نوع مقاله : مقاله پژوهشی
نویسندگان
1 گروه مهندسی عمران، دانشکده فنی و مهندسی، دانشگاه قم، قم، ایران
2 گروه زمین شناسی، دانشگاه اصفهان، اصفهان، ایران
3 دکتری، گروه مهندسی عمران، دانشکده فنی و مهندسی، دانشگاه قم، قم، ایران.
4 گروه مهندسی عمران و محیط زیست، دانشکده مهندسی عمران، دانشگاه صنعتی امیرکبیر، تهران، ایران
چکیده
کلیدواژه‌ها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Background and objects:
Water resources management in the present era, especially in arid and semi-arid regions such as Iran, is a major challenge for societies and engineers. Due to the special climatic conditions of these regions, groundwater is considered as a vital and strategic resource. Global research shows that groundwater makes up a significant portion of the world's freshwater and, as a valuable reserve, provides water to many communities. Population growth and increasing need for water, coupled with limited surface water resources, put severe pressure on ground-water resources. In arid and semi-arid regions, such as Iran, this can lead to irreversible conse-quences for ecosystems and hydrological cycles. Therefore, proper management and careful planning in watersheds are essential to ensure the sustainability of water resources and the preservation of ecosystems dependent on it. Climate, as a key factor, is closely related to veg-etation and the health of ecosystems. The spatial distribution of vegetation is strongly influ-enced by climatic conditions, especially precipitation and temperature. A drought is a pro-longed dry period in the natural weather cycle that can occur anywhere in the world and is a slow-onset disaster characterized by a lack of rainfall and therefore a lack of water. Drought can have a serious impact on health, agriculture, economy, energy, and the environment (van Loon et al., 2016).
According to studies, it is estimated that 55 million people worldwide are affected by drought annually, and this drought is the most serious risk to livestock and agricultural prod-ucts in almost every part of the world. Drought threatens people's livelihoods, increases the risk of illness and death, and fuels mass migration. Water scarcity affects 40% of the world's population, and by 2030 around 700 million people are at risk of being displaced as a result of drought. Rising temperatures caused by climate change are making arid regions drier and hu-mid areas wetter. In arid regions, this means that as temperatures rise, water evaporates faster, thereby increasing the risk of drought or prolonging periods of drought.During droughts, these water sources are reduced and may even dry up, preventing crops from being irrigated and destroyed. Also, drought, lack or insufficient rainfall for a long period of time, which causes significant hydrological (water) imbalances, resulting in water shortages, crop damage, reduced river flow, and depletion of groundwater and soil moisture. It occurs when evapo-transpiration (the movement of water in the soil through plants into the air) exceeds rainfall for a significant period of time.In this study, the aim of this study is to investigate surface and groundwater resources and the distribution and classification of drought in the study area of Hamadan plain. For this purpose, using extracted images from the MODIS and Grace and Landsat 8 satellites, we investigated the trend of changes in each of the parameters in the pe-riod from 2003 to 2016.
Methodology:
Surface runoff:
Remote sensing has valuable applications in climatic studies, especially in monitoring and forecasting atmospheric events. Satellite meteorology provides a powerful tool for analyzing atmospheric conditions by using meteorological satellite images. Landsat satellites with low spatial resolution and high temporal resolution make it possible to monitor atmospheric chang-es on a large scale.
Climate satellites also play an important role in measuring atmospheric parameters. The Uni-versity of Idaho's climate data, combining satellite and terrestrial data, is a valuable source of information for studying the atmosphere and water resources. These data provide researchers with parameters such as actual evapotranspiration, cumulative precipitation, and runoff. groundwater: Groundwater, as a vital and strategic resource for communities, requires careful and continuous management and monitoring. Grace satellite images are an efficient and effec-tive method in monitoring and monitoring groundwater level fluctuations. In this study, a set of 168 Grace satellite images from the hamedan plain during the period of 2003 to 2016 was analyzed. The Grace satellite, an advanced dual gravity satellite, was launched by NASA and DLR in 2002, and its scientific mission ended in 2017.
How to do it:
The study examines and analyzes satellite images with special precision. This research in-cludes the following stages:
1. Benefit from the advanced Google Earth Platform and JavaScript programming language for satellite image processing. Google Earth Engine, as a powerful and free tool, provides re-searchers with a wide range of possibilities.
2. Selection and processing of satellite images related to the study area (Hamedan plain) in a specific time period (2003 to 2016), and applying appropriate spatial and temporal filters for the desired area.
3. Analysis of gravitational images of Grace satellites processed by different centers. Each center processes raw data with its own algorithms, but due to differences in methods, the re-sulting values also vary. Therefore, the use of multiple average values and algorithms increases the accuracy of the results.
4. Improving the quality of results by resampling processed data at high spatial resolution (e.g. 300 meters).
Drought monitoring:
In order to conduct the present study, the Google Earth Engine system and the JavaScript programming language have been used. A web-based system that is widely used to process free satellite images. Google Earth Engine enables users to perform their calculations on large amounts of data without the need for powerful systems. Google Earth Engine was first launched by Google in December 2010 to make it possible to monitor, explore, and measure global change. In this system, there is a large database of different information and images of the world that can be easily recalled and analyzed. It also provides the possibility of quickly viewing the data with the ability to zoom in, change the location anywhere on the planet, and use time series data to check the changes over time. After recalling the Modis product and applying spatial and temporal filters in the first place, in the second place, the cloud mask from the collection of images was taken. In the third place, after selecting the NDVI band, the NDVI average image was created for all months of the year.
کلیدواژه‌ها [English]
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