| Meteorological Terms |
Explanation |
| Absolute Maximum |
Highest value of the parameter ever recorded. |
| Absolute Minimum |
Lowest value of the parameter ever recorded. |
| Air Temperature |
Temperature read on a thermometer which is exposed to the air in a position sheltered from direct solar radiation. |
| Amount of Cloud |
Percentage of the sky covered by any type of cloud. |
| Bright Sunshine |
Period during which solar radiation reaches sufficient intensity to cast distinct shadows. |
| Day with Fog |
A day with fog reported at any time during the day. |
| Day with Lightning |
A day with lightning reported at any time during the day. |
| Day with Strong Monsoon Signal |
A day with Strong Monsoon Signal issued at any time during the day. |
| Day with Thunderstorm |
A day with thunderstorm reported at any time during the day. |
| Day with Tropical Cyclone Warning Signals |
A day with Tropical Cyclone Warning Signals issued at any time during the day. |
| Dew point Temperature |
Temperature to which air must be cooled at constant pressure and water vapor content in order that it shall be saturated with respect to water. |
| Diurnal Range |
Difference between the daily maximum and minimum readings. |
| Duration of Rainfall |
Duration of rainfall in an hour is the sum of the duration of precipitation recorded in an hour to the nearest 5 minutes. Duration for other periods is the sum of the hourly duration to the nearest whole hour. |
| Evaporation |
Amount of water evaporated into the atmosphere from a free water surface. |
| Global Solar Radiation |
Sum of direct solar radiation and diffuse sky radiation received by unit horizontal surface. |
| Maximum Air Temperature |
Instantaneous maximum reading of the air temperature recorded in a specified period. |
| Maximum Gust |
Peak value of wind speed recorded in a specified period. |
| Mean Daily Global Solar Radiation |
Average of the daily values of total global solar radiation in a specified period. |
| Mean Daily Maximum Air Temperature |
Average of the daily values of maximum air temperature in a specified period. |
| Mean Daily Minimum Air Temperature |
Average of the daily values of minimum air temperature in a specified period. |
| Minimum Air Temperature |
Instantaneous minimum reading of the air temperature recorded in a specified period. |
| Percentage of Possible Sunshine |
Percentage ratio of actual amount of bright sunshine to the total possible between sunrise and sunset. |
| Potential Evapotranspiration |
Maximum quantity of water capable of being lost, as water vapor, by a continuous stretch of vegetation covering the whole ground and well supplied with water. |
| Pressure |
Atmospheric pressure reduced to mean sea level. |
| Prevailing Wind Direction |
Wind direction which occurs more frequently than any other in a specified period. |
| Rainfall |
Thickness of the layer of water which accumulates on a horizontal surface, as the result of precipitation, in the absence of infiltration or evaporation |
| Reduced Visibility |
Visibility below 8 kilometres, when there is no fog, mist, or precipitation. |
| Relative Humidity |
Percentage ration of the actual vapour pressure in the air to the saturation vapour pressure with respect to water at the same temperature and pressure. |
| Sea Surface Temperature |
Temperature of the water of the surface layer of the sea. |
| Soil Temperature |
Temperature observed in the interior of the soil at different depths. |
| Thunderstorm |
One or more sudden electrical discharges manifested by a flash of light(lightning) and a sharp or rumbling sound(thunder). It is regarded to have ceased when no further thunder is heard in 10-15 minutes after the last audible thunder. |
| Wet-bulb Temperature |
Temperature read on a thermometer whose bulb is covered by a film of water or ice and which is exposed to the air in a position sheltered from direct solar radiation. |
| Wind Speed |
Horizontal movement of air per unit time. |