UPGRADING THE NORTH-AMERICAN UPPER-AIR OBSERVING NETWORK - WHAT ARE THE POSSIBILITIES

The current modernization and restructuring of the National Weather Se rvice (NWS) to date has not involved the rehabilitation of the upper-a ir observing network over North America. The authors discuss the need for a thorough evaluation of the current upper-air observing system th at examines both the old (current) rawinsonde network and newer remote sensing networks. The key concern is that the meteorological communit y has given insufficient attention to the scientific questions underly ing the choices of observing systems as related to the needs of operat ional forecasting. The authors argue that the principal basis for a sc ientific and objective evaluation of observing strategies is the abili ty of a particular observing system (or component of a system) to impr ove numerical weather prediction in the modernized NWS. Given this sta rting point. a number of possible new (and old) observing systems and observing strategies are discussed that offer the possibility for much improved initialization of mesoscale numerical forecast models. Perha ps the key shift in observation strategy suggested is the establishmen t of many additional radiosonde and pilot balloon sounding stations th at rely on contract observers rather than the NWS workforce. However, a comprehensive and satisfactory upgrading of the upper-air observing system will be possible only after more substantial participation of t he scientific community in the planning and implementation processes.