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PecanProject / pecan

The Predictive Ecosystem Analyzer (PEcAn) is an integrated ecological bioinformatics toolbox.
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RH calculation ans Specific humidity calculation discrepancy in met2cf.ERA5.R #2897

Open mccabete opened 2 years ago

mccabete commented 2 years ago

Bug Description

@DongchenZ Is the one who found this, I am just writing it up. The relative humidity calculation in met2cf.ERA5 has a * 100 term that put relative humidity in terms of percent, rather than proportion.

According to the comments, this is copied from weathermetric's conversion function, which labels that RH is in \%.

Our RH to specific humidity function is expecting a proportion, not a \%.

@DongchenZ's PR #2886 contains the fix, but I wanted to document the bug in case 1) I misinterpreted the use of \% in the descriptions, or 2) this affects anyone else

mccabete commented 2 years ago

@mdietze or @ankurdesai, and I interpreting the inputs to the rh2qair() function correctly?

ankurdesai commented 2 years ago

@mccabete Yes, the function expect RH has a proportion 0-1. e <- rh * es -> this estimates the vapor pressure as a proportion of saturation vapor pressure, that proportion is rh

mccabete commented 2 years ago

Thanks for confirming!

From: Ankur Desai @.> Sent: Wednesday, November 17, 2021 6:05 PM To: PecanProject/pecan @.> Cc: Mccabe, Tempest @.>; Mention @.> Subject: Re: [PecanProject/pecan] RH calculation ans Specific humidity calculation discrepancy in met2cf.ERA5.R (Issue #2897)

@mccabetehttps://github.com/mccabete Yes, the function expect RH has a proportion 0-1. e <- rh * es -> this estimates the vapor pressure as a proportion of saturation vapor pressure, that proportion is rh

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dlebauer commented 2 years ago

Is it worth adding an argument to specify the units (proportion or percent) that RH is returned in.

Poked my head in and also noticed that rh2qair takes pressure in Pa, and qair2rh takes it in mb.

github-actions[bot] commented 1 year ago

This issue is stale because it has been open 365 days with no activity.