The Indian space programme encompasses research in space science besides space technology development and its application. Space science research is mainly carried out  at Physical Research Laboratory (PRL), at Ahmedabad, Space Physics Laboratory (SPL),  at Thiruvananthapuram and ISRO Satellite Centre, at Bangalore. The National Mesosphere-Stratosphere-Troposphere Radar Facility (NMRF) near Tirupati, which is an autonomous society established and funded by the DOS, is available to scientists from universities and research institutions for atmospheric research. Space science research is also supported in universities and research institutions through the ISRO’s Advisory Committee for Space Science (ADCOS) as well as through Sponsored Research (RESPOND) programme of DOS.

Although it is believed that the high mass stars undergo the same phases as do the low mass stars, it is difficult to identify high mass young stellar objects (YSOs), as they are short-lived compared to their low mass counter-parts. A near-infrared study has been started to understand the high mass YSOs while they are still embedded in their cocoons. The current study shows molecular outflows from a high mass YSO akin to the low-mass YSOs.

Recently, the typical BO.3IV star Delta Scorpii has shown a sudden brightening. Simultaneously, the absorption lines in its spectrum have been replaced by emission lines. The star has been studied in the near IR and visible regions. An IR excess is seen which can be attributed to emission from a circumstellar shell. The observed Paschen and Brackett line intensities deviate significantly from Case-B predictions and indicate optical depth effects.

A large scale observation programme at 327 MHz was undertaken in 1999-2000 using the Ooty Radio Telescope to study large scale properties of travelling Inter Planetary disturbances and to map them on a day-to-day basis. A concerted effort is being initiated to observe galaxies in a number of radio frequencies using the Giant Metrewave Radio Telescope (GMRT) to construct spectral energy distributions and understand the underlying processes that force some of the galaxies to take larger morphologies.

In the research related to the origin of universe, multi-wavelength observations in optical and near IR regions are continuing. A state-of-the-art laboratory facility to develop required technologies in the submillimetre wave region is being set up.

In order to understand the energy release and particle acceleration related to solar flares, "Solar X-ray Spectrometer (SoXS)" payload is now being developed. It will enable the study of the break in the spectrum between thermal, superhot and non-thermal components of the solar flare as well as to study short and long term solar coronal variability and its effects on the earth’s environment. The payload is proposed to be flown on board GSAT-2.

A ship cruise was conducted during February-March 2001 to measure concentrations of
ozone and other precursor gases in the Bay of Bengal and the Arabian Sea. Very low levels
of ozone (~15 parts per billion volume) have been observed near the Indian coast. These low levels of ozone are due to the winds coming from the cleaner southern oceanic region. Higher levels of ozone (~ 60 ppbv) were observed away from the coast.

In order to understand the role of background aerosols in altering the earth’s radiation budget, a pilot study has been undertaken at Maitri, Antarctica as part of the 20th Indian Antarctic expedition. Studies have also been made to characterise aerosols over the Bay of Bengal region. Also, as a part of the ongoing stratospheric aerosol studies, a high altitude balloon carrying sun-tracking photometer system was launched from Hyderabad in April 2001. The data is being used to estimate the increase in the background aerosol content at the stratospheric altitudes.

The backscatter Lidar has been used to measure aerosol backscattering coefficient, to study the volcanic perturbations in the stratospheric aerosol loading over the tropics. After the Mount Pinatubo eruption in June 1991, there has been no major eruption to influence the stratosphere and the present condition represent a volcanically quiescent period. Based on nearly one hundred nights of observations of the Rayleigh Lidar at Gurushikhar during the period November 1997 to October 2001, mean temperature profiles have been obtained in the altitude range of 30-75 km for each month. This has provided climatology of the temperature structure in the height range of 30-75 km at a tropical latitude station (25 degree North).

Multi-wavelength imaging observations from Kavalur in Tamil Nadu during a magnetically disturbed period has shown for the first time:

Stratospheric ozone is enriched in the heavy isotopes relative to the ambient oxygen from which it is formed. The enrichment varies with altitude, attaining very high values between 30 to 40 km. While a recent theory explains the isotopic enrichment in the process of ozone formation quite satisfactorily, there is no explanation so far for the enrichment variation with altitude. It has been demonstrated that isotopic enrichment in ozone generated by oxygen photolysis depends on the pressure of the oxygen reservoir and can have very high values, comparable to the stratospheric maximum.

Ar-Ar dating of the St.Mary’s Islands volcanics, the Kerala dykes and the Madagascar flood basalt province suggest that these volcanics and dykes represent magmatic activity associated with the breakup of Greater India (India plus Seychelles) and Madagascar. Identification of 1800-2000Ma old granitoids and gabbros in western Himalayas indicate this era to be a period of major crust formation epoch in a rift tectonic environment.

Theoretical Physics
Under theoretical physics, research in the areas of High Energy Physics including Particle-Astrophysics and Cosmology, Nuclear Physics, Atomics Physics, Relativistic Astrophysics and Plasma physics is being pursued.

It has been shown that the results of the Neutrino detector SNO can be used to constrain magnetic moment of tau neutrino. The question of understanding different neutrino anomalies was also investigated in the context of neutrino mass models based on five dimensional Kalutza Klein type theories with a large extra dimension. In the collider physics, a study has been made to evaluate radiative corrections arising from QCD in the production of top-antitop quarks at electron-positron collider.

Scenarios of inflation have been invoked to solve various cosmological problems. The dynamics of the phase transition has been recalculated in the case where the phase transition is driven by the fluctuations of the inflation field rather than by the evolution of the homogeneous component of the inflation field and it is found that such a situation can constitute a valid scenario for inflation.

The role of group symmetries in two-body random matrix ensembles generating order out of complexity has been demonstrated for the first time, considering random matrix ensembles with spin and in a single j-shell. In addition, nuclear masses have been used to study novel isoscalar correlation effects in heavy odd-odd N=Z nuclei in mass 60-100 region.

The effect of centrifugal reversal is being studied in the case of fluid flows and a close link with the azimuthal velocity has been established. A model, based on condense matter physics arguments has been developed, to describe low frequency response of the dusty crystal, which is a new kind of form of matter in which dust grains in a dusty plasma arrange themselves in a crystalline structure.

Under Non-linear Dynamics and Computational Physics, quantum entanglement in the presence of classical chaos has been studied and the enhanced capacity to entangle has been noted. This has relevance to the fundamental problem of system-environment interaction. A novel method of secure communications using dynamical systems has been proposed which uses initial condition estimation from a scalar time series. The method cannot be attached using local linear approximation which is used to break the code obtained from other methods using dynamical systems.

Under Laser Physics and Quantum Optics, one of the major themes has been the coherent control of the propagation of light pulses. It has been shown that the group velocity of a weak electromagnetic pulse, propagating through a L system can be changed from superluminal to subluminal in a controlled way by the use of additional electromagnetic fields. A scheme has been proposed for slowing down decay into a continuum by using a sequence of ultra-short pulses applied on an auxiliary transition of the system so that there is a destructive interference between the two transition amplitudes - one before the application of the pulse and the other after the application of the pulse. Entanglement of quantum systems is another theme that is being pursued. The feasibility of enhancing the fundamental radiative interactions between distant atoms has been studied. The existence of non-classical spatial correlations in the resonance fluorescence produced by identical coherently-driven two level atoms, has been demonstrated. Apart from coherent control and entanglement, work has been carried out in the field of optical vortices. A symmetrical optical vortex using a computer generated hologram has been produced. The propagation of such a vortex in free space has been studied experimentally and the results explained theoretically. It has been shown that a canonical vortex reverses its helicity after propagating a certain distance through a
Kerr medium.

NMRF at Gadanki near Tirupati is used by scientists from various institutions to conduct advanced research in atmospheric and space sciences.

During the year NMRF has been utilized for conducting a number of experiments and to undertake scientific campaigns. It participated in multi-institution campaigns such as equatorial wave campaign and Leonid Meteor shower observation campaign. Besides, MST radar provided wind data to support the GSLV-D1 and PSLV-C3 flight conducted during the year. The common mode observations of MST radar have been continued for compiling a long term data base. So far, five years of data has been collected, which is valuable for scientific studies and also to provide input for launch vehicle missions. The MST Radar and collocated facilities such as Rayleigh/Mie Lidar, LAWP, Disdrometer, Optical Rain Gauge (ORG) and Automatic Weather Station (AWS) have been operated simultaneously in support of various scientific experiments. The major scientific results using the measurements conducted are
as follows:

LAWP observations have shown that it is an important tool for the study of the evolution, vertical extent and diurnal variation of the boundary layer over Gadanki during fair and precipitating weather conditions. Considerable day-to-day variability is noticed in depth of the boundary layer. Boundary layer height at Gadanki on fair weather day goes up to 2-3 km altitude, in the afternoon hours when convecting plumes may be pushing the boundary layer height. On the days of precipitation, enhancement in radar reflectivity is observed to be much beyond the height of normal boundary layer height along with the strong down drafts associated with the precipitation.

Atmospheric gravity waves play an important role in the dynamics of the middle atmosphere by transporting energy and momentum upward from the troposphere. Rayleigh Lidar observations of atmospheric temperature and Rocketsonde measurements of winds during the period of equatorial wave campaign in February – April, 2000 have provided, for the first time, clear evidence of the modulation of the gravity wave activity by the long period equatorial waves over the tropical middle atmosphere.

The Lidar has been used for observation of stratospheric aerosol clouds which exhibit anisotropy. The high altitude cirrus clouds are observed in the upper troposphere between 12-16 km just below the tropopause whereas stratospheric clouds are observed at about 18 km just about the tropopause. One of the possible mechanisms for the formation of lower stratospheric clouds could be freezing of sulphuric acid water solution resulting in formation of sulphuric acid tetrahydrate. These crystalline particles could depolarise the laser beam as it passes through the lower stratospheric aerosol clouds as observed at radar site.

CRL Lidar system has also made interesting observations of stratospheric and mesospheric temperature. One of these pertains to stratospheric cooling. Analysis of the temperature data collected during the equatorial wave campaign in 2000 shows that stratospheric cooling occurred during the initial period of observations, coinciding with the high latitude stratospheric warming event in the northern hemisphere. At some heights, the observed cooling is as much as 20-300K. Other interesting feature of the temperature profile is the mesospheric temperature inversion in the height range of 70-80 km. This is first such observation reported from the low latitude region. One of the possible causative mechanisms of the observed temperature inversion is the dissipation of energy by gravity waves at these heights.

Studies on surface aerosol loading show a significant influence of sea breeze and also a strong seasonal variation. Also, the mixing region aerosols are sensitive to different meteorological parameters in the atmospheric boundary layer. The data collected at Thiruvananthapuram, Minicoy, Mysore and Visakhapatnam, as part of GBP has been used to evolve a 2-D spectral-temporal climatology of aerosol optical depth. The results indicate an average increase in aerosol optical depth at about 1.5 percent per year over the last
12 years, especially at the shorter wavelengths.

Monte Carlo simulation of the interaction of magnetically field-aligned electrons, as observed by Galileo EPD and PLS instruments, with the atmosphere of Io, a satellite of Jupiter, has been carried out.

Under the Aerosol Climatology and Effects Project of IGBP, aerosol optical depths at a number of wavelengths are being monitored at several stations in the Indian region. Measurements are being made both at remote relatively clean sites and polluted sites in urban areas, coastal regions and continental sites, the island site of Minicoy and the Indian Antarctic Station Dakshina Gangotri as well as over the oceans during ship cruises. Measurements have shown that the aerosol optical depths over the oceans are 2-4 times less than that over coasts. The data has been used to generate an aerosol model for the Indian ocean region. Analysis of ten years data from three stations Thiruvananthapuram, Mysore and Visakhapatnam has shown a steady increase in aerosol optical depths at most of the wavelengths. The increasing trend is especially significant at the relatively remote sites in Thiruvananthapuram and Mysore and at lower wavelengths, due to increased gaseous pollution and the subsequent gas to particle conversion at these stations. This is a clear indication of human impact on the environment.

A relationship has been established between aerosol optical depth and radiance at two wavelengths 440 nm and 650 nm from the vegetation as target for two high ndvi areas, Sarkej-Dholka region near Ahmedabad and Khadakvasla region in Pune by making sunphotometer measurements simultaneous with satellite overpasses. The relationship can be used to determine aerosol optical depths at 650 nm within an error of 15 to 20 percent.

Evapo-Transpiration (ET) is a key bio-physical process controlling the exchange of energy and hydrological flux by terrestrial vegetation. Assessment of the forest ET at the National level has been taken up under IGBP. As part of this, different climatic, biophysical, soil and topographic variables regulating forest ET have been generated for the Western Ghats. IRS WiFS multi-temporal data has been used to develop broad forest type maps and Leaf Area Index (LAI) maps. Medium resolution IRS WiFS data is also being used for a Biome Level classification of vegetation of the Indian region. Detailed Land Use / Land Cover maps including mesoscale level classification of vegetation are being made for assessment of
evapo-transpiration sensible and talent heat transport, biomass accumulation albedo, carbon pool and its dynamics.

SROSS-C2 RPA data analysis: Scientific groups from universities, namely, Andhra, Varanasi, Calcutta, Dibrugarh, Kerala, Osmania, Roorkee and Saurashtra have reduced the raw data from Retarding Potential Analyser (RPA) experiment into ionospheric parameters for a period of two years. Seven scientific projects for utilisation of the reduced RPA data have been supported at these universities for studies in different aspects of ionosphere-thermosphere interaction, ionisation bubbles, models, etc.

INDOEX (Indian OceanExperiment): The multi-agency sponsored campaign experiment involving observations over the Indian ocean region along ship cruises, with balloon borne instrumentation and ground based measurements has been completed. The preliminary results from the two field campaigns have been published. Indian participation in INDOEX is jointly sponsored by DOD, DOE, DOS, DST and CSIR with DOS as the nodal agency.

Project on Environment at Sri Krishnadevaraya University: The third year of the project entitled "Airspace Pollutants and Environment" is in progress. For the first time, systematic and continuous surface observations of trace gases like NOx and CO have been made at Anantapur (14.6N, 77.7E) region along with meteorological data collected. A campaign has been carried out to measure the levels of ozone, water vapour, UV-B radiation and meteorological parameters and aerosol optical properties.

Space Research Projects at Allahabad University: Six projects for carrying out research in space science, technology and application areas have been supported by DOS. These include investigations on atmospheric modelling, microwave characterisation of materials, design of a liquid mirror telescope, laser induced fluorescence spectra for remote sensing application, MST radar studies of troposphere-stratosphere coupling and quantum optics. A multi-user oriented high power computer facility is being set up not only to cater to students working in these projects but also help other research and academic programmes of the university.