Spatial And Temporal Variability In NDWI Water Area And Its Driving Factors In Mongolian Arctic Basin /2005-2014/

The research work was done to study Mongolian Arctic Ocean basin’s NDWI water area change temporal and spatial change of water area and climate factors affect in 2005-2014.This research work used data by MODIS-Terra satellite on arctic ocean basin during 2005-2010 with the frequency of 8 days, determining NDWI water area size, using satellite data scaling is 250 m and 500 m and determined the annual and monthly change correlation by comparing with precipitation of given year and temperature data.The following conclusions are made by research work:1. By observing Mongolian Arctic ocean basin, NDWI’s area and time change of water area in 2005-2014, there is a tendency of water area is increasing generally. Maximum water area of NDWI is in 2010, 2011 and 2013 when minimum of water area is in 2009, 2012, and 2007. There is a study that dry and less precipitation years happened in 2005-2009 by affect of climate change and precipitation is increased from 2010 and drought became less. NDWI area size during 2005-2009 is less than NDWI area size during 2010-2014. As of months, there is a principle of NDWI water area size of May was maximum and it decreased in June, minimum in July and increase started from August.2. Research shows that annual NDWI water spread change is uneven depending on the precipitation and air temperature, when major rivers basins NDWI water area spread is dramatically changed. Arctic basin is surrounded by 3 major mountain ranges and rivers fall from those mountains and pour into lakes. As of monthly spread of NDWI, the highest spread occurs in May and NDWI water area decrease from June and reaches lowest level in July and during this time NDWI meaning observed in major rivers basins like Orkhon, Tuul and Selenge is almost disappeared. The research shows that there is a tendency of NDWI again increases from August and September.3. It is observed that Arctic basin’s NDWI water area annual change is much affected by air temperature, when total precipitation of April to September and average air temperature are studied. Regardless the precipitation size, NDWI water area is less when the air temperature is high. When average air temperature is lower than other years, NDWI water area is increased. There is an attitude of NDWI water area increase depending on the climate change. It is related with the melting of permafrost and glacial of high mountains.4. Air temperature affection to the NDWI area is also clearly seen in the NDWI monthly spread. Spring or May NDWI water area is more than summer or July NDWI water area, which means winter precipitation or snow fall melted in spring and rivers are fed not only by rainfall but also snow water and water area size of lakes are increased and air temperature of spring or May is relatively lower, so that evaporation is less and there is much NDWI. Oppositely, during summer time or in July and August rivers are fed only by rivers and at the same time air temperature is higher, so the evaporation increases that causes decrease of water area. In autumn or fromSeptember, Arctic basin rivers and lakes are fed only by rain like summer, but air temperature is relatively lower and evaporation decreases and again NDWI increases.