Abstracts for the 5th International GAME Conf.
3-5 October 2001
Aichi Trade Center
Nagoya Japan
Combined use of ground based atmospheric radars and TRMM PR for understanding the Indian Monsoon precipitation
Krishna Reddy (1), Kozu Toshiaki (2), Kenji Nakamura (3), Ohno Yuichi (4), A.R.Jain (5)
(1) Fronttier Observational Research System for Global Change (FORSGC), Yokohama
(2) Department of Electronic and Control Systems Engineering, Shimane Univ., Matsue
(3) Hydrospheric Atmospheric Research Center, Nagoya Univ. Nagoya
(4) Communications Research Laboratory, Tokyo
(5) National MST Radar Facility, Gadanki, India
Southern India has two distinct rainfall seasons, namely, South-West (SW, summer) and North-East (NE, winter) monsoon periods. We utilized the ground-based wind profilers, disdrometer, Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar for understand the precipitating cloud systems during monsoon over Gadanki, India. TRMM PR provides a unique data and we are carrying out research work to support ground validate of the TRMM Precipitation Radar. The ground validation results are encouraging. The radar reflectivity agreement is good with variation of 1 -3 dB. The Disdrometer data analysis shows a clear seasonal dependence of rain drop size distributions (DSD) characteristics in Southern India. Large D0 in SW monsoon and low D0 in NE monsoon is observed. We found that during SW monsoon precipitation generally have more big drops than in NE monsoon. The climate in south India during the SW monsoon most of the precipitating cloud systems are associated with lightening and mesoscale convection activities. These storms are short lived around one hour with high intensity of the rain. Whereas in NE monsoon the precipitation is associated with cyclones and also storm height will be decreased about 200 - 700 m compared with the SW monsoon due to the less temperature in the winter months. In the presentation, we also utilized the potential of Indian MST Radar and Gadanki-LAWP for diagnosing the vertical structure of Tropical convective systems. Results indicated that while mesoscale convective systems are prevalent in this region, there are important contributions to rainfall from smaller-scale warm rain systems that do not extend above the freezing level. They also show that extensive regions of upper-tropospheric precipitating clouds often exit at times when no rain is detected at the surface. The evolution of the monsoon TCCS is different from the break regime cases. This system was characterized by a series of convective updrafts embedded in stratiform cloud. Several examples of shallow, deep, and decaying convection were seen and it is shown that only the deep systems have substantial tilts to the draft structure. Long-term observations are utilized to develop climatologies of precipitating cloud systems at the wind profilers' site. For the TRMM PR 3A25 derived storm height and ground temperature seem to correlate with Gadanki DSD characteristics observed during monsoon. In this presentation we also utilize TRMM data for explaining the physical distinction in the summer and winter monsoon DSD characteristics.
Submittal Information
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Frontier Observational Research System for Global Change (FORSGC) | |
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3173-25 Showa-machi, Kanazawa-ku, Yokohama - 236-0001 | |
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