Agromet-Station.pptxvbggggghhhhdxccvvbbvvvccc

Vvhhhffghbnbffgggghhbbvvffghhhhbbbbbbvvvvfffhhbvcfghbcxfggbbbbvffhhffhbcxfvbbvcghbvfghb

1. Agrometeorology 2014 Agricultural Engineering Review Prepared by: Edward R. Lapong , P hD

2. Agrometeorology - study which deals with the relationship of the physical environment and agricultural elements Physical environment: atmosphere, soil and water Agriculture elements: crops and animals Objective : optimally utilize the existing microclimate for agricultural purposes; minimize agri-business losses due to unfavorable weather conditions; gather/record data for future studies

3. Agromet stations are usually found in universities and research institutes/stations, to collect meteorological and biological data Major data collected : - rainfall - temperature (atmospheric and soil) - atmospheric pressure - relative humidity - wind data - solar radiation

4. Major data collected : Phenology – the study of animal and plant life cycle as affected by seasonal variations of climate - evaporation - phenological observations (crop growth and production data, animal diseases outbreak, insect population and infestation, etc.)

5. Recommended Time of Data Collection: 2~3 times daily, from 8 AM~5 or 6 PM (8am, 10am, 12am, 2am, 4pm, 6pm); (8am, 11am, 2pm, 5pm) Parameter Standard Agromet Station AWS Rainfall 24-hr 1-, 5-, 30-min; 1-hr Solar Radiation 12-, 24-hr 1-hr Temperature, Pressure, Humidity 2-, 3-hr 1-hr or less Wind Speed & Direction 2-, 3-hr 1-hr or less Cloud/Sky Condition 2-, 3-hr 1-hr

6. Standard Agromet Station (recommended by PCARRD)

7. Criteria for selection of Agromet Station site : Accessibilty for data monitoring, operation and maintenance Should be in a location truly representative of the natural conditions of the agricultural region it suppose to serve Site has no problem on right of way, ownership and security Site is fairly level and flood-free

8. Site free from obstruction at least 4x the height of the nearest obstruction (other reference: 8-10 times) no shadow casted greater part of the day Facing north (east-west direction should be identified) Criteria for selection of Agromet Station site :

9. Criteria for selection of Agromet Station site : Site has grass cover and no tall weeds Site is not concrete, asphalted, nor made of crushed stone. Security should be provided (fence)

10. Agromet Station Instruments:

11. Agromet Station Instruments: 1. Rainfall-measuring instruments: Standard Rain Gage

12. A = 20 cm (8”) a The actual rainfall depth is magnified 10 times in the collecting cylinder.

13. b. Tipping Bucket Rain Gage

14. b. Tipping Bucket Rain Gage

15. c. Optical Rain Gage

16. d. Weighing-type Rain Gage Consists of a storage bin atop a pen recording the changes of weight on a rotating drum. Unlike Tipping Bucket, it does not underestimate intense rain. Contains a device to measure the quantity of chemicals contained in the locations atmosphere. This is extremely helpful to study the effects of greenhouse gases. However, they are more expensive. e. Acoustic-type Rain Gage

17. Ombrometer – rain gage Disdrometer – measures drop size distribution and velocity of precipitation - distinguish rain, snow, hail, etc Hydrometeors – precipitation

18. Why are rainfall measurements expressed in terms of depth and not by volume? Ans. ‘Depth’ (mm) is the amount of rainfall that would accumulate on a flat, horizontal and impermeable surface in a given time (min or hr) It is not feasible to calculate rainfall volume since areal coverage may be different

19. Why are rainfall measurements expressed in terms of depth and not by volume? b. To provide an international standard and uniform measurement of rainfall. It is more simple, effective and easier to measure, describe and compare amount of rainfall in ‘depth’. For consistency, simplicity and standardization

20. Agromet Station Instruments: 2. Temperature-measuring instruments: Maximum-Minimum Thermometers Ordinary Thermometers

21. Maximum Thermometer When temperature rises, the expanding mercury is forced past the constriction but when the temperature falls the column of mercury remains in the tube, thus indicating the maximum temperature

22. b. Aneroid Barometer Agromet Station Instruments: 3. Pressure-measuring instruments: a. Mercury Barometer

23. Aneroid Barometer It is basically a manometer with one end exposed to the atmosphere It is more sensitive than aneroid barometer since it has Vernier scale on it and has already temperature, elevation and altitude corrections.

24. Other differences between aneroid barometer and mercury barometer? • Aneroid barometer is more stable and compact, less fragile; thus, is easy to transport and take readings. • The mercury barometer can be constructed easily, but the aneroid barometer requires machinery.

25. Why is barometer installed inside rather than outside the building? Ans. To prevent effect of wind and solar radiation b. To prevent effect of outside temperature and humidity (However, if the room is not airtight, no significant difference.) (Vibration and shock may lead to fluctuation) (Barometer does not give a true reading if affected by gusty wind.)

26. Why is barometer installed inside rather than outside the building? Ans. c. To prevent wear and tear. Note: Barometer should not be placed in an air conditioned room. (It may create a pressure differential between the inside and outside environment)

27. Instrument Shelter (Thermometer Screen) It shields the instruments against rain and direct solar radiation while allowing air to circulate freely around them. To provide a standardized environment in which to put or keep the temperature- and humidity-measuring instruments.

28. Why should instrument shelter be painted white? Ans. To reflect the solar radiation and avoid absorption of radiation that may affect the setting/calibration and accuracy of the instruments placed inside.

29. Agromet Station Instruments: 4. Humidity-measuring instruments: a. Hygrometer

30. b. Hygrothermograph

31. c. Psychrometer Sling Psychrometer Hand-held Digital Psychrometer

32. Dry-Bulb Thermometer Wet-Bulb Thermometer

33. Agromet Station Instruments: 5. Wind-measuring instruments: a. Anemometer

34. b. Wind Vane

35. Anemometer installation requirements: Site where wind flow freely and not distracted by obstructions (trees, tall buildings, other structures) Oriented in the prevailing wind direction Mast should be absolutely vertical. 2 m – flat urban terrain 4~10 m – for rural terrain for roof installation: 3 m from the most exposed part 3-cup

36. Wind vane installation requirements: Should be mounted towards true north (use magnetic compass and corrected by the magnetic delineation for specific area) Satisfactorily exposed and can rotate 360 Best mounted in an open terrain, at least 30 m from the nearest obstruction (wind can blow freely, no nearby obstruction) Mounted 6-10 m above the ground

37. Wind vane installation requirements: Could be as simple as handcrafted wooden or light metal; or as elaborate with decorative ornament Lightning rod may be installed to minimize risk of damage during thunderstorm.

38. Agromet Station Instruments: 6. Evaporation-measuring instruments: Evaporation Pan

39. Class A Evaporation Pan 120 cm (47.5’) 25 cm (10’) Stilling Well Class A Evaporation Pan measurement is highly correlated with the potential evapotranspiration of the surrounding area.

40. Class A Evaporation Pan installation requirements: Galvanized iron Gage 20 Operating water level depth: 175~200 mm (water level kept at 50~75 mm from the rim) Installed 150-mm from the ground on wooden stand/platform Measuring stick is 1.0 m and accuracy of 0.02 mm.

41. Measurement should be done in still well as it prevents the effect of waves and ripples which affects accuracy. Why should measurement be done in the stilling well?

42. Agromet Station Instruments: 6. Solar Radiation-measuring instruments: a. Sunshine Recorder

43. Campbell-Stokes Sunshine Recorder: A device that measures or records the amount of sunshine at a given location. Campbell-Stokes Sunshine Recorder

44. b. Actinometer – used to measure heating power of radiation Solar radiation as transmitted directly by the sun, scattered by the atmosphere, or reflected by the earth.

45. c. Pyranometer A type of actinometer used to measure broadband solar irradiance (short wave radiation)

46. c. Pyrheliometer Used to measure intensity of direct solar radiation

47. Agromet Station Instruments: 7. Other instruments: a. Ceilometer A device which uses a laser or other light source to determine the height of a cloud base.

48. b. Radiosonde A group of instruments for simultaneous measurement and radio transmission of meteorological data: temperature , pressure , and humidity of the atmosphere. The instrument package is usually carried into the atmosphere by a balloon.

49. A typical AWS comprises 8 sensors for measuring wind speed , wind direction , air temperature , RH , solar radiation , soil temp. , surface wetness , and rainfall . AWS (Automatic Weather Station) Battery- or solar-powered.

50. What are the differences between a typical Agromet station and AWS? AWS is an automated version of the traditional Agromet station, either to save human labor or to enable measurements from remote areas. An AWS is equipped with data storage system, thus data downloading can be done on a daily , weekly , or monthly basis. The frequency of data collection can also be programmed according to the needs and use of such information.

51. Moreover, a telemetry system could be connected to the AWS so that data can be remotely accessed through mobile SMS or other form of messages in real time. Thus, data from the AWS can be transmitted in real time to a central server which can be viewed from a web-based system through the Internet. While, the data from the existing agromet station are recorded daily in a prescribed form from PAGASA by an assigned agromet observer and are submitted to BSWM every month through mail.

52. Data Logger Rain Gage Anemometer Solar Radiation Humidity Solar Panel

53. End