Generating & Reviewing Your Site's Parameters

First published: October 2026
Last updated: October 23, 2026

[!TIP] Calculating CLIGEN parameters takes only a single click. You can review, fine-tune, or adjust parameters directly in the interactive tables before running simulations or exporting to GoldSim.

Once you have loaded your station or uploaded your custom time series and applied any necessary date filtering, you are ready to calibrate your site's stochastic parameters.

How to Calculate Parameters

1. Navigate to the CLIGEN Parameters card on the dashboard (or click Parameters in the top navigation bar).
2. Click the blue Calculate Parameters button.
3. The calculation engine processes your historical record in real time:
4. Evaluates all day-to-day transitions (Dry-to-Dry, Dry-to-Wet, Wet-to-Wet, Wet-to-Dry) for each calendar month.
5. Fits the Pearson Type III depth distribution to observed wet-day rainfall depths.
6. Segregates daily temperatures by precipitation occurrence to derive wet and dry thermal means and standard deviations.
7. Two interactive tables will immediately populate:
8. Precipitation Parameters Table (12 months $\times$ 4 columns)
9. Temperature Parameters Table (12 months $\times$ 5 columns)

Reviewing the Parameter Tables

The Precipitation Parameters Table

Sanity Checks to Perform: - $P(W|W)$ vs. $P(W|D)$: $P(W|W)$ must always be greater than $P(W|D)$. If $P(W|W)$ is less than $P(W|D)$, it would mean that rain makes tomorrow less likely to rain, which is physically counter-intuitive. - Mean Depth: Typically higher during convective thunderstorm months (e.g. July/August) than during light winter drizzle months. - Skewness: Skewness values typically fall between $1.2$ and $3.5$. Higher values indicate climates prone to intense cloudbursts or tropical storms.

The Temperature Parameters Table

Sanity Checks to Perform: - $T_{\max,\text{dry}}$ vs. $T_{\max,\text{wet}}$: In almost all regions, $T_{\max,\text{dry}}$ will be higher than $T_{\max,\text{wet}}$ by $2^\circ\text{C}$ to $6^\circ\text{C}$ due to cloud cover and evaporative cooling. - Standard Deviations: Temperature standard deviations ($\sigma$) are almost always larger in winter months (when alternating polar and maritime air masses cause large temperature swings) than in summer months.

Manual Overrides & Climate Scenario Adjustments

You can edit any cell directly inside the parameter tables: - Testing Climate Change Impacts: Want to evaluate the impact of warmer summers? Increase the July and August $T_{\max}$ values by $+2.0^\circ\text{C}$. - Testing Intensified Storms: Want to test a $15\%$ increase in extreme rainfall intensity? Multiply the monthly Mean Depth or Skewness columns by $1.15$. - Restoring Defaults: If you want to revert your manual changes, simply click Recalculate from Historical Data to restore the pure historical calibration.

One-Click Copy for GoldSim

Next to each parameter table, you will see a green Copy for GoldSim button: - Clicking this button formats the entire 12-month matrix into a tab-delimited or comma-separated block. - You can paste this directly into a 2D Data element in GoldSim without retyping any numbers.