Pan evaporative changes in transboundary Godavari River basin, India

Abstract

Pan evaporative changes are one of the key components of water resources management of a basin under changing climate and anthropogenic-induced warming. This study was undertaken for trans-boundary Godavari River (India) to identify trends through the Mann-Kendall (MK) test after removing the effect of significant lag-1 serial correlation from the climatic time-series by pre-whitening in pan evaporation (Epan) and in the probable causative meteorological parameters responsible for evaporative climatic changes in a large basin. Further, the Pettitt's test was applied on Epan time series for estimating the change point year of Epan to find out the effective year when the change in pattern started reflecting in the time-series. At seasonal (monthly) time scales, statistically significant decreasing trends in Epan were witnessed in pre-monsoon season (in the months of March, April and May) over all the seven sites of the Godavari basin. Four sites witnessed statistically significant increasing trends in Tmin (Tmax) in July (December) and in monsoon (post monsoon) season in the basin. Statistically significant decreasing (increasing) trends in wind speed (relative humidity) in pre-monsoon and in month of March at these seven sites support the observed decline in the evaporative demand in the basin leading to possible enhancement in the total yield of the basin. Results of stepwise regression analysis showed that wind speed followed by relative humidity was found to be two main causative parameters of the observed decline in the Epan under the warmer environments in the basin. Pettitt's test shows year 1991-1992 to be the probable year of change in the Epan in the Godavari river basin.

Investigating river water quality assessment through non‐parametric analysis: A case study of the Godavari River in India

“…(2014) and subsequently by D. Jhajharia et al. (2021). Similarly, Mann–Kendall's non‐parametric test was utilized to identify the trends in the mean annual sunspot series while observing the patterns in autocorrelation function and Euclidean distance measures (Chattopadhyay et al., 2011b).…”

“…Several researchers have used non-parametric tests instead of parametric tests due to these rationalities (Ahmadi et al, 2018;Jhajharia et al, 2012;Srilakshmi et al, 2022;Zamani et al, 2017). A study to detect the temperature and pan evaporation trends in Godavari River involved the application of non-parametric Mann-Kendall's test, as outlined in studies by D. Jhajharia et al (2014) and subsequently by D. Jhajharia et al (2021). Similarly, Mann-Kendall's non-parametric test was utilized to identify the trends in the mean annual sunspot series while observing the patterns in autocorrela-tion function and Euclidean distance measures (Chattopadhyay et al, 2011b).…”

Studying the Changes in the Hydro‐Meteorological Components of Water Budget in Lake Urmia

“…On the other hand, the limitations of the study are. Components related to the energy budget (e.g., wind, temperature, and sunshine) are neglected due to the application of the water budget. But their effects can be incorporated using more sophisticated approaches (e.g., Jhajharia et al., 2009, 2015; 2021; Stone, 2015) Anthropogenic changes are assumed to be lumped into the time series of groundwater and streamflow. Climate change scenarios are not incorporated directly into the models but assumed to have direct or indirect effect on the time series used in the study. …”

“…Components related to the energy budget (e.g., wind, temperature, and sunshine) are neglected due to the application of the water budget. But their effects can be incorporated using more sophisticated approaches (e.g., Jhajharia et al., 2009, 2015; 2021; Stone, 2015)…”

Long‐term (2001–2020) trend analysis of temperature and rainfall and drought characteristics by in situ measurements at a tropical semi‐arid station from southern peninsular India

“…Numerous researches have investigated the long-term trends in rainfall and temperature in the Indian subcontinent (Mooley and Parthasarathy, 1983;Parthasarathy and Pant, 1985;Kumar et al, 2010). Jhajharia et al (2021) mentioned several studies carried out over different parts of India to analyse trends in various climatic parameters. The spatial and temporal homogeneity of trends is an essential aspect in trend analysis of any hydrometeorological parameter in any region (Jhajharia et al, 2014).…”