Follow the
evidence.

The Influence of Pollution on the Shortwave Albedo of Clouds

S. Twomey

Journal of the Atmospheric Sciences 34, 1149–1152

Physical treatment of how droplet number affects cloud optical thickness and shortwave reflection under specified assumptions.

Balloon-borne photometric studies of the stratospheric aerosol layer after Mt. Pinatubo eruption

S. Ramachandran, A. Jayaraman, Y. B. Acharya & B. H. Subbaraya

Journal of Geophysical Research 99(D8), 16771–16777

Hyderabad flights: 26 October 1991 and 20 April 1992. Direct and scattered solar radiation used to retrieve vertical aerosol properties.

Mode radius and asymmetry factor of Mt. Pinatubo volcanic aerosols from balloon-borne optical measurements over Hyderabad during October 1991

S. Ramachandran, A. Jayaraman, Y. B. Acharya & B. H. Subbaraya

Geophysical Research Letters 21(18), 2011–2014

Particle size and directional scattering were inferred from optical observations, using an assumed size distribution.

Pinatubo volcanic aerosol layer decay observed at Ahmedabad (23°N), India, using neodymium:yttrium/aluminium/garnet backscatter lidar

A. Jayaraman, S. Ramachandran, Y. B. Acharya & B. H. Subbaraya

Journal of Geophysical Research 100(D11), 23209–23214

532 nm lidar observations from April 1992 to May 1994. Decay estimates depend on the observable and particle assumptions.

Compact light-emitting-diode sun photometer for atmospheric optical depth measurements

Y. B. Acharya, A. Jayaraman, S. Ramachandran & B. H. Subbaraya

Applied Optics 34(7), 1209–1214

LED detector and logarithmic electronic response. Calibration and spectral response are central to the measurement.

Direct observations of aerosol radiative forcing over the tropical Indian Ocean during the January–February 1996 pre-INDOEX cruise

A. Jayaraman, D. Lubin, S. Ramachandran, V. Ramanathan, E. Woodbridge, W. D. Collins & K. S. Zalpuri

Journal of Geophysical Research 103, 13827–13836

The 1996 campaign preceded the 1999 intensive phase of the Indian Ocean Experiment.

Latitude gradient in aerosol properties across the Inter Tropical Convergence Zone: Results from the joint Indo-US study onboard Sagar Kanya

A. Jayaraman, S. K. Satheesh, A. P. Mitra & V. Ramanathan

Current Science 80, supplement, 128–137

Cruise: 20 January–12 March 1999. Column optical depth and near-surface physical and optical measurements across contrasting air masses.

Indian Ocean Experiment: An integrated analysis of the climate forcing and effects of the great Indo-Asian haze

V. Ramanathan et al., including A. Jayaraman

Journal of Geophysical Research: Atmospheres, 106(D22), 28371–28398. DOI: 10.1029/2001JD900133

Integrated analysis of INDOEX observations from satellites, aircraft, ships, surface stations and balloons, combined with models to assess aerosol radiative forcing and regional climate effects, including atmospheric heating and changes in rainfall and the hydrological cycle.

Balloon-borne study of the upper tropospheric and stratospheric aerosols over a tropical station in India

S. Ramachandran & A. Jayaraman

Tellus B 55(3), 820–836

Hyderabad balloon observations in April 2001, with comparisons to the 1985 and post-Pinatubo profiles and to Mount Abu lidar. Mode radius is retrieved using an assumed size distribution.

Aerosol characteristics and aerosol radiative forcing over Maitri, Antarctica

H. Gadhavi & A. Jayaraman

Current Science 86(2), 296–304

Observations during 18 January–23 February 2001, followed by radiative-transfer calculations for polar surface and illumination conditions.

Spatial variations in aerosol characteristics and regional radiative forcing over India: measurements and modeling of 2004 road campaign experiment

A. Jayaraman, H. Gadhavi, D. Ganguly, A. Misra, S. Ramachandran & T. A. Rajesh

Atmospheric Environment

February 2004 mobile measurements of several complementary aerosol properties in central India.

Wintertime aerosol properties during foggy and nonfoggy days over urban center Delhi and their implications for shortwave radiative forcing

D. Ganguly, A. Jayaraman, T. A. Rajesh & H. Gadhavi

Journal of Geophysical Research 111, D15217

December 2004 Delhi campaign. Vertical profiles, humidity-sensitive optical properties and modelled shortwave effects.

Airborne lidar study of the vertical distribution of aerosols over Hyderabad, an urban site in central India, and its implication for radiative forcing calculations

H. Gadhavi & A. Jayaraman

Annales Geophysicae 24, 2461–2470

Two sorties on 17–18 February 2004. Downward-looking micro-pulse lidar and radiative-transfer sensitivity calculations.

Aerosol radiative forcing during clear, hazy, and foggy conditions over a continental polluted location in north India

S. Ramachandran, R. Rengarajan, A. Jayaraman, M. M. Sarin & S. K. Das

Journal of Geophysical Research 111, D20214

Hisar observations offer a separate northern-Indian comparison; they are not the Delhi dataset.

A single parameter representation of hygroscopic growth and cloud condensation nucleus activity

M. D. Petters & S. M. Kreidenweis

Atmospheric Chemistry and Physics 7, 1961–1971

A framework connecting particle hygroscopicity, size and cloud activation.

Validation of MODIS derived aerosol optical depth over Western India

A. Misra, A. Jayaraman & D. Ganguly

Journal of Geophysical Research 113, D04203

A comparison of retrieval collections and ground-based measurements; surface assumptions and aerosol models affect performance.

Absorbing aerosols: contribution of biomass burning and implications for radiative forcing

H. Gadhavi & A. Jayaraman

Annales Geophysicae 28, 103–111

Gadanki, April–November 2008. Spectral absorption and AOD; source separation and soot optical depth involve model assumptions.

Aerosols: Tiny Particles, Big Impact

NASA Earth Observatory

Background science

An accessible introduction to aerosol sources, transport and optical effects.

Long-term trend analysis and climatology of tropical cirrus clouds using 16 years of lidar data set over Southern India

A. K. Pandit, H. S. Gadhavi, M. Venkat Ratnam, K. Raghunath, S. V. B. Rao & A. Jayaraman

Atmospheric Chemistry and Physics 15, 13833–13848

Gadanki lidar, 1998–2013, compared with CALIOP. Sampling conditions matter when interpreting cloud occurrence.

Validation of Version 5.1 MODIS Aerosol Optical Depth (Deep Blue Algorithm and Dark Target Approach) over a Semi-Arid Location in Western India

A. Misra, A. Jayaraman & D. Ganguly

Aerosol and Air Quality Research 15, 252–262

Historical MODIS Collection 5.1 assessment using 2002–2005 observations around Ahmedabad and the bright Rann of Kuchchh.

BATAL 2017 mission report

NASA Langley Research Center and Indian collaborating institutions

Balloon measurements of the Asian Tropopause Aerosol Layer

Balloon observations at Gadanki and Hyderabad combined backscatter, particle counting and material collection.

The Earth’s Energy Budget, Climate Feedbacks, and Climate Sensitivity

IPCC Working Group I, Chapter 7

Climate Change 2021: The Physical Science Basis

Assessment of radiative forcing, including aerosol–radiation and aerosol–cloud interactions.

Beauty of doing science: A personal experience

A. Jayaraman

IMPRESS, Indian Institute of Geomagnetism, Navi Mumbai, 16 February

Historical photographs and recollections of instrument development and atmospheric research.

Investigating the role of typhoon-induced waves and stratospheric hydration in the formation of tropopause cirrus clouds observed during the 2017 Asian monsoon

A. K. Pandit et al.

Atmospheric Chemistry and Physics 24, 14209–14238

Hyderabad, 23 August 2017: an interpretation combining balloon observations, trajectories, satellites and reanalysis.

Atmospheric research photographs, instrument diagrams and observations

A. Jayaraman

Personal archive

Research photographs and observational records from PRL, NARL, upper-atmosphere experiments and field campaigns.

A. Jayaraman’s personal archive.

Notable alumni: A. Jayaraman

Physical Research Laboratory

PRL Alumni Association

Lists A. Jayaraman as Director, NARL Tirupati, 2007–2017.

Aerosol optical depth data description

NASA AERONET

Aerosol Robotic Network

Definitions of AOD and spectral dependence. This linked page describes the Version 2 product.