Some periods, I find the wind speed is more at coastal regions and other periods more at offshore regions. If both are correct then which one is more reliable?
I wonder why there wasnt any answer to this question for almost a year? Probably there isn't enough measured data/information on the offshore vs coastal winds to answer this. Although we have many coastal wind stations (by IMD), there hasn't been enough offshore wind data - although MoES (through NIOT/INCOIS) have met-ocean buoys offshore, the comparison between offshore and coastal winds hasn't come to my knowledge. If you have got any useful info/reports/publications, please do share.
Wind speed is normally not as critical as wind speed variation. Offshore wind charateristic are much more stable. Thus, offshore wind turbines are more efficient.