The major theme in the call for papers for the Sixth ... in radar hydrology was a recurrent theme in the ... funding to install and operate the radar networks,.
ATMOSPHERIC SCIENCE LETTERS Atmos. Sci. Let. 6: 1 (2005) Published online in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/asl.103
Special issue on the hydrological applications of weather radar — guest editors’ preface
The Sixth International Symposium on Hydrological Applications of Weather Radar was hosted by the Australian Bureau of Meteorology in Melbourne during February 2004. The unique aspect of the conferences is that they are traditionally attended by hydrologists as well as radar meteorologists. Dialogues between the two groups have proven to be relatively rare and often at rather crossed purposes, so this conference series provides a useful forum for discussion between these two groups. Discussions as to what accuracy hydrologists want in their rain-field data as well as questions as to the accuracy that can be provided have generally not been particularly helpful. What is clear is that weather radar provides the best rainfall estimates for convective rainfall patterns and will continue to do so in the foreseeable future. Moreover, the radar data are capable of providing short-term forecasts by image extrapolation, which is emulated with difficulty by gauge networks. Thus, we must try our best with existing and new networks of weather radars. Certain trends are evident when looking back at the proceedings for the previous Symposia; notably, the impact of networks of weather radars on the use of radar data in hydrological applications, and the need for a sustained focus on characterising and mitigating the errors that are inherent in radar estimates of rainfall. This is not surprising since inadequate radar coverage of areas of interest to hydrologists and rainfall estimates with an unknown but suspect quality are major impediments to using radar data operationally. The major theme in the call for papers for the Sixth Symposium was ‘Success Stories in Radar Hydrology’ and it is clear that radar networks exist in many countries but a lament regarding the lack of progress in radar hydrology was a recurrent theme in the presentations. Radar hydrology remains a work in progress; much has been done and yet much remains to be done. There has been considerable progress in developing networks of radars that are dense
Copyright 2005 Royal Meteorological Society
enough to provide useful estimates of rainfall over large areas, the major sources of errors have been identified, and the number of operational applications using radar rainfall estimates is increasing. Realistic schemes for combining the radar data with other meteorological data and using the combined result for hydrological predictions such as those for floods are surprisingly rare. Although there appears to be funding to install and operate the radar networks, similar funding for the development of integrated operational radar hydrological systems is not generally available. Much research remains to be done before a map of probable error can be estimated and presented alongside the rainfall map in real time, and yet this has to be an achievable goal. A smaller workshop on the measurement, modelling and consequences of the fine-scale structure of rainfall patterns was conducted in Auckland, New Zealand immediately after the main conference. This meeting brought together a number of groups working with high-resolution radars and high spatial and temporal rain gauge networks. A problem highlighted was the very large sampling errors encountered when radar data are compared with sparse gauge data due to the large discrepancy in sampling volumes. The calibration of radars with rain gauges is thus not a trivial exercise particularly for rain fields with high spatial inhomogeneity. A variety of modelling schemes that have the capability of addressing this statistical problem was presented. The editors would like to thank the members of the International Programme Committee for their input into the Symposium and the local organising committee for their assistance. Geoff Austin1 and Alan Seed2 1 University of Auckland, Auckland, New Zealand 2 Bureau of Meteorology, Melbourne, Australia
