DARWIN publication thread

This note tracks the argument the DARWIN publications are assembling, and how the pieces fit. It covers scope, method, and reasoning. Numbers appear in the papers, not here — anything still moving does not belong on a public page, and pointing at the citable version is more useful than a preliminary figure that will be superseded.

The argument

Two claims, in order of how much work they need:

The model reproduces the processes, not just the totals. High-resolution downscaling over an archipelago with sharp elevation gradients and a strong marine inversion is not obviously going to work. Establishing that it does — process by process, against station observations — is what makes everything downstream admissible.

Non-rainfall moisture matters ecologically during the garúa season. This is the claim the programme exists for. It requires the first, because the evidence that highland moisture input exceeds recorded rainfall comes from combining what stations measure with what the model can say about places without stations.

The order matters. Reversing it would mean using an unvalidated model to support the more interesting conclusion, and the more interesting conclusion is exactly where that would be least defensible.

How the evidence is assembled

Observations come from a multi-site network spanning coastal, transition, and highland settings across several islands, with standard near-surface meteorology throughout and enhanced instrumentation at selected sites. Simulations are WRF driven by ERA5 with tropical island physics, evaluated by process-oriented comparison against those stations rather than by aggregate skill scores.

The choice of process-oriented evaluation over summary statistics is deliberate and is discussed in the experiment suite: a correlation coefficient against observed rainfall cannot distinguish a model that is right for the right reasons from one that is right for the wrong ones, and here that distinction is the whole question.

Outputs

See also: the station network, Cerro Crocker, and the projects map.