Ecosystems at Risk: Limestone caves
3b. Climate of the entrance ecosystem

You are walking down to the cave to take readings of the physical environment. It is a hot February day around midday with a temperature of 330C, very low humidity of 29% and no wind. As you approach the cave entrance you feel a cool breeze coming from the cave.These are your readings at the cave entrance.
Hygrometers allow the relative humidity to be calculated. The dry bulb thermometer is just a normal thermometer recording air temperature. The wet bulb thermometer has a wet cloth around the bulb. As this moisture evaporates, it cools the thermometer. To calculate the relative humidity, get the difference in temperature between the dry and wet bulb, in this case about 70C. Then go to the dry bulb temperature at it's reading of 220C. and go across to column 7 at the top of the table. The relative humidity is 38%.

Instruments

Light meters record light intensity in lux.

Anemometers record wind speed. In this case the wind is blowing out of the cave entrance.The speed is recorded in metres per second.

 
 
  climate twilight