Abstract
The Mesopotamian marshes are a group of water bodies located in southern Iraq, in the shape of a triangle, with the cities Amarah, Nasiriyah, and Basra located at its corners. The marshes are appropriate habitats for a variety of birds and most of the commercial fisheries in the region. The normalized difference vegetation index (NDVI) has been derived using observations from various satellite sensors, such as the Moderate Resolution Imaging Spectroradiometer (MODIS), Advanced Very-High-Resolution Radiometer (AVHRR), and Landsat over the Mesopotamian marshlands for the 17-year period between 2002 and 2018. We have chosen this time series (2002–2018) to monitor the change in vegetation of the study area since it is considered as a period of rehabilitation for the marshes (following a period when there was little to no water flowing into the marshes). Statistical analyses were performed to monitor the variability of the maximum biomass time (month of June). The results illustrated a strong positive correlation between the NDVI derived from Landsat, MODIS, and AVHRR. The statistical correlations were 0.79, 0.77, and 0.96 between Landsat and AVHRR, MODIS and AVHRR, and Landsat and MODIS, respectively. The linear slope of NDVI (Landsat, MODIS, and AVHRR) for each pixel over the period 2002–2018 displays a long-term trend of green biomass (NDVI) change in the study area, and the slope is slightly negative over most of the area. Slope values (−0.002 to −0.05) denote a slight decrease in the observed vegetation index over 17 years. The green biomass of the marshlands increased by 33.2% of the total area over 17 years. The areas of negative and positive slopes correspond to the same areas in slope map when calculated from Landsat, MODIS, and AVHRR, although they are different in spatial resolution (30 m, 1 km, and 5 km, respectively). The time series of the average NDVI (2002–2018) for three different sensors shows the highest and lowest NDVI values during the same years (for the month of June each year). The highest values were 0.19, 0.22, and 0.22 for Landsat, MODIS, and AVHRR, respectively, in 2006, and the lowest values were 0.09, 0.14, and 0.09 for Landsat, MODIS, and AVHRR, respectively, in 2003.
Highlights
The Mesopotamian marshes in Iraq are regarded as one of the most vital wetlands in the world
We evaluate the accuracy of the time series trend of Advanced Very-High-Resolution Radiometer (AVHRR) normalized difference vegetation index (NDVI), by comparison, the 1 km resolution Terra Moderate Resolution Imaging Spectroradiometer (MODIS) (MOD13A2) NDVI data, and 30 m Landsat 7 +ETM NDVI data
The NDVI values were derived from the three sensors, AVHRR, MODIS, and Landsat 7 ETM+, for the Mesopotamian marshes corresponding to the maximum biomass period (June) over 17 years (2002–2018)
Summary
The Mesopotamian marshes in Iraq are regarded as one of the most vital wetlands in the world. Several studies have focused on analyzing the time series of AVHRR NDVI and monitoring changes in vegetation phenology [2,27,28,29,30]. We focus on the period of rehabilitation of the marshes (2002–2018) to estimate the increase in vegetation through the use of statistical analysis of the NDVI from the three different satellite sensors (Landsat, MODIS, and AVHRR). 2019, 11, 1245 evaluated against Terra MODIS and Landsat 7 the Enhanced Thematic Mapper Plus (ETM+) data for the Mesopotamian marshlands in Iraq, using statistical analysis. The Landsat 7 ETM+ (30 m) and Terra MODIS NDVI (1 km) data have been resampled to the same spatial resolution as AVHRR LTDR (5 km). We evaluate the accuracy of the time series trend of AVHRR NDVI, by comparison, the 1 km resolution Terra MODIS (MOD13A2) NDVI data, and 30 m Landsat 7 +ETM NDVI data
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.