Browsing by Author "Naja, M."

Aerosol vertical profiles strongly affect their radiative forcing uncertainties: study by using ground-based lidar and other measurements

Reddy, K.; Phanikumar, D. V.; Ahammed, Y. N.; Naja, M. (Taylor & Francis, 2013-08-28)

In the present study, we illustrate for the first time that direct aerosol radia- tive forcing has large uncertainty due to diversity in simulated vertical profile of aerosol over Manora Peak, Nainital (considered to be ...

ARIES, Nainital: a strategically important location for climate change studies in the Central Gangetic Himalayan region

Sagar, R.; Dumka, U. C.; Naja, M.; Singh, N.; Phanikumar, D. V. (Indian Academy of Sciences, 2015)

ARIES, acronym for Aryabhatta Research Institute of Observational Sciences, located in the Central Gangetic Himalayan (CGH) region is emerging as one of the unique sites for climate change studies. The long-term, in ...

The changes in near-surface ozone and precursors at two nearby tropical sites during annular solar eclipse of 15 January 2010

Girach, I. A. et. al.; Ojha, N.; Naja, M. (2012)

Studies on the solar eclipse–induced changes in near-surface ozone and its precursors NOx and CO were carried out at two nearby tropical coastal locations, Thumba (very close to the sea) and the Centre for Earth Science ...

Effect of diurnal variation of aerosols on surface reaching solar radiation

Reddy, K.; Phanikumar, D. V.; Joshi, H.; Ahammed, Y. N.; Naja, M. (Elsevier, 2015)

In this report, we attempt to quantify direct aerosol radiative forcing by considering the diurnal variation of aerosols over central Himalayan region. The measured day time aerosol optical depth (AOD) values are higher ...

Effects of dust aerosols on tropospheric chemistry during a typical pre-monsoon season dust storm in northern India

Kumar, R., et al.; Naja, M.; Ojha, N.; Sarangi, T. (The European Geosciences Union., 2014-07-04)

This study examines the effect of a typical pre-monsoon season dust storm on tropospheric chemistry through a case study in northern India. Dust can alter pho- tolysis rates by scattering and absorbing solar radiation ...

Enhanced SO₂ concentrations observed over northern India: role of long-range transport

Mallick, C.; Lala, S.; Naja, M.; Chand, D.; Venkataramani, S.; Joshi, H.; Pant, P. (Taylor & Francis, 2013)

The combustion of fossil fuels (coal and petroleum products) constitutes a source of continuous release of anthropogenic SO₂ into the atmosphere. Furthermore, natural sources such as volcanoes can inject large amounts ...

Estimation of the mixing layer height over a high altitude site in Central Himalayan region by using Doppler lidar

Shukla, K. K.; Phanikumar, D. V.; Newsom, Rob K.; Kumar, K. Niranjan; Ratnam, M. Venkat; Naja, M.; Singh, Narendra (Elsevier, 2014-01-17)

A Doppler lidar was installed at Manora Peak, Nainital (29.4 °N; 79.2°E; 1958 amsl) to estimate mixing layer height for the first time by using vertical velocity variance as basic measurement parameter for the period ...

Front-end digital signal processing scheme for 206.5 MHz atmospheric radar application

Kumar, A.; Bhattacharjee, S.; Naja, M.; Kumar, Phani (2011)

This paper describes the digitization and front-end digital signal processing scheme for the atmospheric Radar operating at 206.5 MHz. The atmospheric Radar operating at this frequency will have the capability to probe ...

Generation, analysis and evaluation of bi-phase complementary pairs

Kumar, A.; Srivastava, A.; Bhattacharjee, S.; Kumar, PHani; Naja, M. (2012)

Bi-phase complementary codes are commonly used in radar application to achieve high resolution spatial and temporal measurements with suppressed range sidelobes. In this paper, a user friendly interactive graphical user ...

Influence of regional pollution and long range transport over western India: analysis of ozonesonde data

Srivastava, S.; Lal, S.; Naja, M.; Venkataramani, S.; Gupta, S. (Elsevier Ltd., 2012)

Four years (April 2003 - July 2007) of ozonesonde observations over Ahmedabad have been studied for the first time using ten days backward trajectories in the boundary layer (lower 2 km) and lower troposphere (2.5-4 km). ...

Influences of the boundary layer evolution on surface ozone variations at a tropical rural site in India

Reddy, K. K.; Naja, M.; Ojha, N.; Mahesh, P.; Lal, S. (2012)

Collocated measurements of the boundary layer evolution and surface ozone, made for the first time at a tropical rural site (Gadanki 13.5◦N, 79.2◦E, 375 m amsl) in India, are presented here. The boundary layer related ...

Influences of the springtime northern Indian biomass burning over the central Himalayas

Kumar, Rajesh; Naja, M.; Satheesh, S. K.; Ojha, N.; Joshi, H.; Sarangi, T.; Dumka, U. C. (AGU, 2011-10-06)

The influences of the springtime northern Indian biomass burning are shown for the first time over the central Himalayas by using three years (2007–2009) of surface and space based observations along with a radiative ...

On the processes influencing the vertical distribution of ozone over the central Himalayas: Analysis of yearlong ozonesonde observations

Ojha, N.; Naja, M.; Sarangi, T.; Kumar, R.; Bhardwaj, P.; Kumar, A. (Elsevier, 2013-01-27)

First yearlong (2011) balloon-borne measurements of ozone vertical distribution (EN-SCI 2ZV7 ECC Ozonesonde) and meteorological parameters (iMet-1-RSB 403 MHz GPS Radiosonde) over Nainital (79.5° E, 29.4° N, 1958 m amsl) ...

Optical properties and CCN activity of aerosols in a high-altitude Himalayan environment: Results from RAWEX-GVAX

Gogoi, M. M.; Babu, S. S.; Jayachandran, V.; Moorthy, K. K.; Satheesh, S. K.; Naja, M.; Kotamarthi, V. R. (American Geophysical Union, 2015-03-23)

The seasonality and mutual dependence of aerosol optical properties and cloud condensation nuclei (CCN) activity under varying meteorological conditions at the high-altitude Nainital site (~2 km) in the Indo-Gangetic ...

Pre-monsoon air quality over Lumbini, a world heritage site along the Himalayan foothills.

Rupakheti, D. et al.; Naja, M. (Atmospheric Chemistry and Physics, 2017-09)

Lumbini, in southern Nepal, is a UNESCO world heritage site of universal value as the birthplace of Buddha. Poor air quality in Lumbini and surrounding regions is a great concern for public health as well as for preservation, ...

Science at high-altitude sites of ARIES – astrophysics and atmospheric sciences

Sagar, R.; Naja, M.; Maheswar, G.; Srivastava, A. K. (INSA, 2014)

In this article we discuss various frontline research activities those are being carried out in the fields of Astronomy and Astrophysics and Atmospheric Sciences at Aryabhatta Research Institute of Observational Sciences ...

Signatures of Rossby wave modulations in aerosol optical depth over the central Himalayan region

Phanikumar, D. V.; Niranjan Kumar, D. K.; Shukla, K. K.; Joshi, H.; Ratnam, M. Venkat; Naja, M.; Reddy, K. (Annales Geophysicae, 2014-02-21)

Long-period modulations are shown in aerosol optical depth measured by the Microtops II Sun photometer over a high-altitude site the central Himalayan region (Nainital, 29.4◦ N, 79.5◦ E, 1958 m a.m.s.l.) for the first ...

Simulations over South Asia using the Weather Research and Forecasting model with Chemistry (WRF-Chem): set-up and meteorological evaluation

Kuamr, R.; Naja, M.; Pfister, G. G.; Barth, M. C.; Brasseur, G. P. (2012)

The configuration and evaluation of the meteorology is presented for simulations over the South Asian region using theWeather Research and Forecasting model coupled with Chemistry (WRF-Chem). Temperature, water vapor, dew ...

Simulations over South Asia using theWeather Research and Forecasting model with Chemistry (WRF-Chem): chemistry evaluation and initial results

Kumar, R.; Naja, M.; Pfister, G. G.; Barth, M. C.; Brasseur, G. P. (2012)

This study presents annual simulations of tropospheric ozone and related species made for the first time using the WRF-Chem model over South Asia for the year 2008. The model-simulated ozone, CO, and NOx are evaluated ...

Source attribution of carbon monoxide in India and surrounding regions during wintertime

Kumar, R.; Naja, M.; Pfister, G.; Barth, M. C.; Brasseur, G. P. (Wiley Online, 2013)

This study presents a CO source contribution analysis for the atmosphere of South Asia during January–February 2008. The approach includes into the Weather Research and Forecasting Model with Chemistry 11 CO tracers, ...

Browsing by Author "Naja, M."

Browsing by Author "Naja, M."

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