As an international reference site for the Coordinated Energy and water cycle Observation Project (CEOP) until now, observation for semi‐arid climate and environment research has been performed at Tongyu. Since the Tongyu site is beside a small town with no major emission sources except scattered, sparse anthropogenic activities, measurements at Tongyu are expected to have “background” atmospheric properties for the whole focusing region that are determined largely by the transport of air masses from upwind.