Agromet data is collected from the various agromet observatories maintained by the State Agricultural Universities, ICAR Institutes and other organizations in India. Air temperature, relative humidity and wind speed are recorded everyday at 07-00 h Local Mean Time (LMT) and 14-00 h LMT. Wind speed is expressed in km/hr, mean of past 24 h ending at 07-00 h LMT. Rainfall and evaporation are recorded in mm at 08-30 h Indian Standard Time (IST). Sunshine is recorded in hours per day.
Temperature is measured using dry bulb, wet bulb, maximum and minimum thermometers, housed in a Single Stevenson Screen kept at height of 1.2 m above ground. Relative humidity is computed from dry bulb and wet bulb temperatures using Hygrometric Tables. Rainfall is measured by FRP non-recording raingauge and evaporation by open pan evaporameter. Wind speed is measured by Anemometer installed at height of 3 metres above ground. Campbell Stoke's Sunshine Recorder installed at height of 3 m above from ground is used to record bright sunshine hours.
Potential Evapotranspiration is computed following the modified Penman method as described by Doorenbos and Pruitt (1977). Water balance is computed following the modified water balance technique of Thornthwaite and Mather (1955).
Weekly / Monthly / Seasonal / Annual values of data provided for parameters Max. Temp., Min. Temp., Relative Humidity (both hours), Wind Speed and Sunshine Hours are averages while those of Rainfall and Evaporation are totals. Whenever missing data for a short period 2 to 3 days is seen, gaps are filled with normal data of the same station.
Dorrenbos, J and Pruitt, W.O. 1977. Guidelines for predicting crop-water requirements. FAO Irrigation and Draiange Paper No. 24, Rome, Itlay.
Thornthwaite, C.W. and Mather J.R. 1955. The Water Balance . Publ. In Climatology. Laboratory of Climatology, NJ, USA. 8(1):pp 104.