Unit conversions of ET data from MOD16A2 and missing MOD16A2 pixels
Posted: Mon Jun 10, 2024 8:02 pm America/New_York
Hello,
I am trying to calculate ET over the Phoenix, AZ metropolitan area over 2 decades. I have a few questions about the units, first for MOD16A2. I add all of the ET pixels for every month, then multiplied by the scaling factor 0.1, and then took the mean within a defined zone. From my understanding, this returns ET values in mm. Is it correct that the value is only in mm, so the amount of water that evaporated/transpired in that area in a month? A colleague of mine calculated ET for the area using a different method, and has ET in units of mm/m^2/day (for the zone). How can I convert the data in mm/m^2/day to my ET data in mm to compare the values? Also, it seems that many of the MOD16A2 pixels over the Phoenix area are missing. I'd estimate about half of the pixels over my study area are NA. Can my methodology here still work if that many pixels are missing? (I am using Google Earth Engine for this work)
I am trying to calculate ET over the Phoenix, AZ metropolitan area over 2 decades. I have a few questions about the units, first for MOD16A2. I add all of the ET pixels for every month, then multiplied by the scaling factor 0.1, and then took the mean within a defined zone. From my understanding, this returns ET values in mm. Is it correct that the value is only in mm, so the amount of water that evaporated/transpired in that area in a month? A colleague of mine calculated ET for the area using a different method, and has ET in units of mm/m^2/day (for the zone). How can I convert the data in mm/m^2/day to my ET data in mm to compare the values? Also, it seems that many of the MOD16A2 pixels over the Phoenix area are missing. I'd estimate about half of the pixels over my study area are NA. Can my methodology here still work if that many pixels are missing? (I am using Google Earth Engine for this work)