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ILLUSTRATIVE · NASA / SVS · NOT ADITYA-L1 DATA

Model cardsrandom_forest

Model card · candidate detector

Random forest

An ensemble of decision trees, averaged.

What is this?

A model card for Random forest, one of eight detectors evaluated on the frozen Aditya-L1 flare benchmark.

Why should I trust it?

Every figure below is read at build time from the committed benchmark artifact; none is transcribed. The judgements are traceable to the written evaluation protocol and the dataset limitations record.

Where can I verify it?

Section 1

Purpose and intended use

Why it is in the benchmark. A high-capacity, low-tuning learner. If nonlinearity and feature interaction were the missing ingredient, this is where it should have shown up.

Intended use. Benchmark comparison and impurity-based feature attribution.

Out of scope. Impurity importance is biased toward high-cardinality continuous features and says nothing about direction. It is not a substitute for a physical account.


Section 2

Inputs, outputs, training

Inputs. Fourteen features per minute, all derived from the SoLEXS 1-minute count rate in T1: the log rate, rolling means over 5/15/30/60 minutes, a 15-minute rolling maximum, rolling standard deviations, a background-excess term, two rise rates, and three data-quality terms (GTI fraction, seconds present, partial-minute flag).

Outputs. A probability per minute, from the fraction of trees voting positive.

Training protocol. Chronological split with a held-out test period beginning at the frozen test start date; no shuffling, so no future minute can inform a past one. The protocol — split, seed, metric set and bootstrap scheme — was fixed in EVALUATION_PROTOCOL.md before any model was fitted.

Operating point. Decision threshold 0.9126, selected on the training period and then frozen.


Section 3

Evaluation

Both tasks, both reported.

M/X NOWCAST · 192,541 held-out minutes · base rate 1.24%

MetricValueWhat it measures
ROC-AUC0.966Ranking quality across all thresholds
PR-AUC0.699The informative curve at a low base rate
Precision0.766Of the minutes flagged, how many were flares
Recall0.590Of the flare minutes, how many were flagged
F10.667Harmonic mean of the two above
MCC0.669Correlation, robust to imbalance
Brier0.019Probability accuracy; undefined for hard classifiers
Balanced accuracy0.794Mean of the two class recalls
Events detected
80 / 82
Event recall 0.976 · 95% CI 0.930–1.000
False alarm runs
61
Of 149 alarm runs raised. A run, not a minute — the unit an operator actually responds to.
ROC-AUC interval
0.956–0.976
95%, day-block bootstrap.

M/X 30-MIN PREDICTION · 192,541 held-out minutes · base rate 1.29%

MetricValueWhat it measures
ROC-AUC0.784Ranking quality across all thresholds
PR-AUC0.115The informative curve at a low base rate
Precision0.152Of the minutes flagged, how many were flares
Recall0.332Of the flare minutes, how many were flagged
F10.208Harmonic mean of the two above
MCC0.210Correlation, robust to imbalance
Brier0.051Probability accuracy; undefined for hard classifiers
Balanced accuracy0.654Mean of the two class recalls
Events detected
34 / 82
Event recall 0.415 · 95% CI 0.220–0.547
False alarm runs
243
Of 276 alarm runs raised. A run, not a minute — the unit an operator actually responds to.
ROC-AUC interval
0.694–0.850
95%, day-block bootstrap.

Confusion matrix · M/X NOWCAST

True negative

189,717

False positive

431

False negative

980

True positive

1,413


Section 4

Feature attribution

Which of the fourteen features the fit relied on.

  • log_rate0.2686
  • roll_max_150.1943
  • roll_mean_50.1338
  • bg_excess0.0867
  • roll_mean_150.0835
  • rise_50.0566
  • roll_mean_300.0552
  • roll_mean_600.0461
  • rise_150.0409
  • roll_std_600.0180
  • roll_std_150.0162
  • gti_fraction0.0000
  • n_seconds_present0.0000
  • q_partial0.0000
Mean impurity decrease, normalised to sum to one. Unsigned by construction, and known to favour continuous features with many split points.

Attribution is not explanation. These features are strongly collinear — four of them are rolling means of the same series — so credit assigned to one is credit withheld from another, and none of it constitutes a physical account of flare onset.


Section 5

Strengths and failure modes

Strengths

  • Captures interactions and thresholds without them being specified.
  • Insensitive to feature scaling and to monotone transforms.

Failure modes

  • Capacity far exceeds the effective sample size, so it can fit event-specific noise (L-1).
  • Probabilities from vote fractions are not calibrated by construction.

Section 6

Limitations and ethical considerations

Ethical considerations. Its opacity makes an unexplained alarm hard to contest. On a surface where every claim must be checkable, that is a cost, not a neutral property.

Governing limitation clauses

Clause text is not restated here. It is published in full on the dataset card, from the frozen DATASET_LIMITATIONS_FOR_ML.md report, so there is exactly one copy of every caveat.