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Planetary boundary layer and precipitation studies using lower atmospheric wind profiler over tropical India
Author(s) -
Krishna Reddy K.,
Kozu Toshiaki,
Ohno Yuichi,
Nakamura Kenji,
Higuchi Atsushi,
Madhu Chandra Reddy K.,
Anandan V. K.,
Srinivasulu P.,
Jain A. R.,
Rao P. B.,
Ranga Rao R.,
Viswanathan G.,
Narayana Rao D.
Publication year - 2002
Publication title -
radio science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.371
H-Index - 84
eISSN - 1944-799X
pISSN - 0048-6604
DOI - 10.1029/2000rs002538
Subject(s) - wind profiler , environmental science , atmospheric sciences , troposphere , precipitation , monsoon , planetary boundary layer , wind speed , climatology , boundary layer , diurnal temperature variation , forcing (mathematics) , radar , meteorology , geology , geography , physics , telecommunications , computer science , thermodynamics
For the first time in India, an L‐band (1357.5 MHz) lower atmospheric wind profiler (LAWP) has been installed and successfully operated at Gadanki, India, since September 1997. The first results of the accuracy can be given on the basis of about 24‐day intercomparisons between LAWP and mesosphere‐stratosphere‐troposphere radar data. The root‐mean‐square differences (RMS deviation) have been found to range between 1.18 m/s and 1.6 m/s for the wind speed. The two wind profilers compliment each other quite well, considering both the availability and the reliability of the wind measurements. Statistics of the data availability can be shown based on 775 days of data in low mode and about 532 days of data in high mode. The 80% availability of the LAWP was determined with 3.6‐km wind measurements in low mode and 5‐km wind measurements in high mode. LAWP observations show well‐marked planetary boundary layer diurnal variation on clear sunny days. We found that with a few exceptions the drier period has a higher boundary layer compared with the wet period, indicating that in the wet season, most of the net solar radiation evaporated moisture rather than heating the surface and therefore contributed little to buoyant forcing. We classified precipitating clouds into three types: convective, transition, and stratiform. Diurnal and seasonal variation of the occurrence of precipitating cloud systems shows that the precipitation primarily occurs in the afternoon and the convective and transition clouds are most frequent in the summer monsoon, while the occurrence of stratiform clouds is predominant in the winter monsoon.