Automated Weather Station

An automated weather station records near-surface meteorology continuously and unattended. In DARWIN they are the observational backbone, and the interesting decisions were about where to put them rather than what they measure.

What they record

Air temperature, relative humidity, wind speed and direction, surface pressure, and shortwave radiation at all sites, with rainfall and drizzle detection depending on the site. Selected locations carry enhanced instrumentation.

Why the network is arranged by elevation

The Galapagos question is about a gradient. Sea level is arid, the highlands support cloud forest, and the transition happens over a few hundred metres of elevation. A dense network at one elevation would characterise that elevation precisely and say nothing about the gradient. So the stations span coastal, transition, and highland environments across three islands, trading local density for coverage of the axis that actually varies.

Three things this arrangement was meant to resolve:

• Elevation dependence of precipitation and cloud exposure, which is the primary signal.
• The seasonal transition between convective wet-season conditions and the garúa regime, which happens at different elevations at different times.
• Enough spatial coverage to evaluate downscaled fields against something other than a single point.

The measurement problem worth naming

A standard rain gauge does not capture fog interception, and during the garúa season that is much of the moisture input — the whole reason occult precipitation is central to this work. A station in the garúa zone can therefore record almost no rainfall while sitting in air delivering water continuously to the vegetation around it.

This is not a defect in the instruments; it is a mismatch between what a gauge is defined to measure and what the ecosystem receives. It is also why the network cannot answer the water balance question alone, and why the modelling exists.

Role in validation

The network is what the refined analysis was evaluated against, packaged as the validation dataset. Cerro Crocker is the highland reference site.

Siting is described here by elevation band and environment class. Exact positions and maintenance detail stay private.

See also: the DARWIN project and the Galapagos climate system map.