The tenth IMSC, Beijing, China, 2007 - International Meetings on ...

Tropical cyclones have their origins from areas of low atmospheric pressure over warm
waters in the tropics or subtropics. We have carefully studied the interconnection between the
West African Weather Systems (WAWS) and their subsequent development into Tropical
Cyclones.
Between 2004 and 2005, we studied the interconnection and the teleconnection between
the WAWS and the various occurrences of Tropical Cyclones and their eventual development
into Hurricanes. We noted that critical synoptic characteristic and the environmental properties
of the Systems; the thermodynamic conditions of the storms trajectory and the conditions of
the ocean are all closely linked. It is therefore believed that proper understanding and
monitoring of these systems will play a very vital role in early detection of potential WAWS that
may develop into Tropical Cyclones and even Hurricanes. More practical issues will be
presented.
It was recorded that over the period 1992-2001, weather and climate-related disasters
especially those of Tropical Cyclones origin killed about 622 000 people, affected more than
two billion, left millions more homeless, devastated arable land and spread diseases.
Intense Precipitation Events in the Reanalysis Datasets over the Asia
Kiyotoshi Takahashi
Meteorological Research Institute, JMA
ktakahas@mri-jma.go.jp
Nobuo Yamazaki
Meteorological Colledge, JMA
Masaru Chiba
Meteorological Research Institute, JMA
Hirotaka Kamahori
Japan Meteorological Agency
Recently, many studies for occurrance trends of intense precipitation have been
conducted based on both observational data analysis and model simulation in association with
the global warming. Basically detection of such trends should be based on the long-term
surface observation, but there is a problem that its distribution is not homogeneous and
localized geographically. On the other hand, estimation based on satellite observation is
homogenous spatially. However, its temporal coverage is limited for just recent ten years for
daily base products. As another available data sources, there are atmospheric reanalysis
datasets, which are useful because they provide not only precipitation but also other quantities
with spatial homogeneity and physical consistency although reanalysis datasets may suffer
from artificial trends due to changes in observational input data.In this study, statistical
characteristics of intense precipitation events in reanalysis datasets are examined by
comparison with newly produced observational gridded precipitation data for India and
<strong>China</strong>.<strong>The</strong> annual index for intense precipitation used in Takahashi, K. et al (2006) as well as
annual precipitation calculated from each reanalysis dataset, especially the latest product
JRA-25, shows significant correlation with observation at one percent level.
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