Continuous measurements of atmospheric CO2 are being made at four sites to quantify temporal (diurnal, seasonal and intra/inter-annual) and spatial CO2 variability and to understand CO2 source and sink relationships. The four sites – (1) Dehradun, Uttarakhand (IIRS Campus, since October 2008), (2) Nainital, Uttarakhand (since June 2009), (3) Gadanki, Andhra Pradesh (since March 2010), (4) Haldwani, Uttarakhand (since January 2009), and (5) Mount Abu, Rajasthan (since July 2010). Highly precise (accuracy + 3 ppm) CO2 sensors (GMP 343, make-Vaisala) along with 16-channel data loggers are installed at these sites. The data obtained through this network will be used as inputs in estimating C-fluxes over India as a part of National Carbon Project taken up by the Institute under the ISRO-Geosphere Biosphere Programme (IGBP). Two more CO2 measurement stations are planned at Sriharikota (Andhra Pradesh) and in NE region.

A nationwide network of carbon flux towers in major forests, croplands and grasslands for the measurement and modeling of the net carbon flux using eddy covariance techniques, satellite remote sensing data and models is planned within the framework of National Carbon Project (NCP) under the ISRO-Geosphere Biosphere Programme. Initially, 15 towers are envisaged in different ecological regions of the country. Presently, three towers at Haldwani (Uttarakhand), Barkot (Uttarakhand) and Meerut (Uttar Pradesh) are operational. These flux towers are equipped with state-of-art, high-precision instruments to measure energy, water vapor and CO2 exchanges in agriculture and forest ecosystems.

A 50m high flux tower in moist sal forest of the Barkot Range of the Dehradun Forest Division, Uttarakhand. The system enables measuring energy, water vapor and CO2 exchanges over sal forest. The flux-tower site is equipped with – open path gas analyzer, ultrasonic anemometer, IR hygrometer, digital tension meter, and other sensors for measuring wind speed and direction, temperature, humidity, pressure, precipitation, longwave and shortwave radiation, soil moisture profile probes, etc. (Collaborating Agencies: State Forest Department, Uttarakhand; Department of Forestry, Kumaun University, Nainital).

As a part of Aerosol Radiative Forcing (ARFI) network, aerosol characterization studies are being done at IIRS since 2006. An aerosol observatory is set-up in IIRS campus to study the optical and physical properties of aerosols in and around Dehradun. The instruments being used for the measurements are – (a) Multi-wavelength solar Radiometer (MWR) for studying the spectral variation in aerosol characteristics at 10 narrow band wavelengths, (b) Aethalometer for measuring real-time concentration and diurnal behaviour of black carbon (BC) aerosol particles, (c) High Volume Air Sampler for studying the aerosol concentration and particle size, and (d) Sunphotometer and Ozonometer for studying the optical properties of aerosols. IIRS has also participated in a number of land and sea/ocean campaigns to study aerosol properties.
 

An instrumented field observatory was set-up in Sitla rao watershed (near Langha village in Dehradun, Uttarakhand) in March 2003 to study soil hydrological processes and carry out process-based modeling of runoff and erosion in Himalayan landscape. Field-based measurements are being made using automatic weather stations (two nos.), self-recording rain-gauges (two nos.), and stage level runoff (discharge) recorder (one no.). It is also a study site for various training and education programmes of the Institute.
 

An instrumented field observatory has been set in collaboration with National Institute of Hydrology (NIH), Roorkee, for generating ground-based data on hydrological variables at regular time interval which will be used along with RS data-derived inputs for hydrological modeling in Solani watershed. The Solani watershed, a sub watershed of the river Ganges, lies between 77° 44¢ - 77° 58¢ E longitudes and 29° 52¢ - 30° 18¢ N latitudes in the States of Uttarakhand & Uttar Pradesh in northern part of India. The watershed is equipped with automatic weather stations, soil moisture sensors and an automatic discharge gauge site. It is also a study site for various training and education programmes of the Institute.