简介：Inthispaper,theconceptofstationary-wavenonstationarityispresentedandelucidatedintheframeworkoftheLorenzcirculationdecomposition.Thisconceptindicatestherelativemagnitudeofthezonalnonuniformabnormitytotheintensityofstationarywavesonthemonthlymeanscale.BasedontheLorenzcirculationdecomposition,thenonstationaritydegreeI_(us)(I_(us)~1)oftheglobal(local)stationarywavesisdefined,andthenusedtoanalyzethestationary-wavenonstationarityat30°-60°N,wheretheintensityofstationarywavesat500hPaintheNorthernHemisphere,asiswellknown,isveryhigh.Thefollowingfindingsareobtained:(1)Thereexistseasonalsouthwardandnorthwardmovementsinthepositionofthenonstationarityzonesoftheglobalstationarywaves.Thesteadystationarywavesoccurinmidlatitudes(35°-55°N)inwinterandinthesubtropicalregion(southof35°N)insummer,associatedwiththemajortroughsoverEastAsiaandNorthAmericaandtheweakEuropeantroughinwinter,andwiththerelativelysteadysubtropicalhighsysteminsummer.AhighvaluecenterofI_(us)isat35°Ninspringand50°Ninsummer,whichmightbecausedbytheseasonalvariationofstationary-waveintensity,particularlyinassociationwiththeinterannualvariabilityoftrough/ridgepositionsofstationarywavesonthemonthlymeanmaps.(2)ThereexistsobviousasymmetryinI_(us)~1,withthesteadyzonesalwayslocatedintheareascontrolledbystrongtroughs/ridgesandtheunsteadyonesintheareaswherethestationary-waveintensityislow.TheI_(us)~1inthesubtropics(southof35°N)islargerinwinterthaninsummer,andviceversainthemidlatituderegion(northof35°N).ThesummertimedistributionofI_(us)~1onthewholeshowsarathercomplicatedstructure.However,NorthEuropeisthemostunsteadyareaforlocalstationarywaves,asrepresentedbyhighvaluesofI_(us)~1inbothsummerandwinter,whileovertheNorthAmericancontinent(about120°E-60°W),theI_(us)~1isslightlylessthan1