Long Term Homogeneity, Trend and Change-Point Analysis of Rainfall in the Arid District of Ananthapuramu, Andhra Pradesh State, India

Abstract

Daily rainfall data was collected for the arid district of Ananthapuramu, Andhra Pradesh state, India from 1981 to 2016 at the sub-district level and aggregated to monthly, annual and seasonal rainfall totals and the number of rainy days. The objective of this study is to evaluate the homogeneity, trend, and trend change points in the rainfall data. After quality checks and homogeneity analysis, a total of 27 rain gauge locations were considered for trend analysis. A serial correlation test was applied to all the time series to identify serially independent series. Non-Parametric Mann-Kendall test and Spearman’s rank correlation tests were applied to serially independent series. The magnitude of the trend was calculated using Sen’s slope method. For the data influenced by serial correlation, various modified versions of Mann-Kendall tests (Pre-Whitening, Trend Free Pre-Whitening, Bias Corrected Pre-Whitening and two variants of Variance Correction Approaches) were applied. A significant increasing summer rainfall trend is observed in 6 out of 27 stations. Significant decreasing trends are observed at two stations in the south-west monsoon season and at two stations in the north-east monsoon season. To identify the trend change-points in the time series, distribution-free Cumulative SUM test and sequential Mann-Kendall tests were applied. Two open-source library packages were developed in R language namely, ‘modifiedmk’ and ‘trendchange’ to implement the statistical tests mentioned in this paper. The study will benefit water resource management, drought mitigation, socio-economic development and sustainable agricultural planning in the region.

Multidecadal Trend Analysis of Armenian Mountainous Grassland and Its Relationship to Climate Change Using Multisensor NDVI Time-Series

“…It is interesting to note that the Modified Mann-Kendall methods suggested by Yue and Wang [152] showed a significant trend in most of the cases as compared with other methods. The same situation was observed also in other investigations [170].…”

“…The results of the MK and MKK tests applied to the NDVI data series at a confidence interval of 90% are shown in Table 9. In an experiment reported in the scientific literature, the trend is considered significant only if at least three of the five tests suggest a significant trend [170]. In the same time, Sen's slope method was applied to discover trends in time series.…”

Trend and change point detection of seasonal rainfall for effective crop planning over southern transition zone of Karnataka, India

“…Control charts are superior at identifying isolated abnormal points and detecting major changes rapidly, while change-point analysis can detect subtle changes that control charts frequently miss. These two approaches may be used in conjunction for the analysis (Patakamuri et al, 2020). A change-point analysis has the benefit of controlling change-wise error rate.…”

Agroclimatic Zone-Based Analysis of Long-Term Rainfall Trends and Variability in the Wabi Shebele River Basin, Ethiopia.

“…Numerous studies were conducted on climate variability and trends analysis in Ethiopia and abroad [13,16,17,[31][32][33]36,[39][40][41][42][43]. Some of the studies include, Abay basin [7,17,32,44,45], Awash basin [8,36,40,46,47], Omo Gibe basin [10,23,24], and Tekeze basin [21,37,48].…”