| Date: | 2006-02-07 23:56:00 | |
| Sender: | Jim Ray <Jim Ray (NGS 301-713-2850 x112) <jimr@ngs.noaa.gov>> | |
| Subject: | [SLR-Mail] No. 1438: new ocean tide loading routine ready | |
| Author: | Jim Ray | |
| Content: | ******************************************************************************** SLR Electronic Mail 2006-02-07 23:56:00 UTC Message No. 1438 ******************************************************************************** Author: Jim Ray Subject: new ocean tide loading routine ready Dear Analysis Colleagues, A new Fortran routine, written by Duncan Agnew (UCSD), has been posted which implements in part the recommendations of section 7.1.1 of IERS Conventions 2003 concerning local site displacements due to ocean tidal loading (OTL). The code can be found at the Conventions Update site at ftp://tai.bipm.org/iers/convupdt/chapter7/ Given pre-computed site-dependent amp & phase values for the 11 main tides (in BLQ format), as generated by the Bos-Scherneck OTL service at http://www.oso.chalmers.se/~loading/ hardisp.f determines local dU, dS, dW displacements considering a total of 141 constituent tides using a spline interpolation of the tidal admittances. The precision is about 1%. Run without inputs, the routine provides usage information. Validation test data are included as in-line comments. Changes have been made in the latest version of hardisp.f so please delete any earlier versions that you might have. In test comparisons against a simple OTL routine with no minor tides and no nodal modulations, Urs Hugentobler (AIUB) found RMS dU differences over 14 days of about 2 mm for a globally distributed network of ~250 stations using the GOT00.2 ocean model. Differences tend to be larger at higher latitudes, with the largest RMS difference being 5.0 mm at OHIG. Users should also note that Hans-Georg Scherneck has recently added the new TPXO.7.0 and FES2004 ocean models to his OTL website. Older models can be problematic in areas such as Antarctica (King and Padman, GRL, 32, L23608, 2005). The IERS and the general user communities are deeply indebted to Duncan Agnew, Machiel Bos, and Hans-Georg Scherneck for their continuing efforts to support and improve the ocean loading services. Thanks very much. --Jim From: Jim Ray ”(NGS” 301-713-2850 ”x112)” ******************************************************************************** |