|
Exploring the Relationship Between Vegetation Growth Patterns and Elevation-Related Terrain Components in Northwestern Iran
|
Amirhossein Halabian *   , Bromand Salahi,2 |
Department of Geography, Payame Noor University, Tehran, Iran, Department of Geography, Payame Noor University, Tehran, Iran , am_halabian@pnu.ac.ir
2- Department of Geography, Faculty of Social Sciences, University of Mohaghegh Ardabili, Iran |
|
|
Abstract: (15 Views) |
Vegetation cover, as a critical environmental indicator, is significantly influenced by physiographic factors, especially in mountainous regions. This study investigated the spatial distribution of vegetation cover in Northwestern Iran in relation to terrain components derived from elevation. The analysis used Normalized Difference Vegetation Index (NDVI) products from the Terra and Aqua MODIS sensors (V006-MOD13Q1 and V006-MYD13Q1) spanning 2003–2020, with a 16-day temporal resolution. Elevation data were derived from an ALOS-based Digital Elevation Model (DEM), while slope and aspect were generated through kernel-based raster processing and pixel analysis. All preprocessing and data management procedures were conducted in Python. The results demonstrate that vegetation cover decreases substantially during the cold period (October–February), reaching its minimum NDVI in January and February. The May pattern, with a maximum value of 0.875, indicates an increase in NDVI compared with April, while peak NDVI values occurred in August and September, mainly reflecting agricultural activities in lowland plains. Elevation played a pivotal role in vegetation dynamics, showing a general decline in NDVI at higher altitudes. The maximum NDVI values linked to elevation were observed in April (0.609) and May (0.556), as well as during the spring (0.498) and summer (0.533) seasons, corresponding to the lowland areas of the Moghan Plain and its western extensions. Conversely, the lowest NDVI values were associated with snow cover and frost at elevations exceeding 2,183 m during October–March, and with persistent snowpack over high mountain peaks during April–May. Minimum NDVI was observed at elevations above 2,483 m in winter and above 3,983 m in autumn. Vegetation responses to slope gradients exhibited a slight positive trend and high variability in greenness across slopes ranging from 3° to 45°, largely attributed to reduced anthropogenic disturbance in these areas. By contrast, NDVI declines at slopes below 3 corresponded with urban and rural settlements. Slope aspect also exerted a significant influence: maximum NDVI values occurred on North-facing slopes during May and the spring season, whereas minimum values were recorded on West-facing slopes during January and winter.
|
Article number: 2 |
| Keywords: Anthropogenic, Greenness Index, MODIS, Northwestern Iran, NDVI |
|
|
Full-Text [PDF 2345 kb]
(11 Downloads)
|
Type of Study: Research |
Subject:
Special
Received: 2025/08/27 | Accepted: 2025/12/29 | Published: 2026/09/17
|
|
|
|
|
|
|
| Send email to the article author |
|
|
|
| Add your comments about this article |
|
|
|
