rdtools.soiling.monthly_soiling_rates

rdtools.soiling.monthly_soiling_rates(soiling_interval_summary, min_interval_length=14, max_relative_slope_error=500.0, reps=100000, confidence_level=68.2)

Use Monte Carlo to calculate typical monthly soiling rates. Samples possible soiling rates from soiling rate confidence intervals associated with soiling intervals assuming a uniform distribution. Soiling intervals get samples proportionally to their overlap with each calendar month.

Parameters

  • soiling_interval_summary (pandas.DataFrame) -- DataFrame describing soiling intervals. Typically from soiling_info['soiling_interval_summary'] obtained with rdtools.soiling.soiling_srr() or rdtools.soiling.SRRAnalysis.run() Must have columns soiling_rate_high, soiling_rate_low, soiling_rate, length, valid,``start``, and end.

  • min_interval_length (int, default 14) -- The minimum number of days a soiling interval must contain to be included in the calculation. Similar to the same parameter in soiling_srr() and SRRAnalysis.run() but with a more conservative default value as a starting point for monthly soiling rate analyses.

  • max_relative_slope_error (float, default 500.0) -- The maximum relative size of the slope confidence interval for an interval to be included in the calculation (percentage).

  • reps (int, default 100000) -- The number of Monte Carlo samples to take for each month.

  • confidence_level (float, default 68.2) -- The size of the confidence interval, as a percentage, to use in determining the upper and lower quantiles reported in the returned DataFrame. (The median is always included in the result.)

Returns

DataFrame describing monthly soiling rates.

Column Name

Description

'month'

Integer month, January (1) to December (12)

'soiling_rate_median'

The median soiling rate for the month over the entire dataset, in units of day^−1. Negative value indicates soiling is occurring. E.g. a rate of −0.01 indicates 1% soiling loss per day.

'soiling_rate_low'

The lower edge of the confidence interval for the monthly soiling rate in units of day^−1

'soiling_rate_high'

The upper edge of the confidence interval for the monthly soiling rate in units of day^−1

'interval_count'

The number of soiling intervals contributing to the monthly calculation. If only a few intervals contribute, the confidence interval is likely to underestimate the true uncertainty.

Return type

pandas.DataFrame