The presentation by ACWADAM deals with measurement of weather parameters and outlines the methods used in weather related data collection and analysis. Weather information is necessary for the planning and implementation of watershed programmes, especially in understanding factors like groundwater recharge, the relationship between recharge & discharge and in aspects like irrigation planning.
Rainfall and other weather data are not easily available and the weather data by Indian Meteorological Department (IMD) is expensive. The only long term data available are the meteorological datasets available on India Water Portal (at district level). There are no hard facts and figures or historic data available during the planning and implementation of most watershed development programmes in India. The presentation details the following parameters which can be measured in the field and the measuring equipment for each –
- Rainfall: Rain Gauge
- Evaporation: Evaporimeter
- Wind Speed: Wind Anemometer
- Wind Direction: Wind Vane
- Solar Radiation: Pyranometer
- Temperature: Thermometer
- Humidity: Humidity Sensor or Wet and Dry Thermometer
- Pressure: Barometer or Pressure Sensor
Other measurable parameters are, cloud cover, sunshine hours and evapo-transpiration. Some of this information is gathered using satellite data for weather forecasting. The weather parameters can be measured at one place through the installation of a weather station and can be manual or automatic. In a manual station, all the parameters are measured and noted manually while in an automatic station the data is measured and stored automatically in the data logger.
Rain gauge and evaporimeter are two most commonly used equipments in watershed management programmes. With the help of weather data collected over a period of time some spatial and temporal analysis can be done like –
- Variability in evaporation or rainfall within the area (micro-scale)
- Variability as per the location (micro-scale)
- Change in trends or pattern (macro-scale)
- Variability as per seasons (macro-scale)
This presentation is part of the training modules on planning, development and management of groundwater with special reference to watershed management programmes by ACWADAM. Please write to ACWADAM at acwadam@vsnl.net for sourcing these presentations.