1. Background
To achieve one of the main goals of the project that consists in making accessible information about drought and floods at the catchment level to the larger public, a structured website (called from now on IMDROFLOOD project geoportal) was designed to be user-friendly, accessible online and offer the data on demand. These aspects support an easier access to the data by removing usability barriers that could prevent or delay the optimal use of the data. Additionally, the geoportal follows the principles of open, modular and scalable technologies. This facilitates the development of a stable and flexible product by allowing a stepwise approach during the implementation of the geoportal. The prototype of the geoportal was built using exclusively open source solutions . Everyone is welcome to explore, download and test the obtained results using the IMDROFLOOD Geoportal functionalities.
2. Products
2.1. Normalized Difference Water Index (NDWI)
Product description:
The NDWI represents the water content in vegetation canopies. The NDWI has different formulas depending on the purpose. Two formulas were published in 1996 by McFeeters and Gao. First is more useful for open water features or flood delineation. The second is more useful for vegetation monitoring. IMDROFLOOD is implementing the second type of NDWI index
- NDWI = (NIR - SWIR) / (NIR + SWIR). Where, SWIR is MODIS band 6 and NIR is MODIS band 2.
Data characteristics:
- File format: GeoTiff
- Spatial resolution: 500m x 500m
- Temporal resolution: 2000 - 2018
- Projection: Pseudo Mercator (EPSG:3857)
Example:
2.2. Normalized Difference Vegetation Index - NDVI
Product description:
NDVI is a measure of the amount and vigor of vegetation on the land surface (Prince and Justice 1991). It is used to monitor the vegetation cover, chlorophyll content and other vegetation properties. The contrast between intense chlorophyll pigment absorption in the red channel and high reflectance of leaf mesophyll in the near infrared channel is the main characteristic used for operating NDVI. It can be used to indicate vegetation stress, particularly due to water shortage, which is the main factor affecting vegetation and controls leaf pigment content and integrity (Maselli, 2004). The NDVI is calculated according to the following formula:
- NDVI = (NIR - Red) / (NIR + Red). Where, Red is MODIS band 1 and NIR is MODIS band 2.
Data characteristics:
- File format: GeoTiff
- Spatial resolution: 500m x 500m
- Temporal resolution: 2000 - 2018
- Projection: Pseudo Mercator (EPSG:3857)
Example:
2.3. Normalized Difference Drought Index - NDDI
Product description:
NDDI can offer an appropriate measure of the dryness of a particular area, because it combines information on both vegetation and water. NDDI takes advantage of the fact NDVI senses plant matter and NDWI senses plant moisture. NDDI had a stronger response to summer drought conditions than a simple difference between NDVI and NDWI, and is therefore a more sensitive indicator of drought than NDVI alone (Gu et al., 2007). The NDDI is calculated according to the following formula:
- NDDI = (NDVI - NDWI) / (NDVI + NDWI). Where, NDVI is Normalized Difference Vegetation Index and NDWI is Normalized Difference Drought Index.
Data characteristics:
- File format: GeoTiff
- Spatial resolution: 500m x 500m
- Temporal resolution: 2000 - 2018
- Projection: Pseudo Mercator (EPSG:3857)
Example:
2.4. Normalised Difference Infrared Index - NDII
Product description:
NDII formula is similar to the NDVI. In addition to determining the water content of vegetation, the NDII can be effectively used to detect plant water stress according to the property of shortwave infrared reflectance, which is negatively related to leaf water content due to the large absorption by the leaf (Steele-Dunne et al., 2012; Friesen et al., 2012; Van Emmerik et al., 2015). The NDII is calculated according to the following formula:
- NDII = (NIR - SWIR) / (NIR + SWIR). Where, NIR is MODIS band 2 and NDWI is MODIS band 6.
Data characteristics:
- File format: GeoTiff
- Spatial resolution: 500m x 500m
- Temporal resolution: 2000 - 2018
- Projection: Pseudo Mercator (EPSG:3857)
Example:
2.5. Leaf Area Index - LAI
Product description:
LAI appears as a key variable in many models describing vegetation-atmosphere interactions, particularly with respect to the carbon and water cycles (GCOS, 2004). The LAI parameter reflects the biochemical and physiological processes of vegetation, therefore indicating the productivity of vegetation, and it serves as an important input variable in land surface process models highlight that to understand the LAI for crops and its dynamics is very important for a wide range of agricultural studies, such as crop growth monitoring and crop yield estimation (Fang et al. 2011).
Data characteristics:
- File format: GeoTiff
- Spatial resolution: 500m x 500m
- Temporal resolution: 2000 - 2018
- Projection: Pseudo Mercator (EPSG:3857)
Example:
2.6. Fraction of Absorbed Photosynthetically Active Radiation Index - fAPAR
Product description:
(FAPAR) plays a critical role in the energy balance of ecosystems and in the estimation of the carbon balance over a range of temporal and spatial resolutions (GTOS, 2008). It is defined like the fraction of the incoming solar radiation in the Photosynthetically Active Radiation spectral region that is absorbed by a photosynthetic organism, typically describing the light absorption across an integrated plant canopy. This biophysical variable is directly related to the primary productivity of photosynthesis and some models use it to estimate the assimilation of carbon dioxide in vegetation.
Data characteristics:
- File format: GeoTiff
- Spatial resolution: 500m x 500m
- Temporal resolution: 2000 - 2018
- Projection: Pseudo Mercator (EPSG:3857)
Example:
2.7. Global Drought Monitor - SPEI
Product description:
SPEI Global Drought Monitor is based on the Thortnthwaite equation for estimating potential evapotranspiration, PET.
Data characteristics:
- File format: GeoTiff, NetCDF
- Spatial resolution: 0.1º x 0.1º
- Temporal resolution: 1961 - 2018
- Projection: Pseudo Mercator (EPSG:3857)
Example:
3. Data access
We provide two ways to download the IMDROFLOOD products:
Direct download
Use the control to filter the calendar by the dates when products are available for each collection. Then, use the download icons to download the products in the desired format:
- Download Google Earth KML
- Download PNG
- Download Colour GeoTiff
- Download Raw GeoTiff
- Download full collection archive (top toolbar)
Data services
License
This work is licensed under a
Creative Commons Attribution 4.0 International License.
Credits
IMDROFLOOD Geoportal is build entirely with standard compliant free and open source software and open data.
Data
Software
Graphics
Ideas
References
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Contact
For more information about IMDROFLOOD geoportal access and data products please contact vasile.craciunescu@meteoromania.ro
