Calculate Relative Humidity via Magnus Tetens Equation #2286

kurt-rhee · 2024-10-30T18:45:38Z

Closes implement Tdew to RH conversions #1744
I am familiar with the contributing guidelines
Tests added
Updates entries in docs/sphinx/source/reference for API changes.
Adds description and name entries in the appropriate "what's new" file in docs/sphinx/source/whatsnew for all changes. Includes link to the GitHub Issue with :issue:`num` or this Pull Request with :pull:`num`. Includes contributor name and/or GitHub username (link with :ghuser:`user`).
[ x ] New code is fully documented. Includes numpydoc compliant docstrings, examples, and comments where necessary.
Pull request is nearly complete and ready for detailed review.
Maintainer: Appropriate GitHub Labels (including remote-data) and Milestone are assigned to the Pull Request and linked Issue.

Reasoning

There are some occasions where dew point temperature is available, but relative humidity is not.
Relative humidity can be converted to precipitable water in pvlib via guemard94.
Precipitable water is used by first solar to calculate spectral correction factors.
This function would allow a user with dew point temperature to convert it to relative humidity.

Caveats

Caveat 1

In the issue thread implement Tdew to RH conversions #1744 there is some controversy about the simpleness of this approach. Some users would prefer a more well known solution.
I would argue that because this approach was used in the creation of the First Solar spectral correction function, that it has historical significance and should therefore be included.
If any user should desire, they could add an alternative function and then create a controller function which allows the user to choose different relative humidity calculation methods, which is a pattern than exists already inside pvlib.

Caveat 2

I placed these functions inside of spectrum, but I could also see them living inside of pvlib.atmosphere.py where the gueymard94 function exists. I'd like the maintainers opinion before proceeding to update the docs and what's new file.

adriesse · 2024-10-30T20:03:37Z

@kurt-rhee Perhaps it would be better to continue the discussion in #1744 rather than start a new thread here.

kurt-rhee · 2024-10-30T20:25:58Z

@adriesse good idea, I've copied the comment above to the thread in question

pvlib/spectrum/magnus_tetens.py

kandersolar · 2024-11-10T15:44:38Z

pvlib/spectrum/magnus_tetens.py

I agree that atmosphere.py is a better home for this functionality

moved in latest commit

Still need to remove this magnus_tetens.py file

pvlib/spectrum/magnus_tetens.py

pyproject.toml

uv.lock

pvlib/spectrum/magnus_tetens.py

…, changed type hints in docstring, changed to suggested coefficient format

pvlib/atmosphere.py

Co-authored-by: Anton Driesse <[email protected]>

kurt-rhee · 2024-11-18T20:54:24Z

@adriesse agreed, anecdotal and unnecessary, it has been removed.

I have left the formatting of functions outside of the tdew and rh conversion functions. I can format them to satisfy flake8 linter if that is desired by maintainers. Just let me know how I can help.

kandersolar

Some more comments. A what's new entry will be needed before too long!

kandersolar · 2024-11-12T20:08:23Z

pvlib/spectrum/magnus_tetens.py

Still need to remove this magnus_tetens.py file

pvlib/atmosphere.py

kandersolar · 2024-11-25T20:14:41Z

pvlib/tests/test_atmosphere.py

@@ -82,12 +82,50 @@ def test_gueymard94_pw():
    pws = atmosphere.gueymard94_pw(temps_humids[:, 0], temps_humids[:, 1])

    expected = np.array(
-        [  0.1       ,   0.33702061,   1.12340202,   0.1       ,
+        [0.1       ,   0.33702061,   1.12340202,   0.1       ,


I suggest reverting the changes to lines 85 and 36, just to prevent the linter from complaining at you

hey @kandersolar thanks for the look and sorry for the late response, I have been out for the holiday. I was wondering, should I try to remove all of the flake8 linter complaints? I could revert how the function looks in main, but flake8 still doesn't like the white space, or I could remove the white space and make the linter happy..

kandersolar · 2024-11-25T20:17:50Z

pvlib/tests/test_atmosphere.py

+        rh,
+        tdew_rh_conversion_relative_humidity,
+        check_names=False
+    )


For completeness, let's add corresponding tests where the inputs are float and array. We will also need to include tests where alternative coefficient values are specified.

@kandersolar just reworked the unit tests, I added tests which take in a numpy array and a float as well as a pandas series with a different set of coefficients. Let me know what you think, happy to adjust in any way.

Co-authored-by: Kevin Anderson <[email protected]>

Kurt Rhee added 5 commits October 29, 2024 12:52

changed default types to float in solarposition.py

70e0156

switched to floats in the docstrings and removed type hints

0ec0cbf

added magnus_tetens equations

5eb9d00

line too long in solarposition.py

ab2de3a

revert solarposition.py to pre-PR state

f62bd8e

set default magnus coefficients per conversation in pvlib#1744

77025c7

kandersolar reviewed Nov 10, 2024

View reviewed changes

cwhanse reviewed Nov 10, 2024

View reviewed changes

pvlib/spectrum/magnus_tetens.py Show resolved Hide resolved

Kurt Rhee added 6 commits November 11, 2024 08:14

moved equations to atmosphere.py, updated function names to suggested…

b52f9a9

…, changed type hints in docstring, changed to suggested coefficient format

moved tests to atmosphere.py tests

58b246e

changed reference to WMO

a06871a

dry-bult temperature in the docstring

caa4417

revert pyproject.toml

edd84b1

remove uv.lock

9c32f6a

cwhanse added the enhancement label Nov 11, 2024

cwhanse added this to the v0.11.2 milestone Nov 11, 2024

adriesse reviewed Nov 17, 2024

View reviewed changes

pvlib/atmosphere.py Outdated Show resolved Hide resolved

Update pvlib/atmosphere.py

63ed5c7

Co-authored-by: Anton Driesse <[email protected]>

fixing flake8 errors for tdew/rh functions

6312f92

I have left the formatting of functions outside of the tdew and rh conversion functions. I can format them to satisfy flake8 linter if that is desired by maintainers. Just let me know how I can help.

kandersolar changed the title ~~Calculate Relative Humidity via Magnus Tetens Equation with AEKR coefficients~~ Calculate Relative Humidity via Magnus Tetens Equation Nov 25, 2024

kandersolar reviewed Nov 25, 2024

View reviewed changes

kurt-rhee and others added 6 commits November 25, 2024 12:53

Update pvlib/atmosphere.py

410e95f

Co-authored-by: Kevin Anderson <[email protected]>

Update pvlib/atmosphere.py

d94df47

Co-authored-by: Kevin Anderson <[email protected]>

Update pvlib/atmosphere.py

e6b5908

Co-authored-by: Kevin Anderson <[email protected]>

Update pvlib/atmosphere.py

63a9226

Co-authored-by: Kevin Anderson <[email protected]>

Update pvlib/atmosphere.py

459d5a6

Co-authored-by: Kevin Anderson <[email protected]>

Update pvlib/atmosphere.py

05b846f

Co-authored-by: Kevin Anderson <[email protected]>

added some unit tests for different coefficients and input types

0ae31e1

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Calculate Relative Humidity via Magnus Tetens Equation #2286

Calculate Relative Humidity via Magnus Tetens Equation #2286

kurt-rhee commented Oct 30, 2024 •

edited by cwhanse

Loading

adriesse commented Oct 30, 2024

kurt-rhee commented Oct 30, 2024

kandersolar Nov 10, 2024

kurt-rhee Nov 11, 2024

kandersolar Nov 12, 2024

kurt-rhee commented Nov 18, 2024

kandersolar left a comment

kandersolar Nov 12, 2024

kandersolar Nov 25, 2024

kurt-rhee Dec 1, 2024

kandersolar Nov 25, 2024

kurt-rhee Dec 1, 2024

Calculate Relative Humidity via Magnus Tetens Equation #2286

Are you sure you want to change the base?

Calculate Relative Humidity via Magnus Tetens Equation #2286

Conversation

kurt-rhee commented Oct 30, 2024 • edited by cwhanse Loading

Reasoning

Caveats

Caveat 1

Caveat 2

adriesse commented Oct 30, 2024

kurt-rhee commented Oct 30, 2024

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

kurt-rhee commented Nov 18, 2024

kandersolar left a comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

Choose a reason for hiding this comment

kurt-rhee commented Oct 30, 2024 •

edited by cwhanse

Loading