An example is provided to show how SWD sensor data was processed into
wetting periods. The calculations were made with a
fortran program which can be downloaded. In this example program inputs
are temperature, humidity, rain and three leaf wretness sensors but obviously
the program can be easily adapted .
Return to surface wetness definitions
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Example of processing of data
| Raw data from 5 sensors in a grape canopy | ||||||
| Data are proportion of hour wet for each sensor | ||||||
| Sensors | ||||||
| EST |
1
|
2
|
3
|
4
|
5
|
|
|
10
|
0.2
|
0
|
0.2
|
0
|
0
|
|
|
11
|
0.7
|
0.7
|
0.7
|
0.7
|
0.7
|
|
|
12
|
0.5
|
0.5
|
0.5
|
0.5
|
0.5
|
|
|
13
|
0.1
|
0.9
|
0.9
|
0.8
|
0.1
|
|
|
14
|
0
|
0.4
|
0.4
|
0.6
|
0
|
|
|
15
|
0
|
0
|
0
|
0
|
0
|
|
| Step 1 - the data from each sensor should be converted into a hourly binary variable. Threshold = 0.2 of hour. | ||||||
| EST |
1
|
2
|
3
|
4
|
5
|
|
|
10
|
0
|
0
|
0
|
0
|
0
|
|
|
11
|
1
|
1
|
1
|
1
|
1
|
|
|
12
|
1
|
1
|
1
|
1
|
1
|
|
|
13
|
0
|
1
|
1
|
1
|
0
|
|
|
14
|
0
|
1
|
1
|
1
|
0
|
|
|
15
|
0
|
0
|
0
|
0
|
0
|
|
|
|
||||||
| Step 2 - The canopy surface area wet for each hour is alculated | ||||||
| EST |
Proportion of canopy wet surface area each hour
|
|||||
|
10
|
0
|
|||||
|
11
|
1
|
|||||
|
12
|
1
|
|||||
|
13
|
0.6
|
|||||
|
14
|
0.6
|
|||||
|
15
|
0
|
|||||
| Step 3 - The binary
canopy surface wetness hourly variable is created from a threshold of 0.1
(10%).
|
||||||
| EST |
|
|
||||
|
10
|
0
|
0
|
||||
|
11
|
1
|
1
|
||||
|
12
|
1
|
1
|
||||
|
13
|
0.6
|
1
|
||||
|
14
|
0.6
|
1
|
||||
|
15
|
0
|
0
|
||||
| Step 4 From the canopy surface area wet calculate the wetting period | ||||||
| Start of wetting period 11 hrs EST | ||||||
| End of wetting period 14 hrs EST | ||||||
| Duration 4 hours | ||||||
Return to surface wetness definitions
Return to table of contents