2015_MODIS_RelativeHumidity_FourierProcessed

This is a set of images produced by Temporal Fourier Analysis (TFA) of MODIS Relative Humidity data:

Abstract :

This is a set of images produced by temporal Fourier analysis of global MODIS data for Middle Infra Red (MID) derived from the MOD11A2 Product from USGS. The imagery summarises key environmental indicators, incorporating seasonal dynamics, for the MOOD study area.
MODIS is a sensor on two NASA satellites, providing near-daily coverage of the entire Earth. The MOD11A2 product contains an 8-day average of MIR at 1-kilometre resolution. Reflectance values have been adjusted to remove the distortion caused by the view angle and land surface texture.

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 the 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 VIIRS 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 to give data users more flexibility.

File naming scheme:  

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

Projection + EPSG code:
Latitude-Longitude/WGS84 (EPSG: 4326)
Spatial extent:
Extent  -32.0000000000000000,10.0000000000000000 : 68.9999999999999574,81.9999999999999716
Spatial resolution:
0.0083333 deg (approx. 1000 m)  
Temporal resolution:
 Decadal 

Pixel values

Parameter Fourier Variable Image values are
RH values A0, A1, A2, A3, Min, Max, Vr Reflectance values 

ALL D1,D2,D3,Da Percentages
ALL E1,E2,E3 Percentages
ALL P1,P2.P3 Months*100. (Jan=100)

Source: 
Middle Infra Red (MID) derived from the MOD11A2(MODIS NASA) Product from USGS

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