Proceedings with Extended Abstracts (single PDF file) - Radio ...

esolution were 3.0 km, 5.4 km and 6.4 km,respectively. Considering these heightcoverages, we selected the height resolution of300m as the default operation mode inWINDAS. 300m is a sufficient heightresolution for producing initial values of thecurrent NWP models.Signal power of 1.3GHz wind profilers highlydepends on the amount of water vapor in themiddle and lower troposphere. Figure 2 showsthe monthly total means of height coverage atall the profiler sites from June 2001 to April2002. The height coverages of WINDAS are 6to 7 km in summer and at 3 to 4 km in winterand they have reached the original goal of JMA.The measurement accuracy of WINDASwas evaluated by comparisons with the modelforecast winds in June and July 2001. RMSEsof profiler winds from model winds as well asthose between rawinsonde winds are shown inFigure 3. There is no significant differencebetween profiler winds and rawinsonde windsin the RMSEs. This means that the accuracy inthe wind measurement of WINDAS iscomparable to that in rawinsonde observation.The data of WINDAS have been used asan initial value in all the NWP models operatedin JMA since June 2001. The 4-dimensionalvariational data assimilation (4D-VAR) startedto be in operation in MSM in April 2002. 4D-VAR makes the best use of the potential ofprofiler data because of the capability ofcontinuous measurement of upper-air winds.Figure 4 illustrates a result of an impactexperiment made by MSM using WINDAS datawith the 4D-VAR for a severe rain stormoccurred in June 2001 (Tada, 2001, privatecommunications) . The profiler data and the4D-VAR well improved the accuracy of thelocation of the severe rain storm in MSM.6. PERFORMANCE IN OPERATIONIn order to evaluate the reliability of theoperation of WINDAS, the percentage of datareceived in real-time at the Control Center wereexamined. The monthly total means over all thesites have been over 98.8% since May 2001.This indicates that stable operation of thesystem has been accomplished7. CONCLUSIONSJMA has operated the wind profilernetwork for tow years and the profiler data areeffectively used in real-time for numericalweather prediction. Issues on ground clutterand migrating birds have been practicallysolved. Retrieval of vertical water vapor fromsignal power and spectrum width of profilerswill be one of the future plans.ACKNOWLEDGMENTSWe thank the NOAA Profiler Networkstaff of the Forecast Systems Laboratory ofNOAA for providing useful information onprofiler operation. The technical reportspublished by COST74/76 gave us suggestiveinformation. The impact experiments describedin Section 5 was made by the ForecastPrediction division of JMA.REFERENCESEngerbart, D and U. Gorsdorf, 1997 : Effectsand observation of migrating birds on aboundary-layer wind profiler in a easternGermany. Extended Abstract of COST-76Profiler Workshop, 227-230.Hashiguchi, H., S. Fukao, T. Tsuda, M. D.Yamanaka, D. L. Tobing, T. Sribimawati, S.W. B. Harijono and H. Wiryosumarto,1995 : Observations of the planetaryboundary layer over equatorial Indonesiawith an L-band clear-air Doppler radar :Initial results. Radio Sci., 30, 1043-1054.Ishihara, M. and H. Goda, 2000 : Operational1.3GHz wind profiler network of JapanMeteorological Agency. Proceeding of theMST and COST76 Workshop. 538-540.354