An evaluation of the Standardized Precipitation Index, the China-Z Index and the statistical Z-Score

Citation
H. Wu et al., An evaluation of the Standardized Precipitation Index, the China-Z Index and the statistical Z-Score, INT J CLIM, 21(6), 2001, pp. 745-758
Citations number
20
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Earth Sciences
Journal title
INTERNATIONAL JOURNAL OF CLIMATOLOGY
ISSN journal
0899-8418 → ACNP
Volume
21
Issue
6
Year of publication
2001
Pages
745 - 758
Database
ISI
SICI code
0899-8418(200105)21:6<745:AEOTSP>2.0.ZU;2-D
Abstract
The Standardized Precipitation Index (SPI) was developed to detect drought and wet periods at different time scales, an important characteristic that is not accomplished with typical drought indices. More and more users emplo y the SPI to monitor droughts. Although calculation of the SPI is easier th an other drought indices, such as the Palmer Drought Index, it is still rel atively complex. In China, an index called the China-Z Index (CZI) has been used since 1995 by the National Climate Centre of China to monitor moistur e conditions across the country. The calculation of this index is easier th an the SPI. A third index, the statistical Z-Score, can also be used to mon itor droughts. This paper evaluates the SPI, CZI and Z-Score on 1-, 3-, 6-, 9- and 12-month time scales using monthly precipitation totals for four lo cations in China from January 1951 to December 1998 representing humid and arid climates, and cases of drought and flood. Advantages and disadvantages for the application of each index are compared. Study results indicate tha t the CZI and Z-Score can provide results similar to the SPI for all time s cales, and that the calculations of the CZI and Z-Score are relatively easy compared with the SPI, possibly offering better tools to monitor moisture conditions. Copyright: (C) 2001 Royal Meteorological Society.