requirements.txt has some issues

[grische]

1. If I am not horribly mistaken, you are not able to specify a python version in a requirements.txt. At least for this throws the following errors. Did you mean to create a Pipfile (for use with pipenv) instead?

   $ python3.6 -m pip install -r requirements.txt
   Collecting python>=3.6 (from -r requirements.txt (line 1))
   Could not find a version that satisfies the requirement python>=3.6 (from -r requirements.txt (line 1)) (from versions: )
   No matching distribution found for python>=3.6 (from -r requirements.txt (line 1))
   You are using pip version 8.1.1, however version 19.2.3 is available.
   You should consider upgrading via the 'pip install --upgrade pip' command.

2. After removing the first python line, I get an error with xesmf: It does not seem to be (publicly?) available

   $ python3.6 -m pip install -r requirements.txt
   Collecting xarray (from -r requirements.txt (line 1))
   Using cached https://files.pythonhosted.org/packages/e0/7b/b969f686fa7d15232be520d7d82f9818afc2e7027c1c215d742dd9e244b2/xarray-0.13.0-py2.py3-none-any.whl
   Collecting xesmf (from -r requirements.txt (line 2))
   Using cached https://files.pythonhosted.org/packages/38/a0/da05e9d79a620fc6d38ba7c9112d8c325a19b01acef9ade5f9f7cc0458ce/xesmf-0.2.1.tar.gz
   Collecting fire (from -r requirements.txt (line 3))
   Using cached https://files.pythonhosted.org/packages/d9/69/faeaae8687f4de0f5973694d02e9d6c3eb827636a009157352d98de1129e/fire-0.2.1.tar.gz
   Collecting numpy (from -r requirements.txt (line 4))
   Using cached https://files.pythonhosted.org/packages/e5/e6/c3fdc53aed9fa19d6ff3abf97dfad768ae3afce1b7431f7500000816bda5/numpy-1.17.2-cp36-cp36m-manylinux1_x86_64.whl
   Collecting cdsapi (from -r requirements.txt (line 5))
   Using cached https://files.pythonhosted.org/packages/a1/a6/2a5892374e091f688ccdbe2400f8d508ac542b6db6b41ed479701a328dd8/cdsapi-0.2.3.tar.gz
   Collecting pandas>=0.19.2 (from xarray->-r requirements.txt (line 1))
   Using cached https://files.pythonhosted.org/packages/73/9b/52e228545d14f14bb2a1622e225f38463c8726645165e1cb7dde95bfe6d4/pandas-0.25.1-cp36-cp36m-manylinux1_x86_64.whl
   Collecting esmpy (from xesmf->-r requirements.txt (line 2))
   Could not find a version that satisfies the requirement esmpy (from xesmf->-r requirements.txt (line 2)) (from versions: )
   No matching distribution found for esmpy (from xesmf->-r requirements.txt (line 2))
   You are using pip version 8.1.1, however version 19.2.3 is available.
   You should consider upgrading via the 'pip install --upgrade pip' command.

EDIT: Ok, I noticed these packages are available in conda-forge. Do you use (ana/mini)Conda to install the requirements?

[raspstephan]

Now a environment.yml conda file instead