| Abstract | Significant elevation-dependent warming (EDW) of maximum near-surface air temperature and diurnal temperature range (DTR) has been observed in Nepal (southern central Himalaya) until 2566ma.s.l., over the last four decades (1976-2015). During this period, on the average and across the entire country, maximum air temperature increased (+0.045 °C y-1, p < .001) more than minimum temperature (+0.009 °C y-1, p < .05) and, as a consequence, DTR also increased significantly (+0.034 °C y-1, p < .001). Maximum temperature increases have been observed during all seasons of the year. This warming pattern differs from the symmetrical one observed at global level in the same period, and it is in contrast to more prominent minimum temperature increases observed in the north of Himalaya (Tibetan Plateau). Furthermore, the near-surface air temperature change observed in Nepal contrasts the global evidence of main increasing trends occurring during the winter months. We point out that this asymmetric warming pattern could have more serious impacts in Nepal than in other regions of the world, considering the consequences of associated warm maximum-temperature extremes (heatwaves, hot days) on human life, increased primary production, and modifications in the hydrological cycle. We conclude sustaining that the observed EDW of maximum temperature and the DTR could be attributed to the monsoon weakening, namely to the reduced number of rainy days observed in the region during the last decades. These phenomena could have been accompanied by decreasing cloudiness and consequent increasing of daytime shortwave and decreasing of nighttime longwave incoming solar radiation. |
| Text | 404249 2019 10.1016/j.atmosres.2019.06.006 ISI Web of Science WOS WOS 000477686700021 Scopus 2 s2.0 85067577214 Temperature trends Elevation dependent warming Nepal Maximum temperature Diurnal temperature range Himalaya Elevation dependent warming of maximum air temperature in Nepal during 1976 2015 Sudeep Thakuri, Suchana Dahal, Dibas Shrestha, Nicolas Guyennon, Emanuele Romano, Nicola Colombo, Franco Salerno Central Department of Environmental Science, Tribhuvan University, 44618 Kirtipur, Nepal GoldenGate International College, Kathmandu, Nepal Central Department of Hydrology and Meteorology, Tribhuvan University, Kirtipur, Nepal Water Research Institute IRSA CNR , Montelibretti, Rome, Italy Water Research Institute IRSA CNR , Montelibretti, Rome, Italy University of Turin, Department of Earth Sciences, Turin, Italy Water Research Institute IRSA CNR , Brugherio, MB, Italy Significant elevation dependent warming EDW of maximum near surface air temperature and diurnal temperature range DTR has been observed in Nepal southern central Himalaya until 2566ma.s.l., over the last four decades 1976 2015 . During this period, on the average and across the entire country, maximum air temperature increased 0.045 °C y 1, p < .001 more than minimum temperature 0.009 °C y 1, p < .05 and, as a consequence, DTR also increased significantly 0.034 °C y 1, p < .001 . Maximum temperature increases have been observed during all seasons of the year. This warming pattern differs from the symmetrical one observed at global level in the same period, and it is in contrast to more prominent minimum temperature increases observed in the north of Himalaya Tibetan Plateau . Furthermore, the near surface air temperature change observed in Nepal contrasts the global evidence of main increasing trends occurring during the winter months. We point out that this asymmetric warming pattern could have more serious impacts in Nepal than in other regions of the world, considering the consequences of associated warm maximum temperature extremes heatwaves, hot days on human life, increased primary production, and modifications in the hydrological cycle. We conclude sustaining that the observed EDW of maximum temperature and the DTR could be attributed to the monsoon weakening, namely to the reduced number of rainy days observed in the region during the last decades. These phenomena could have been accompanied by decreasing cloudiness and consequent increasing of daytime shortwave and decreasing of nighttime longwave incoming solar radiation. 228 Published version https //www.sciencedirect.com/science/article/pii/S0169809519300493 Elevation dependent warming of maximum air temperature in Nepal during 1976 2015 Significant elevation dependent warming EDW of maximum near surface air temperature and diurnal temperature range DTR has been observed in Nepal southern central Himalaya until 2566ma.s.l., over the last four decades 1976 2015 . The observed EDW of maximum temperature and the DTR could be attributed to the monsoon weakening, namely to the reduced number of rainy days observed in the region during the last decades. Thakuri et al 2019.pdf Articolo in rivista Elsevier 0169 8095 Atmospheric research Print Atmospheric research Print Atmos. res. Print Atmospheric research. Print franco.salerno SALERNO FRANCO emanuele.romano ROMANO EMANUELE nicolasdominique.guyennon GUYENNON NICOLAS DOMINIQUE |
