Assessment of Vegetation Temperature Status (VTCI) for monitoring drought in the watershed of Lake Urmia by using MODIS satellite imagery
Continuous decline in Lake Urmia water levels In recent years, the decline of rainfall and river flows and constant droughts has become the main concern of the people and the people. To study climate change and increase of temperature in the catchment area of Lake Urmia, two factors for measuring...
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Kharazmi University
2018-03-01
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| Series: | تحقیقات کاربردی علوم جغرافیایی |
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| Online Access: | http://jgs.khu.ac.ir/article-1-2916-en.pdf |
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| author | Adel Nabi Zadeh Balkhanloo zahra hejazizadeh Parviz zeaiean Firoozabadi |
| author_facet | Adel Nabi Zadeh Balkhanloo zahra hejazizadeh Parviz zeaiean Firoozabadi |
| author_sort | Adel Nabi Zadeh Balkhanloo |
| collection | DOAJ |
| description | Continuous decline in Lake Urmia water levels In recent years, the decline of rainfall and river flows and constant droughts has become the main concern of the people and the people. To study climate change and increase of temperature in the catchment area of Lake Urmia, two factors for measuring the temperature and properties of satellite images were used which indicate the importance of land surface temperature changes (LST) and normalized vegetation differences (NDVI). This study was carried out using the satellite data of the periodic watershed (2008-2008) to investigate the spatial relationship between NDVI-Ts and NDVI-ΔT to investigate the actual agricultural drought occurrence. The goal is to extract the VTCI (vegetation temperature index) index, which is capable of identifying drought stress at regional scale. The results showed that the slope is negative for the warm edge, where it is positive for the cold edge. The gradient gradient shows that the maximum temperature is reduced when the NDVI value increases for any interval. The slope on the cold edge indicates that the minimum temperature rises when the NDVI value rises. Overall, at the warm and cold edges, it has been observed that the drought trend over 2009-2008 is higher than in 2010. In the days of Julius Day 257, the slope of the cold edge from 2008 to 2010 is decreasing. But at the hot edge, intercept pixels for 2008 is more than 323 degrees Kelvin, where in 2009-2010 it is less than 323 degrees Kelvin. In general, the correlation coefficient (R2) is different in the TS-NDVI spacing between (0.90-0.99). The present study showed that with the integration of satellite satellite data with meteorological data, the VTCI threshold for drought stress varies from year to year depending on the data conditions. |
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| institution | Kabale University |
| issn | 2228-7736 2588-5138 |
| language | fas |
| publishDate | 2018-03-01 |
| publisher | Kharazmi University |
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| series | تحقیقات کاربردی علوم جغرافیایی |
| spelling | doaj-art-6abaf214f05a441e9a7c688c8eec436e2025-01-31T17:24:38ZfasKharazmi Universityتحقیقات کاربردی علوم جغرافیایی2228-77362588-51382018-03-011850129139Assessment of Vegetation Temperature Status (VTCI) for monitoring drought in the watershed of Lake Urmia by using MODIS satellite imageryAdel Nabi Zadeh Balkhanloo0zahra hejazizadeh1Parviz zeaiean Firoozabadi2 Ph.D. student of Agricultural Climatology, Faculty of Geographic Sciences, Kharazmi University, Tehran, Iran . Professor and member of faculty of hydrology, Faculty of Geographic Sciences, Kharazmi University, Tehran, Iran. Associate Professor and Faculty Member of Geoinformatics Department, Faculty of Geographic Sciences, Kharazmi University, Iran. Continuous decline in Lake Urmia water levels In recent years, the decline of rainfall and river flows and constant droughts has become the main concern of the people and the people. To study climate change and increase of temperature in the catchment area of Lake Urmia, two factors for measuring the temperature and properties of satellite images were used which indicate the importance of land surface temperature changes (LST) and normalized vegetation differences (NDVI). This study was carried out using the satellite data of the periodic watershed (2008-2008) to investigate the spatial relationship between NDVI-Ts and NDVI-ΔT to investigate the actual agricultural drought occurrence. The goal is to extract the VTCI (vegetation temperature index) index, which is capable of identifying drought stress at regional scale. The results showed that the slope is negative for the warm edge, where it is positive for the cold edge. The gradient gradient shows that the maximum temperature is reduced when the NDVI value increases for any interval. The slope on the cold edge indicates that the minimum temperature rises when the NDVI value rises. Overall, at the warm and cold edges, it has been observed that the drought trend over 2009-2008 is higher than in 2010. In the days of Julius Day 257, the slope of the cold edge from 2008 to 2010 is decreasing. But at the hot edge, intercept pixels for 2008 is more than 323 degrees Kelvin, where in 2009-2010 it is less than 323 degrees Kelvin. In general, the correlation coefficient (R2) is different in the TS-NDVI spacing between (0.90-0.99). The present study showed that with the integration of satellite satellite data with meteorological data, the VTCI threshold for drought stress varies from year to year depending on the data conditions.http://jgs.khu.ac.ir/article-1-2916-en.pdfsimineh rooddroughtndvi indexlst indexvtci index |
| spellingShingle | Adel Nabi Zadeh Balkhanloo zahra hejazizadeh Parviz zeaiean Firoozabadi Assessment of Vegetation Temperature Status (VTCI) for monitoring drought in the watershed of Lake Urmia by using MODIS satellite imagery تحقیقات کاربردی علوم جغرافیایی simineh rood drought ndvi index lst index vtci index |
| title | Assessment of Vegetation Temperature Status (VTCI) for monitoring drought in the watershed of Lake Urmia by using MODIS satellite imagery |
| title_full | Assessment of Vegetation Temperature Status (VTCI) for monitoring drought in the watershed of Lake Urmia by using MODIS satellite imagery |
| title_fullStr | Assessment of Vegetation Temperature Status (VTCI) for monitoring drought in the watershed of Lake Urmia by using MODIS satellite imagery |
| title_full_unstemmed | Assessment of Vegetation Temperature Status (VTCI) for monitoring drought in the watershed of Lake Urmia by using MODIS satellite imagery |
| title_short | Assessment of Vegetation Temperature Status (VTCI) for monitoring drought in the watershed of Lake Urmia by using MODIS satellite imagery |
| title_sort | assessment of vegetation temperature status vtci for monitoring drought in the watershed of lake urmia by using modis satellite imagery |
| topic | simineh rood drought ndvi index lst index vtci index |
| url | http://jgs.khu.ac.ir/article-1-2916-en.pdf |
| work_keys_str_mv | AT adelnabizadehbalkhanloo assessmentofvegetationtemperaturestatusvtciformonitoringdroughtinthewatershedoflakeurmiabyusingmodissatelliteimagery AT zahrahejazizadeh assessmentofvegetationtemperaturestatusvtciformonitoringdroughtinthewatershedoflakeurmiabyusingmodissatelliteimagery AT parvizzeaieanfiroozabadi assessmentofvegetationtemperaturestatusvtciformonitoringdroughtinthewatershedoflakeurmiabyusingmodissatelliteimagery |