Sea Surface Height Anomaly product includes along-track sea surface height above Mean Sea Surface, Significant Wave Height, Inverted Barometer, Sigma Naught, Total Electron Content, Ocean Depth, and Mean Sea Surface.
The Sea Surface Height Anomaly, the principal parameter in this product, represents the difference between the best estimate of the sea surface height and a mean sea surface. The sea surface height used was corrected for atmospheric effects (ionosphere, wet and dry troposphere), effects due to surface conditions (electromagnetic bias), and other contributions (ocean tides, pole tide, and inverse barometer). Because some users may want to provide their own values for the mean sea surface and inverse barometer effect, the values used in calculating this SSHA are included in the data product.
The Jason-1 Sea Surface Height Anomaly product is generated from the Jason-1 Geophysical Data Record (J1 GDR). There are 127 orbits per cycle and each orbit has a period of 112 minutes. The ground track of the orbits are about 315 km apart at the equator. Along track measurements are approximately 1 sec and 6 km apart.
The TOPEX/POSEIDON Sea Surface Height Anomaly product is generated from the TOPEX/POSEIDON Merged Geophysical Data Record, Generation B (MGDRB), Reference 1. It is organized as 10 day (actually 9.915 days) repeat cycles, the same as the MGDRB. There are 127 orbits per cycle and each orbit has a period of 112 minutes. The ground track of the orbits are about 315 km apart at the equator. Along track measurements are approximately 1 sec and 6 km apart.
Each orbit is composed of 2 passes, one ascending from -66 deg to +66 deg latitude and the other descending from +66 deg to - 66 deg. The passes are organized this way to avoid data boundaries in the middle of the oceans. All odd-numbered passes are ascending and all even-numbered passes are descending.
It is organized as 10 day repeat cycles containing a maximum of 254 pass files per cycle, the same as the J1 GDR and TP MGDRB. There is a one to one correspondence between the SSHA and J1/TP GDR/MGDRB cycles and pass files. Each pass file of the SSHA consists of header records followed by data records containing 11 parameters: time of record in days and milliseconds, latitude, longitude, sea surface height anomaly, significant wave height, inverse barometer, sigma0, total electron content of the atmosphere, ocean depth, and mean sea surface. It is swath data and no images are provided with this product.
Calculation of the sea surface height anomaly is derived from J1/TP GDR/MGDRB parameters using a set of editing criteria (see User's reference manual).
Jason-1 Sea Surface Height Anomaly (J1SSHA) product and TOPEX/POSEIDON Sea Surface Height Anomaly (TPSSHA) product are compatible; they have the same number of header records, data records, and data sizes. They can both be read by the same read software.