[IGSMAIL-5618]: revision of IERS Conventions Chapter 9

["Jim.Ray" <jim.ray @ noaa.gov>]

******************************************************************************
IGS Electronic Mail      05 Jul 12:16:43 PDT 2007      Message Number 5618
******************************************************************************

Author: Jim Ray (IERS Conventions Advisory Board)

Please note that a new version of IERS Chapter 9 on tropospheric
models was posted on 28 June 2007.  The text was completely
rewritten, thanks mainly to J. Boehm, G. Hulley, A. Niell, and E. Pavlis

In addition, a new set of subroutines is available:

* FCUL_a.f <ftp://tai.bipm.org/iers/convupdt/chapter9/FCUL_a.f> - 
Function to compute the global total FCULa mapping
function for SLR analyses, dependent on latitude, height, and surface
temperature. Provided by V. Mendes.
* FCUL_b.f <ftp://tai.bipm.org/iers/convupdt/chapter9/FCUL_b.f> - 
Function to compute the global total FCULb mapping
function for SLR analyses, dependent on latitude, height and day of year.
Provided by V. Mendes.
* fcul_ztd_hPa.f 
<ftp://tai.bipm.org/iers/convupdt/chapter9/fcul_ztd_hPa.f> - Subroutine 
to compute the Mendes-Pavlis zenith total
delay, for optical wavelengths, valid for infrared to ultraviolet. 
Provided by
V. Mendes.
* gmf.f <ftp://tai.bipm.org/iers/convupdt/chapter9/gmf.f> - Subroutine 
to compute the Global Mapping Functions, GMF,
for radio techniques. Provided by J. Boehm.
* vmf1.f <ftp://tai.bipm.org/iers/convupdt/chapter9/vmf1.f> - Subroutine 
to compute the Vienna Mapping Functions 1,
VMF1, to be used with "a" coefficients computed for a given site.
Provided by J. Boehm.
* vmf1_ht.f <ftp://tai.bipm.org/iers/convupdt/chapter9/vmf1_ht.f> - 
Subroutine to compute the Vienna Mapping Functions 1,
VMF1, with height corrections, to be used with "a" coefficients computed
for a grid. Provided by J. Boehm.
* gpt.f <ftp://tai.bipm.org/iers/convupdt/chapter9/gpt.f> - Subroutine 
to compute the Global Pressure and Temperature,
based on Spherical Harmonics up to degree and order 9. Provided by
J. Boehm.

Please refer to the IERS Conventions update website:
http://tai.bipm.org/iers/convupdt/convupdt_c9.html