I am trying to do a correlation between SO2 data obtained from satellite AURA OMI and SO2 data obtained from Ground Monitoring Stations.
Since both values show the level of concentration of SO2 in the atmosphere, though in different units, and one should increase if other is increasing but then why do they show a weak and negative correlation?
The study area is the Ahmedabad District. The correlation has been done for annual mean values for the years 2014-18.
Here is the screenshot of scatter plots generated from the regression analysis.