PROGRESS IN GEOGRAPHY ›› 2008, Vol. 27 ›› Issue (4): 110-116.doi: 10.11820/dlkxjz.2008.04.016

• Original Articles • Previous Articles     Next Articles

Tempor al Var iations in Par ameter s of Gr avity Model: an Analysis on China's Inter - city Railway Passenger Flows

DAI Teqi1,2, LIU Yi1   

  1. 1. Institute of Geographic Science and Natural Resource Research, CAS, Beijing 100101, China;
    2. Graduate School, the Chinese Academy of Sciences, Beijing 100039, China
  • Received:2008-02-01 Revised:2008-04-01 Online:2008-07-25 Published:2008-07-25


Gravity models are the basic tools which are widely applied in the research of spatial interaction (SI). It is well known that SI decreases as the distance increases or the mass decreases. The measurement and explanation on parameters are hot topics but the temporal variations of them are not discussed so frequently. This paper deals with how and why the parameters change with time by using the unrestrained gravity model and the data set consists of China's railway passenger flows between about 200 cities. We find that scale parameters show an increasing trend with a little fluctuation and distance - decay parameters grow over time instead of monotonic decrease over time. And an empirical and theoretical explanation will be given to why the general assumptions of monotonic increasing scale parameters and monotonic decreasing distance - decay parameters are not obeyed.

Key words: distance- decay parameters, gravity model, scale parameters, temporal variations