با سلام خدمت کاربران در صورتی که با خطای سیستم پرداخت بانکی مواجه شدید از طریق کارت به کارت (6037997535328901 بانک ملی ناصر خنجری ) مقاله خود را دریافت کنید (تا مشکل رفع گردد).
ردیف | عنوان | نوع |
---|---|---|
1 |
The forgotten land use class: Mapping of fallow fields across the Sahel using Sentinel-2
کلاس استفاده از اراضی فراموش شده: نقشه برداری از مزارع مزرعه در ساحل با استفاده از سنتینل-2-2020 Remote sensing-derived cropland products have depicted the location and extent of agricultural lands with an
ever increasing accuracy. However, limited attention has been devoted to distinguishing between actively
cropped fields and fallowed fields within agricultural lands, and in particular so in grass fallow systems of semiarid
areas. In the Sahel, one of the largest dryland regions worldwide, crop-fallow rotation practices are widely
used for soil fertility regeneration. Yet, little is known about the extent of fallow fields since fallow is not
explicitly differentiated within the cropland class in any existing remote sensing-based land use/cover maps,
regardless of the spatial scale. With a 10 m spatial resolution and a 5-day revisit frequency, Sentinel-2 satellite
imagery made it possible to disentangle agricultural land into cropped and fallow fields, facilitated by Google
Earth Engine (GEE) for big data handling. Here we produce the first Sahelian fallow field map at a 10 m resolution
for the baseline year 2017, accomplished by designing a remote sensing driven protocol for generating
reference data for mapping over large areas. Based on the 2015 Copernicus Dynamic Land Cover map at 100 m
resolution, the extent of fallow fields in the cropland class is estimated to be 63% (403,617 km2) for the Sahel in
2017. Similar results are obtained for five contemporary cropland products, with fallow fields occupying
57–62% of the cropland area. Yet, it is noted that the total estimated area coverage depends on the quality of the
different cropland products. The share of cropped fields within the Copernicus cropland area is found to be
higher in the arid regions (200–300 mm rainfall) as compared to the semi-arid regions (300–600 mm rainfall).
The woody cover fraction within cropped and fallow fields is found to have a reversed pattern between arid
(higher woody cover in cropped fields) and semi-arid (higher woody cover in fallow fields) regions. The method
developed, using cloud-based Earth Observation (EO) data and computation on the GEE platform, is expected to
be reproducible for mapping the extent of fallow fields across global croplands. Future applications based on
multi-year time series is expected to improve our understanding of crop-fallow rotation dynamics in grass fallow
systems being key in teasing apart how cropland intensification and expansion affect environmental variables,
such as soil fertility, crop yields and local livelihoods in low-income regions such as the Sahel. The mapping
result can be visualized via a web viewer (https://buwuyou.users.earthengine.app/view/fallowinsahel). Keywords: Fallow fields | Cropland | Satellite image time series | Land use/cover mapping | Sentinel-2 | Drylands | Sahel |
مقاله انگلیسی |