In the context of the tasks SAON SG steering group, the topology of the Arctic hydrometeorological observation network can be presented in the following concise form: 1. Agrometeorological; 2. Actinometric; 3. Aerological (radiosounding); 4. Water balance; 5. Hydrological on rivers; 6. Hydrometeorological on lakes; 7. Glaciological; 8. Meteorological; 9. Marine hydrometeorological (in the coastal zone, river estuaries, open areas including marine vessel and expeditionary); 10. Avalanche; 11. Ozone measuring; 12. Heat balance; 13. Atmospheric electricity; 14. Water, soil and snow surface evaporation; 15. Chemical composition of water and air. Observation network data are operationally transferred to Roshydromet’s data telecommunication network except for those indicated in items 4, 7,12-15. The main networks in terms of the number of observation points and volume of information obtained are meteorological, marine hydrometeorological, river hydrological, aerological and actinometric ones. Meteorological observations are considered as the main type of observations. To establish a common database and control timely and complete collection and distribution of information, a catalog of meteorological bulletins is being created to be the plan of hydrometeorological information transfer from the sources to Roshydromet’s data telecommunication network to distribute among information recipients The catalog of meteorological observations is maintained by State Institution “Hydrometeorological Center” and State Institution “Main Radio-Meterological Center”. Electronic version of the catalogs of meteorological bulletins is maintained by State Institution “Main Radio-Meterological Center” and located on the Internet site http://grmc.mecom.ru. The catalog of meteorological bulletins contains the following information: − Name of Roshydromet’s subordinate Federal State Institution and observation point to input data into the automated data system; − shortened title of the hydrometeorological bulletin in proper format; − observation data coded form; − hours of observation; − data transfer check time; − number of observation points taking part in one bulletin; − lists of five-digit indices for observation points. Changes are entered into the catalogs of meteorological bulletins quarterly. WMO’s WWW is considered as the main foreign information consumer. The lists of WMO correspondent stations are given in WMO publications # 9, vol. C, part 1 (Catalog of Meteorological Observations), vol. A (Observation Stations). 2. SAON is expected to stimulate the process of improving configuration and completeness of the circumpolar region monitoring system as a potential tool for international consolidation of the opportunities available in the functioning of observation networks in order to improve national standards quality and ensure more complete compliance of the Arctic research strategies proposed to socioeconomic needs and interests of Arctic countries 3. The catalog of points and main observations is given in Table 1 (see Fig. 1). The maximum development of the Russian hydrometeorological observations in the Arctic was reached in early 1980s, when information was received from 110 stations. In subsequent years, the number of stations decreased more than twice (Fig. 2). The current level of observations is determined by the functioning of a network consisting of 49 points two of which are automatic weather stations. Three points are temporarily removed from operation. In short term, 8 automatic stations are expected to be opened; while in medium and long term, the number of manned observation points will increase up to 52-54, and the number of automatic ones – up to 20-25. For the manned network, the meteorological program includes a set of eight-hour observations of: atmosphere pressure, wind parameters, air and soil temperature, relative humidity, weather phenomena, cloud height, visual range, precipitation, while for automatic weather stations – a set of reduced 4-hour observations. The marine hydrometeorological program includes coastal observation of temperature, water salinity (density), sea-level variations, heave, ice distribution (and thickness) as well as meteorological parameters under the change of observation conditions from hourly to ten-day observations. The river hydrological program is quite similar to the marine one. It does not include observations of water density, however, they can be included for the stations having a special status, measurement of water discharge, alluvia and chemical composition of water. The programs will include hourly and ten-day observations. The aerological program will include 1-2 –hour measurements of: atmosphere pressure and wind parameters on selected isobaric surfaces. Actinometric observations include measurement of 5 components of atmosphere radiation balance in case of the full program and measurement of total radiation under a reduced program. Network type: The main networks in terms of the number of observation points and volume of information obtained are meteorological, marine hydrometeorological, river hydrological, aerological and actinometric ones.