TITLE:
The Trend of Changes in Surface Wind in the Indian Ocean, in the Period from 1981 to 2015, Using Reanalysis Data, NCEP/NCAR
AUTHORS:
Ghazi Mirsaeid Mojgan, Mohammad Mehdizadeh Mehdi, Bannazadeh Mohammad Reza
KEYWORDS:
North Indian Ocean, Wind Fields, Climatic Trend, Monthly Probability of Density Function (PDF), Cumulative Distribution Function (CDF)
JOURNAL NAME:
Open Journal of Marine Science,
Vol.7 No.4,
August
7,
2017
ABSTRACT: Knowing the pattern of surface winds on the seas and oceans and how it
changes over time is of great importance. In this research, the monthly surface
wind fields on the Indian Ocean have been studied and analyzed for a 35-year
period (1981-2015), using NCEP/NCAR data reanalysis. The results show that
transition from cold to warm pattern happens in May and that the summer
monsoon pattern begins in June and continues until August. The wind speed
pattern tends to the winter monsoon from November on. The maximum average
wind speed in June is 13 m/s and its minimum is 2 m/s in October. Direction
of prevailing winds is the southwest in the summer. The highest wind
speed happens in the latitude of 10 - 15 degrees. Analysis of the wind distribution
shows that the wind speed of 2 - 5 m/s happens in about 60% of the cases.
There is probability of blowing 0.5 - 4 m/s wind for all months; but this probability
is higher in the autumn (October and November) than that in the
summer (July and August). Probability of the monthly over 5 m/s winds
shows a definitely opposite distribution; that is, wind speed in July and August
is higher than that in October. A long-term survey on the speed of surface
water wind and sea surface temperature shows an opposite changing trend in
wind speed and sea surface temperature during a 55-year statistical period.
Wind speed reduced, while the sea surface temperature was increasing. The
wind speed gradient in the upper levels of atmosphere graph has been increasing;
this phenomenon confirms the effects of global warming and ocean
warming on the monsoon system patterns in the Indian Ocean.
Keywords
North