In this study, real time estimates of cloud attenuation have been made using ground based microwave radiometric observations of Liquid Water Content at a tropical location. It is found that the significant amount of cloud attenuation occurs during monsoon season. Individual case study additionally shows that cloud attenuation can contribute significantly to the overall signal degradation at various frequency bands. © 2017 URSI.

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University of Calcutta (informally known as Calcutta University or CU) is a collegiate public state university located in Kolkata, West Bengal, India.&nbsp;Within India it is recognized as a &quot;Five-Star University&quot; and accredited &quot;A&quot; Grade by National Assessment and Accreditation Council.

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The University of Calcutta has secured the Fifth position among the Universities of India in the prestigious &quot;Indian University Ranking 2019&quot; list, released by the NIRF of the Ministry of Human Resource Development, Government of India.

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It was established on 24 January 1857, and was one of the first institutions in Asia to be established as a multidisciplinary and Western-style university. Its alumni and faculty include several heads of state, heads of government, social reformers, prominent artists, only academy award winner and Dirac medal winner in India, many Fellows of the Royal Society and five Nobel laureates as of 2019 which is highest in South Asia.

University Of Calcutta

Radiometric measurements of cloud attenuation over Earth-space path at a tropical location

2017 32nd General Assembly and Scientific Symposium of the International Union of Radio Science, URSI GASS 2017

In this letter, the tropospheric scintillations occurring just before rain commencement have been investigated. This letter indicates the association of the prerain scintillations with both the cloud thickness and the prevailing convection. The convective available potential energy has been considered as a parameter indicating the strength of the associated convection. © 2016 IEEE.

IEEE Geoscience and Remote Sensing Letters

Prerain Scintillations of Ku-Band Satellite Signal in Relation to Cloud and Convective Parameters at a Tropical Location

In the present study, the effectiveness of nowcasting convective activities using a microwave radiometer has been examined for Kolkata (22.65° N, 88.45° E), a tropical location. It has been found that the standard deviation of brightness temperature (BT) at 22. GHz and instability indices like Lifting Index (LI), K Index (KI) and Humidity Index (HI) has shown definite changes before convective events. It is also seen that combination of standard deviation of BT at 22. GHz and LI can be most effective in predicting convection. A nowcasting algorithm is prepared using 18 isolated convective events of 2011 and in all cases, a marked variation of these parameters has been seen an hour before the event. Accordingly, a prediction model is developed and tested on convective events of 2012 and 2013. It is seen that the model gives reasonable success in predicting convective rain about 7075. min in advance with a prediction efficiency of 80%. © 2015 Elsevier B.V.

Atmospheric Research

Prediction of convective events using multi-frequency radiometric observations at Kolkata

The present study proposes a technique by which the diversity gain can be estimated for a site utilizing the propagation data obtained at a single station. The technique is crucial in estimating diversity parameters in the absence of multi-station data. The rain decay parameter, as defined in the Simple Attenuation Model (SAM), is used to derive the rain rate and consequently rain attenuation at different distances from the single receiving site. The tropical location has been found to experience a wide variability of rain features during different periods of the year causing strong seasonal variations in the diversity gain. A comparison of the diversity gain obtained from the present propagation data and the ITU-R model indicates the necessity of modifying the model parameters of the ITU-R model. The modified model incorporates the seasonal variation and exhibits better prediction capability than the ITU-R model as related to the tropical location. © 2015 COSPAR. Published by Elsevier Ltd. All rights reserved.

Advances in Space Research

Diversity gain for rain attenuation over Earth-space path at a tropical location

Tropospheric scintillation has relation with rain rate and signal attenuation. The present study indicates strong connection of the pre-rain scintillations with the turbulence associated with convective systems. The role of atmospheric structure constant in enhancing the scintillation effect is also observed. © 2016 IEEE.

2016 URSI Asia-Pacific Radio Science Conference, URSI AP-RASC 2016

Pre-rain scintillation of Ku-band satellite signal at a tropical location

Nowcasting of heavy rain events using microwave radiometer has been carried out at Kolkata (22.65°N, 88.45°E), a tropical location. Microwave radiometer can produce the temperature and humidity profiles of the atmosphere with fairly good accuracy. Definite changes are observed in temperature and humidity profiles before and at the onset of heavy rain events. Concurrent changes in the brightness temperatures (BT) at 22. GHz and 58. GHz are found to be suitable to nowcast rain. The time derivatives of brightness temperatures at 22. GHz and 58. GHz are used as inputs to the proposed nowcasting model. In addition, the standard deviation of the product of these time derivatives is also considered. The model has been developed using the data of 2011 and validated for rain events of 2012-2013 showing a prediction efficiency of about 90% with alarm generated about 25. min in advance. © 2014 Elsevier B.V.

Journal	Data powered by Typeset2017 32nd General Assembly and Scientific Symposium of the International Union of Radio Science, URSI GASS 2017
Publisher	Data powered by TypesetInstitute of Electrical and Electronics Engineers Inc.