I am trying to determine the amount of precipitable water vapor (PWV), ozone and aerosols as a function of time over specific spots on the Earth, namely our astronomical observatories. To do this, I've already got some Python code using modapsclient which will download the twice daily MODIS Aqua and Terra MYDATML2 and MODATML2 products that cover the specific latitude and longitude I am interested in.

What I'm not sure about is how to extract the specific quantities I want such as the time the MODIS data were taken and PWV for the particular latitude and longitude position of my observatory to make them into a time series of values. The MYDATML2 products seem to contain 2D latitude and longitude grids of Cell_Along_Swath_5km and Cell_Across_Swath_5km so I guess this makes it swath data as opposed to tile or grid data ? The quantities I want such as Precipitable_Water_Infrared_ClearSky also seem to be against the Cell_Along_Swath_5km and Cell_Across_Swath_5km butI'm not sure how to get that PWV value at the specific lat,long I am interested in. Help please ?