final_program_abstracts[1]

11 IMSC Session Program
Simulation of multisite precipitation using an extended chaindependent
process
Tuesday - Parallel Session 5
Xiaogu Zheng 1 , James Renwick 2 and Anthony Clark 2
1
College of Global Change and Earth System Science, Beijing Normal University,
Beijing, China
2
National Institute of Water and Atmospheric Research, Wellington, New Zealand
The chain-dependent process is a popular stochastic model for precipitation sequence
data. In this paper, the effect of daily regional precipitation occurrence is incorporated
into the stochastic model. This model is applied to analyze the daily precipitation at a
small number of sites in the upper Waitaki catchment, New Zealand. In this case
study, the probability distributions of daily precipitation occurrence and intensity,
spatial dependences, and the relation between precipitation and atmospheric forcings
are simulated quite well. Specifically, some behaviors which are not well modeled by
existing models, such as the extremal behavior of daily precipitation intensity, the lag-
1 cross correlation of daily precipitation occurrence, spatial intermittency, and spatial
correlation of seasonal precipitation totals, are significantly improved. Moreover, a
new and simpler approach is proposed which successfully eliminates the
overdispersion, i.e. underestimation of the variance of seasonal precipitation totals.
Abstracts 145