title: Coverte 1D DataFrame into 3D Xarray Dataset
body: <p>I am new to programming and I am stuck with a problem.
  I have a 1D pandas DataFrame with time, lat and lon and the corresponding variable adt.
  This is the DataFrame:</p>
  <p><img src="https://i.stack.imgur.com/okmUD.png" alt="enter image description here" /></p>
  <p>I want to converte the DataFrame into a 3D xarray Dataset which looks like this:</p>
  <p><img src="https://i.stack.imgur.com/BbrJ6.png" alt="enter image description here" /></p>
  <p>I have searched the internet but have not found a solution to my problem.
  Thanks for your help :)</p>