D. Narayana Rao

SRM University

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Trends

Author Order

Document Type

Co-Authors

T. Narayana Rao

National Atmospheric Research Laboratory

S. Vijaya Bhaskara Rao

Sri Venkateswara University

Y. Bhavani Kumar

National Atmospheric Research Laboratory

P. Kishore

University of California, Irvine

P. Vishnu Prasanth

Laboratoire de l'Atmosphère et des Cyclones

Venkataraman Sivakumar

University of KwaZulu-Natal

K. Krishna Reddy

Yogi Vemana University

Amit Jain

Advanced Micro Devices (Canada)

Karanam Kishore Kumar

Vikram Sarabhai Space Centre

M. Venkat Ratnam

National Atmospheric Research Laboratory

Cooperative Institutions

National Atmospheric Research Laboratory

Sri Venkateswara University

Indian Space Research Organisation

Vikram Sarabhai Space Centre

Centre National de la Recherche Scientifique

SRM Institute of Science and Technology

Government of India

Physical Research Laboratory

Kyoto University

Mahatma Gandhi University

Author Statistics

Papers

Citation

H-Index

i-10 index

Research Field

Onset of Indian summer monsoon over Gadanki (13.5°N, 79.2°E): Study using lower atmospheric wind profiler

Geophysical Research Letters (2007)

V. V. M. Jagannadha Rao M. Roja Raman M. Venkat Ratnam D. Narayana Rao S. Vijaya Bhaskara Rao

The onset of Indian summer monsoon (ISM) over Gadanki (13.5°N; 79.2°E) is identified using variations in signal‐to‐noise ratio (SNR), wind speed, wind direction and vertical velocity at 1.5 km (∼850 hPa) using lower atmospheric wind profiler (LAWP). Strengthening of the low level wind speed attaining 8 ms −1 with directional change from south‐easterlies to south‐westerlies defines the beginning of the monsoon. Enhancement in SNR few days before with noticeable magnitude of 5–10 dB at the time of onset combined with clear‐air vertical velocity reversal from downward to upward few days before onset and persisting during monsoon activity supplements the wind speed criteria in identifying onset. Hydrometeor velocity shows large downward values exceeding more than 1 ms −1 indicating occurrence of rainfall. It is proposed that UHF radar at a location can be used to identify the onset of ISM based on wind speed without considering rainfall separately.

Wind profiler

Westerlies

10.1029/2007gl031592

Cite

Citations (9)

Mesospheric turbulence studies using over low latitude: campaign of July, 2004

36th COSPAR Scientific Assembly (2006)

H. Chandra H. S. S. Sinha R. N. Misra Saurabh Das Uma Kota

Source

Cite

Citations (0)

Effect of Fresnel zone clearance on propagation characteristics of microwave links in hilly terrains

Indian Journal of Radio & Space Physics (1991)

D. Narayana Rao K. Krishna Reddy K.S. Ravi S. Vijaya Bhaskara Rao M.J. Kesava Murthy

Fresnel equations

Fresnel zone

Source

Cite

Citations (0)

Inferring microphysical processes occurring in mesoscale convective systems from radar measurements and isotopic analysis

Geophysical Research Letters (2008)

T. Narayana Rao Basivi Radhakrishna R. C. Srivastava T. Satyanarayana D. Narayana Rao

An attempt has been made, for the first time, to effectively utilize the synergy of various approaches providing microphysical information of precipitation to study short term variations in a Mesoscale Convective System (MCS). A campaign has been conducted wherein rain samples are collected during the passage of MCSs over Gadanki, India, and simultaneously a powerful VHF radar and disdrometer have been operated to infer the characteristics of the vertical structure and rain drop size distribution (DSD) of precipitation. Besides the convection and transition rain, two distinctly different phases of the stratiform rain are identified. Evaporation of rain drops seems to be significant in both convection and stratiform portions of MCS. Observed changes in the temporal variation of the stable oxygen isotope ratios (δ 18 O) of precipitation are interpreted in terms of microphysical processes leading to isotopic fractionation. The pattern of variability in isotopic abundance is found to be different from convection to transition and to stratiform rain. The present analysis clearly shows that the height (or temperature) and the rain regime of condensation are of paramount importance in determining δ 18 O. Correlations of δ 18 O with rainfall integral parameters stress the need for caution in interpreting the depleted isotopic ratios are due to high rainfall and/or bigger drops.

Disdrometer

Drizzle

10.1029/2008gl033495

Cite

Citations (25)

MST radar: Wind shear and its correlation with Atmospheric turbulence parameters

D. Narayana Rao P. Kishore

Source

Cite

Citations (0)

Rayleigh lidar observations of planetary waves in the middle atmosphere over Gadanki (13.5°N, 79.2°E)

Journal of Atmospheric and Solar-Terrestrial Physics (2006)

P. Kishore S. P. Namboothiri K. Igarashi Venkataraman Sivakumar S. Thulasiraman

Kelvin wave

Dominance (genetics)

10.1016/j.jastp.2006.01.010

Cite

Citations (12)

• A COMMON FIXED POINT THEOREM FOR FOUR SELF MAPS ON A FUZZY METRIC SPACE CONTROLLED BY A SB-FUNCTION

International Journal of Mathematical Archive (2013)

K. P. R. Sastry G. Appala Naidu D. Narayana Rao R. Venkata Bhaskar

In this paper we introduce a new class of control functions called SB-functions, using this, we prove a common fixed point theorem for four self maps on a fuzzy metric space controlled by a SB- function. Our result improves the results of Aage. C.T and Salunke [1], Rajesh Kumar Mishra and Sanjay Choudhary [6] and Rajesh Shrivastava and Manavi Kohil[7].

Source

Cite

Citations (0)

Altitude variation of Drop Size Distribution and their parameters

36th COSPAR Scientific Assembly (2006)

N. V. P. Kirankumar T. Narayana Rao D. Narayana Rao

Variation (astronomy)

Source

Cite

Citations (0)

VHF radar observations of weak echo regions in tropical mesoscale convective systems

Geophysical Research Letters (2005)

Karanam Kishore Kumar Jojo Joseph Amit Jain D. Narayana Rao

A multibeam VHF radar experiment, which was carried out to explore the mesoscale convective systems over Gadanki (13.5°N, 79.2°E), is discussed. These observations revealed an interesting pattern in the height horizontal distance section of radar reflectivity. A weak echo region (WER) is observed in the height region of ∼8–14 km well above the melting layer, which is believed to be first of its kind in VHF radar observations. A single vertical velocity core of ∼7 km vertical extent with ∼10 ms −1 vertical velocity is observed and it has been noticed that the WER is forming in the peripheral region of large vertical velocities. An attempt has been made to explain the plausible mechanism responsible for the formation of WERs. Significance of present results lies in showing the capability of VHF radar to scan the convective system in vertical plane and in providing observational evidence for existence of WER above the melting level.

Mesoscale convective system

Echo (communications protocol)

10.1029/2004gl022238

Cite

Citations (5)

Classification of tropical precipitating systems and associated Z‐R relationships

Journal of Geophysical Research Atmospheres (2001)

T. Narayana Rao D. Narayana Rao K. Rama Mohan S. Raghavan

Simultaneous observations of Indian Mesosphere‐Stratosphere‐Troposphere (MST) radar, Lower Atmospheric Wind Profiler (LAWP) and disdrometer, located at Gadanki (13.5°N, 79.2°E), over two seasons are used to derive the Z ‐ R relationships, of the form Z = AR b , for different types of precipitation and for different seasons. Disdrometer data are classified into three types, convection, transition, and stratiform, based on the variation of the median volume diameter D 0 with the rain rate R . The disdrometer classification is verified by comparing with the profilers classification, based on reflectivity (in terms of range corrected signal‐to‐noise ratio), Doppler velocity, spectral width, and vertical air velocity. Overall agreement between the two classification schemes is found to be reasonable. The variations in the coefficient A and the exponent b in the Z ‐ R relation for the case studies presented here are explained with the help of variations in drop size distribution parameters. From the total data the percentage occurrence of precipitation is found to be 55% stratiform, 9% convective, and 36% transition, whereas the total rainfall is 12, 54, and 34%, respectively. Interestingly, the exponent b (coefficient A ) is found to be smaller (larger) in the case of stratiform (convective) precipitation than that in convective (stratiform) precipitation, in contrast to the earlier results. The values of A and b are also derived for different monsoon seasons.

Disdrometer

Precipitation types

Wind profiler

10.1029/2000jd900836

Cite

Citations (124)