What is the definition of the HISATZEN MODIS flag?

Please enter here to ask a question about any NASA Science related topics!
Post Reply
imaginaryfish
Posts: 1
Joined: Fri Jun 04, 2021 4:12 pm America/New_York

What is the definition of the HISATZEN MODIS flag?

by imaginaryfish » Fri Jun 04, 2021 4:14 pm America/New_York

The HISATZEN is the "Sensor view zenith angle exceeds threshold" sure, but what angle is the threshold set at? How can I define my own angle? The Level 2 MODIS data does not contain the sensor angle that I can find. The only angle is the Center Solar Zenith Angle, which is not helpful.

Tags:

OB.DAAC - SeanBailey
User Services
User Services
Posts: 1194
Joined: Wed Sep 18, 2019 6:15 pm America/New_York

Re: What is the definition of the HISATZEN MODIS flag?

by OB.DAAC - SeanBailey » Mon Jun 07, 2021 10:24 am America/New_York

The HISATZEN Level-2 flag is set when the sensor zenith angle is greater than or equal to 60 degrees.
It is controlled by the l2gen input parameter satzen. No, the sensor zenith angle is not included in the L2 files. It is in the geolocation file that was used in the L2 processing. For MODIS, we generate that geolocation file as part of the L2 processing step, and it is not retained. However, the LAADS archive does distribute these files (referred to as MOD03): https://ladsweb.modaps.eosdis.nasa.gov/ ... odis-L0L1/

Regards,
Sean

bturley
Posts: 1
Joined: Mon Jun 07, 2021 2:11 pm America/New_York

Re: What is the definition of the HISATZEN MODIS flag?

by bturley » Mon Jun 07, 2021 2:13 pm America/New_York

Thank you! That is exactly what I wanted to know.

Post Reply