PUNE: Karina D’Souza makes sure to get her daily dose of
vitamin D by soaking up in the sun for at least five minutes, four times a week. The 30-year-old working professional from Aundh, however, missed out on her daily dose this July as the city’s bright
sunshine hours for the month hit an 18-year low.
The city, on an average, got just one hour of bright sunshine throughout July, something that has not happened in the month since 2000, India Meteorological Department (IMD) data revealed.
Pune’s average global solar radiation also dipped to 11.6 mega joule/m2 in July 2018, as against the normal of 16.6 mega joule/m2 (see graphics). Though July is marked with cloudy skies, the month this year seemed to be an extreme instance when Pune remained mostly overcast with a 70% decrease in solar radiation.
IMD scientist Nahush Kulkarni IMD told TOI that the two most important factors affecting solar radiation are the sun’s altitude and cloud cover. “While changes in the sun’s altitude and duration of the daylight period play a role in determining the amount of solar radiation reaching the surface, cloud cover mainly accounts for the monthly and annual variation in the average solar radiation,” he said.
“The increased cloud cover this July was the main reason for the dip in solar radiation. The contribution of pollutants and aerosol needs to be investigated further,” he said.
There were 11 days in July when the sun did not appear at all. “In fact, nine days in the month had bright sunshine hours in the range of 1-3 hours, while eight days recorded bright sunshine hours in the range of 4-6 hours. Only one day in July saw over seven hours of bright sunshine,” Kulkarni said.
The people of Pune got nearly 65% less bright sunshine hours in July compared to the 30-year normal value of 3.7 hours a month.
People of Pune got nearly 65% less bright sunshine hours in July compared to the 30-year normal value of 3.7 hours a month
