commercialization.10 The World Meteorological Organization's Global Runoff Data Center in Koblenz, Germany, holds information on nearly 3,000 discharge monitoring stations. However, in accordance with the wishes of the donor nations, access to this information is restricted and no transfer of the complete global dataset or substantial portions of it are possible. A recent UNESCO (United Nations Educational, Scientific, and Cultural Organization) publication and related digital data bank of approximately 1,000 discharge monitoring stations11represents the last digitized global data bank of river runoff that is freely available to the global change community (at Oak Ridge National Laboratory Data Acquisition and Archive Center). Lamentably, its last data entry is for 1991.
A set of long-term index stations should be identified, some of which should be as free from the effects of upstream regulation and diversions as possible. In the United States the logical responsible agency would be the U.S. Geological Survey (USGS). However, the funding method currently used for the USGS stream gauge network is not necessarily consistent with the needs of a climate network (e.g., only about 10 percent of USGS stations are funded from the agency's core funds; the remainder are funded cooperatively with state agencies and by other federal agencies for operational purposes). Moreover, there is a significant need for this information on a global scale, which poses a difficult operational and political challenge. This topic of in situ riverine information is important and should be addressed.
Station data. The United States must maintain existing long-term stations within the National Climatic Data Center (NCDC) cooperative network, particularly the subset of stations that make up the Hydroclimatic Data Network and the U.S. Historical Climate Network. Precipitation measured at first-order stations has recently undergone radical changes and considerable technical problems, making these networks even more important.
Radar precipitation data. The National Center for Environmental Prediction has recently started to archive a merged WSR88-D (Doppler radar)/gauge product (4-km resolution) that covers most of the United States. The suitability of these data for climatological purposes needs to be evaluated, and steps must be taken to ensure the security of the long-term archive of the data and to ensure that the data are freely available to the scientific community. From a more global perspective, the recent Tropical Rainfall Measurement Mission (TRMM) launch holds great promise for tropical regions.
Only a very small number of stations now operate in the continental United States that collect a full suite of surface radiation observations (the SURFRAD