Which is the vegetation index of mod13q1?
The MOD13Q1 product provides two primary vegetation layers. The first is the Normalized Difference Vegetation Index (NDVI) which is referred to as the continuity index to the existing National Oceanic and Atmospheric Administration-Advanced Very High Resolution Radiometer (NOAA-AVHRR) derived NDVI.
What are the data fields of the mod13c2?
The MOD13C2 has data fields for the NDVI, EVI, VI QA, reflectance data, angular information, and spatial statistics such as mean, standard deviation, and number of used input pixels at the 0.05 degree CMG resolution. The 16-day composite VI is generated using the two 8-day composite surface reflectance granules ( MOD09A1) in the 16-day period.
When did Terra MODIS NDVI data come out?
Terra MODIS NDVI data from the MOD13Q1 product over part of Brazil July 28 – August 12, 2018. It AppEEARS we have a solution to many of your data issues! AGC 2019 Presentation and Workshop Materials
How often are vegetation indices calculated on Terra?
The Terra Moderate Resolution Imaging Spectroradiometer (MODIS) Vegetation Indices (MOD13Q1) Version 6 data are generated every 16 days at 250 meter (m) spatial resolution as a Level 3 product. The MOD13Q1 product provides two primary vegetation layers.
Where are the QA bit flags for AppEEARS?
In addition to data access and transformation processes, AppEEARS also has the capability to unpack and interpret the quality layers. The QA bit flags for the “250m 16 days pixel reliability” layer are provided in Table 4 on page 15 and the “250m 16 days VI Quality” in Table 5 on page 16 of the User Guide.
How does the MODIS VI algorithm filter data?
The MOD13A1 algorithm separates all observations by their orbits providing a means to further filter the input data. Once all 16 days are collected, the MODIS VI algorithm applies a filter to the data based on quality, cloud, and viewing geometry (Fig. 3).
How often do we get global mod13q1 data?
Global MOD13Q1 data are provided every 16 days at 250-meter spatial resolution as a gridded level-3 product in the Sinusoidal projection. Cloud-free global coverage is achieved by replacing clouds with the historical MODIS time series climatology record.
What does MODIS enhanced vegetation index ( EVI ) do?
MODIS also includes a new Enhanced Vegetation Index (EVI) product that minimizes canopy background variations and maintains sensitivity over dense vegetation conditions. The EVI also uses the blue band to remove residual atmosphere contamination caused by smoke and sub-pixel thin cloud clouds.