Wind speeds over the world’s oceans have increased over the past two decades, as have wave heights. Studies of climate change typically consider measurements or predictions of temperature over extended periods of time. Climate, however, is much more than temperature. Over the oceans, changes in wind speed and the surface gravity waves generated by such winds play an important role. We used a 23-year database of calibrated and validated satellite altimeter measurements to investigate global changes in oceanic wind speed and wave height over this period. We find a general global trend of increasing values of wind speed and, to a lesser degree, wave height, over this period. The rate of increase is greater for extreme events as compared to the mean condition.

https://researchbank.swinburne.edu.au/file/bca43746-6f16-4ad2-a4b7-27f8d8d60fed/1/PDF (Published version).pdf

Global trends in wind speed and wave height over the past 25 years

Preparing the books to read every day is enjoyable for many people. However, there are still many people who also don't like reading. This is a problem. But, when you can support others to start reading, it will be better. One of the books that can be recommended for new readers is dynamics and modelling of ocean waves. This book is not kind of difficult book to read. It can be read and understand by the new readers.

Dynamics and Modelling of Ocean Waves

The Indian summer monsoon is influenced by numerous factors, including aerosol-induced changes to clouds, surface and atmospheric heating, and atmospheric circulation. An analysis of satellite data and global climate model simulations suggests that dust aerosol levels over the Arabian Sea, West Asia and the Arabian Peninsula are positively correlated with the intensity of the Indian summer monsoon.

Short-term modulation of Indian summer monsoon rainfall by West Asian dust

Brazil has one of the largest electricity markets in South America, which needs to add 6000 MW of capacity every year in order to satisfy growing the demand from an increasing and more prosperous population. Apart from biomass, no other renewable energy sources, besides hydroelectricity, play a relevant role in the energy mix. The potential for wind and wave energy is very large. Brazil's Santa Catarina state government is starting a clean energy program in the state, which is expected to bring more than 1 GW of capacity. Assessment of wave energy resources is needed along the coastline. This work studied the potential wave energy along the north-central coasts of Santa Catarina, in Southern Brazil, by analysis of the hindcast data from the European Centre for Medium-Range Weather Forecasts (ECMWF). The annual offshore wave power was found to be equal to 15.25 kW/m, the bulk of which is provided by southeastern waves. The nearshore energetic patterns were studied by means of a numerical coastal propagation model (Mike21 SW). The mean wave power of 20 m isobaths is 11.43 kW/m. Supplementary considerations are drawn on realistic perspectives for wave energy converters installations.

https://www.mdpi.com/1996-1073/8/12/12423/pdf

Wave Energy Resource along the Coast of Santa Catarina (Brazil)

Wave hindcast studies using SWAN nested in WAVEWATCH III - comparison with measured nearshore buoy data off Karwar, eastern Arabian Sea

The climate over the north Indian Ocean (NIO) is one of the most dynamic in the world because of seasonally reversing monsoon winds. In this study, the climate of the NIO and the variability of its surface waves using the European Centre for Medium-Range Weather Forecasts (ECMWF) global atmospheric reanalysis product (ERA-Interim) for the period 1979–2012 are analyzed. Annual average significant wave height (SWH) of the NIO ranges from 1.5 to 2.5 m and the seasonal average is highest (3–3.5 m) during the monsoon period [June–September (JJAS)]. Swells propagating from the Southern Hemisphere are present in the NIO during the premonsoon [February–May (FMAM)] and postmonsoon [October–January (ONDJ)] periods. The waves are separated into wind seas and swells based on the wave energy statistical method. The results show that the NIO is swell dominated and that wind sea heights are lower compared to the swell heights. Higher wind sea and swell heights are observed during the monsoon in the western NIO b...

/pdf/surface-wave-climatology-and-its-variability-in-the-north-g2s2k02v2c.pdf

Surface Wave Climatology and Its Variability in the North Indian Ocean Based on ERA-Interim Reanalysis*

https://drs.nio.org/drs/bitstream/handle/2264/4689/Renew_Energ_76_212a.pdf?sequence=1&isAllowed=y

Wave energy resource assessment for the Indian shelf seas

The spatial and temporal variations of wave height in shelf seas around Indian mainland are examined based on the ERA-Interim dataset produced by the European Centre for Medium-Range Weather Forecasts. The study shows that during the summer monsoon, higher wave heights are observed in all locations except at the southern locations in the shelf seas around India, where the winter monsoon is predominant. The annual average significant wave height is highest (~1.6 m) at the southern location. During 1979–2012, a weak statistically significant increasing trend (maximum ~0.20 cm/year) in wave height is observed in the northern and southern region of eastern Arabian Sea, whereas the middle region shows negligible negative trend. A weak decreasing trend (maximum ~−0.18 cm/year) in wave height is observed in the western Bay of Bengal except along the southern region. At most of the locations weak decreasing trend (0.1–2.5 cm/s/year) is observed for the annual mean wind speed. The conflicting trends in the wind speed and wave height are mainly due to the swell dominance in the North Indian Ocean.

Spatial and temporal variations of wave height in shelf seas around India

. The wave statistical parameters during Cyclone Phailin which crossed the northern Bay of Bengal are described based on the Directional Waverider buoy-measured wave data from 8 to 13 October 2013. On 12 October 2013, the cyclone passed within 70 km of the Waverider buoy location with a wind speed of 59.2 m s−1 (115 knots), and during this period, a maximum significant wave height of 7.3 m and a maximum wave height of 13.5 m were measured at 50 m water depth. Eight freak wave events are observed during the study period. The ratio of the maximum wave height to significant wave height recorded is found to be higher than the theoretical value and the ratio of the crest height to wave height during the cyclone was 0.6 to 0.7. The characteristics of the wave spectra before and after the cyclone is studied and found that the high-frequency face of the wave spectrum is proportional to f−3 before the cyclone and is between f−4 and f−5 during the cyclone period.

/pdf/waves-off-gopalpur-northern-bay-of-bengal-during-cyclone-1hr78zyirb.pdf

Waves off Gopalpur, northern Bay of Bengal during Cyclone Phailin

. Intrinsic modes of variability have a significant role in driving the climatic oscillations in the oceanic processes. In this paper, we investigate the influence of an inter-annual mode of variability, the Indian Ocean Dipole (IOD), on the wave climate of the eastern Arabian Sea (AS). Using measured, modeled and reanalysis wave data and reanalysis wind data, we show that the IOD plays a major role in the variability of wave climate of the study region. Due to the IOD-induced changes in equatorial sea surface temperature and sea level pressure, the winds from the northern AS gets modified and cause inter-annual variability in the wave climate over the eastern AS. The changes in wind field over the AS due to the IOD influence the generation or dissipation of the wave field and hence cause a decrease in northwest short-period waves during positive IOD and an increase during negative IOD.

/pdf/indian-ocean-dipole-modulated-wave-climate-of-eastern-1sy3tgoc7d.pdf

T. R. Anoop

Papers

Surface Wave Climatology and Its Variability in the North Indian Ocean Based on ERA-Interim Reanalysis*

Wave energy resource assessment for the Indian shelf seas

Spatial and temporal variations of wave height in shelf seas around India

Waves off Gopalpur, northern Bay of Bengal during Cyclone Phailin

Indian Ocean Dipole modulated wave climate of eastern Arabian Sea