Atmospheric Sciences
The scientific research of the atmospheric group is primarily focused on investigating various atmospheric processes through studies related to trace gases, aerosols and radiations in troposphere and stratosphere over continents and oceans besides modeling for developing better understanding about changing atmosphere and climate change and their impacts.

Scientific Activities undertaken:

  1. Greenhouse Gas Emission Inventories:
  2. Emission inventories of greenhouse gases from different anthropogenic sources are being prepared for the Indian region which will help in identifying priority targets for mitigation
    measures for abatement of climate change and also in reducing the uncertainties in climate change modeling.
  3. Development of emission factors:
  4. Development of emission factors of greenhouse gas emissions from landfills , emissions of black carbon from bio-fuels used in rural households and ammonia emissions from
    agriculture fields are being undertaken using field and laboratory based measurements to generate country specific values of these emission factors for reducing the uncertainties
    in emission inventories from these sectors.
  5. Measurements of trace gases:
  6. Measurement of different trace gases like Carbon dioxide Ozone, carbon monoxide, Sulfur dioxide, Non-methane Volatile Organic Compounds, ammonia, Oxides of nitrogen
    etc. are being measured in different regions of the country and in polar regions to study the atmospheric chemistry.
  7. Aerosol Studies:
  8. Measurements of morphological, physical and chemical properties of different kinds and sizes of aerosols in different regions of the country and in Antarctic a region are being
    carried out to investigate their role in various atmospheric processes.
  9. Lidar and FTIR based atmospheric probing:
  10. These instruments are being used to probe the atmosphere for cloud-aerosols interactions and trace gas profiles.
  11. Isotopic studies of particulate matter:
  12. Stable isotopic data of C, N, S are being used for deciphering contributing sources (source characterization) and secondary processes involved in chemical processing
    of particulate matter.
  13. Modeling of atmospheric aerosols’ radiative properties:
  14. Impacts of aerosol loading on the atmospheric radiative budget is being modeled to help understand the contribution of aerosols in climate forcing.
  15. Stratosphere-troposphere exchange processes:
  16. Upper Troposphere and Lower Stratospheric water vapor distribution and its variability over tropical region is being studied.
  17. Atmospheric chemistry modeling:
  18. Atmospheric chemical transport model and atmospheric photochemical model are being used to study the atmospheric chemistry issues.
  19. Impact of Ultra Violet Radiation on Ocular health:
  20. The impact of Environmental changes and Ultra Violet Radiation (UVR) exposure on ocular health in India is being studied through monitoring of ocular health and radiation
    parameters at different sites in India.
  21. Climate change modeling:
  22. MAGICC–SCENGEN Climate change model is being used to develop scenarios of greenhouse gas concentrations and other climate related parameters for future time scales
  23. Climate change vulnerability assessments:
  24. Climate change vulnerability assessments: Impact assessment of climate change on heat stress vulnerability in India has been undertaken using the future climate change scenarios.

Major Facilities:

Primary Ozone Calibration Facility (Standard Ozone Photometer, SRP-43)


Ground level Ozone concentration is an important air quality parameter which is monitored and reported worldwide. The increase of ground level Ozone is of concern because of impact on human health, crop, vegetation, oxidizing capacity of the atmosphere and climate. International efforts are being focused on monitoring and reducing surface Ozone concentrations. The reference method of Ozone concentration determination is ultraviolet photometry. This method is described as the reference method for Ozone analyzers as well as calibration instruments, following the ISO standard 13964. In 1980s National Institute of Standards and Technology (NIST), under the joint collaboration with the US Environmental Protection Agency (USEPA), developed Ozone reference standard (NIST SRP) to ensure the traceability in the ozone measurements. NIST SRP is acting as the primary standard for all the national and international Ozone monitoring network. Various units of these instruments, called standard Reference Photometers (SRP), are located worldwide which are maintained by respective National metrology institutes of different countries for ambient ozone analyzers calibration. The NIST Standard Reference Photometer, serial number 43(SRP43) has been setup at CSIR, National Physical Laboratory-India (NPLI) .It works on the principle of the absorption of 253.7 nm UV-light by Ozone molecule.

  • The objective is to provide the facility for Quality assurance and APEX Level traceability in ground level Ozone measurements in the Country and South Asian Region
Calibration Capabilities:
Parameter Range Measurements Uncertanity at coverage factor k =2 (level of confidence 95%)
Ozone (0 to 500)ppb

U(x)=[(1.0) 2 +(0.020x) 2 ] 1/2
x=ozone concentration
U(x)=Q[1.0,0.020x]; Q[a, b]=[a 2 +b 2 ] 1/2

Highlights and Achievements

  • BIPM.QM-K1 Key comparison of the SRPs:
  • Micro-Pulse LIDAR
  • Open Path Very High Resolution FTIR
Open Path-Fourier Transform Infrared Spectrometer (OP-FTIR)
  • CF-IRMS facility

Pyro-Cube ( Elemental Analyzer ) coupled with I soprime 100 Stable isotope mass-spectrometer

  • Capable of measuring C, N, S, and H and O isotopic analyses of particulate matter (e.g. Atmospheric dust, Soil, Sediment, biogenic products)
  • Stable isotopic data of C, N, S are vital for deciphering contributing sources (source characterization) and secondary processes involved in chemical processing of particulate matter.
  • H, O isotopes of particulate matter can provide insights to degree as well as source of moisture during natural particle formation.

Aethelometer and Nephelometer :

  • OC/EC analyzer
  • Ion-Chromatograph
  • Wide Range Aerosol Spectrometer:
  • Gas Chromatographs / Gas Analyzers for Ozone, NOx, CO, NMVOC, NH3
  • UV-VIS-IR Pyranometers/Biometer/Pyrgometer
UVB & UVA Flux Measurement setup
Multi- Wavelength Radiometer
  • MWR, Microtops