Special Issue on the Global Network of Isotopes in Precipitation

The Global Network of Isotopes in Precipitation consisted of 153 active stations in 2001. As can be seen in the map above, active stations are classified as " IAEA " or " National Network " (NN). The " IAEA " stations are those where national institutes are performing the monthly sampling, compiling the meteorological parameters and shipping samples to the IAEA for isotope analyses. The " National Networks " stations report results to the IAEA, once a year, for their incorporation into the GNIP database. In 2001, efforts made to contact hydrologists and meteorological services permitted the re-activation of stations in New-Delhi (India), Santana (Domini-can Republic), Teheran (Iran) and Jakarta (Indonesia). In addition , isotope and meteorological data from Alexandria and El Cairo (Egypt), N'Dola (Zambia) and Perth-CSIRO (Australia) were received once again for the GNIP database. These stations were previously active, but data was not being sent to the IAEA. New stations were opened in Dax (France), Algiers (Algeria), Haut-de-Sainte-Rose (La Réunion, France) and Quezon City (Phil-ippines). The national networks of Spain and China increased the number of active stations respectively by 15 and 9 units. As part of a research programme on Mediterranean climate study (see page 4), about 20 short-term stations were opened. It is expected that, after data interpretation , some of these stations will be selected for long-term observation of the Mediterranean basin. A two-year delay is neede for data analyses and quality control and to allow data provider to publish their data if desired. Therefore, the 1999 data were recently entered into the GNIP/ ISOHIS database and are now available for download through the Internet page. From the 153 active stations, the data of 44 stations are not yet in the database because part of the information is still missing. The net increase of stable isotope data entered into the GNIP database, 10 % from 1998 to 1999, is very encouraging for the scientific and water management community but should not mask the still significant disparity in geographical distribution. Only 36 stations are active in the Southern hemisphere. Stations located on islands represent only 10 % of the total number of stations and are very difficult to maintain.