WaPOR, remote sensing for water productivity

Database versions

A participatory methodology review process alongside the whole programme has provided the opportunity to collectively prioritize improvements of WaPOR.

Taking into account the findings of the validation assessments carried out by different research institutions (IHE-DELFT, University of Twente) and feedback received from users, has allowed to define priorities for improvement of the various WaPOR versions.

This version will be launched on 4 October 2023.

  • Level-1 data is now global: all the Level-1 datasets are now available globally allowing for the easy evaluation of actual evapotranspiration, biomass production and water productivity in any agricultural area in the world.
  • A new root-zone soil moisture variable is included in the dataset (beta): a new variable has been added to the WaPOR dataset giving an estimation of the stress experienced by vegetation due to a lack of water in the local root zone.
  • Daily AgERA5 and hourly ERA5 meteorological data replaces GEOS-5 for final processing: ERA5 is a state of the art reanalysis dataset with a higher spatial and temporal resolution compared to GEOS-5 and provides the required meteorological data for the model.
  • VIIRS-LST replaces MODIS-LST at level-2 and complements Landsat-LST at level-3: VIIRS was designed to expand upon the data collected by the aging MODIS sensors by collecting radiometric measurements of Earth in the visible and infrared spectra. WaPOR v3 uses these infrared spectra to create 375m resolution Land Surface Temperate maps which are consequently downscaled (i.e. thermal sharpened) to the level-2 and level-3 resolutions.
  • Thermal sharpening approach added for level-2 and level-3: WaPOR v3 uses an advanced thermal sharpening algorithm (pyDMS) to downscale LST maps using a variety of indices based on Sentinel-2 reflectances and elevation data.
  • Sentinel-2 replaces PROBA-V at level-2 and complements Landsat at level-3: sentinel-2 data is used to replace (the decommissioned) PROBA-V data at level-2. It has a finer resolution than PROBA-V and is now also used at level-3 to complement the Landsat measurements, resulting in a higher frequency of overpasses.
  • Sentinel-3 LST serves as VIIRS-LST backup: in cases where VIIRS-LST data is of low quality, Sentinel-3 data, which has a coarser resolution, is used to complement the data in order to assure a continuous high quality time-series.
  • Copernicus-DEM replaces SRTM: copernicus-DEM is a state-of-the-art digital surface model with a resolution comparable to that of SRTM, but with fewer artefacts and more current data.
  • New cloud mask procedure: with a 0.05° buffer for land, a 0.10° buffer for water and the replacement of Sen2Cor with KappaMask which is an AI-based approach that is compatible with the new higher resolution Sentinel inputs and has proven to be more accurate and reliable. This new procedure is more suitable for the now global coverage of the data and helps increase data quality and usability in agricultural applications.

Wapor database version 2 was released on 17/06/2019.

This 2.1 interface release introduces:
  • One additional analysis tool (Area Water Productivity)
  • Improvements of existing features and bug fixes: areas are now downloadable from My Areas
  • Clearer metadata interface in the Catalog

WaPOR 2.0 was launched on 17 June 2019 during the celebration of the World Day to combat Desertification and Drought. The findings of validation studies and quality assessments allowed the team to implement a number of improvements on the v2.0 of the database, including:

  • ETo is now calculated using Tmin and Tmax instead of Tavg. This brings the methodology fully in line with FAO I&D Paper N. 56;
  • E, T, I: soil moisture has increased in high vegetation areas, and the land cover input was changed from GlobCover to the v2.0 Land cover data (which is based on Copernicus Global Land Cover product at 100 m, released in May 2019);
  • NPP: based on the validation results, the Light Use Efficiency (LUE) value applied for cropland (2.49) in v1.0 was replaced by a LUE value of 2.7 for cropland in v2.0. This change was made to avoid double accounting of water stress because a soil moisture stress factor is included in the NPP calculation. A value of 2.7 represents the LUE under optimal water availability conditions (e.g. for irrigated cropland).
  • Biomass: Total Biomass Production (TBP) replaces Above Ground Biomass Production (AGBP) as suggested in the review process for higher flexibility in agricultural output calculations. In addition, Seasonal Biomass Production now also applies to vegetation without a detected growing season. This is done in evergreen areas by considering the annual NPP sum.
  • Land Cover at Continental and National level: following the release of the Copernicus Global Land Cover product in May 2019, WaPOR land cover takes that as the base layer, on which the rainfed / irrigation distinction is applied. This last process takes the Water Deficit Index as it was for Version 1, but now applying a temporal check over a 5 years window.

More information can be found in Annex to the  Quality Assessment.

Download the  WaPOR database methodology, Version 2 release, April 2020

WaPOR 1.1 was released in December 2018. This release includes two major features, plus some improvements of existing features and bug fixes.

  • MyWaPOR area: The user profile area is now enriched with 3 more sections for storing users’ preferred choices for time-series (My Time Series), areas (My Areas) and locations (My Points).
  • Analysis tool: The Analysis tool, available from the tools menu in the WaPOR Map, allows for interactive on-the-fly calculations of: point time series, area time series, area water productivity (on user-defined time range) and area selection for raster clip and download. In addition to drawing area of interest on the map, users can now upload a shapefile (zipped collection of x.shp, x.dbf, x.shx and x.prj files) containing the polygon to be used in the analysis. Only one polygon at a time can be processed in the current settings.
  • Improvements and bug fixes: An Open Geospatial Content (OGC) link is now available in the catalogue to directly access the web map service (wms) of the selected data. Seasonal gross biomass water productivity at the national level now properly takes into account accumulated evapotranspiration for growing seasons that span over more than one year.

WaPOR users all over the world and project team members have provided, during the course of 2017, useful comments both on the user interface of the portal and on the content. In addition, two independent evaluations of the accuracy of the data have been carried out on the different data components by IHE-Delft and by ICT-Twente, the Netherlands, to feed the beta version internal review process. Project partners discussed the findings of the evaluations during a workshop held in FAO headquarters in January 2018. The review process lead to the formulation of WaPOR Version 1.0, including the updated methodology and the updated portal and functionalities.

WaPOR 1.0 was released in June 2018, with the following improvements on the portal:

  • Location search through coordinates or name of places.
  • Personal area (MyWaPOR) for saving user preferences and accessing enhanced functionalities (work currently on going).
  • Improved interface usability and visual consistency.
  • Low bandwidth - friendly technology.
  • Easier access to information and guidance documents.

and on the data:

  • Actual evapotranspiration now takes interception explicitly into account resulting in higher values in tropical areas compared to beta version.
  • Evaporation, Transpiration and Interception are now calculated and made available separately.
  • Improved algorithm for open water evaporation.
  • Soil moisture calculations improved with regard to temperature (now using wet bulb temperature) and solar radiation (now using instantaneous transmissivity instead of daily average). This change specifically lead to improved evapotranspiration values in arid areas.
  • Reference evapotranspiration now takes into account wind speed at 2 m height.

A methodology review workshop took place in October 2016 with the following objectives: i) review the methodology and preliminary results proposed by the FRAME Consortium, ii) discuss approaches to assess water and land productivity at different levels and, iii) discuss the dissemination portal. A full agenda of the workshop is available here.

The review process lead to the formulation of the methodology used to produce the beta version of the database at Level I, released on WaPOR portal on April 20 2017. The methodology documents of the beta version are available under resources.