absoulte velocityabstactionabstract modelabyssal sedimentac soilaccelerated erosionaccelerating flowaccelerationacceleration lineaccelermeteraccessaccess timeaccessory cloudaccmulation areaaccost accoastaccretionaccretion of levelaccumulatedaccumulated storageaccumulated temperatureaccumulationaccumulation terraceaccumulative rain gaugeaccuracyacid precipitationacid preciptationacidic cationsacidimeteracidulous wateracoustic cloudacoustic flow meteracoustic probeacoustic thermometeracoustic waveactinographactinometeractinometryactinomycetesactivated sludgeactive absorptionactive capacityactive channelactivewateractual cvapotranspirationactual evapotranspirationactual headactual land degradationactual lapse rateactual outflow hydrographactual pressure