Ultra-wideband radars for remote sensing of snow and ice

Abstract

We developed two ultra-wideband microwave radars for measuring the thickness of snow over sea ice, mapping near-surface internal layers in polar firn, and measuring the ice-surface elevation with fine resolution. One of these radars operates over the frequency range of 2-8 GHz and is referred to as the “snow radar”. The other operates over the frequency range of 12-18 GHz and is called the “Ku-band radar” or “Ku-band altimeter”. Both radars use a Frequency-Modulated Continuous Wave (FM-CW) transmit signal with about 150 mW of power. The radars have been operated on NASA long-range P-3 and DC-8 aircraft to collect data over snow-covered sea ice in the Arctic and Antarctic, as well as over the ice sheets in Greenland and Antarctica. The results from recent data show that we can determine the thickness of snow from about 20 cm to 200 cm over sea ice and can map near surface internal layers to a depth of about 50 m in the dry snow zone with the snow radar. We are currently developing a radar that operates over the frequency range of 2-18 GHz and an antenna array to perform multi-polarized measurements. In this paper we will provide a brief overview of the current radars and present results from data collected with these radars over sea ice and the ice sheets. We will also discuss the design of the radar being developed and our plans to collect data over the ice sheets and over snow on ice and land.