The Assimilation of GPS Radio Occultation Data and its Impact on Rainfall Prediction along the West Coast of India during Monsoon 2002     

Ching-Yuang Huang  Ying-Hwa Kuo  Shu-Ya Chen  Anisetty S. K. A. V. Prasad Rao  Chien-Ju Wang 《Pure and Applied Geophysics》2007,164(8-9):1577-1591

In this study, the Weather Research and Forecasting (WRF-2.0.3.1) model with three-dimensional variational data assimilation (3DVAR) was utilized to study a heavy rainfall event along the west coast of India with and without the assimilation of GPS occultation refractivity soundings in the monsoon period of 2002. The WRF model is a next-generation mesoscale numerical weather prediction system designed to serve both operational forecasting and atmospheric research communities. The Global Positioning System (GPS) radio occultation (RO) refractivity data, processed by UCAR, were obtained from the CHAMP and SAC-C missions. This study investigates the impact of thirteen GPS occultation refractivity soundings only, as assimilated into the WRF model with 3DVAR, on the rainfall prediction over the western coastal mountain of India. The model simulation, with the finest resolution of 10 km, was in good agreement with rainfall observations, up to 72-h forecast. There are some subtle but important differences in predicted rainfalls between the control run CN (without the assimilation of refractivity soundings) and G13 (with the assimilation of thirteen GPS RO soundings). In general, the assimilation run G13 gives a better prediction in terms of both rainfall locations and amounts at later times. The moisture increments were analyzed at the initial and forecast times to assess the impact of GPS RO data assimilation. The results indicate that remote soundings in the forcing region could have significant impacts on distant downstream regions. It is anticipated, based on this study, that considerably occultation soundings available from the six-satellite constellation of FORMOSAT-3/COSMIC would have even more significant impacts on weather prediction in this region.  相似文献   

Application of the time-predictable model in Peninsular India for future seismic hazard assessment   总被引：1，自引：0，他引：1  

Daya Shanker  H. N. Singh 《Acta Geophysica》2007,55(3):302-312

It has been the belief among Earth scientists that the Peninsular Shield is aseismic, as the region attained stability long ago. However, the earthquake at Koyna (10 December 1967), Bhadrachalam (13 April 1969), Broach (23 March 1970), Hyderabad (30 June 1983), Khillari (30 September 1993), Jabalpur (22 May 1997), Gujarat (26 January 2001), and additional ones of smaller magnitudes, altered this concept. This area has experienced many widely distributed shallow earthquakes, some of them having large magnitudes. It is now widely accepted that seismic activity still continues with moderate events. Therefore, a need has arisen to take into consideration recent seismological data to assess the future seismic status of Peninsular India. Earthquake generation model has been studied to develop the statistical relations with surface wave magnitude (M _S ≥ 4.5). Five seismogenic sources showing clustering of earthquakes and including at least three main shocks of magnitude 4.5 ≤ M _S ≤ 6.5 giving two repeat times, have been identified. It is mainly based on the so-called “regional time-predictable model”. For the considered region it is observed that the time interval between two consecutive main shocks depends on the preceding main shock magnitude (M _p ) not on the following main shocks magnitude M _f suggesting the validity of time predictable model in the region.  相似文献   

Secular pilgrimages and sacred tourism in the Indian Himalayas     

Shalini Singh 《GeoJournal》2005,64(3):215-223

Assuming the above quote as a true portrayal of pilgrims, this article attempts to describe the prototypical pilgrim from amongst the wide array of contemporary religious and secular tourists. To achieve this end, two approaches have been adopted. Firstly, the phenomenon/concept of pilgrimages have been discussed, so to distinguish it from the tourism phenomenon and; Secondly, the geographical notion of genus loci has been employed to exemplify the fundamental quest for ‘geopiety’ attained through the unification of the pilgrim’s intrinsic belief with its external location. The second part of the article illustrates the forgoing through an exploration of Himalayan pilgrimages. This has been achieved with a discussion of the emerging practices and recent trends in Himalayan pilgrimology. This appraisal alludes to Cohen’s quest for a ‘Theology of Tourism.’ The article concludes with an examination of a specific genre of contemporary tourists in the Indian Himalayas, who have been identified as ‘environmental pilgrims.’

相似文献   

Obituary Prof. R.S. Chaturvedi founding director, UPRSAC (5.9.1936–9.11.2001)     

A. N. Singh 《Journal of the Indian Society of Remote Sensing》2001,29(3):vi-vi

  相似文献   

Effect of parallel electric field on charged particle precipitation     

R. Prasad  R.N. Singh 《Planetary and Space Science》1981,29(9):915-924

Considering the presence of electric field parallel to geomagnetic field in the magnetosphere, the problem of wave-particle interaction has been considered. Dispersion equation of whistler mode wave in presence of parallel electric field has been derived. Using the effective dispersion equation, the wave-particle interaction has been reformulated to account for the effect of parallel electric field. Using charged particle energy spectrum and magnetospheric field and plasma models, the flux of electron precipitation has been computed. It is shown that the parallel electric field plays an important role and may work in simultaneity with other processes known for enhancement of electron precipitation.  相似文献   

Consequences of CP-violation in cosmic-ray sources     

P. N. Okeke  Santokh Singh 《Astrophysics and Space Science》1981,75(2):527-530

In this paper we show that CP-violation is operating in most cosmic-ray sources such as black holes, active galactic nuclei, supernova remnants, and that this leads to the in-equality of the electron—positron component of cosmic rays.Further implications of this result are also discussed.  相似文献   

Simulation of nose whistlers: An application to low latitude whistlers     

Kalpana Singh  R.P. Singh  R.N. Singh 《Planetary and Space Science》2006,54(6):594-598

Simulation technique for whistler mode signal propagating through inhomogeneous plasma using WKB approximation has been developed (Singh, K., Singh, R.P., Ferencz, O.E., 2004. Simulation of whistler mode propagation for low latitude stations. Earth Planet Space 56, 979-987). In the present paper, we have used it for the analysis of recorded signals at low latitudes and estimated the nose frequency, which is not observed on the dynamic spectra. At low latitudes nose frequency is ∼100 kHz or more and therefore it is absent in the dynamic spectra due to attenuation of the signal at higher frequencies. The importance of nose frequency is in determining the exact path of propagation, which is required in probing of ambient medium. It is shown that the method permits to study the nose frequency variation, it can be used to deduce physical parameters as the global electric field. A case study permits to get a reasonable value of the electric field, which up to now could not be done at very low latitude.  相似文献   

Singularities and cosmic censorship     

T. P. Singh 《Journal of Astrophysics and Astronomy》1997,18(4):335-338

We give an elementary overview of the subject of gravitational collapse in classical general relativity. Recent theoretical evidence for the formation of black-holes and naked singularities is summarised.  相似文献   

Massive compact dwarf stars and C-field     

L. P. Singh  P. K. Sahu 《Journal of Astrophysics and Astronomy》1997,18(1):15-21

The effect of C-field in high density matter has been studied. We find that the negative energy and negative pressure of the C-field helps in formation of massive compact stable neutron stars of mass ∼ 0.5 solar mass which is in the range of 0.01 to 1.0 solar mass of recently observed dwarf stars.  相似文献   

Point Source in a Layer Overlying a Semi-infinite Solid with Special Reference to Diffracted Waves–Aperiodic Source     

Sarva Jit Singh 《Geophysical Journal International》1967,12(2):209-223

  相似文献