12-14 September, 2011, Lucknow - Earth Science India
12-14 September, 2011, Lucknow - Earth Science India
12-14 September, 2011, Lucknow - Earth Science India
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National Conference on <strong>Science</strong> of Climate Change and <strong>Earth</strong>’s Sustainability: Issues and Challenges ‘A Scientist-People Partnership’<br />
<strong>12</strong>-<strong>14</strong> <strong>September</strong>, <strong>2011</strong>, <strong>Lucknow</strong><br />
TREND IN MID- LATITUDE WESTERLY TROUGH AT 500<br />
H PA AND IN EXTREME SUMMER MONSOON OVER<br />
INDIAN REGION<br />
S.S. Dugam<br />
<strong>India</strong>n Institute of Tropical Meteorology, Pune-411008<br />
email: dugam@tropmet.res.in<br />
In this paper, quantification of Mid- Latitude Westerly Trough Index called as<br />
(MWTI) is derived by using the Principal Component Analysis (PCA) technique on<br />
daily basis, over the Indo-Pak region and over North West <strong>India</strong>n for the period 1957-<br />
2002. The gradient between (PC1+PC2) time series of daily geo potential field of the<br />
first region and second region is calculated during the <strong>India</strong>n summer monsoon period<br />
(June- <strong>September</strong>) and these index referred to as Mid- Latitude Westerly Trough Index<br />
(MWTI). The trend analysis of MWTI in extreme monsoon years i.e. in drought and<br />
flood monsoon years have been studied and it is observed that the intrusion of westerly<br />
trough is showing the significant negative trend in drought monsoon year, while in<br />
flood monsoon it shows a significant positive trends. The trend analysis of upper<br />
troposphere temperature is also studied simultaneously. It is seen that cold temperature<br />
anomalies is present over NW <strong>India</strong>n region in drought monsoon year while it is reverse<br />
in flood monsoon years. The study was further carried out the relationship between<br />
daily North Atlantic Oscillation Index (NAOI) and MWTI in same period. The analysis<br />
suggested that during the weak phase and active phase of monsoon the relationship<br />
between NAOI and MWTI is an reverse and statistically significant. This relationship is<br />
concurrent and may be useful for explaining the role of NAO activity and intrusion of<br />
mid-latitude troughs over the <strong>India</strong>n region, which affects the rainfall variability during<br />
the monsoon period.<br />
LONG TERM TREND OF HEAVY PRECIPITATION OVER<br />
NORTHWEST HIMALAYAS<br />
Naresh Kumar and B.P. Yadav<br />
<strong>India</strong> Meteorological Department, Lodi Road, New Delhi-110003<br />
email: naresh-nhac@gmail.com<br />
In the <strong>India</strong>n subcontinent context, Himalaya governs the climate and weather of<br />
the region and drive the major weather system like Western Disturbances (WDs) during<br />
20