• Omvir Singh

Articles written in Journal of Earth System Science

• On rising temperature trends at Dehradun in Doon valley of Uttarakhand, India

Climate change is one of the most important issues among researchers, scientists, planners and politicians in the present times. Of all the climatic elements, temperature plays a major role in detecting climatic change brought about by urbanization and industrialization. This paper, therefore, attempts to study the temperature changes at Dehradun city by analyzing the time series data of annual maximum, minimum and mean temperature from 1967 to 2007. Data for the study has been analyzed in three parts by running linear regression and by taking anomalies for the whole period from 1967 to 2007, phase one 1967–1987 and phase two 1988–2007. The study of linear trend indicated increasing trends in annual maximum, annual minimum and annual mean temperatures. During 1967–2007 annual maximum, annual minimum and annual mean temperatures increased about 0.43°C, 0.38°C and 0.49°C, respectively. The analysis of temperature data in two phases also revealed an increase in annual maximum, annual minimum and annual mean temperature. However, temperature increase in second phase was more pronounced in relation to first phase. During second phase (1988–2007) annual maximum, annual minimum and annual mean temperatures increased about 0.42°C, 0.59°C and 0.54°C, respectively. The perceptible increase in temperature during second phase is mainly attributed to urbanization and industrialization process initiated at Dehradun particularly after becoming the state capital of newly carved out state of Uttarakhand since the year 2000. The analysis also highlight significantly the role of extreme vulnerability of rising temperatures at Dehradun and urban population will constantly be affected by the change in the temperature which controls the comfort level of the inhabitants. Also, the rising temperatures in Doon valley are not a healthy signature for crop production and water resources in the region.

• Assessing rainfall erosivity and erosivity density over a western Himalayan catchment, India

The present study aims to assess rainfall erosivity and erosivty density both in space and time over the Suketi River catchment of western Himalayan region in India during 1971–2015. The data used comprises of daily rainfall measurements at three rain gauge stations, which are sparsely distributed over the catchment. Rainfall erosivity was assessed by employing Wischmeier and Smith algorithms, whereas erosivity density was estimated by applying Kinnell’s algorithm. The spatial distribution of both algorithms was analyzed through Kriging method based on geographical information system. The obtained results indicate remarkable year-to-year, seasonal and monthly variations in average annual rainfall erosivity and erosivity density. Apart from this, individual cases of high and very high rainfall erosivity and erosivity density were noticed. The long-term average annual rainfall erosivity and erosivity densityrevealed a general decreasing trend. This decreasing trend in rainfall erosivity was found to be statistically significant at 0.05 significance level, whereas it was found to be non-significant for erosivity density. The highest values of both indices were observed in the month of July followed by August and June particularly in northern parts. These results indicate that July month followed by August and June arethe most susceptible months for soil erosion over the Suketi River catchment with lower reaches (northern) being the most vulnerable one. Finally, results of this study will be valuable for farmers, agronomists and regional planners in chalking out best management practices for reducing water erosion in vulnerable areas of the catchment.

• Active and inactive tropical cyclone years over the Bay of Bengal: 1972–2015

The present study examines the tropical cyclones (TCs) activity over the Bay of Bengal (BoB) during post-monsoon season (October–December) for the period 1972–2015 (44 years period). The study has explored the active and inactive TC years on the basis of mean  $\pm$  1 standard deviation, respectively. A total of nine active (when TCs frequency is $\geq$4 in a year) and 18 inactive (when TCs frequency is $\leq$1 in a year) TC years have been identified during the 44 years period. The mean frequency of TCs during the active TC years (4.22 TCs/year) is approximately five times higher than the inactive TC years (0.78 TCs/year). These active and inactive TC years have shown association to some extent with El Niño-Southern Oscillation and Indian Ocean Dipole events. Various environmental factors influencing the occurrence of TCs have been investigated, by analyzing the composites of nine active and 18 inactive TC years. Further, the existence of more precipitable water, strong convective activities, less sea level pressure, reduced vertical wind shear, upper-level easterly winds and high low-level cyclonic vorticity have provided favourable conditions for the TCs genesis during the active TC years.

• # Journal of Earth System Science

Volume 130, 2021
All articles
Continuous Article Publishing mode

• # Editorial Note on Continuous Article Publication

Posted on July 25, 2019