Studies of variations in the vertical ozone profiles over India

Mani, A.; Sreedharan, C. R.

doi:10.1007/bf00881070

Cited by 11 publications

(5 citation statements)

References 4 publications

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“…Most of the studies were based on mid and high latitude regions. Long-term variability of atmospheric ozone and regional variation of tropical total column ozone over Indian stations are reported by many authors [5] [20]- [26]. From 1970, observations show that the amount of total ozone on earth's atmosphere is decreasing due to the catalytic destruction of ozone by atomic halogens.…”

Section: Introductionmentioning

confidence: 99%

Temporal Distribution of Total Column Ozone over Cochin—A Study Based on <i>in Situ</i> Measurements and ECMWF Reanalysis

Madhu¹,

Gangadharan²

2016

OJMS

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The variability of Atmospheric ozone is very important to understand the radiative balance of the earth-atmospheric system and climate change. In order to understand the temporal variability of total column ozone (TCO) over the coastal station Cochin (9.95˚N, 76.27˚E), we used the ECMWF (European Centre for Medium-Range Weather Forecasts) reanalysis TCO and ground based measurements using Microtop II Sun Photometer (Ozonometer). The trend, seasonal changes and diurnal variation of ozone concentration have been studied in detail for the period 1981-2014. Cochin is a tropical coastal station with tropical monsoon climate and hence we examined the variability of TCO during pre-monsoon (March-May), monsoon (June-September) and post monsoon (October-December) seasons. Significant variations are noted in the TCO for the different seasons during the period of study. Based on the measurements and analysis, it is observed that TCO is maximum during monsoon and minimum during pre-and post-monsoon. We computed the TCO climatology for pre-monsoon (262.0 DU), monsoon (275 DU) and post-monsoon (253 DU) seasons and found that TCO shows a decadal trend (solar cycle). During monsoon season TCO varies with an increase of approximately 14 DU from the pre-monsoon value and a decrease of 22 DU from the post-monsoon value. The increase in TCO concentration during monsoon may be attributed to the monsoonal wind circulations and organized convection. The validation of ECMWF TCO with in situ measurements using Microtop II Ozonometer has been carried out for the year 2015 and found that the values are positively correlated. The diurnal variability of TCO was examined for vernal and autumnal equinox days and noticed the change in variability.

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Section: Introductionmentioning

confidence: 99%

Temporal Distribution of Total Column Ozone over Cochin—A Study Based on <i>in Situ</i> Measurements and ECMWF Reanalysis

Madhu¹,

Gangadharan²

2016

OJMS

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“…Many have studied the seasonal cycles [21], trends [19] and interannual variability [22] of tropical ozone. A very few studies are available on long-term variations of total ozone over Indian stations [23]- [25]. Ozone data for the period 1957 to 1994 has been used for the trend analysis of total column ozone over Indian stations [26].…”

Section: Introductionmentioning

confidence: 99%

Spatial and Temporal Variability of Total Column Ozone over the Indian Subcontinent: A Study Based on Nimbus-7 TOMS Satellite

Madhu¹

2014

ACS

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How to cite this paper: Madhu, V. (2014) Spatial and Temporal Variability of Total Column Ozone over the Indian Subcontinent: A Study Based on Nimbus-7 TOMS Satellite. Atmospheric and Climate Sciences, 4, 884-898. http://dx. AbstractThe distribution and variability of ozone is very important to the atmospheric thermal structures, and it can exert their greater influence on climate. Present study is based on Nimbus-7 TOMS overpass column ozone for a period of 14 years (1979-1992) over twelve selected Indian stations from south to north latitude and it explores the spatial and temporal variability of Total Column Ozone (TCO). For this investigation an advanced statistical methods such as Factor Analysis and Morlet wavelet transform are employed. Total column ozone variability over these stations is grouped into two clusters (Eigen value greater than 1) by the Multivariate Factor analysis. It is found that the Group I stations shows the same nature of variability mainly due the first factor as the primarily loading and whereas as the Group II stations shows the same nature of variability due to second factor as the primary loading. The correlation value of TCO decreases from 0.9 to 0.32 as we move from south to north stations (lower latitude to higher latitude). The total column ozone over tropical stations is maximum during monsoon season with peak in the month of June and that for the higher latitude stations is during the pre-monsoon season. Annual average of TCO for tropical stations is about 265 DU and that for subtropical stations is about 280 DU and a difference of 15 DU is noted in the annual average of TCO between tropical and subtropical stations. A large reduction in TCO is noted over the Indian subcontinent in the year 1985, the same year in which the ozone hole over Antarctica was discovered. It is also found that two prominent oscillations are present in total column ozone one with a periodicity of 16 to18 months and other with 28 to 32 months (QBO periodicity) apart from the annual oscillations. These oscillations are found to be significant at above 95% level of confidence when tested with Power Spectrum method. Tropical TCO shows high concentration during the westerly phase and low concentration during the easterly phase of the equatorial stratospheric quasi-biennial oscillation.

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“…In India from 1971 onwards, every fortnight ozonesonde launchings have been conducted by the India Meteorological Department (IMD) from three stations (Mani and Sreedharan, 1973) namely Trivandrum (8.4 • N, 76.92 • E), Pune (18.53 • N, 73.85 • E), and New Delhi (28.6 • N, 77.2 • E). Rocketsonde ozone observations from Trivandrum were conducted during 1980-1981 to study the day to night changes of ozone at different levels in the tropical stratosphere and the lower mesosphere.…”

Section: Introductionmentioning

confidence: 99%

Long-term trends in stratospheric ozone, temperature, and water vapor over the Indian region

et al. 2018

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Abstract. We have investigated the long-term trends in and variabilities of stratospheric ozone, water vapor and temperature over the Indian monsoon region using the long-term data constructed from multi-satellite (Upper Atmosphere Research Satellite (UARS MLS and HALOE, 1993-2005), Aura Microwave Limb Sounder (MLS, 2004(MLS, -2015, Sounding of the Atmosphere using Broadband Emission Radiometry (SABER, 2002(SABER, -2015 on board TIMED (Thermosphere Ionosphere Mesosphere Energetics Dynamics)) observations covering the period 1993-2015. We have selected two locations, namely, Trivandrum (8.4 • N, 76.9 • E) and New Delhi (28 • N, 77 • E), covering northern and southern parts of the Indian region. We also used observations from another station, Gadanki (13.5 • N, 79.2 • E), for comparison. A decreasing trend in ozone associated with NO x chemistry in the tropical middle stratosphere is found, and the trend turned to positive in the upper stratosphere. Temperature shows a cooling trend in the stratosphere, with a maximum around 37 km over Trivandrum (−1.71 ± 0.49 K decade −1 ) and New Delhi (−1.15 ± 0.55 K decade −1 ). The observed cooling trend in the stratosphere over Trivandrum and New Delhi is consistent with Gadanki lidar observations during 1998-2011. The water vapor shows a decreasing trend in the lower stratosphere and an increasing trend in the middle and upper stratosphere. A good correlation between N 2 O and O 3 is found in the middle stratosphere (∼ 10 hPa) and poor correlation in the lower stratosphere. There is not much regional difference in the water vapor and temperature trends. However, upper stratospheric ozone trends over Trivandrum and New Delhi are different. The trend analysis carried out by varying the initial year has shown significant changes in the estimated trend.

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Studies of variations in the vertical ozone profiles over India

Cited by 11 publications

References 4 publications

Temporal Distribution of Total Column Ozone over Cochin—A Study Based on <i>in Situ</i> Measurements and ECMWF Reanalysis

Temporal Distribution of Total Column Ozone over Cochin—A Study Based on <i>in Situ</i> Measurements and ECMWF Reanalysis

Spatial and Temporal Variability of Total Column Ozone over the Indian Subcontinent: A Study Based on Nimbus-7 TOMS Satellite

Long-term trends in stratospheric ozone, temperature, and water vapor over the Indian region

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Studies of variations in the vertical ozone profiles over India

Cited by 11 publications

References 4 publications

Temporal Distribution of Total Column Ozone over Cochin—A Study Based on &lt;i&gt;in Situ&lt;/i&gt; Measurements and ECMWF Reanalysis

Temporal Distribution of Total Column Ozone over Cochin—A Study Based on &lt;i&gt;in Situ&lt;/i&gt; Measurements and ECMWF Reanalysis

Spatial and Temporal Variability of Total Column Ozone over the Indian Subcontinent: A Study Based on Nimbus-7 TOMS Satellite

Long-term trends in stratospheric ozone, temperature, and water vapor over the Indian region

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Temporal Distribution of Total Column Ozone over Cochin—A Study Based on <i>in Situ</i> Measurements and ECMWF Reanalysis

Temporal Distribution of Total Column Ozone over Cochin—A Study Based on <i>in Situ</i> Measurements and ECMWF Reanalysis