http://nopr.niscair.res.in/handle/123456789/2796 Search the Channel search http://nopr.niscair.res.in/simple-search http://nopr.niscair.res.in/handle/123456789/2831 Title: Behaviour of methane emission from a paddy field of high carbon content <br/> <br/>Authors: Purkait, N N; Saha, A K; De, Sanghamitra; Chakrabarty, D K <br/> <br/>Abstract: Behaviour of methane emission from the paddy field of Lakshmikantapur has been studied for two full crop years, 1998-99 and 2003-04. The soil of this place has carbon content greater than 0.7 %. Two types of crops, namely, Kharif and Rabi are grown during a full crop year. Measurements were made from the beginning to the end of the plant life. Simultaneously water level and soil temperature were also measured. It is found that occasionally methane emission takes place by ebullition-yielding high value of concentration. It has diurnal variation with maximum around 1400 hrs LT. There are two peaks of emission in the whole plant life; for Kharif, the second peak is lower than the first peak and for Rabi, it is the other way round. Soil temperature affects methane emission more than water level. <br/> <br/>Page(s): 52-58 Mon, 29 Jan 2007 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/2830 Title: Retrieval of atmospheric temperature and moisture profiles from satellite data over India using the ICI inversion model <br/> <br/>Authors: Singh, Devendra; Bhatia, R C <br/> <br/>Abstract: Radiance measurements from satellites offer the opportunity to retrieve atmospheric variables at much higher spatial resolution than is presently afforded by in situ measurements (e.g., radiosondes). However, the accuracy of these retrievals is crucial to their usefulness, and the ill-posed nature of the problem precludes a straight forward solution. In this paper, Inversion Coupled with Image (ICI) model has been investigated to retrieve vertical temperature and moisture profiles of earth’s atmosphere from infrared and microwave brightness temperatures from a polar-orbiting satellite. The analyses were done using the Advanced TIROS Operational Vertical Sounder (ATOVS) data for the January and July 2002 representing winter and summer conditions. The results are compared with NCEP (National Center for Environmental Prediction) reanalysis data 1 × 1 degree latitude and longitude. Emphasis has been given in analyzing the role of the channels combination used in the retrieval process. Different surface types (sea and land) and atmospheric conditions (clear and cloudy sky) were also considered. <br/> <br/>Page(s): 44-51 Mon, 29 Jan 2007 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/2829 Title: Atmospheric subsidence and the surface temperature variability in the pre-monsoon month over a semi-arid north peninsular Indian station: A case study <br/> <br/>Authors: Deshpande, S M; Kulkarni, J R; Joshi, R R; Singh, N; Damle, S H; Pant, G B <br/> <br/>Abstract: Variability in maximum temperature in the month of March 2004 over Pune, a station representative of semi-arid re-gion of north peninsular India, has been studied. The vertical wind velocity data measured by UHF wind profiler, installed at Pune (18.31ºN, 73.58ºE) has been utilized. Hourly averaged vertical wind velocity profiles were obtained four times a day, on a three hourly basis from 0800 to 1700 hrs IST (Indian Standard Time) in March 2004. The vertical velocity is found to have a typical mean and standard deviation of 10 and 15-20 cm/s, respectively. The mean structure of the vertical distribu-tion showed predominately upward motion extending up to 2-3 km and predominately downward motion in the 3-6 km lay-ers. After removing the effects of radiative and advective heating, the anomalies in the maximum temperature over Pune are found to be statistically related with the depth of the atmospheric column over which the subsidence occurs. <br/> <br/>Page(s): 33-43 Mon, 29 Jan 2007 22:58:59 GMT http://nopr.niscair.res.in/handle/123456789/2823 Title: Study of aerosol optical depth and precipitable water vapour content at Rajkot, a tropical semi-arid station <br/> <br/>Authors: Ranjan, Ritweej Rajeev; Ganguly, Nandita D; Joshi, H P; Iyer, K N <br/> <br/>Abstract: Aerosol optical depth (AOD) at 1020 nm for the period July 2004 - July 2005 and at six different wavelengths ranging from 380 nm to 1020 nm for March-June 2005 is studied. The measurements are being made at the tropical semi-arid location Rajkot (22º18' N, 70º44' E, 142 m above sea level) using a hand-held microprocessor-based sun photometer, MICROTOPS-II under the aegis of ISRO’s Geosphere Biosphere Programme (IGBP). Precipitable water vapour is estimated from the measurements of solar intensity at 936 nm and 1020 nm. The AOD shows seasonal variation with high values (0.41) in summer and low values (0.11) in winter. Angstrom wavelength exponent ⍺ has been found to be high (0.59) during March, indicating relative dominance of accumulation-mode particles. During summer season, low value (0.25) of Angstrom wavelength exponent ⍺ indicates relative dominance of coarse-mode particles. The changes in the column water vapour have been found to be correlated with the changes in AOD. This is supported by the observed increase of AOD with relative humidity at high humidity values. <br/> <br/>Page(s): 27-32 Mon, 29 Jan 2007 22:58:59 GMT