fix negative pet, error in water balance remains

[lcunha0118]

Fix possibility of negative PET due to negative net radiation over night.

Additions

Condition to turn PET into zero if negative

Changes

Testing

Tested with current make_and_run_bmi_pass_forcings_pet.sh

Screenshots

Notes

Todos

Checklist

• [x ] PR has an informative and human-readable title
• [ x] Changes are limited to a single goal (no scope creep)
• [ x] Code can be automatically merged (no conflicts)
• [ x] Code follows project standards (link if applicable)
• [ x] Passes all existing automated tests
• [ x] Any change in functionality is tested
• [ x] New functions are documented (with a description, list of inputs, and expected output)
• [ x] Placeholder code is flagged / future todos are captured in comments
• [ x] Visually tested in supported browsers and devices (see checklist below 👇)
• [ x] Project documentation has been updated (including the "Unreleased" section of the CHANGELOG)
• [ x] Reviewers requested with the Reviewers tool ➡️

Testing checklist

Target Environment support

• Windows
• Linux
• Browser

Accessibility

• Keyboard friendly
• Screen reader friendly

Other

• Is useable without CSS
• Is useable without JS
• Flexible from small to large screens
• No linting errors or warnings
• JavaScript tests are passing

[madMatchstick]

@lcunha0118 When running make_and_run_bmi_pass_forcings_pet.sh with a few different methods (1-5), at glance it seems like potential ET (et_struct.potential_et_m_per_timestep) is often negative and actual ET (et_struct.actual_et_m_per_timestep) is always 0. Just want to confirm this is the expected behavior? It's possible that I'm calling the wrong variable name(s)...

Please disregard this, I was in the wrong branch and looks like I can only edit a comment here, but cannot delete. My mistake.

[madMatchstick]

@lcunha0118 : Now working in the correct branch :) ... Not seeing any negative values for PET nor AET. -thx