DOI: 10.5281/zenodo.17870102
title: 2019_2024_Sentinel_Fourier Processed__1k_ER_Day_Night_LST

description: Overview:

This is a set of images produced by Temporal Fourier Analysis (TFA) of Sentinel data  (3B SLSTRB):

DLST: Day-time Land Surface Temperature

NLST: Night-time Land Surface Temperature

The imagery summarises some key environmental indicators, incorporating seasonal dynamics, for the European and North African extent.This series of Sentinel data, processed according to Scharlemann et al (2008), has been updated to include imagery from 2019 to 2024. 

Process:

Image values were extracted from Sentinel imagery from 2019 to 2024. The day and night land temperatures came from monthly Sentinel data  (3B SLSTRB) , Each parameter extract dataset was 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 time series's mean, minimum, and maximum, and the 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 VIIRS land/sea layer, and the images were projected to geographic. The  E4warning study region was a subset of global images. Idrisi rasters were converted to GeoTIFF format in order to give data users greater flexibility.

This new Sentinel Dataset is used as an update and continuation of our MODIS and VIIRS TFA products and can be utilised similarly. 

 

Projection + EPSG code:Latitude-Longitude/WGS84 (EPSG: 4326)

Extent    -32.0000000000000000,10.0000000000000000 : 68.9999999999999574,81.9999999999999716File names:

The es at the start of each file name indicates that the image covers the wider Europe and North Africa region included in the E4warning study area and is in geographic projection. 94 refers to the year timeline of 2019-2024. In this version, we only have bands 07 and 08. We will update 03 and 14 soon. The next two characters identify the channel:03 - middle infra-red07 - daytime land surface temperature08 - nighttime land surface temperature14 - NDVI: Normalised Difference Vegetation Index15 - EVI: Enhanced Vegetation IndexThe last two characters of each file name denote the output from the Fourier processing:a0 - meanmn - minimummx - maximuma1 - amplitude of annual cyclea2 - amplitude of bi-annual cyclea3 - amplitude of tri-annual cyclep1 - phase of annual cyclep2 - phase of bi-annual cyclep3 - phase of tri-annual cycled1 - variance in annual cycled2 - variance in bi-annual cycled3 - variance in tri-annual cycleda - combined variance in annual, bi-annual, and tri-annual cyclesvr - variance in raw dataParameter 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)

Global Files can be accessed here.