Interpolation between base_inv_dict years for contrail climate impact calculations of single flights

[liammegill]

Description

This pull request adds functionality that allows the years defined in inv_dict to vary independently from those defined in base_inv_dict. This is helpful if the climate impact of a flight or yearly inventory in for example the year 2024 is desired, but global emission inventories only exist in for example the years 2020 and 2050.

The new function interp_base_inv_dict uses a custom nearest neighbour method to regrid the base emission inventories onto the contrail grid, then linearly interpolates between them to get the values at any years in inv_dict that are not defined in base_inv_dict. It is not possible to include years in inv_dict that are outside of the range of years defined by the inventories in base_inv_dict. Going forward, I will consider whether this could be possible if one of the scaling functions were to be used on the base emission inventories.

Linked issues

Closes #45.

Type of change

• New feature (non-breaking change which adds functionality)

How has this been tested?

• Introduced pytest test classes TestCheckContInput and TestInterpBaseInvDict in tests/calc_cont_test.py
• Using randomly generated and DEPA 2050 data

Test configuration:

• Operating system: Windows 11

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[stefan-voelk]

Looks good to me!