Age The age of a sample Palmer Drought Index Julian day North Atlantic Oscillation (NAO) Arctic Oscillation (AO, AAO) Moisture content Ocean chemistry Atmospheric chemistry Southern oscillation index (SOI) Precipitation amount Nino 2 Bottom water temperature Temperature Thermodynamic property which quantifies how cold or warm an object, a fluid, or a substance is. Ocean mixed layer temperature Precipitation Inferred variable Isotopic composition Carbon dioxide concentration Temperature Thermodynamic property allowing to quantitatively measure how warm or cold a material, fluid is. Nino 3.4 Nino 1 Year Surface air temperature Climate index Carbonate saturation Sea surface temperature The temperature close to the ocean's surface Palmer Drought Severity Index (PDSI) Salinity d180 Hydrology Nino 4 Southern Annular Mode (SAM) DD Free oxygen levels Time PH Radiocarbon age Nino 1+2 Methane concentration le http://linked.earth/ontology# 1.0.0 The Inferred Variable Ontology Carbonate ion concentration Deuterium excess (excessD) Nitrous oxide concentration Atlantic Multi-decadal Oscillation (AMO) Nino 3