Browsing by Author "Amit Singh Chandel"

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Aerosols properties over desert influenced locations situated in four different continents
(Elsevier Ltd, 2021) Manish Soni; Amit Singh Chandel; Sunita Verma; Swagata Payra; Divya Prakash; Brent Holben
This paper investigates aerosol properties (physical, optical and radiative) to understand the aerosol climatology (2008–17) over four Aerosol Robotic Network (AERONET) sites situated in different continents. For this purpose, the chosen sites are Jaipur, India in Asia, Ilorin, Nigeria in Africa, Birdsville, Queensland in Australia and White Sand, New Mexico in America. The higher AOD were found at Jaipur (AOD≈0.57; α = 0.38) during month of June and at Ilorin (AOD ≈ 1.12 and α ≈ 0.56), Africa during February. The value of SSA are also found higher i.e. 0.94 and 0.96 during the MAM over Jaipur and Ilorin respectively due to dominance of dust aerosols. Ilorin experiences the influence of harmattan winds from November to March and shows significant increase not only in coarse mode but also in fine particles fraction. While the remaining sites i.e. White Sand, America; and Birdsville, Australia are found relatively pristine based on monthly averaged AOD, AE (α) and SSA. The estimated direct radiative forcing using SBDART indicates that Ilorin and Jaipur sites in Africa-Asia exhibit much higher values of TOA and BOA as compared to White Sands and Birdsville in America-Australia. The annual averaged radiative forcing are estimated over Ilorin (38.38 ± 16.89 W m−2) and Jaipur (36 ± 8.34 W m−2). Similarly, high radiative forcing efficiency of 66.86 ± 16.69 W m−2 τ0.55nm−1 and 67.96 ± 20.46 W m−2 τ0.55nm−1 are calculated for Ilorin and Jaipur, respectively. The influence of emission differs in different continents i.e. Africa-Asia to America-Australia sites. © 2021 Elsevier Ltd
Impact of climate change and water quality degradation on food security and agriculture
(Elsevier, 2021) Priyanshu Gupta; Janhavi Singh; Sunita Verma; Amit Singh Chandel; Rajeev Bhatla
The gradual increase in climate change leads to a serious concern toward food security and agriculture production. Despite considerable progress, around 800 million people are malnourished, 161 million under age of five are considered obese and 2 billion do not receive the essential micronutrients in their healthy life. © 2021 Elsevier Inc. All rights reserved.
Validation of Surface Temperature Derived From MERRA-2 Reanalysis Against IMD Gridded Data Set Over India
(Wiley-Blackwell Publishing Ltd, 2020) Priyanshu Gupta; Sunita Verma; R. Bhatla; Amit Singh Chandel; Janhavi Singh; Swagata Payra
The first detailed validation of maximum temperature of Modern-Era Retrospective analysis for Research and Application Version 2 (TMERRA-2) against Indian Meteorological Department (TIMD) has been carried out for 35 years (1981–2015) over India. For this purpose, India has been divided into seven different zones, i.e Western Himalaya (WH), Northwest, North Central, Northeast (NE), West Peninsula India, East Peninsula India, and South Peninsula India. The descriptive statistics and correlation between TMERRA-2 and TIMD have been determined for monthly, seasonal, and annual basis. A significant correlation (>0.9) has been found for monthly TMERRA-2 and TIMD with a root-mean-square error value closer to 1 except for WH where a high root-mean-square error value of 18.2 is obtained. Seasonal analysis also indicates a significant correlation for all the zones except for WH and NE with a correlation value of <0.3 during monsoon season; this may be due to sparse network, cold climate, and heterogeneity due to topography. Percent bias indicates that TMERRA-2 generally overestimates the TIMD monthly observations for all the zones, that is, Northwest, North Central, NE, West Peninsula India, East Peninsula India, and South Peninsula India by 4.1%, 2.4%, 1.6%, 0.5%, 0.2%, and 0.8%, respectively, except WH where an underestimation (−82.5%) is determined. Thus, after calibration, MERRA-2 Reanalysis maximum temperature may be used for further study of extreme weather events. © 2019. The Authors.