Weather data from AWS units not official: IMD
These automated stations are controlled by the development and planning wing of the respective state governments.
Hyderabad: Indian Meteorological Department (IMD) has 11 temperature observation stations in Telangana and 18 in AP. In other areas, temperatures are recorded at the district collectors’ office and other places through 34 automatic weather stations or AWS.
These automated stations are controlled by the development and planning wing of the respective state governments. IMD staff inspects AWS every month to calibrate the data. If the data is within the range of the IMD data, it is approved.
On April 13, Tallaproddutur mandal in Kadapa district and Srisailam in Kurnool district recorded 48.9ºC and 47ºC. The IMD being the authorised body, could not deliver data as it had no stations there. IMD officials said temperatures recorded by the AWS had to be cross-checked and authenticated and cannot be counted as official.
IMD Hyderabad director Y.K. Reddy said, “Only the figures given by the IMD are official. The development and planning wing is the custodian of automatic weather stations, all the data is put on their portal. How these stations are being maintained is important and I cannot comment on the authenticity of the data.
As of now they are installed at electric power stations. Due to the voltage, there might be a possibility of heat being generated, which could add to the temperature readings. But the temperature cannot be high in one mandal and 2-3 degrees less in another. So if a mandal in Kadapa has recorded 48.9ºC degrees and nearby areas reported 43ºC, I am doubtful of data quality.”
It’s sensors vs humans for temperature data
At IMD stations, the temperatures are recorded manually by trained staff with four types of thermometers. They record the maximum and minimum temperatures and relative humidity every day.
At AWS stations, the temperatures are recorded through electronic sensors. These sensors need to be calibrated regularly. The state government’s development and planning wing officials say they do it regularly. The equipment used by AWS and IMD are different.
The IMD equipment is said to be better than those used at the AWS. Since the IMD does not have its stations at places where the AWS is located, it cannot authenticate the temperatures.
The AWS had recently reported that Tallaproddutur mandal in Kadapa district and Srisailam in Kurnool district as recording 48.9ºC and 47ºC respectively.