Journal of Spatial Analysis

Analyzing and Monitoring of Light Pollution in Iran Using Night Light Satellite Data (1997 to 2013(
 
Introduction
Light pollution generally refers to an unplanned increase in artificial lighting and the consequent change in light levels is not guided (Lu, 2002). Light pollution is called standard pollution at an inappropriate time or place and is said to be annoying and polluting the environment and the night sky.Studies show that excessive exposure to artificial light, especially in the dark hours of the night, can be considered as light pollution and adversely affect the environment and humans. Studies show that excessive exposure to artificial light, especially in the dark hours of the night, can be considered as light pollution and adversely affect the environment and humans. The exponential growth of population and the rapid rate of urbanization and industrialization in Iran has significantly increased the amount of artificial light at night and increased the amount of light pollution. There are various tools for assessing night light variations, including operational linear satellite scanning data for the Meteorological Defense Satellite Program (DMSP / OLS). This data not only helps in assessing the severity of light pollution but can also be used as a tool for risk management and high-risk zoning and susceptibility of this pollution. This study attempts to analyze the spatio-temporal pattern of light pollution in Iran.
Material and method
This study was conducted at national and provincial level. DMSP / OLS night light images were used as data for this study. The data were downloaded from the National Geophysical Data Center (NGDC) Office of the National Oceanic and Atmospheric Administration (NOAA). The brightness in these images reflects the night light in residential areas of DMSP / OLS night optical illumination from six satellites (F10, F12, F13, F14, F15 and F16) and the spatial resolution of these images is 850 meters. The calibrated digital data of the DMSP / OLS satellite are digital numbers (DN) of each pixel between zero and 63 and were therefore classified into 6 classes in order to better analyze the images was used. Classes with digital numbers (DN) less than 1 are as areas without luminosity, 1/12/4 with very low luminance, 12/24/4/8/8 with low luminosity, 24/37/2/2 with Moderate luminosity, 37 / 49-2 / 37 high brightness and 49-6 / 63 high brightness areas. The rate of change of digital number (DN) at the national and provincial levels, as well as the percentage and area of ​​each class in each time period, and the rate of change in each class over the period 1991 to 2001, 2001 to 2004, 2004 to 2006, 2006 to 2011, 2011 to 2013. In order to investigate the effect of human factors on night light changes, the relationship between night light and relative population density at country and provincial level and its variation over time periods were studied and statistical relationship between them was calculated.
Discussion and Results
The three provinces that occupy most of the area with the most glare in the provinces are: Tehran with 2621 square kilometers, Khuzestan with 2214 square kilometers (Figure E2), 3- Isfahan with 1891 sq. Km. In addition, the lowest luminosity area belongs to the three North Khorasan provinces (95 km2), South Khorasan (118 km2) and Ardabil province (127 km2). Have earned their own. mong the provinces of the country, DMSP / OLS Satellite and Satellite Provinces in 2013 are the most glare-free region of the country, covering an area of ​​about 168002 km, followed by Kerman provinces with 161800 km and Yazd with 121491 sq km is next in rank. The highest relative density of the country was observed in Tehran provinces (654 people / km2), Alborz (270 people / km2), respectively.
This high relative density of population in these two provinces has increased the amount of artificial light produced so that Tehran province accounts for the highest percentage of night light area with very high brightness (8.8%) in 1996 and a total of 0.5%. 46% of the province is in the range of light with very low, low, medium, high and very high brightness, and the rest of the province lacks brightness at night, which accounts for the least percentage of night light in the country. Is. Alborz province has the second highest relative density of population in the year 1996 and at the same time after Tehran province has the highest brightness of light with 5/16.
Conclusion
The results of this study show that the amount of night light in the country has been steadily increasing from 1996 to 2013, and the percentage of the area with very low brightness has increased by 25.8%, for the low brightness area (111.8%). , Increased in the region with moderate luminosity 142.5%, in high luminosity region (140.2%), and in high luminosity region 156.8%, which could be a warning for the spread of light pollution in the country.. In 2013, the two provinces of Tehran, Alborz and Tehran provinces had the highest amount of artificial light in terms of area and percentage of the area with high brightness at night, and Khuzestan, Bushehr, Fars and Isfahan provinces. There are other provinces that rank next.
 
Keyword: Artificial Night Light, DMSP/O Satellite, Light Pollution, Iran