1 State of Snow Depth Retrieval Using FMCW Radar Data: Precaution from Mountain Tsunami Kamal Chapagain* and Nanda B. Adhikari Department of Electronics and Computer Engineering, Institute of Engineering, Pulchowk Campus Tribhuvan University, Nepal *E-mail: kamal_chapagain@ioe.edu.np Abstract: Gradual increment in the temperature of Earth‟s atmosphere due to the effect of global warming is being an alarming issue today. Evidences of sea level rising and formations of glaciers over Himalayan region due to the melting of snow and ice are the direct and immediate effects of the global warming. An outbreak of Seti river near Pokhara causing a „mountain blasted tsunami‟ in Nepal in 5th May, 2012 is one of such evidences. Unusual melting of surface ice is the main reason behind it. This paper therefore considers a model study to analyze the state of ice and snow and their rate of melting using a Ku-band Frequency Modulated Continuous Wave (FMCW) radar simulation. The aim of this study is mainly to set a model that can be used to extract the state of surface ice or snow in the regions like Himalayas so that post-precaution can be taken from possible glacier outbreaks. Refractive indices of dry and wet snow and radar reflectivity factors are the main parameters taken to characterize the state of the snow depth. The model retrieves the thickness of the snow in two steps using 3 to 4 cm of range resolution of 2- 8GHz frequency. Refractive indices of wet and dry snow and the reflected signal from the medium with respect to original frequency is considered to calculate the beat frequency. Since the radar signal usually contains interference due to surface scattering, volume scattering and radar system, these parameters are also taken into account for the analysis. In first step, beat frequency is calculated from the delay time of received signal reflected back from different layers of snow. After all Fast Fourier Transform is applied to calculate the depth of those snow layers; and the results are presented and discussed accordingly. The model is then tested with satellite data collected from 1978 to 2012 over Arctic and Antarctic regions. The preliminary results of our model study reveal that these regions have experienced an increasing rate of melting of surface ice by 0.1% to 3.7% for every five years. Keywords: FMCW Radar, Beat Frequency, Fast Fourier Transform, Refractive Indices, sea ice extent 1. Introduction Snow covered on mountains as well as sea-ice is an important physical variables that impact energy, physical and chemical processes. The thickness of sea ice is the integrated result of heating and forcing from the atmosphere. Shrinking of snow covered in the polar regions leads to faster loss of ice by melting. A significant reduction in the mean thickness of the Arctic sea ice occurred during the 1990's as compared with earlier decades based on submarine mounted upward looking sonar measurements of ice draft [1], [2]. Melting of small glaciers and polar ice caps is expected to give second largest contribution to sea level rise in this century after thermal expansion of water [3]. Greenhouse gases absorb the thermal infrared radiation, emitted by the earth's surface, by the atmosphere and by clouds. Thus, the greenhouse gases trap heat within the surface-troposphere system that results in thermal expansion of water on the surface of earth and melting of polar ice sheets and lacier, which in turn leads to rise in seal level. This global warming effect is highly observed in the Himalaya region of Nepal where, geologically young and tectonically active Himalaya Range is creating elevated mountains and deep river valleys which is characterized by dynamical in physical process [4]. This global warming effect can be observed at high altitude where snow and ice covered Himalaya is converting continuously into bedrocks. The thickness of ice become low due to the increase in melting rate of ice and results weakness on the junction of ice bed and bedrock so that landslides of ice and bedrock in terms