Buishand Range Test Research Articles

HOMOGENEITY ANALYSIS OF RAINFALL IN KELANTAN, MALAYSIA

Good quality of rainfall data is required for the hydrological studies, water resources planning and sustainable environmental management. Consequently, the assessment of the homogeneity of rainfall data at different region is becoming increasing popular in the past few decades. In this study, the homogeneity analysis of rainfall data was carried out in Kelantan River Basin, Malaysia. The methods, namely standard normal homogeneity test (SHNT), Buishand range test, Pettitt test and von Neumann ratio test were applied to the monthly, yearly and seasonal data. The historical rainfall data from 10 rainfall stations covering the study period from 28 to 60 years were selected. The four tests were applied to 120 monthly series, 10 yearly series and 40 seasonal series. ‘Useful’, ‘doubtful’ and ‘suspect’ were used to classify the results of the four tests. The results showed that 94.17% of the monthly rainfall series, 70% of yearly rainfall series and 97.5% of seasonal rainfall series are labelled ‘useful’. There is 5% of monthly rainfall series, 30% of yearly rainfall series and 1% of seasonal rainfall series are classified as ‘doubtful’. Meanwhile, there is only 0.83% of monthly rainfall series and no yearly rainfall series and seasonal rainfall series detected in the class ‘suspect’. Overall, the percentage of inhomogeneity detected in the monthly, yearly and seasonal rainfall data series of Kelantan River Basin is very small, thus most of the data is suitable to be used for further hydrological and variability analysis.

Statistical analysis of temperature regime change on the example of Sokobanja basin in eastern Serbia

The changes and oscillations in air temperature during the second half of the 20th and in the early 21st century, have become one of the major concerns of almost all scientific disciplines. Such changes are noticeable both at the local and global level. The objective of this paper is to point out that the changes of this climate element can also be detected at the local level. The research underlying this paper is, in terms of territory, limited to the Sokobanja basin in Eastern Serbia. The analysis relies on the data on air temperature for the period 1946-2012 taken from the Meteorological weather station located in Sokobanja. The obtained data were processed in line with the recommendations of the World Meteorological Organization (WMO). The evidenced statistically significant changes in air temperature were examined using the following statistical tests: Pettit test, Standard Normal Homogeneity test, Buishand range test, and von Neumann test.

Homogeneity Test on Daily Rainfall Series for Malaysia

In this study, homogeneity tests have been applied at 76 meteorological stations in Peninsular Malaysia from 1975 to 2010 and also 7 stations in Sabah and Sarawak. A twostep approach is followed. First, four homogeneity tests, namely standard normal homogeneity test (SNHT), Buishand range test, Pettittt test, and von Neumann ratio tests are applied to evaluate the daily series. In order to evaluate the performance of the methods used, two testing variables i.e. annual rainfall amount and annual number of wet days with threshold 1mm are selected. After that, the results of the different tests are classified into three classes: ‘useful’, ‘doubtful’ and ‘suspect’. Each test is evaluated separately and inhomogeneous stations are determined. By considering both of the testing variables, the result shows that 22% of the station series in Peninsular Malaysia are detected as inhomogeneous series and the remaining 59 stations which are equivalent to 78% are considered homogeneous. Meanwhile, for Sabah and Sarawak all stations or 100% are classified into homogenous series. Keywords: Homogeneity Tests; Standard Normal Homogeneity Test; Buishand Range Test; Pettitt Test; Von Neumann Ratio Test; Rainfall Amount Series; Wet Day Series. 2010 Mathematics Subject Classification: 62P12

Homogenization of Climate Data: Review and New Perspectives Using Geostatistics

The homogenization of climate data is of major importance because non-climatic factors make data unrepresentative of the actual climate variation, and thus the conclusions of climatic and hydrological studies are potentially biased. A great deal of effort has been made in the last two decades to develop procedures to identify and remove non-climatic inhomogeneities. This paper reviews the characteristics of several widely used procedures and discusses the potential advantages of geostatistical techniques. In a case study, the geostatistical simulation approach is applied to precipitation data from 66 monitoring stations located in the southern region of Portugal (1980–2001). The results from this procedure are then compared with those from three well established statistical tests: the Standard normal homogeneity test (SNHT) for a single break, the Buishand range test, and the Pettit test. Promising results from the case study open new research perspectives on the homogenization of climate time series.