AYBE- İklim ve Deniz Bilimleri Lisansüstü Programı - Doktora
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Yazar "Ghale, Yusuf Alizade Govarchin" ile AYBE- İklim ve Deniz Bilimleri Lisansüstü Programı - Doktora'a göz atma
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ÖgeUrmia lake desiccation as a new source of dust in themiddle east: Investigation of the anthropogenic impactsand climatic factors on drying up of urmia lake(Eurasia Institute of Earth Sciences, 2020-01-30) Ghale, Yusuf Alizade Govarchin ; Ünal, Alper ; 601142005 ; Climate and Marine Sciences ; İklim ve Deniz Bilimleri Anabilim DalıIn recent decades, some of the world's water bodies, such as the Aral Sea, Dead Sea, Lake Poopó, Lake Eyre and Lake Mead have been shrinking mostly due to human-induced activities and climate change. Desertification and salinization caused by the drying up of these lakes have led to soil degradation and dust storms, which have negative impacts on people's health and the environment as well. Urmia Lake, the largest inland lake of Iran has lost most of its water surface area over the past 2 decades mainly due to agricultural development and decreasing precipitation in the basin. As a result, more than 90% of the water surface area of this unique hypersaline lake has changed to saline body. Preparing a comprehensive rehabilitation plan for Urmia Lake is essential. A critical step for preparing such a plan is quantifying the water budget (balance) changes and real factors that cause the decline in the water level of Urmia Lake. On the other hand, understanding the dynamics of Land Use Land Cover (LULC) is one of the main issues to have a sustainable water management system in Urmia Lake Basin. Remote sensing technology and Geographical Information Systems (GISs) can help to determine the systematic and random changes over time to provide an environmental management system, prevent environmental degradation and act correctly and effectively. Due to the lack of detailed studies in these fields, the main objectives of this thesis are; 1- Monitoring the long-term salinization progress, land cover changes and development of irrigated lands in Urmia Lake Basin between 1975 and 2019. This study used hydroclimatic data, Landsat satellite images, and image processing techniques in conjunction with field survey data to analyze the interaction between agricultural lands and Urmia Lake ecosystem. Understanding the interaction between agricultural lands and Urmia Lake ecosystem helps to determine a lake recovery plan and a sustainable water resources management system in the northwestern Iran. In this section, Maximum Likelihood Classification (MLC) method was used to monitor Land Use Land Cover (LULC) changes and agricultural development in the basin. Vegetation changes and salinization progress were investigated using Normalized Difference Vegetation Index (NDVI) and soil Salinity Index (SI), respectively. 2- Determining the underlying factors for the drying up of Urmia Lake based on drought analysis and water budget equation. In this section, a multidisciplinary and comprehensive investigation were performed on Urmia Lake to propose a new hypothesis and method to separate the effects of climate change from anthropogenic factors in the shrinkage of Urmia Lake. Standardized Precipitation Index (SPI) derived from precipitation data of meteorological stations around Urmia Lake was analyzed to identify drought condition and its effects on the Urmia Lake desiccation. 3-Investigating the impacts of Urmia Lake desiccation on the local and regional aerosol pollution in the northwestern Iran and eastern Turkey using hourly ground observation PM10 data of 2 air quality stations located in the northwestern Iran (Urmia and Tabriz) and 5 stations located in the eastern Turkey (Hakkari, Van, Agri, Igdir and Kars), meteorological data of MERRA-2, Aerosol Optical Depth (AOD) data of Terra MODIS and Aqua MODIS and Ultraviolet Aerosol Index data of Ozone Monitoring Instrument (OMI) observed between 2010 and 2017. Contrary to studies that emphasize the role of climatic factors in the shrinkage of Urmia Lake, the hypothesis of this study states that the role of anthropogenic factors in the dryness of the lake is more important than climatic factors and lake bed can be known as a new source of dust in the Middle East. This study shows how urbanization, land use change and agricultural expansion over time have led to disruption of water cycle and gradual drying up of Urmia Lake. Misguided water and agricultural policies along with climate change have had negative impacts on Urmia Lake environment leading up to salinization, desertification and air pollution as well. The results of this study indicated that the water surface area of Urmia Lake decreased from 5982 km2 in 1995 to 4058 km2 in 2006. In other words, slightly over one third of the lake dried up during the period of 1995 until 2006. Nearly 90% of the total area dried up by 2014. The water surface area has increased after 2014 due to increase in precipitation and releasing more water from dams to the lake. The input runoff has decreased extremely especially in the years between 1998 and 2002. In general, moderate drought condition has occurred in the basin between 2003 and 2010, but 2003, 2004 and 2007 could be considered as years with normal condition. As a result of the dramatic decrease in input runoff into the lake, the area of Urmia Lake has decreased extremely. Water balance changes of Urmia Lake from 1985 to 2010 and SPI results indicated that Urmia Lake has been affected by both anthropogenic and climatic factors. However, human impacts on the lake and its basin are more excessive than climatic factors. Decreased rivers discharge into the lake could be known as the main factor in decline of the volume of Urmia Lake. Droughts have intensified and accelerated the shrinkage of Urmia Lake. In addition, with the overuse of groundwater and surface water resources and developing of agricultural lands and mismanagement of water resources, the water input into Urmia Lake has decreased significantly. Despite previous studies which assumed groundwater output from Urmia Lake is negligible, the results of this study indicated a significant output of groundwater from the lake. This factor can be one of the reasons of groundwater salinization in regions close to Urmia Lake. The final results of this study indicated that major changes in the variables, which reduced the volume of Urmia Lake, started since 1998. Anthropogenic and climate change have roughly 80% and 20% effects on Urmia Lake shrinkage in period 1998– 2010, respectively. The area of irrigated lands was estimated about 4850 km2 in 2018, which indicated a decrease by 12% comparing with its maximum area (5525 km2 in 2011) in the study period. Inverse correlation between shrinking Urmia Lake and expanding the area of salt and salt affected lands is concerning. The final results of land cover change in the basin indicated that the current conditions of Urmia Lake (2018–2019) is very similar to its conditions in 2013 and lake recovery is possible. Based on the results of this study, PM10 concentration in Urmia and Igdir stations were higher than other stations. At both stations, the annual mean PM10 concentration significantly increased after 2013, while, no significant changes were observed at other stations. The maximum annual mean concentrations of PM10 at Urmia (104.247 μg/m3) and Igdir (129.757 μg/m3) were observed in 2015 and 2017, respectively. The analysis of monthly and seasonal PM10 variations indicated that winter accounts for high level PM10 concentration in the northwestern Iran and eastern Turkey. The results indicated that AOD values in the northwestern Iran and eastern Turkey were strongly correlated. In total, 129 days with mean AOD values more than 1 were observed in box covering all parts of the lake between 2010 and 2017, which indicated the severity of aerosol pollution and dust emission from the dried bottom of the lake. The daily mean AOD in the west part of the lake and east part of the lake was 0.348 and 0.508, respectively. The extensive of salinization and desertification in the eastern part of the lake and prevailing wind direction from west to east can be the reasons of high level AODs in this part. Restoration of Urmia Lake is the only solution of the environmental problem in the northwestern Iran. Compromise with climate change and providing a sustainable water resources management system under a changing climate can be the most effective ways to revive the lake. Teaching the local people to understand the importance of water, training water saving skills, improvement of agricultural methods, agricultural water management and cultivation of low-water-use crops can play positive role in the lake rehabilitation. People should be discouraged from growing crops that consume a lot of water and they should be courage to grow crops which modify the unfair effects of soil texture. It seems better to release more water from dams to the lake and stop the establishment of new dams and wells in the basin.