Research On Retrieving Wave Period From Satellite Altimeters

The capability of satellite altimeters to provide precise measurement of sea state has been demonstrated repeatedly, it provides an efficient way for monitoring global and regional oceanographic parameters. These data offers however an opportunity to retrieve much wanted information on wave conditions, in addition to SWH. So far, about 20 kinds of wind speed model function has been proposed, but the retrieval of wave period from altimeters has received little attention.This paper firstly gives a brief description of previous studies on wave period retrieval, uses Gulf of Mexico and Hawaii sea area collocated data to make comparisons and verifications. Then based on the relationship between wave age and non-dimensional wave height we propose a new wave period retrieval model function, and apply this model to Gulf of Mexico and Hawaii sea area to test its behavior on different sea conditions, the result shows that when non-dimensional wave height lower than 0.5, the RMSD between retrieved wave period and buoy observation in both sea area, when non-dimensional wave height bigger than 1, the RMSD in Gulf of Mexico and Hawaii sea area is 0.8s and 1s respectively.Another empirical model depends on the wave development degree by using the normalized radar cross section and wave height data, which are available from satellite altimeter, was proposed in the form of tabulation. With the collected coincident data in Gulf of Mexico and Hawaii Sea, the new model is compared with the previous models. It is found that our model is superior to others in retrieval of wave period with the RMSD of 0.50 and 0.52 in Gulf of Mexico and Hawaii Sea, respectively. But because lack of data that wind speed bigger than 19m/s, this model can not work on high wind conditions.In general, the obtained wave periods from wind wave dominated area are consistent...