Three Years of Tracking Temperature Variations from Rooftop down to a Deep Hole

Abstract:

The Earth’s climate system is a dynamic system incorporating interactions among its various components. A good understanding of temperature changes across the land-air boundary is of great importance to our understanding of the transportation and storage of the earth system energy and the interaction between land thermal environment and boundary layer development. It is also critical to the approach to climate reconstruction based on borehole temperatures. However, there are very few reports on long-term simultaneous observation of temperature changes across air, ground surface, soil, and rock. A unique observatory, the Land-Air Thermal Environmental Observatory of the Xi’an Jiaotong University (LATEOX) in central China, has been constructed to fill this observational data gap. From top down, it consists of two rooftop meteorological masts 25 m and 50 m above ground surface respectively, a standard ground based meteorological station, four 5-m multi-layer soil temperature/moisture sensor arrays, and more specially, a 500-m deep observation borehole. Since its commencement in June 2012, the observatory has been measuring air temperature, soil temperature, rock temperature, air humidity, air pressure, precipitation, radiation, wind speed and direction, daylight duration, net radiation, soil moisture, carbon dioxide concentration, and atmospheric electricity at a 6-second data sampling rate in a typical university campus environment. The temperature of the 500m borehole is logged on a two-week basis. Preliminary analysis of the LATEOX data shows a clear signal of urban heat island effect and seasonal variabilities in the soil thermal diffusivity and energy flux.