Spatial and temporal variation in daily temperature indices in summer and winter seasons over India (1969–2012)

Abstract

Spatial and temporal variations in summer and winter extreme temperature indices are studied by using daily maximum and minimum temperatures data from 227 surface meteorological stations well distributed over India for the period 1969-2012. For this purpose, time series for six extreme temperature indices namely, hot days (HD), very hot days (VHD), extremely hot days (EHD), cold nights (CN), very cold nights (VCN), and extremely cold nights (ECN) are calculated for all the stations. In addition, time series for mean extreme temperature indices of summer and winter seasons are also analyzed. Study reveals high variability in spatial distribution of threshold temperatures of extreme temperature indices over the country. In general, increasing trends are observed in summer hot days indices and decreasing trends in winter cold night indices over most parts of the country. The results obtained in this study indicate warming in summer maximum and winter minimum temperatures over India. Averaged over India, trends in summer hot days indices HD, VHD, and EHD are significantly increasing (+1.0, +0.64, and +0.32 days/decade, respectively) and winter cold night indices CN, VCN, and ECN are significantly decreasing (−0.93, −0.47, and −0.15 days/decade, respectively). Also, it is observed that the impact of extreme temperature is higher along the west coast for summer and east coast for winter.

Study of Cold Wave and Cold Stress in the Four Metropolitan Cities of India for the Period 1985–2020

“…It can be noted that for Kolkata region during the year 2015 experiences the most significant with 22 warm nights contributing to a CumExc of 43.58 °C, and an AbsExc peaking at 5.14 °C, indicating severity in warm nights (Figure 5a). During 2010, Kolkata experienced 20 warm nights (Table S4) and a CumExc of 28.81 °C, whereas, for the year 2016 has recorded the highest number of warm nights (27), with a slightly lower CumExc of 27.10 °C compared to the year 2015. The characteristics of cold night events in Kolkata, for the year 2012, are notable for its 33 cold nights (Table S3), resulting in a CumExc of -39.44 °C and an AbsExc of -2.74 °C, signifying cold conditions.…”

“…The recent study [24] showed that during 2001-2010, cold waves in the winter season increased over the northern part of India (eastern Uttar Pradesh, Khiri, Lucknow, Baharaich, Gorakhpur, Allahabad). An increase in the intensity and frequency of cold waves has been observed in multiple locations in India in the recent period [25][26][27] . They showed that the Jammu and Kashmir regions experience the coldest waves, followed by Rajasthan and Uttar Pradesh.…”

Estimation of surface PM2.5 with MODIS Aerosol optical depth and source identification using trajectory analysis: A case of Hyderabad City, India

“…The study region is dominate by transportation, industrial, commercial and residential land uses with mixed land uses as well. Seasonal climate prevails in the study area with hot summer (March-June), cold winters (November to February) and rains during monsoon season (July to October) (Kumar et al, 2017). The Hyderabad PM2.5 annual average is 56μg m -3 peaking during the winter morning rush hours (140μg m -3 ) (Chen et al, 2020).…”