Comparison of Gridded Precipitation Time Series Data in APHRODITE and Asfazari Databases within Iran’s Territory

Esmail Nasrabadi,Seyyed Abolfazl Masoodian,Hossein Asakereh

doi:10.4236/acs.2013.32025

Abstract

The V1003R1 version of the monthly, seasonal and annual precipitation time series of the Middle East APHRODITE database and Asfazari database within Iranian territory in the time interval 1961 and 2004 were compared with each other. The monthly, seasonal and annual time series of the both databases in most cases show a random behavior and the time series follow a similar pattern with a significant autocorrelation of both databases. Studying cross-correlation between the time series of the two bases indicate that the zero lag significance in the monthly, seasonal and annual time series statistically confirm the coincidence of the peak and fall in the time series of both bases. Wilcoxon Test with 95% confidence confirms significance of the mean difference of the two series. However, there is not enough evidence to confirm the null hypothesis suggesting lack of difference between means of the two series. The statistical-objective analysis of the two bases’ time series indicates that although the series follow a similar course, the estimated precipitation quantity in monthly, seasonal and annual time series of APHRODITE base, except in several monthly time series and in trivial quantities, has been less than the estimated precipitation of Asfazari bases, but the amount of the difference was not constant and did not follow a regular pattern, although this difference has been narrowed in recent years.

Highlights

Precipitation data at international, regional and national scale are prepared by different research and commercial institutes and scientists
Studying cross-correlation between the time series of the two bases indicate that the zero lag significance in the monthly, seasonal and annual time series statistically confirm the coincidence of the peak and fall in the time series of both bases
The statistical-objective analysis of the two bases’ time series indicates that the series follow a similar course, the estimated precipitation quantity in monthly, seasonal and annual time series of APHRODITE base, except in several monthly time series and in trivial quantities, has been less than the estimated precipitation of Asfazari bases, but the amount of the difference was not constant and did not follow a regular pattern, this difference has been narrowed in recent years

Summary

Introduction

Precipitation data at international, regional and national scale are prepared by different research and commercial institutes and scientists. Precipitation’s spatial behavior in the Baden-Wuerttemberg region of Germany from 1997 through to 2004 using Doppler Radar Combined Images data in networks of 4 × 4 km and the data of 101 rain gauging stations using cross-correlation were compared. This approach shows that cross correlation varies depending on the chosen quantile. The correlation is very similar in rain gauge and radar data [2] As another example, the analysis of autocorrelation and cross-correlation between time series of air temperature, soil temperature, rainfall, relative humidity, and Diaprepes root weevil across a period of 30 month in Florida suggested an association of temperature and precipitation with time distribution of Diaprepes root weevil [3].

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Conclusion