readings, the probe was installed 3 m aboveground inside a "coolie hat" to 



shade it from direct sun, yet provide proper ventilation. 



Results 



13. Daily and average air temperature values are tabulated in Table 2 

 and shown in Figure 3 . 



Atmospheric Pressure 



Measurement instruments 



14. Electronic atmospheric pressure sensor. Atmospheric pressure was 

 measured with a YSI electronic sensor with analog output located in the 

 laboratory building at 9 m above NGVD. Data were recorded on the FRF com- 

 puter. Data from this gage were compared with those from an NWS aneroid 

 barometer to ensure proper operation. 



15. Microbarograph , A Weather tronics , Incorporated (Sacramento, CA) , 

 recording aneroid sensor (microbarograph) located in the laboratory building 

 also was used to continuously record atmospheric pressure variation. 



16. The microbarograph was compared daily with the NWS aneroid 

 barometer, and adjustments were made as necessary. Maintenance of the 

 microbarograph consisted of inking the pen, changing the chart paper, and 

 winding the clock every 7 days. During the summer, a meteorologist from the 

 NWS checked and verified the operation of the barometer. 



17. The microbarograph was read and inspected daily using the following 

 procedure : 



a. The pen was zeroed (where applicable) . 



b. The chart time was checked and corrected, if necessary. 



c. Daily reading was marked on the chart for reference. 



d. The starting and ending chart times were recorded, as 

 necessary. 



e. New charts were installed when needed. 



10 



