Automatic weather station their working principle and importance

AWS

1. PRESENTATION ON: “ Automatic weather station their working principle and importance ” Course name- Master Seminar Course No.- AGM-591 Session - 2018-19 Presented by KHILESH KUMAR SAHU Dept. of Agrometeorology

2. Automated Observing Sysyetms Automatic Weather Station(AWS)is a modern electronic integrated system using software and hardware in which meteorological and other data sensed by various sensors is acquired automatically with or without physical attendance from remote or desired site. An AWS has multifunctional ability of acuiring,registering,recording,storing,transmiting,processing,presenting the various data in the form of analog, digital or graphic output. It consists of Data Logger – The main function of data is to read and and record automatically the output from the various sensors. data is automatically recorded at the exact interval or time of day or every minute, hours a day for any weather parameter. Sensors – Detects various weather parameters Telemetry(Optional ) – Enable to transfer the data Solar Panel – To charge the battery

3. Types of AWS Real-time AWS It records the observations and sends observations to a remote network on a real-time basis, either regularly or upon request by the user. This type of station is used for ordinary synoptic meteorological analysis and monitoring of critical warning states such as storms and river or tide levels. Off-line AWS It records observations on storage devices & not able to send to a remote network. This type of station is used for climatological analysis or as an auxiliary facility to manual observations. Deployed in regions where no communication lines are available in order to reduce observer workload.

4. Real-time continuous measuring of parameters day-time and night-time More accurate and reliable Automatic data archiving and collection of data in a greater volume Higher resolution Adjustable sampling interval for different parameters Free from reading errors Standardization of observations (both time and quality ) Automatic message generation and transmission Access of archived data locally or remotely Importance of AWS

5. Different type of sensors Sensor Parameter Thermometer Temperature Cup Anemometer with interrupter Wind speed Wind Vane Wind direction Capacitive sensor Humidity Barometer( tranducer ) Atmospheric pressure Ceilometer Cloud height Tipping bucket Rainfall Ultrasonic Snow Depth Sensor Depth of snow Pyranometer Solar radiation

6. Communication Unit Telephone/Fax line Satellite Communication AWS based on GPRS network AWS Satellite Receiving Station

7. Data Logger It is the heart of AWS which acts as interlink between sensors, power supply and communication system. It receives data from various meteorological sensors and store the values within itself and sends it to the communication port for transmission. Power Supply The main power source for an AWS is usually one or more solar panels connected in parallel with a regulator and one or more rechargeable batteries. As a rule of thumb, solar output is at its optimum for only 5 hours each day. In the Northern Hemisphere the solar panel would be mounted facing south and vice versa for the Southern Hemisphere. The angle of the panel differs from place to place but it should never be mounted with an angle of 5 deg as dust build up will dramatically decrease the panel's output.

8. Mast The standard mast heights used with AWS are 2, 3, 10 and 30m . The 2m mast (head height) is used for the measurement of parameters that effect a human subject. The 3m mast (crop top) is used for the measurement of parameters that effect crops (such as wheat, sugar cane etc). The 10m mast is used for the measurement of parameters (wind speed & direction) without interference from objects such as trees, buildings or other obstructions. The 30m mast is used for the measurement of parameters over stratified distances for the purposes of data modelling and boundray layer study. A common application is to take measurements of wind, humidity and temperature at 30, 10, and 2 meters.

9. Disadvantages Automated observations have also some disadvantages as follows: Limited represented area of 3-5 km of sensor site. It is not possible to observe all parameters automatically. e.g. Cloud coverage and types Ongoing periodic maintenance Periodic test and calibration Well trained technicians and specialists High cost of instrumentation and operation

10. CONCLUSION AWS is a software which is simple and easy to use. It requires no specific programming skill and user can use it to read and collect the data by simply making use of is user id. In addition to this data is saved in a format which is easy to understand and read such as HTML,MS Excel, word, PDF etc. Due to its wide range of profitability by AWS even the private companies from India and abroad are showing intrest in this field such as Indiamart , Ecotech etc.