DOI: 10.5281/zenodo.11187269
title: 2015_RelativeHumidity_RawData_FourierProcessed_5km

description: Abstract:

Minimum raw RH datasets

The RH data were calculated from the dew point, derived from  Land Surface Temperature  provided by NASA from the MODIS satellite image archive The projection of these data was derived from ensembles of 17 Global climatic models,  downscaled to 1km using the MARKSIM utility and extracted for 2015. 

Fourier Processed for RH

TFA*.zip  is a set of images produced by Temporal Fourier Analysis (TFA) of ERA5 data:

MODIS: Relative Humidity

The imagery summarises some key environmental indicators, incorporating seasonal dynamics, for The European and North African extent.This series of ERA5 data, processed according to Scharlemann et al (2008), has been updated to include imagery from 2010 to 2022. 

 

Precipitation from the ERA5 reanalysis archive supplied by the European Centre ofr Medium Range Weather Forecasting for 2010 - 2022. Abstract: Precipitation from the ERA5 reanalysis archive supplied by the European Centre for Medium-Range Weather Forecasting . for 2010 - 2022. The original data is at 0.25 degree resolution and was downscaled by ERA extraction algroithms. The daily data have been aggregated into dekadal, monthly, and annual datasets to match the outputs produced by NASA from the MODIS imagery temperature and vegetation Index datasets. The resolution was also chosen to match these MODIS datasets.

Process:

Image values were extracted from Modis ( RH) 5 km imagery from 2015.  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 output 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 (WGS84) and later nibbled in arcmap to transfer to 1km resolution by reducing zeros in mask areas. The E4Warning study region was a subset of global images. Idrisi rasters were converted to GeoTIFF format in order to give data users more flexibility.

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

File names:

The Tif files are  in geographic projection, W refer to world coverage. The last two characters of each file name denote the output from 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 areERA5  A0, A1, A2, A3, Min, Max, Vr Reflectance values  Relative Humidity ALL D1,D2,D3,Da PercentagesALL E1,E2,E3 PercentagesALL P1,P2.P3 Months*100. (Jan=100)