014642   Sreehari C V;Bhuvanendran C;Prabhakaran Nayar S R (Department of Physics, University of Kerala, Trivendram-695 581, Email: srp@md2.vsnl.net.in) : Hf doppler radar observations of vertical and zonal plasma drifts-signature of a plasma velocity vortex in evening f-region. Indian J Radio Space Phys 2006, 35(4), 242-8.

The simultaneous vertical and zonal plasma drift measurements using an HF Doppler radar system around March equinox of 1995 at the magnetic equatorial station, Trivandrum, India (8.33°N, 77°E, dip 0.4°N) are analyzed to evaluate the vector plasma drift at the F-region. It is found that the pre-reversal enhancement in vertical drift and the direction change of zonal drift from westward to eastward occur almost simultaneously. The velocity vector in the vertical-zonal plane, the resultant of vertical and zonal velocities, exhibits a gradual rotation in the evening time. The characteristics of velocity vector clearly promulgate the existence of a plasma velocity vortex in the equatorial F-region during post-sunset period.

2 illus, 5 ref

014641   Sethi N K;Dabas R S (Radio & Atmospheric Sciences Div, National Physical Laboratory, Dr K S Krishnan Road, New Delhi-110 012) : Predicted and measured bottomside total electron content under high and moderate solar activity conditions over New Delhi. Indian J Radio Space Phys 2006, 35(5), 335-43.

Digital ionosonde measurements at a low-middle latitude station, New Delhi (28.6°N, 77.2°E, dip 42.4°N) are used to derive bottomside total electron content (BTEC) for a period of high (2001-2002) and moderate (2003) solar activity periods. These observations are then used to evaluate the predictability of the latest available IRI-2001 model using both the options, i.e. (B₀ Tab. and Gulyaeva). The study reveals that for both the solar activity periods, the diurnal variations of BTEC show more or less similar trend during all the seasons (i.e. maximum around daytime and minimum around midnight) and BTEC exhibits a large day-to-day variability at any given local time. Comparison of BTEC with those predicted by the IRI model using both the options during moderate solar activity reveals, in general, good agreement, except for post-noon hours during summer and equinox. However around noontime, IRI (B₀ Tab.) option shows somewhat better agreement with the observations than by IRI (Gulyaeva) option. During high solar activity, a comparative analysis shows that discrepancies do exist during winter and equinox during daytime with both the options of the IRI, however the agreement between the IRI (B₀ Tab.) and observations is reasonably good for summer during daytime, whereas IRI (Gul.) option overestimates the BTEC. Solar activity variations of observed median BTEC show that the peak content in general increases by a factor of more than two from moderate to high solar activity.

9 illus, 21 ref

014640   Oyekola O S;Ojo A;Kinrimisi J A (Department of Physics, University of Ibdan, Ibdan, Nigeria, Email: osoyekola@yahoo.com) : Nocturnal variation of f- region verical ionization velocities near the magnetic equator. Indian J Radio Space Phys 2006, 35(4), 227-33.

F-region vertical plasma drifts at the magnetic equatorial station, Ibadan (7.4 °N. 3.9 °E; 6 °S dip) are inferred from the time variation of the hourly-recorded ionosonde virtual height (h' F ) of F-layer data; obtained during 1957/58 International Geophysical Year (IGY) period under geomagnetically quiet and disturbed nights. Prominent nocturnal vertical drift characteristics are presented at African longitudinal sector. Seasonal effects appeared to be pronounced during undisturbed and disturbed nighttime conditions. Also, pre-reversal peak velocity obviously varies considerably with season. In addition, pre-reversal peak velocity exhibits significant variability with 10.7 cm Solar Flux Index and average Zurich monthly sunspot numbers. Furthermore the threshold parameters, such as, E x B vertical drifts and virtual height (h'F) required to cause spread-F irregularities are determined to be approximately 30 m/s and 400 km, respectively. Results obtained by the authors are in good accord with those for other low-latitude regions that employ other observational techniques. There are several likely processes responsible for the quiet and disturbed times plasma drift variability in the night hours at equatorial regions.

6 illus, 29 ref

014639   Mishra R K;Mishra R A (Computer and IT Section, Tropical Forest Research Institute, Mandla Road, Jabalpur-482 021) : Long-term variation of cosmic ray anisotropy during high amplitude days. Indian J Radio Space Phys 2007, 36(1), 9-13.

In the study the occurrence of a large number high amplitude event (HAE) of cosmic ray diurnal anisotropy during 1981-1994 has been examined as a function of solar activity using the hourly neutron monitor data of Deep River station. The diurnal time of maximum for both HAE as well as for all days is found to shift significantly towards an earlier time as compared to the co-rotational/azimuthal direction since the year 1991 onward. It is found that diurnal amplitude significantly deviates and reaches its maximum, and phase remains in the co-rotational direction during the years close to solar activity maximum for HAE. The occurrence of HAE is dominant in the declining phase of solar activity. The amplitude as well as phase of the cosmic ray diurnal anisotropy during HAEs is well correlated with the sunspot numbers.

illus, tables, ref

014638   Jana P K;Nandi S C;Sarkar D (Chemistry Dep, Institute of Education (PG) for Women, Chandernagore, Hooghly-712 138) : Depletion of ozone and its effect on night airglow intensity of Na 5893 at Srinagar and Halley Bay. Indian J Radio Space Phys 2006, 35(6), 401-6.

Present the effect of O₃ depletion on night airglow emission of Na 5893 A line at Srinagar (34°N, 74.8°E). India and Halley Bay (76°S, 27°W), a British Antarctic survey station. Calculations based on chemical kinetics reveal that the airglow intensity of Na 5893 Angstrom line is also affected due to ozone decline. The nature of yearly and seasonal variation of intensity of Na 5893 Angstrum line for the above two stations are shown and compared. It is shown that the rate of decrease of yearly intensity of Na 5893 Angstrum line is comparatively more at Halley Bay due to dramatic decrease of Antarctic O₃ concentration. During Antarctic spring time, stratospheric ozone is depleted dramatically at Antarctic region because of very low temperature (-80°C), elevated concentration of atomic chlorine and chlorine oxides, low abundances of nitrogen oxides and large appearance of polar stratospheric clouds (PSCs).

3 illus, 2 tables, 20 ref

014637   Iyer K N;Jivani M N;Abdu M A;Joshi H P; Aggarwal M (Department of Physics, Saurasthra University, Rajkot-360 005) : Power spectral studies of VHF ionospherpic scintillations near the crest of the equatorial anomaly in India. Indian J Radio Space Phys 2006, 35(4), 234-41.

Scintillation of VHP (250 MHz) signals from FLEETSAT (73°E) was recorded at the equatorial anomaly crest location, Rajkot, in India during 1991-93. The irregularity parameters: S₄ index, and fade rate and spectral parameters: spectral slope and upper roll off frequency, f_u are derived and their variation with time of night and with solar activity studied. S₄ index and fade rate increase with solar activity. The spectral slope does not show any systematic dependence on solar activity but f_u increases with solar activity. These results, when interpreted in terms of Fresnel size, indicate a shifting of irregularity spectrum towards longer scales in low solar activity period. The temporal variation of these parameters, after the irregularity generation phase, also indicate preponderance of large (kilometer) scale irregularities around midnight-post-midnight period, consistent with earlier simultaneous radar and scintillation observations at Jicamarca. The solar activity dependence of s₄ index is interpreted as due to the variation of background F-region plasma density variations. The results suggest that when strong scattering causes strong scintillations, f_u is not representative of the Fresnel scale.

6 illus, 30 ref

014636   Gupta M;Mishra V K;Mishra A P (Physics Dep, A P S Univ, Rewa-486 003, Email: soumya_rishi@rediffmail.com) : Correlation of long-term cosmic ray intensity variations with sunspot numbers and tilt angle. Indian J Radio Space Phys 2006, 35(6), 387-95.

Based on the monthly data of sunspot numbers (SSN), tilt angle (TA) and cosmic ray intensity (CRI), a detailed correlative analysis has been performed to study the relationship of CRI (observed by the neutron monitor stations having different cut-off rigidity) with SSN and TA for the period 1976-2005, covering solar cycles 21, 22 and 23. It is an observed fact that SSN and TA are highly correlated with each other and cosmic ray intensity shows anti-correlation with them. The present analysis is found to support the earlier findings and holds good for solar cycles 21, 22 and current cycle 23. Further, the cross-correlation coefficients between CRI-SSN and between CRI-TA have been obtained considering the time-lag factor and it is found that time-lag is larger for odd solar cycles in comparison to even cycles. The odd-even behaviour in relation to time-lag is also evident from the hysteresis curve between CRI-SSN and between CRI-TA, where wider loops for odd solar cycles have been observed. Moreover, it was found that correlation between CRI and SSN as well as between CRI and TA is better during negative polarity than the positive polarity of solar magnetic cycle. From the tilt angle observations, it has been noticed that the behaviour of cycle 23 in declining phase is different from that of cycle 21 and 22.

10 illus, 2 tables, 24 ref

014635   Gudhe S D;Jain S L;Kulkarni P S;Ashok Kumar; Arya B C (Radio and Atmospheric Sciences Division, National Physics Laboratory, Dr K S Krishnan Marg, New Delhi-110 012, Email: sljain@mail.nplindia.ernet.in) : Year to year variation of ozone hole over Schirmacher region of East Antartica: a synopsis of four-year measurement. Indian J Radio Space Phys 2006, 35(4), 253-8.

During the 16th, 21st, 22nd and 23rd Indian Antarctic expedition conducted in 1997, 2002-03 and 2004 respectively, measurement of columnar ozone have been made using MICROTOPS II Sun-photometer from the Indian station Maitri (70° 45 S, 11° 44 E). It is found that the ozone hole depth fluctuated from year-to-year. The minimum columnar ozone observed over Maitri was 135 (±9.3) DU, 185 (±12) DU, 126 (±9.7) DU and 159.8 (±8.8) DU during spring 1997, 2002, 2003 and 2004, respectively. Ozone concentration below 220 DU (nominal ozone threshold value) during Antarctic spring (day 225-365) over Maitri has been observed to be 45.1%, 20.7%, 62.7% and 60% in 1997, 2002, 2003 and 2004, respectively. The chemical loss of ozone (total ozone values below 220 DU) over Maitri during 2003 (day 225-365) was found to increase by a factor of 0.4 when compared to 1997, and by a factor of 2 when compared to 2002. The observations at Maitri also showed an event of major stratospheric warming during 2002. The ozone hole in the year 2002 was not found to be deep and further recovered quite early when compared to 1997, 2003 and 2004.

4 illus, 1 table, 6 ref

014634   Chakrabarty D K;Patel S;Vala P (Centre for Environment Survey, , Vidyanagar Society 29/251, Ahmedabad-380 015) : Seasonal and solar activity variation of NO₂ over Ahmedabad. Indian J Radio Space Phys 2006, 35(5), 344-48.

Nitrogen dioxide, NO₂, has strong absorption signatures in 436-448 nm region. Using this property, column density of this species has been determined at Ahmedabad, a low latitude station. Absorption spectrum has been measured by a ground-based spetroscopy technique during twilight period. Scattered zenith sunlight has been used as the source of light. The twilight slant column density (SCD) values have been found to be <126> 10¹⁷ cm^-2. A summer maximum and a winter minimum, and a decreasing trend of NO₂ with an increase of solar activity level are seen. These results have been compared with the UARS and GOME satellite values.

5 illus, 19 ref

013569   Chakravarty S K;Tiwari D R (NO, , C/o Shri Kalyanji, III/8, C.I.A.E. Colony, Nabibagh, Berasia Road, Bhopal-462 038) : Soil mapping a part of Datia block, Datia district Madhya Pradesh, India with reference to remote sensing techniques. Ultra Scient phys Sci 2006, 18(3), 393-6.

Soil is a very precious natural resources gifted to man by nature. Soil is a natural body developed by natural force acting on natural (Tambane, 1964). All forms of life derive their nutrition either directly from the soil or through other life supporting systems controlled by the soil. According to Gawande (1990)" Soil and land form a natural resource base which sustains most of the life forms. "Experts like Chatterjee et at. (1990) feel that soil is a component of land Karale et a/.(1978). Singh and Das (1990), emphasized on soil for scientific planned development especially, watershed management, irrigation project planning etc.

2 illus, 10 ref

012491   Dwivedi B N (Applied Physics Dep, Institute of Technology, Banaras Hindu Univ, Varanasi-221 005, Email: bholadwivedi@yahoo.com) : Our ultraviolet sun. Curr Sci 2006, 91(5), 587-95.

High-resolution ultraviolet observations of the Sun from SOHO and TRACE spacecraft have provided a wealth of new information on plasma temperature, density, abundance anomaly, plasma flows, turbulence, wave motions, etc. in various solar structures. Presents ultraviolet Sun that has provided some landmark new results, especially from the line-shifts and broadenings of vacuum ultraviolet spectral lines, pinpointing the physical processes that maintain the Sun's hot corona, and accelerate the fast solar wind as well as locate its source region.

10 illus, 41 ref

006135   Iyengar R N (Dep of Civ Engng, Indian Inst of Sci, Bangalore-560 012, Email: rni@civil.iisc.in) : Comet observation in acient India. J Geol Soc India 2006, 67(3), 289-94.

A brief review of the ancient prose text of Parasara, referring to comets, as transmitted by later non-religious Sanskrit literature is presented. The information passed on appears to belong to 2nd millennium BC or earlier. A sequence of 26 comets with names and purported effects are given. The form of each comet sometimes with its position in the sky is presented vividly. A year number, mentioned as the time interval between each appearance, is also given. The total period covered adds to about 1300 years. The first comet is said to have appeared in the era of the Floods. This would date the Floods to about 2500-2700 BC. Whether this has any historical importance needs to be further investigated. The names of many comets correspond with names of Vedic deities. This raises the possibility of comet sightings being alluded to in the Rig Veda.

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006134   Bhosle B;Prakash B;Awasthi A K (Dep of Earth Sci, Indian Inst of Technol, Roorkee-247 667) : Delineation of an active fault using DTM in the western gangetic plain. Curr Sci 2006, 90(7), 1001-3.

Integrated studies of satellite images using digital image processing techniques of image data, DTM and field work to check the geomorphic expressions have helped in inferring an active fault in a gently sloping and apparently featureless region of the Gangetic Plain near Muzaffarnagar (named Muzaffarnagar Normal Fault) with a throw of about 6-9 m.

3 illus, 1 table, 7 ref

005133   Vikas Kumar;Vohra A;Srivastava V (NO, Amity Inst of Telecom Technol & Mgmt, Sector-125, Noida-201 301) : RF loss profile measurement for a high gain, broadband helix TWT. Indian J Radio Space Phys 2006, 35(2), 129-32.

Helix type structure is widely used as slow wave structure in the travelling wave tube (TWT) due to its natural wide bandwidth. Reflections present in the structure may cause oscillations and hence instability in the device. In order to minimize the reflections, a coating of lossy material is done on the helix support rods in a TWT. The loss introduced by such coating has significant effects on the characteristics of the device. In the conventional methods the loss due to this coating (also known as the loss profiles) can be measured only on a single rod before fabrication of the slow wave structure (SWS) assembly. A new and convenient method has been developed for the measurement of loss profiles of a fabricated SWS assembly. Using the new method an experimental study has been made on a high gain TWT that is made in two sections with sever in between. The loss profiles along the axis of helical SWS have been measured at the sever end. This measurement is found to be very helpful to ensure the accuracy of the final fabricated assembly.

7 illus, 6 ref

005132   Tiwari V K;Kimothi A;Bhatnagar D;Saini J S; Saxena V K;Kumar P (Phys Dep, Univ of Raj, Jaipur-302 004) : Theoretical analysis on circular sector microstrip antennas. Indian J Radio Space Phys 2006, 35(2), 133-8.

A rigorous theoretical analysis of a circular sector microstrip antenna with sector angle a is carried out. General expressions for radiated fields by antenna are derived by applying cavity model based modal expansion technique and are used to study its radiation parameters. Similar to a circular disk antenna, better results for circular sector antenna are also obtained in TM11 mode of excitation. The computed results of a sector antenna with α= 60° are compared with simulation results and a difference of 2.5%, 38%, 7% and 1.9%, respectively in resonance frequency; input impedance, directivity and bandwidth is recorded.

8 illus, 3 tables, 13 ref

005131   Shanker B;Banerji Babu A (Math Dep, Nizam Coll Osmania Univ, Hyderabad-500 007) : Convection due to oblique magnetic field in the penumbral region of sunspot. Indian J Radio Space Phys 2006, 35(2), 84-9.

The linear stability of convection due to oblique magnetic field in the penumbral region of sunspot has been investigated. Authors have obtained the values of Takens-Bogdanov bifurcation points and co-dimension two-bifurcation points by plotting graphs of neutral curves corresponding to stationary and oscillatory convection for different values of physical parameters relevant to convection in the penumbral region of sunspot.

3 illus, 7 ref

005130   Sahoo R N;Tomar R K;Rao C S;Sehgal V K; Charchi N;Abrol I P;Tiwari M K;Wadhawani M K (Agric Phys Div, Indian Agric Res Inst, New Delhi-110 012) : Radiometric scene correction of temporal multi-spectral satellite data for crop discrimination. Indian J Radio Space Phys 2006, 35(2), 116-21.

Multi-date satellite images under different conditions of the same area are difficult to compare because of change in atmospheric propagation, sensor response and illuminations. To overcome this problem, a radiometric normalization technique, which is based on the statistical invariance of the reflectance of man-made in-scene elements (pseudo invariant features) was attempted. The LISS-III data of IRS-ID of three dates were taken for discrimination of crops and retrieval of crop statistics. To develop temporal NDVI profile of the various crop types, relative image-to-image radiometric scene normalization of each band was done using linear transformation. Water body, orchard and other less dynamic features were excluded and multidate-NDVI image having only agricultural crops was obtained for identification and classification of various crops. Nine classes were identified and discriminated as different crops by analyzing temporal NDVI profile pattern based on ground truth, crop calendar and information on crop sowing and harvesting time. Spatial distribution of different crops was analyzed and crop area statistics was computed.

6 illus, 2 tables, 12 ref

005129   Midya S K;Chattopadhyay R (Phys Dep, Serampore Coll, Serampore-712 201) : Evening twilightglow of sodium 5893 Å line emission at Calcutta and its typical relation with astronomical parameters. Indian J Radio Space Phys 2006, 35(2), 77-83.

Sodium line (5893 Å) represents one of the most important airglow emission lines. The photometric observations of evening twilightglow for this line were taken at Narendrapur (Lat. 22°35' Long. 88°21 'E), a town in extended Calcutta, during the period between 1983 and 1988. Two distinctly recognizable enhancements or peaks were found to exist in time-versus-emission-intensity curve in evening twilight. One enhancement around sunset and the other a few minutes later were found to be a regular feature in everyday observation. On plotting the time of occurrence of the first peak relative to the sunset time for a complete month authors we obtained a sinusoidal curve having its troughs and crests coinciding with the different phases of the moon. This observation shows that the time of occurrence of the peak depends on the moon's age.

5 illus, 23 ref

005128   Manju G;Viswanathan K S (Space Phys Lab, Vikram Sarabhai Space Cent, Trivandrum-695 022, Email: manju_spl@vssc.org ) : Short period fluctuations in the equatorial electrojet electric fields. Indian J Radio Space Phys 2006, 35(2), 90-7.

A study is made on the short period fluctuations in the equatorial electro jet parameters at the magnetic equatoriallocation of Trivandrum (8.5 °N, 77 °E; dip 0.5 °N), during daytime for a number of magnetically quiet days, using coherent VHF backscatter radar observations in the altitude region of 90-115 km. For this study ΔH values at and off equatoriallatitudes have also been used. The detailed analysis of radar and magnetometer data show the following: (a) Significant fluctuation amplitudes in the period range of 25-35 min are present in the radar observations at different range bins over and above the dominant diurnal pattern of the height invariant large scale E-W electric field (E_y). The same periods do manifest when the radar data products are divided into sub-intervals of 1-1.5 h. (b) Values of H also indicate the same periods as that of radar observations. (c) A decrease in the amplitudes of the fluctuating components in H is seen from equator to low latitudes. The implications of the observations in terms of the possible origin of the fluctuations are discussed.

8 illus, 1 table, 17 ref

005127   Krishna Reddy K;Kozu T;Narayana Rao D (NO, Inst of Observational Res for Global Change (IORGC)/Japan Ag for Mari, Yokosuka, Japan) : Wind profiler radar for understanding the tropical convective boundary layer during different seasons. Indian J Radio Space Phys 2006, 35(2), 105-15.

Elucidates tropical continental boundary layer structures and their evolutions during different seasons over Gadanki, Southern India. Gadanki-LA WP (Lower Atmospheric Wind Pro filer Radar) has proved to be an excellent tool for studying convective structures and boundary layer depth with good temporal (~ 10 min) and vertical resolution (150m). Author used LA WP reflectivity, Doppler velocity and spectral width data in time versus altitude to characterize general behaviour of convective boundary layer based on the "morning" and "evening" transition. From a wide variety of observed patterns, three categories are identified: (i) Descent, (ii) Ascent, and (iii) Inversion Layer (IL). Long-term Gadanki-LA WP observational results show the Ascent cases occur on relatively warm and moist days with strong turbulence and weak capping inversion [maximum occurrence in monsoon], descent days occur [pre-monsoon] on warm dry convection days and IL days occur [winter] on dew/fog and drier days with subsidence inversion and/or advection of warm air from the Bay of Bengal.

7 illus, 1 table, 24 ref

005126   Kanaujia B K (Electron and Commun Engng Dep, M.J.P. Rohilkhand Univ, Bareilly-243 006, Email: bkkanaujia@yahoo.co.in ) : Relatively loaded annular ring microstrip antenna for multi-band operation. Indian J Radio Space Phys 2006, 35(2), 122-8.

Reactively loaded probe-fed annular ring microstrip antenna (ARMSA) has been theoretically investigated for multi-band operation. The patch loaded with shorting post is analyzed taking the effect of feed probe into account. It is found that the resonance frequency of the patch increases with number of shorting pins and bandwidth of operation is also affected.

7 illus, 1 table, 13 ref

005125   Iyer K N;Souza J R;Pathan B M;Abdu M A;Jivani M N;Joshi H P (Phys and Electron Dep, Saurashtra Univ, Rajkot-360 005) : Model of equatorial and low latitude VHF scintillation in India. Indian J Radio Space Phys 2006, 35(2), 98-104.

Using the observed VHF scintillations at equatorial and anomaly crest stations in India during the years 1987-1989, an empirical model is developed. The model employs the cubic spline technique to reproduce the variation of scintillation occurrence with local time, season, solar activity and latitude. The modelled values are compared with observed ones and the agreement is found to be quite good.

10 illus, 1 table, 17 ref

004095   Singh J S (NO, Banaras Hindu Univ, Varanasi-221 005) : Sustainable development of the Indian Himalayan region: linking ecological and economic concerns. Curr Sci 2006, 90(6), 784-8.

The Indian Himalayan region occupies a special place in the mountain ecosystems of the world. These geodynamically young mountains are not only important from the standpoint of climate and as a provider of life, giving water to a large part of the Indian subcontinent, but they also harbour a rich variety of flora, fauna, human communities and cultural diversity. Despite the abundance of natural resources, most of its people are marginalized and still live on subsistence level. The unscientific exploitation of natural resources is leading to increasing environmental degradation and aggravating the impact of natural hazards. There is a need to evolve new paradigm to restore balance between economic interest and ecological imperatives with due regards to socio-cultural principles.

2 illus, 25 ref

003112   Prasad M V S N;Rao T Rama;Ahmad I;Paul K M (Division of Radio & Atmospheric Sciences, National Physical Laboratory, New Delhi-110 012) : Investigation of VHF signals in bands I and II in southern India and model comparisons. Indian J Radio Space Phys 2006, 35(3), 198-205.

In order to achieve a highly reliable communication with a simple and small receiver, one requires the knowledge of the spatial and temporal variability of field strength. This assumes greater significance in broadcasting applications where the user expects a very high quality signal. The performance of any communication circuit depends on the models employed to calculate the coverage area and interference problems. The development and identification of models is a continuing and ongoing process and there is always scope for refinement. With this objective some field strength measurements were conducted using Chennai TV and FM stations in several radials. The variability of the path loss as a function of distance has been studied and path loss exponents deduced from the observed values were compared with the model available in literature. The agreement and deviations of the model with the observed results are presented and discussed and two approaches have been proposed to compare the observed results.

8 illus, 10 ref

003111   Gupta M;Mishra V K;Mishra A P (Department of Physics, A P S University, Rewa-486 003) : Study of cosmic ray intensity variations in relation to solar activity for sunspot cycles 19 to 23. Indian J Radio Space Phys 2006, 35(3), 167-73.

Based on the monthly data of various solar activity (SA) parameters, e.g. sunspot numbers (SSN), solar flux (SF), grouped solar flares (GSF), solar flare index (SFI) and coronal index (CI), a correlative study between solar activity (SA) and cosmic ray intensity (CRI, monthly mean of neutron monitor count rates) has been performed by the "running cross-correlation method". Overall behaviour of the running cross-correlation function between CRI and different SA parameters is almost similar, except during the maxima of solar cycles. Moreover, the time-lag analysis has been performed by the method of "minimizing correlation coefficient" and it is found that observed time-lag between CRI and various SA parameters is similar, except the coronal index (CI). The time-lag is found to be larger for odd solar cycles (19, 21 and 23) in comparison to even solar cycles (20 and 22), showing odd-even asymmetry of solar cycles. The correlation between CRI and different SA parameters considering time-lag factor during the whole period of investigation has been presented. The differences observed in the time-lag between CRI and different SA parameters, especially for CI, have also been discussed.

6 illus, 1 table, 27 ref

003110   Ganguly N D;Ranjan R R;Joshi H P;Iyer K N (Department of Physics, St. Xavier's College, Ahmedabad-380 009, Email: nanditad@icenet.net) : Diurnal and seasonal variation of columnar ozone at Rajkot. Indian J Radio Space Phys 2006, 35(3), 181-6.

Ozone data obtained from Earth-Probe Total Ozone Mapping Spectrometer (TOMS) has been used to calibrate a Microtops-II Sun photometer. Results of observed diurnal and seasonal variation of ozone at Rajkot, obtained using Microtops-II Sun photometer is reported. Since the ozone concentrations measured by Dobson spectrometers in India and TOMS are found to correlate well, it is possible to calibrate Microtops-II Sun photometer with the help of TOMS to get accurate ozone values over Indian low latitudes. This will in turn reduce the inconvenience of carrying the Microtops Sun photometer to a Dobson center for calibration. The diurnal variation of ozone measured by Microtops-II Sun photometer indicates 2 higher vertical column density of ozone during morning compared to evening hours. This may be due to an increase in daytime temperature and the corresponding increase in ozone by photolysis. An examination of the monthly mean ozone values obtained from Microtops-II Sun photometer indicates a marked seasonal variation with a maximum ozone concentration around June and a minimum around December.

5 illus, 12 ref

003109   Abdul Kalam A P J (Rashtrapathi Bhavan, , New Delhi) : Exploration and utilization of moon. J Aerospace Sci Technol 2006, 58(3), 167-72.

12 illus

001071   Vasundhara R;Kuppuswamy K;Ramamoorthy S;Velu C;Venkataramana A K (NO, Indian Inst of Astrophys, Bangalore-560 034, Email: rvas@iiap.res.in) : Occultation of 2UCAC 42376428 by (423) Diotima on 2005 March 06. Bull Astr Soc India 2006, 34(1), 21-6.

Observations of the occupation of the star 2UCAC 42376428 by (423) Diotima on 2005 March 06 at the Vainu Bappu Observatory are reported. The observed mid time of the event at 15:12:25.1 UT occurred 3.4 s later than the predicted time but within the 1 σ uncertainty of 4.3 s of the predictions by IOTA. The duration of the event of 4.2 s was found to be shorter than the predictions even allowing for a one sigma uncertainty in the impact parameter. This implies a narrower projected width of the asteroid along the occultation track at the time of the event.

2 illus, 2 tables, 11 ref

001070   Sinvhal S D (91 Vigyan Kunj, I.I.T. Roorkee, Uttaranchal-247 667, Email: sdsinvhal@hotmail.com) : The Uttar Pradesh state observatory-some recollections and some history (1954-1982). Bull Astr Soc India 2006, 34(1), 65-81.

An attempt has been made to present a picture of pre-historic and initial formative years of the well known Uttar Pradesh State Observatory, Nainital. The development of academic activities along with infrastructure are described. The emphasis on the frontline research work, self-reliance and international interaction was given during the formative years of the observatory. The largest telescope 104-cm of the observatory was installed in 1972 and has produced good scientific results.

001069   Sharma A;Soni U A;Rai H K;Hussain M Z;Chander S;Mishra A K;Sehgal M;Kalra N (Unit of Simulation and Informatics, Indian Agric Res Inst, New Delhi-110 012) : Estimating solar radiation from temperature. J Agrometeorol 2005, 7(1), 14-20.

Historical at weather dataset of some locations of India were compiled for radiation, maximum and minimum temperature relationship of solar radiation with the square root of the difference maximum and minimum temperatures was obtained. The northern region showed greater range of annual variation in solar radiation when compared with central and peninsular regions'. The relationship of ratio of solar radiation to square root of temperature range with the Julian day for various diverse locations could account for 30-64 per cent variability, which was statistically significant. The rate of change of solar radiation, which was found to vary spatially as well as temporally.

1 illus, 3 tables, 7 ref

001068   Shah D (NO, Astro-Meterological Res Project, 24/11 Shivajinagar, Pune-411 005) : Monsoon rainfall forecasting of Saurashtra on astronomical basis. J Agrometeorol 2005, 7(1), 140-7.

^iia4 tables, 3 ref

001067   Richtler T (Departamento de Fisica, Universidad de Concepcion, Concepcion, Chile, Email: tom@mobydick.cfm.udec.cl) : Some remarks on extragalactic globular clusters. Bull Astr Soc India 2006, 34(1), 83-97.

Comments (in a review fashion) on a few selected topics in the field of extragalactic globular clusters with strong emphasis on recent work has been made. The topics are: bimodality in the colour distribution of cluster systems, young massive clusters, and the brightest old clusters. Globular cluster research, perhaps more than ever, has lead to important (at least to astronomers) progress and problems in galaxy structure and formation.

6 illus, 78 ref

001066   Ram Sagar (NO, Aryabhatta Res Inst of Observational Sci, Manora Peak, Nainital-263 129, Email: sagar@aries.ernet.in) : Aryabhatta Research Institute of Observational Science : reincarnation of a 50 year old state observatory of Nainital. Bull Astr Soc India 2006, 34(1), 37-64.

The fifty year old State Observatory, well known as U.P. State Observatory till the formation of Uttaranchal in November 2000, was reincarnated on March 22, 2004 as Aryabhatta Research Institute of Observational Sciences with acronym ARIES, an autonomous institute, under the Department of Science & Technology, Government of India. The growth of academic and technical activities and new mandate of the Institute are briefly described. In early 60's, the Institute was one of the 12 centres established by the Smithsonian Astrophysical Observatory, USA, all over the globe but the only centre in India for imaging artificial earth satellites. Commensurating with its observing capabilities, the Institute started a number of front-line research programmes during the last decade, e.g., optical follow up observations of GRB afterglows, radio and space borne astronomical resources, intra-night optical variability in active galactic nuclei as well as gravitational microlensing and milli-magnitude variations in the rapidly oscillating peculiar A type stars. , As a part of atmospheric studies, characterisation of aerosol at an altitude of about 2 km is going on since 2002. ARIES has plans for establishing modern observing facilities equipped with latest backend instruments in the area of both astrophysics and atmospheric science. Formation of ARIES, therefore augurs well for the overall development of astrophysics and atmospheric science in India.

8 illus, 45 ref

001065   Piskunov A E;Kharchenko N V;Roser S;Schilbach E;Scholz R D (NO, Astrophysikalisches Inst Potsdam, An der Sternwarte 16, D-14482 Potsdam, Germany, Email: piskunov@inasan.rssi.ru) : Hipparcos mission and galactic open clusters. Bull Astr Soc India 2006, 34(1), 129-40.

Presents some results of a study of the galactic open cluster population. This study is based on the all-sky catalogue ASCC-2.5 compiled from Tycho-2, Hipparcos and other catalogues. Screening the ASCC-2.5 resulted in the identification of 520 known clusters and the detection of 130 new ones. A uniform combined kinematic-photometric cluster membership was established for these objects and new uniform scales of cluster structure (angular sizes), kinematics (average proper motions and radial velocities), photometry (reddening and distance) and evolution (age) were established. Two parts of our more extended open cluster population study (some details on the spatial and age distributions of open clusters) are presented.

3 illus, 2 tables, 28 ref

001064   Pal S;Chakrabarti S K;Kraus A;Mandal S (NO, Cent for Space Phys, Chalantika 43, Garia Station Rd., Garia, Kolkata-700 084, Email: space_phys@vsnl.com) : Broadband radio spectrum of SS433. Bull Astr Soc India 2006, 34(1), 1-9.

Obtained a broadband radio spectrum of the galactic compact object SS433 through the multi-wavelength campaign using the Giant Meter Radio Telescope (GMRT) and the Effelsberg 100-m Radio Telescope. The observations took place from 2005 January 03 to 2005 February 08 using eight different frequencies. Observed a flare which appeared to have started prior to January 18 and lasted till February 08. The light curves show a progressively larger time-delay as the radio frequency goes down. The peak of the 6 cm lightcurve is delayed by <126> 3 days with respect to the peak of the 9 mm lightcurve. There is an indication of the flattening of the spectrum and possibly a turnover at <126> 1.5 GHz. If interpreted this to be due to synchrotron self-absorption, the required magnetic field would become too large, however, free-free absorption by hot thermal surrounding medium formed due to stellar winds is still a possibility. All sky monitor (ASM) aboard Rossi X-ray Timing Experiment (RXTE) showed very high X-ray count on 2005 January 25 when the flare was well underway. This may be due to slamming of the radio 'bullets' with previously ejected, relatively slowly moving material.

4 illus, 14 ref

001063   Ojha D;Tamura M (NO, Tata Inst of Fundamental Res, Homi Bhabha Road, Coloba, Mumbai-400 005, Email: ojha@tifr.res.in) : Luminosity functions of YSO clusters in Sh-2 255, W3 main and NGC 7538 star forming regions. Bull Astr Soc India 2006, 34(1), 119-28.

Conducted deep near-infrared surveys of the Sh-2 255, W3 Main and NGC 7538 massive star forming regions using simultaneous observations of the JHKs-band with the near-infrared camera SIRIUS on the UH 88-inch telescope. The near-infrared surveys cover a total area of <126> 72 square arcmin of three regions with 10-σ limiting magnitudes of <126> 19.5, 18.4 and 17.3 in J, H and K_s-band, respectively. Based on the colour-colour and colour-magnitude diagrams and their clustering properties, the candidate young stellar objects are identified and their luminosity functions are constructed in Sh-2 255, W3 Main and NGC 7538. A large number of previously unreported red sources (H - K <62> 2) have also been detected around these regions. Authors argue that these red stars are most probably pre-main sequence stars with intrinsic colour excesses. The detected young stellar objects show a clear clustering pattern in each region: the Class I-like sources are mostly clustered in molecular cloud region, while the Class II-like sources in or around more evolved optical H II regions. Find that the slopes of the K_s-band luminosity functions of Sh-2 255, W3 Main and NGC 7538 are lower than the typical values reported for the young embedded clusters and their stellar populations are primarily composed of low mass pre-main sequence stars. From the slopes of the K_s-band luminosity functions, infered that Sh-2 255, W3 Main and NGC 7538 star forming regions are rather young (age ≤ 1 Myr).

2 illus, 1 table, 18 ref

001062   Ogura K (NO, Kokugakuin Univ, Higashi, Shibuya-ku, Tokyo 150-8440, Japan, Email: ogura@kokugakuin.ac.jp) : Star formation associated with H II regions. Bull Astr Soc India 2006, 34(1), 111-17.

Star formation associated with H II regions is briefly reviewed. Special emphasis is laid on series of observational studies on bright-rimmed clouds (BRCs), in which found a phenomenon called "small-scale sequential star formation." In addition a new hypothesis is advocated on the two modes of star formation associated with H II regions, i.e., the cluster and dispersed modes. The former gives birth to a rich cluster and in the associated H II region BRCs are formed only at a later stage of its evolution in the peripheries. In the latter mode no clusters or only loose ones are formed, but BRCs can appear at earlier stages in inner part of the H II region. Presumably these modes depend on the initial density distribution of the natal molecular cloud.

2 illus, 18 ref

001061   Lee M G (Astr program SEES, Seoul Nationl Univ, Seoul-151 742, Korea, Email: mglee@astrog.snu.ac.kr) : Star clusters in late-type galaxies. Bull Astr Soc India 2006, 34(1), 99-110.

Presents an overview of recent progress in the study of star clusters in nearby late-type galaxies. Colour-magnitude diagrams of star clusters in several nearby spiral galaxies show some differences in the mean colour of the globular clusters and in the magnitude of the brightest clusters. Recent wide field CCD survey of star clusters in M33 found that the star cluster system of M33 is dominated by blue clusters, and that the red clusters are more dispersed in a wider region than bluer clusters. Age distribution of the clusters in the interacting system M51 shows that a significant number of clusters in M51 were probably formed during the interaction of NGC 5194 and NGC 5195. About 50 faint fuzzy clusters are found in NGC 5195, SBO. Recent wide field CCD survey of star clusters in NGC 6822 discovered a new kind of extended clusters in the remote halo of NGC 6822. These new clusters in NGC 6822 share several common features with the faint fuzzy clusters found in the interacting SBO galaxies, providing an important clue to understanding the origin of extended clusters.

6 illus, 20 ref

001060   Kalirai J S (Univ of Calif Observatories/Lick Obs, Univ of Calif at Santa Cruz 1156 High Street, Santa Cruz, California 95064, USA) : Probing stellar evolution with open star clusters. Bull Astr Soc India 2006, 34(1), 141-52.

Derived the age, distance, reddening, binary fraction, metallicity, and star formation rate for the rich open star cluster NGC 2099 by comparing a high quality observational colour-magnitude diagram (CMD) with synthetic CMDs based on MonteCarlo numerical simulations. This approach accounts for all of the main parameters which determine the shape of the CMD for a stellar population and, unlike theoretical isochrone fits, allows a detailed comparison of the number of stars in various evolutionary phases. The resulting parameters are a key input into determining how much mass stars in NGC 2099 have lost through post main-sequence evolution. Followed up deep imaging study with multi-object spectroscopy of <126>20 cluster white dwarf stars and constrain the initial-final mass relationship. The results clearly indicate that stars with initial masses between 2.8 and 3.4 M_(.) lose 70-75% of their mass through stellar evolution. For the first time, finds some evidence for a metallicity dependence on the initial-final mass relationship.

4 illus, 27 ref

001059   Carraro G (Departamento de Astronomia, Universidad de Chile, Casilla 36-D, Santiago, Chile) : Open cluster remnants : an observational overview. Bull Astr Soc India 2006, 34(1), 153-62.

The state of the art in the current research on the final stages of Open Star Clusters dynamical evolution is presented. The focus will be on observational studies and their achievements. By combining together photometric, spectroscopic and astrometric material, a new look at this exciting topic is now possible, thus providing a solid observational foundation for a new generation of theoretical studies on the subject.

^iia3 illus, 2 tables, 32 ref

001058    (NO, , ) : Intermediate-sized black hole: a new class of black holes?. Sci Soc 2004, 2(2), 83-4.

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007768   Sinha A K;Vohat P;Pathan B M (NO, Indian Institute of Geomagnetism, Navi Mumbai, Email: pvohat@iigm.res.in) : Solar wind-magnetosphere-ionosphere coupling: Pi2 observations. Indian J Radio Space Phys 2010, 39(5), 257-64.

There had been a number of studies using satellite and ground based observations on the interaction between the solar wind and the magnetosphere, which shows highly complex temporal and spatial interaction between the two. The magnetotail provides an important channel for the flow of energy from solar wind to the ionosphere and atmosphere. Solar wind drives reconnection under certain conditions on the dayside magnetopause, connecting the interplanetary and geomagnetic fields. As a result, the field lines are swept back to the magnetotail where magnetic energy is built up. This stored energy may be converted to plasma kinetic energy either in continuous mode or impulsive mode. In either case, this kinetic energy appears in the energization of the electrons and ions which stream along the magnetic field line in the plasma sheet boundary layer towards the Earth. This flow of energized charged particles results in the form of energy deposition in the high latitude ionosphere and high latitude atmosphere manifesting in terms of aurora. It has been shown from the results obtained from the analysis of ground based magnetic data that, the solar wind driven energy through the magnetotail makes global appearance in the night side of the Earth in the form of Pi2 pulsations. Compressional waves, following plasma sheet thinning due to reconnection, move Earthward and cause plasmasphere to oscillate at discrete frequencies. The present analysis reveals that Pi2 energy is having a global impact on the low latitude in transferring the energy and momentum from solar wind to ionosphere through tail region. During a geomagnetic quiet period (Kp= -3), the scrutiny of the magnetic records from a wide chain of magnetic observatories in the low and mid latitudes gave signatures of plasmaspheric cavity oscillations at dominant frequencies of 11.72 mHz and 23.44 mHz. It has been confirmed from various other parameters such as solar wind dynamic pressure, interplanetary magnetic field and AE-indices that the observed waves are Pi2 type pulsations and may be associated with substorm onset.

7 illus, 20 ref

007767   Sharma S;Chandra H;Vats H O;Pandya N Y;Jain R (NO, Physical Research Laboratory, Ahmedabad-380 009, Email: somkumar@prl.res.in) : Ionospheric modulations due to solar flare over Ahmedabad. Indian J Radio Space Phys 2010, 39(5), 296-301.

Earth's ionosphere responds quickly to the enhanced X-rays and ultraviolet (UV) radiation emitted from the Sun during solar flares. Ground and satellite based observations are important for unravelling the consequences of these essentially unpredictable events. Regular ionospheric soundings are made over Ahmedabad (23°N, 72.4°E) using KEL digital lonosonde. Using this data, the influence of the excess X-ray emission from the flares/CMEs in different regions of the Earth's ionosphere over Ahmedabad has been studied. Based on the X-ray spectral characteristics of the flares, the variation in the minimum frequency of reflection, f_min, an indicator of the ionization in D-region of ionosphere, in contrast to daily quiet time variation, has been measured. The studies of the excess absorption, due to the solar flares, in the D-region of ionosphere over Ahmedabad are made for the events during 1996-2000. The deviation from Chapman's layer behaviour of E-layer over Ahmedabad during few solar flares have been also found.

4 illus, 2 tables, 7 ref

007766   Santosh Kumar;Raizada A (Physics and Electronics Dep, R D Univ, Jabalpur-482 001, Email: s_kumar123@rediffmail.com) : Geomagnetic storms with Dst <60> - 100 n T during 1999-2002. Indian J Radio Space Phys 2010, 39(5), 284-9.

Ninety geomagnetic storms (GMSs) of intense nature, i.e. with Dst <60> -100 nT have been noticed using solar geophysical and interplanetary data during solar cycle 23. Out of which, 36 GMSs of intense (-200 nT ≤ Dst <60> -100 nT) nature and 10 of super intense (Dst <60> -200 nT) nature have occurred during the maximum phase, i.e. from 1999 to 2002, of solar cycle 23. The variation in time delay between the commencement and peak time of GMS is observed to be 5.5 to 42.5 h for different storms. The strength of GMS does not reveal any dependence with the duration of the storm as well as with the number of CMEs involved in the occurrence of storm. The high speed solar wind plasma, may be in the form of CMEs or else, is more likely to cause the intense and super intense GMSs. The solar features, i.e. X-ray solar flares (SFs), active prominences and disappearing filaments (APDFs), coronal mass ejections (CMEs), etc. responsible for causing GMSs have been studied. The geo-effective CMEs show longitudinal as well as hemispherical bias. Geo-effective CMEs causing intense and super intense GMSs are mostly confined between ±30° latitude and ±40° longitude. The correlation coefficients of 0.71 and 0.66, respectively of Bz and Vsw.Bz with Dst index indicates that Bz and Vsw.Bz may be considered as key contributors in determining the strength of GMSs.

6 illus, 1 table, 15 ref

007765   Raymond J C;Ciaravella A (NO, Center for Astrophysics, 60 Garden St, Cambridge MA 02138, USA) : Current sheet of 4 November 2003 flares. Indian J Radio Space Phys 2010, 39(5), 249-51.

Reconnection current sheets are a central feature of models of solar flares and coronal mass ejections (CME) but they are still not understood. Ultraviolet spectra from the UVCS instrument aboard SOHO are combined with white light observations from MLSO to obtain the temperature, density, thickness and depth of the flare-CME current sheet that developed during the powerful flare on 4 November 2003. This paper summarizes the observations and the results. It was found that the thickness of the current sheet is far larger than expected from the Sweet-Parker picture of reconnection. It may be consistent with the region formed by slow-mode shocks in the Petschek picture, and it is probably consistent with models of reconnection in a turbulent layer such as that of Lazarian and Vishniac.

2 illus, 11 ref

007764   Pankaj Kumar;Wahab U;Taori A;Ramesh Chandra; Bisht S (NO, Aryabhatta Research Institute of Observational Sciences (ARIES), Nainital-263 129, Email: pkumar@aries.res.in) : Ionospheric response to the space weather event of 18 november 2003-an investigation. Indian J Radio Space Phys 2010, 39(5), 290-5.

The study explores the ionospheric effects of the well cited solar flare events (M3.2, M3.9/2N) of 18 November 2003 associated with CMEs. The Ha observations of these flares (taken with 15 cm Solar Tower Telescope at ARIES, Nainital) have been analysed to see an association of these flare events with the geomagnetic storm occurred on 20 November 2003. The ionospheric data from Puerto Rico (18.5°N, 67.2°W), Dyess (32.4°N, 99.7°W) and Millstone Hill (42.6°N, 71.5°W) together with the disturbance storm time indices (Dst index) variability exhibited a corresponding associations having a delay in the solar wind parameters, triggered by these flare events.

5 illus, 11 ref

007763   Mujiber Rahman A;Manoharan P K;Umapathy S (School of Physics, Madurai Kamaraj Univ, Madurai-625 021, Email: mujib 73@gmail.com) : Propagation characteristics of coronal mass ejections and their effects at the near-earth environment. Indian J Radio Space Phys 2010, 39(5), 276-9.

Deals with the geo-effective analysis of halo and partial halo coronal mass ejections (CME_s) observed during solar cycle 23. The analysis is based on lists of white-light CME_s and associated ICME_s and interplanetary shocks analyzed in recent studies [Manoharan P K, Gopalswamy N, Yashiro S, Lara A, Michalek G & Howard R A, Influence of CME interaction on propagation of interplanetary shocks, J Geophys Res (USA), 109 (2004), 6109, doi: 10.1029/2003JAO10300; and Manoharan P K, Evolution of Coronal Mass Ejections in the inner heliosphere: A study using white-light and scintillation images 2003, Sol Phys (Netherlands), 235 (2006) pp 345-368, doi: 10.1007/sll207-006-0100-y]. The link between the initial speed of the CME, its speed at 1 AU, speed of the associated IP shock, its strength, magnetic field within the CME and the geomagnetic storm have been studied using the spacecraft data and radio scintillation images from Ooty. The southward component of the CME magnetic field (B_z) and the geo-storm index (Dst) are highly correlated. But a large scatter is evident in this correlation as well as in correlations of speeds of the CME at the near-Sun and at 1 AU with arrival times of IP shock and ICME at the Earth. The preliminary results suggest that each CME has its own unique propagation signature, which is likely determined by the internal energy possessed by the CME and the interaction of the CME with the ambient (i.e., background) solar wind plasma and also with the preceding CME(s) occasionally encountered in the propagation path.

3 illus, 11 ref

007762   Joshi I S (NO, Indian Institute of Tropical Meteorology, Dr. Homi Bhabha Road, Pashan, Pune-411 008, Email: indira@tropmet.res.in) : Influence of solar variability on rainwater. Indian J Radio Space Phys 2010, 39(5), 312-14.

The significant effect of the high-energy charged particles, entering the earth's environment from interplanetary space, on the space and terrestrial weather is well known. Solar flares emit electron particles. These electrons interact with Earth's magnetic field and atmosphere causing weather, geophysical and behavioural changes. These charged particles from the sun affect Earth's magnetic field and increase atmospheric nucleation which then affects cloud formation and thus the weather. Keeping this in view, a study has been undertaken to examine the changes in rainwater associated with the high energy charged particles entering the earth's environment from interplanetary space. It is observed from the analysis that an increase in proton and electron fluences is followed by an increase in electrical conductivity and decrease in pH of rainwater over Pune.

3 illus, 2 tables, 8 ref

007761   Joshi A D;Mathew S K;Srivastava N;Martin S F; Gupta S K (Udaipur Solar Observatory, Physical Research Laboratory, Udaipur, Email: janandd@prl.res.in) : Dual beam Hα doppler system to acquire, analyse and anticipate solar eruptive events directed towards earth. Indian J Radio Space Phys 2010, 39(5), 315-18.

A new instrument with a dual-beam Ha Doppler system is being developed at the Udaipur Solar Observatory (USO) in order to improve the quality and quantity of data on quiet, activated and erupting filaments and prominences on the Sun, especially those associated with geo-effective coronal mass ejections. These data can be potentially used to construct three-dimensional topology of erupting filaments as they leave the surface of the Sun and can be compared with multi-wavelength data obtained from space missions such as STEREO, SOHO and Hinode. The characterization of various optical components for the instrument is being carried out, and some preliminary results are presented in the paper.

6 illus, 1 table, 7 ref

007760   Hazra S;Sinha A K;Pathan B M (NO, Indian Institute of Geomagnetism, Navi Mumbai-410 218, Email: susmitah@iigs.iigm.res.in) : Variation of Schumann resonance frequency observed at Allahabad (Lat 22°N, long 81.51°E). Indian J Radio Space Phys 2010, 39(5), 308-11.

The lightening bolts throughout the Earth stimulate the cavity between the Earth's surface and lower ionosphere to resonate at extremely low frequency (ELF). This causes the Earth's magnetic field to oscillate at these frequencies and the phenomenon is known as Schumann resonance (SR). Theoretically, the harmonics of the oscillations are found to be at approximate frequencies of 7.8, 14, 20, 26, 33, 39 and 45 Hz, which depend on the conductivity of the lower ionosphere, conductivity of the ground and different propagation properties of the Earth-ionosphere cavity. With the improved sensitivity, accuracy and sampling rate of the search coil magnetometer installed at low latitude (Allahabad, lat 22°N, long 81.51°E), the characteristics of SR frequency have been studied and presented.

2 illus, 11 ref