Abstract:
Considering the importance of climatic variability on availability of water, irrigation
demand, crop yield and other areas of life, an assessment of change detection and trend on
monthly, seasonal and annual historical series of different climatic variables of Raipur, a capital
city of newly created Chhattisgarh state of India, have been carried out. The change detection
analysis has been conceded using Pettitt’s test, von Neumann ratio test, Buishand’s range test
and standard normal homogeneity (SNH) test, while non-parametric tests including linear
regression, Mann-Kendall and Spearman rho tests have been applied for trend analysis. The
annual series of minimum temperature, wind speed, sunshine hour showed significant change
points, while evaporation indicated a doubtful case and maximum temperature confirmed the
homogeneity at 95 % confidence level. The change point analysis results of meteorological
variables indicated different change points from year 1990 to 2000, with maximum change
points in and around 1995. This was due to the industrialization and urbanization in this period
as this city was selected as capital of Chhattisgarh state. Based on the results of change point
analysis and development scenarios in and around Raipur city, trend analysis was applied for
three different time periods namely: P-1 from 1971 to 1995, P-2 from 1986 to 2012, and P-3
the whole series from 1971 to 2012. The significant rising trend in the summer and rainy
months in case of minimum temperature, and the winter months in case of maximum
temperature during the periods P-2 and P-3 may affect water availability and water demands
in the region. The relative humidity showed a significant rising trend in few summer and rainy
months series of all three periods under investigation, while sunshine hours and evaporation
indicated random distribution prior to 1995 (P-1), but a significant falling trend in few winter
months and annual series during period P-3. Although the annual minimum, maximum
temperatures and relative humidity showed a rising trend, the falling trend of pan evaporation may be due to strong declining trends in wind speed and falling trend in sunshine hour series
on a long term basis.
