Significant Wave Height Comparisons 13 etween TOPEX and Platform Harvest

Two sources of H113 estimates were available at Platform Harvest; a NOAA buoy and CU depth sensor highrate data. H113 estimates from the NOAA buoy were based on twenty minutes of data every hour, CU pressure measurements were taken every 1.1 seconds. For purposes of this paper, H113 estimates from the (7U depth sensor were based on one hour of data, This paper compares H113 measurements from TOPEX with each of these sources, Differences between H113 estimates from the (7U depth sensors based on twenty minutes and estimates based on one hour of data varied by up to 10% with an rms uncertainty of +5%. l’here is an rms difference between the NOAA buoy and altimeter values of O. 17m with a mean oflset of 0.03m such that the H113 values from the altimeter are higher than from the buoy. There is an rms di~erence between the CU values and altimeter values of O. 19m with a mean offset of O. lm such that the H113 values from the altimeter are higher than from the CU depth sensors. This strongly suggests that the 11113 measurements from the l’OPEX altimeter are well within project specifications