subterranean cloversubterranean watersubtropical highsubtropical regionsubtropical zonesubwatershedsuccessivesuction scoursuddsudden injectionsuden expansionsullagesumatrasummation curve of soil particlesummer solsticesumpsunradiationsunshinesunshine recordersunspotsuper coolingsuper permafrost watersupercoold cloudsupercoold watersupercooled fogsupercooled rainsupercritical flowsuperdiabatic lapse ratesupergeostrophic windsuperheated steamsuperimposition principlesupernatentsuperpositionsupersaturationsupplemental irrigationsupplemental pasturesupplemental watersupportsuppressed measuring weirsurcharge storagesurfacesurface boundary layersurface crustingsurface curvesurface detentionsurface eddiessurface erosionsurface flowsurface hoarsurface observation
