MOC Climate Processes and Variables
This map collects the notes that are not specific to any one project. They sit underneath the Galapagos work, the urban and regional modelling, and the data standards work alike, and are grouped here by the question they answer rather than by subdiscipline.
What climate is, and how it is described
Climate is the distribution weather is drawn from — a definition that gets awkward once the distribution starts moving, which is most of what makes the field difficult now. Physical climatology explains it through mechanism; applied climatology turns it into something a decision can rest on. The quantities themselves are climate variables, and getting their definitions right matters more than it appears — see climate data for why observations, model output, and reanalysis are not interchangeable.
Water
Precipitation is the headline variable and the one with the most definitional traps. Convective rain behaves differently enough from stratiform that the same daily total means different things, and occult precipitation delivers water that no rain gauge records at all — the mechanism that makes the Galapagos highlands habitable. Evapotranspiration returns it to the atmosphere, soil moisture stores it with a memory of weeks to months, and the water balance is the constraint tying them together. Hydroclimate is the integrated view.
Vertical structure and convection
Whether the atmosphere convects depends on CAPE against CIN — available energy against the barrier gating it. A temperature inversion can shut the process down entirely, which over cold water produces a shallow marine boundary layer capped by stratocumulus rather than deep cloud. When convection does occur, detrainment moistens the mid-troposphere and sets convective cloud fraction, which is what radiation actually sees. Surface schemes supply the fluxes that drive all of it.
Ocean forcing
SST is the atmosphere’s lower boundary condition over water, and thermocline depth controls how easily it changes. Transports come in sverdrups.
Large-scale drivers
ENSO is the dominant mode of interannual variability in the tropical Pacific, operating through the Walker circulation and expressed regionally through ITCZ position. Galapagos seasonality is what this produces locally.
Optics
Atmospheric scattering and the Tyndall effect account for what the atmosphere looks like, which matters for visibility, remote sensing retrievals, and radiation alike.
Getting to regional scale
ERA5 supplies the driving fields, dynamical downscaling and regional climate modeling bring them to usable resolution, and counterfactual climate data supports attribution. The Qaidam Basin is a separate regional application of the same machinery.