odd–even traffic rule (implemented in Delhi during 1–15 January 2016) on primary traffic emissions using measurements of 13 volatile organic compounds, carbon monoxide, carbon dioxide and methane at a strategic arterial road in Delhi (28.57°N, 77.11°E, 220 m amsl). Whole air samples (n = 27) were collected during the odd–even rule active (OA) and inactive (OI) days, and analysed at the IISER Mohali Atmospheric Chemistry Facility. The average mass concentration ranking and toluene/benzene ratio were characteristic of primary traffic emissions in both OA and OI samples, with the largest fraction comprising aromatic compounds (55– 70% of total). Statistical tests showed likely increase (p ≤ 0.16; OA > OI) in median concentration of 13 out of 16 measured gases during morning and afternoon periods (sampling hours: 07 : 00–08 : 00 and 13 : 30–14 : 30 IST), whereas no significant difference was observed for evening samples (sampling hour: 19 : 00–20 : 00 IST). This suggests that many four-wheeler users chose to commute earlier, to beat the 8 : 00 AM–8 : 00 PM restrictions, and/or there was an increase in the number of exempted public transport vehicles. Thus, the odd–even rule did not result in anticipated traffic emission reductions in January 2016, likely due to the changed temporal and fleet emission behaviour triggered in response to the regulation.

Keywords

Odd–Even Rule, Pollution, PTR-MS, Traffic, VOCs.

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Sachin D. Ghude ¹, Rajesh Kumar ², Chinmay Jena ¹, Sreyashi Debnath ¹, Rachana G. Kulkarni ¹, Stefano Alessandrini ², Mrinal Biswas ², Santosh Kulkrani ³, Prakash Pithani ¹, Saurab Kelkar ¹, Veeresh Sajjan ¹, D. M. Chate ¹, V. K. Soni ⁴, Siddhartha Singh ⁴, Ravi S. Nanjundiah ¹, M. Rajeevan ⁵

Affiliations
1 Indian Institute of Tropical Meteorology, Ministry of Earth Sciences, Pune 411 008, IN
2 National Center for Atmospheric Research, Boulder, CO 80301, US
3 Centre for Development of Advanced Computing, Pune 411 008, IN
4 India Meteorological Department, Ministry of Earth Sciences, New Delhi 110 003, IN
5 Ministry of Earth Sciences, Government of India, New Delhi 110 003, IN

Abstract

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 applied to improve the PM2.5 forecast via assimilation of MODIS aerosol optical depth retrievals using threedimensional variational data analysis scheme. Near real-time MODIS fire count data were applied simultaneously to adjust the fire-emission inputs of chemical species before the assimilation cycle. Carbon monoxide (CO) emissions from biomass burning, anthropogenic emissions, and CO inflow from the domain boundaries were tagged to understand the contribution of local and non-local emission sources. We achieved significant improvements for surface PM2.5 forecast with joint adjustment of initial conditions and fire emissions.

Keywords

Air Quality, Particulate Matter, Chemical Data Assimilation, Aerosol Optical Depth, Fire Emissions.

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