CTD Data from Lake Michigan 
  PI: Harvey Bootsma (UW-Milwaukee) 
  Co-PI: Qian Liao (UW-Milwaukee) 
  Version history: 
   version 2 (current; online 2019-05-22) - contains 2017 & 2018 data. 
   version 1 (2018-05-25) - contains 2017 data.