Tropospheric ozone (TOR) trend over three major inland Indian cities: Delhi, Hyderabad and Bangalore

Pavan S. Kulkarni,Sachin D. Ghude,D. Bortoli

doi:10.5194/angeo-28-1879-2010

Abstract

Abstract. An analysis of tropospheric column ozone using the NASA Langley TOR data during 1979–2005 has been done to investigate the trend over major Indian cities Delhi, Hyderabad and Bangalore. India was under social democratic-based policies before 1990s. Economic Liberalization began in nineties which lead to a significant growth in industrial, energy and transport sectors in major cities. Our analysis shows that there is a systematic increase in the number of months with higher tropospheric ozone values after 1990. A comparison of TOR climatology before and after 1990 over these cities shows evidence of increase in the tropospheric ozone after 1990. Trend obtained from the model shows significant change during monsoon over Delhi and during pre-monsoon and post-monsoon over Hyderabad and Bangalore. The present analysis using TOR technique demonstrates the TOR potential to detect changes in tropospheric ozone over large cities which are impacted by large anthropogenic pollution.

Highlights

Tropospheric ozone (O3) is one of the most important greenhouse gases (Mickley et al, 2001) and contributes to global warming and climate change
While numerous studies have been conducted in Europe, North America, and Japan (Logan, 1985, 1994; Liu et al, 1987; Oltmans et al, 1998; Monks, 2000; Akimoto et al, 1994; Pochanart et al, 2002), there is limited knowledge of the temporal and spatial distribution of tropospheric O3 in India where rapid urbanization and industrial developments have been taken place in the latest decades
We examine the change in the climatology in tropospheric O3 between 1979–1989 and 1990–2005 and temporal distribution of O3 and trend during 1979–2005 over these cities

Summary

Introduction

Tropospheric ozone (O3) is one of the most important greenhouse gases (Mickley et al, 2001) and contributes to global warming and climate change. Available few scattered ground-based measurements within India have shown frequent O3 pollution during photo-chemically active seasons in urban areas (Naja and Lal, 2002; Jain et al, 2005; Ghude et al, 2006) All these studies seldom describe long term changes in tropospheric ozone, except over cities like Ahamadebad and Delhi (Lal et al, 2002; Ghude et al, 2009) where increasing daytime surface ozone has been reported. Considering the potential of large economic development in and around the major cities Delhi, Hyderabad and Bangalore, one can expect enhancement of anthropogenic activities such as increased consumption of fossil fuel and large scale industrialization This will result in extra burden of pollution in troposphere, which can lead to further increase in ozone concentration over these cities. Tropospheric ozone Jan 1979 to Dec 2005 Monthly data 57 Months, 17.6% (Aug 1990, Mar 1991, May 1993 to Sep 1997 and Nov–Dec 1998) 50◦ S to 50◦ N 1.00◦ latitude by 1.25◦ longitude

Dataset

Trends in tropospheric O3

Findings

Conclusion