GLOSS Status October 1995

email: psmsl@pol.ac.uk

For the last few years, usually coinciding with a GLOSS GE meeting, the PSMSL has provided a summary of the status of GLOSS from its viewpoint. This summary has usually been made in October so as not to bias the statistics because of the seasonal cycle of data receipts.

An 'operational' station from a PSMSL viewpoint means that recent MSL monthly and annual values have been received at Bidston, have been checked as far as possible, and have been included in the databank. For each of the GLOSS stations we have used the year of the last data entered into the databank, if any, to place the station into one of four categories:

Category 1: 'Operational' stations for which the latest data is 1991 or later;
Category 2: 'Probably operational' stations for which the latest data is within the period 1981-1990;
Category 3: 'Historical' stations for which the latest data is earlier than 1981;
Category 4: For which no PSMSL data exist.

Table 1 lists the number of stations which fall into each category for all stations, then for the subset which have been 'committed to GLOSS'. ('Committed to GLOSS' means that formal commitments have been made by national authorities to IOC to keep gauges operational). Also shown are the numbers in each category reported at previous GLOSS meetings with the category definitions adjusted backwards one, two, three etc. years appropriately.

Note that before 1993 we used the 'GLOSS90' definition of GLOSS (306 stations total), whereas 1993 onwards we have used 'GLOSS93' (308 stations total). However, I don't believe that modifies the statistics to a great extent.

It can be seen that, following the gradual improvements in the number of Category 1 stations for many years, this year saw a decline which is very disappointing. This can be traced largely to the fact that for several countries with large numbers of GLOSS stations, the latest data available is from 1990. Consequently, those stations have been Category 1 for the last couple of years but have now fallen into Category 2. The two main countries in this set are Australia and Indonesia.

This reversal is so large so as to hide definite progress in other areas. For example, several stations have moved from Category 4 into 1 (e.g. South African stations), as can be seen from the number of Category 4's dropping to 59 from 64. This is partly a consequence of the on-going installation of new gauges as part of GLOSS, WOCE etc. The number of Category 3's has also been reduced. The overall result is that there is now a vast number of Category 2 stations (more than there ever been, about a third of the number of Category 1 stations), which implies that there is a lot of data out there which is not finding its way into the data banks.

Note that GLOSS will again be redefined slightly in 1996, removing some stations from the official list which will be unlikely ever to be installed.

                            Table 1

      Number of Stations in Each Category (All Stations)

Category      Bidston   Miami     Vienna    Paris   Nowhere Nowhere Nowhere
              GE Mtg.   GE Mtg.   IUGG      GE Mtg.         (pre-
                                                            Bordeaux
                                                            GE Mtg.)
              Jun 89    Oct 90    Aug 91    Oct 92  Oct 93  Oct 94  Oct 95

     1        105       133       136       158     177     183     168
     2        51        50        57        46      33      35      59
     3        47        42        36        29      26      26      22
     4        103       81        77        73      72      64      59

Total         306       306       306       306     308     308     308

   Number of Stations in Each Category (Committed to GLOSS)

Category      Bidston   Miami     Vienna    Paris   Nowhere Nowhere Nowhere
              GE Mtg.   GE Mtg.   IUGG      GE Mtg.         (pre-
                                                            Bordeaux
                                                            GE Mtg.)
              Jun 89    Oct 90    Aug 91    Oct 92  Oct 93  Oct 94  Oct 95

     1        98        122       118       135     151     156     140
     2        45        40        47        38      25      26      45
     3        28        25        21        15      13      12      10
     4        44        28        29        27      28      23      22

Total         215       215       215       215     217     217     217

using 'GLOSS
Definition'   90        90        90        90      93      93      93