antarctic circleantarctic plateantecedent basin conditionsantecedent epipedonantecedent moisture contentantecedent precipitationantecedent precipitation indexanthropic epipedonanthropogenic erosionanti vortex devicesanticlinal springanticlineanticyclogenesisanticycloneanticyclone movementanticyclonicanticyclonic circulationanticyclonic rotationanticyclonic vorticityantiduneantithetic variableanvil cloudapatiteaphelionapiapparent accelerationapparent cohesionapparent dipapparent specific gravityapparent velocityapparent verticalapplied climatologyapplied hydrologyapplied meteorologyappoximate original conturappr0ach channelappraisalapproach flowapproach velocityappron angleapproximating functionapronaqueductaqueous metamorphismaquicludeaquiferaquifer boundaryaquifer lossaquifer managementaquitard