CLIMATE STUDIES GROUP MONA · THE UNIVERSITY OF THE WEST INDIES, MONA

Physical constraints, learned models and climate evidence

These eight papers examine physical constraints in rainfall allocation, temperature prediction and local flux models. They compare learned methods with simpler alternatives and define tests for a proposed atmospheric reconstruction.

Results and comparison methods

P1 · MONTHLY RAINFALL

P1: Compare rainfall allocation errors

The exact-constraint network records 14.23 mm/month RMSE. Seasonal allocation reaches 9.73 using the same supplied coarse total. This is conditional CHIRPS downscaling.

Read the comparison and driver-error bound

P4 · DAILY RAINFALL

P4: Compare absolute and squared errors

Both Timestral checkpoints have lower next-day mean absolute error than the four local controls. Persistence and ridge regression perform better on root-mean-square error; the heavy-day comparison also favours persistence.

Read the matched-baseline study

P6 · SOIL TEMPERATURE

P6: Compare the safeguard with exact finite differences

The learned-flux model records 0.591 °C mean block RMSE against 0.590 °C for exact finite differences. The oracle-assisted gate has slightly higher mean reconstruction error.

Read the controlled negative result

CURRENT MANUSCRIPTS

Eight papers, with their evidence and limits

Review the paper collection

P1

Exact volume conservation in neural rainfall downscaling over Jamaica: a conditional CHIRPS benchmark with a driver-error bound

Rainfall downscaling and driver error: figure from the author manuscript

This study divides a known monthly rainfall total among smaller cells in Jamaica. Forcing the estimates to add back to the supplied total improves the neural network. A seasonal rainfall pattern has lower error against CHIRPS. When the supplied total is wrong, exact conservation passes that error into the detailed map.

Draft for supervisor review

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P2

Satellite predictors, a reduced physical closure and frozen foundation models for seven-day temperature forecasts at Jamaican grid cells

Seven-day temperature forecasts: figure from the author manuscript

The study compares seven-day temperature forecasts at three Jamaican grid cells. It tests satellite predictors, nearby cells and a reduced physical rule. The rule improves its matched graph network in 2026, but the full-period interval includes zero. Neither satellite augmentation nor the larger graph gives a reliable gain.

Draft for supervisor review

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P3

Daily rainfall learning at Caribbean CHIRPS cells under three data constraints: stale inputs, post hoc recalibration and scarce local labels

Rainfall under data constraints: figure from the author manuscript

Three experiments test old inputs, recalibration on an earlier period and scarce local training labels. At the Jamaica mean, the neural advantage over climatology is absent with seven days of added delay. Isotonic recalibration worsens later neural wet-day scores at all seven cells. Pooling helps local neural fits, but local ridge still wins at Kingston.

Draft for supervisor review

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P4

Zero-shot Timestral-5M and Timestral-28M against matched local baselines for Jamaican daily rainfall

Timestral and Jamaican rainfall: figure from the author manuscript

Two pretrained Timestral checkpoints receive the same Jamaican rainfall history as four local controls. Both have lower next-day mean absolute error than the four local controls. Persistence has lower next-day RMSE and detects more heavy days. Ridge has lower RMSE at three and seven days. With a 45-day observation delay, seasonal climatology has the lowest RMSE everywhere tested.

Draft for supervisor review

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P5

CLEAR-PINN: closure-limited, evidence-adaptive residual learning for precipitation nowcasting

CLEAR-PINN closure and tolerance: figure from the author manuscript

This study separates moving rain across a map from allowing it to grow or fade. Its numerical update keeps a correct account of every transfer, but that does not prove the rain forecast is right. In a small constructed test, learning growth helped when growth existed. The proposed adaptive tolerance did not beat a simpler method given the same information.

Draft for supervisor review

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P6

Neural flux stencils and oracle-assisted safeguards for soil-temperature reconstruction: a controlled negative result

Neural fluxes for soil temperature: figure from the author manuscript

This study hides the soil temperature at 20 cm depth and tries to recover it from other measurements. Replacing a known flux calculation with a small neural network did not improve the result. A safeguard kept the replacement's local error inside its limit but had slightly higher mean reconstruction error. A conventional numerical reconstruction matched the exact-flux PINN at the reported precision.

Draft for supervisor review

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P7

D-LEGOS: space-time control volumes, shared-face flux ledgers and the limits of what conservation proves

D-LEGOS reconstruction framework: figure from the author manuscript

D-LEGOS divides an atmospheric reconstruction into local blocks and gives each shared boundary one recorded transfer. That makes neighbouring blocks agree on what crosses the boundary. It does not guarantee that the transfer is correct. The paper proves the accounting rules, tests them on a small constructed heat system and sets out the observations and comparisons needed to test an atmospheric reconstruction.

Draft for supervisor review

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P8

A cross-island test of thermodynamic features for next-day heavy-rain probabilities: a bounded negative result

Cross-island heavy-rain probabilities: figure from the author manuscript

This pilot asks whether converting temperature and dew point into moisture variables helps a rainfall model at a Caribbean grid cell excluded from training and calibration. The change was small and uncertain. A simple model using the season and yesterday's rainfall performed best. The results support comparisons with rainfall-history baselines and tests at locations excluded from model development.

Draft for supervisor review

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SATELLITE STUDIES AND THESIS BACKGROUND

Further studies and the literature review

Browse the complete collection

THE PROGRAMME · PAPER P7

D-LEGOS: reconstructing states from incomplete observations

D-LEGOS proposes local neural fields connected through shared physical transfers. Paper P7 collects the mathematics, the constructed graph test and a falsifiable evaluation protocol for retrospective atmospheric reconstruction.

The atmospheric reconstruction has not been tested. The remaining test is whether coupling recovers more withheld physical information under matched observations, model capacity and compute. The component studies have their own questions and evidence; P7 explains their place in the programme.

Two different tests for a coupled model

Accounting and reconstruction accuracy are separate testsObservations and a background state constrain two local neural fields. One shared transfer enters one cell and leaves its neighbour. The domain ledger checks accounting. Withheld observations test the recovered state. Atmospheric reconstruction remains proposed.Permitted observations + background stateInformation used to reconstruct the atmospheric fieldsLocal neural field AState, capacity and sourcesLocal neural field BState, capacity and sourcesShared transferOne signed recordDoes the ledger balance?Check transfers and external sourcesIs the recovered state accurate?Check independent, withheld observations
Paper P7 proves the conditions for shared-face accounting and defines the atmospheric comparison still to be run. A balanced ledger does not establish an accurate flux, forecast or uncertainty estimate. Read P7.

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Researcher

Adrian Dunkley
Climate Studies Group Mona · Department of Physics
The University of the West Indies, Mona

adrian.dunkley@mymona.uwi.edu