Wave height

About: Wave height is a research topic. Over the lifetime, 5920 publications have been published within this topic receiving 100257 citations.

A shallow water experiment to determine the source spectrum level of wind‐generated noise

Abstract: An experiment was conducted in a shallow water region of the Mediterranean Sea to study wind‐generated noise. In addition to measuring the noise field, propagation‐loss data were collected and used in a detailed modeling of the environment. The environmental information was then used as input to a noise model based on wave theory that computes the noise field in the water column for a given (unknown) source strength. By comparing model predictions with data, the influence of the environment on recorded noise levels could be removed and a measure of the noise source spectrum levels obtained as a function of wind speed. It was found that noise levels correlate better with wind speed than with wave height. In addition it was found that the nearfield contribution dominates the noise level, with the result of producing virtually constant noise intensity over depth from moderate to high wind speeds and frequencies above 200 Hz.

Extremes and Decadal Variations of the Northern Baltic Sea Wave Conditions

Abstract: Average wave conditions, their seasonal cycle and decadal variations, and extreme wave storms in the northern Baltic Sea are studied on the basis of long-term time series from Almagrundet (1978–2003) and Vilsandi (1954–2005), and wave statistics from the middle of the northern Baltic Proper. The typical wave periods are 3–4 s in coastal areas and 4–6 s on the open sea. The monthly mean wave height varies from about 0.4 (0.5) m in April–July to 0.8 (1.3–1.4) m in January at Vilsandi (Almagrundet). The annual mean wave height varied insignificantly in the 1960s–1970s, considerably increased in the 1980s, was at highest in the mid-1990s, and rapidly decreases in 1998–2005. Significant wave heights H S ≥ 4m occur with a probability of about 1%. Extreme wave conditions with H S ≥ 7m have been registered five times since 1978. The records overlook 2–3 such cases. The overall recorded maximum H S is 7.8 m. The estimated maximum of H S was 9.5 m in cyclone Gudrun in January 2005.

Surf zone measurements of suspended sediment

Abstract: Suspended sediment concentration was measured in approximately 250 breaking waves on undeveloped beaches near Price Inlet, South Carolina, U.S.A., using portable in situ bulk water samplers. As many as 10 instantaneous 2-liter water volumes were obtained in each wave for a total of 1500 samples. Concentrations of suspended sediment were determined at fixed intervals of 10, 30, 60 and 100 cm above the bed for various surf zone positions relative to the breakpoint. The majority of waves sampled during 22 days in June and July, 1977 were relatively long crested, smooth, spilling to plunging in form, with breaker heights ranging from 20 to 150 cm. Surf zone process variables measured included breaker height and depth, breaker type, wave period, surface longshore current velocity, wind velocity and direction. Scatter plots of mean concentration against various process parameters indicate the amount of sediment entrained in breaking waves is primarily a function of elevation above the bed, breaker type, breaker height and distance from the breakpoint. Concentration ranged over 3 orders of magnitude up to 10 gm/1, but varied less than 1 order for samples collected under similar conditions with regard to elevation and breaker type. Plunging breakers generally entrain 1 order more sediment than spilling breakers equal in height. Despite considerable scatter, these data indicate concentration decreases with increasing wave height for waves 50 to 150 cm high, suggesting that small waves can be important in the transport of sand on gently-sloping open coasts.