DOI: 10.5281/zenodo.13134557
title: 2001_2021_ MODIS_FourierProcessed_1k_ER

description: Overview: 

This is a set of images produced by Temporal Fourier Analysis of global MODIS data

NDVI: Normalised Difference Vegetation Index

EVI: Enhanced Vegetation Index

MIR: Middle Infra-Red

DLST: Day-time Land Surface Temperature

NLST: Night-time Land Surface Temperature

 

Abstract: 

MODIS is a sensor on board two NASA satellites, providing near-daily coverage of the entire Earth. The MOD11A2 product contains an 8-day average of land surface temperature at 1-kilometre resolution. Reflectance values have been adjusted to remove the distortion caused by the view angle and land surface texture. The MOD13A2 Product used for NDVI, EVI, and Middle Infra-red from USGS. The imagery summarises key environmental indicators, incorporating seasonal dynamics, for the MOOD study area.

This is an update of the 2001-2019 series, which adds to 2021 and is then processed by a temporal Fourier processing algorithm.

A stepwise system of thresholds and interpolations screened erroneous values and bridged gaps in the time series. The smoothed series was sampled at 5-day intervals and transformed into a set of sine curves describing annual, bi-annual, and tri-annual fluctuations. For each of these curves, the Fourier algorithm generated images expressing the amplitude, phase, and variance. Other outputs recorded the mean, minimum, and maximum of time series, and error measured during the Fourier transform. For a detailed description of the Fourier algorithm and its output, please see the article by Scharlemann et al., 2008 (https://doi.org/10.1371/journal.pone.0001408) Sea pixels were masked with a MODIS land/sea layer and the images were projected from sinusoidal to geographic. The MOOD study region was a subset of global images. Idrisi rasters were converted to Geotiff format in order to give data users more flexibility 

File naming scheme:  

 The er at the start of each file name indicates that the image covers the wider Europe and North Africa region included in the MOOD study area and is in geographic projection. 11 refers to the year timeline from 2001-2021.  The next two characters identify the channel: 03 - middle infra-red 07 - daytime land surface temperature 08 - nighttime land surface temperature 14 - NDVI: Normalised Difference Vegetation Index 15 - EVI: Enhanced Vegetation Index  The last two characters of each file name denote the output from Fourier processing: a0 - mean mn - minimum mx - maximum a1 - amplitude of annual cycle a2 - amplitude of bi-annual cycle a3 - amplitude of tri-annual cycle p1 - phase of annual cycle p2 - phase of bi-annual cycle p3 - phase of tri-annual cycle d1 - variance in annual cycle d2 - variance in bi-annual cycle d3 - variance in tri-annual cycle da - combined variance in annual, bi-annual, and tri-annual cycles vr - variance in raw data

 

Files can be accessed here as well (including Global files). 

 Projection + EPSG code:Latitude-Longitude/WGS84 (EPSG: 4326)Spatial extent:Extent  -32.0000000000000000,10.0000000000000000 : 68.9999999999999574,81.9999999999999716Spatial resolution:0.0083333 deg (approx. 1000 m)  Temporal resolution: 8-day and 16-day  from 2001 to 2021

Pixel values

Parameter Fourier Variable Image values areMIR (03) A0, A1, A2, A3, Min, Max, Vr Reflectance values * 10000LST (07 day,08 night) A0, A1, A2, A3, Min, Max, Vr (Degrees Centigrade+273)*50NDVI (14) and EVI (15) A0, A1, A2, A3, Index Value * 1000NDVI (14) and EVI (15) A0, Min, Max, Index Value * 1000 + 10000NDVI (14) and EVI (15) VR Value * 10000ALL D1,D2,D3,Da PercentagesALL E1,E2,E3 PercentagesALL P1,P2.P3 Months*100. (Jan=100)

Source: MODIS  NASA :MOD11A2 and MOD13A2

Software used:Codes for modelling are in Python and C++The software used for map production is ESRI ArcMap 10.8

License: CC-BY-SA 4.0Processed by:ERGO (Environmental Research Group Oxford) https://ergoonline.co.uk/ for the H2020 MOOD project