http://ocotal.iarc.uaf.edu/index.php?action=history&feed=atom&title=DewPoint_Calculator_RoutineDewPoint Calculator Routine - Revision history2026-05-12T22:48:00ZRevision history for this page on the wikiMediaWiki 1.34.2http://ocotal.iarc.uaf.edu/index.php?title=DewPoint_Calculator_Routine&diff=1641&oldid=prev137.229.92.251 at 20:53, 28 November 20112011-11-28T20:53:06Z<p></p>
<p><b>New page</b></p><div>This shorty calculates dew point from dry bulb air temperature and relative humidity so daily / monthly averages can be computed.<br />
<br />
<pre><br />
Sub DewPoint_Calcs()<br />
<br />
'' This subroutine runs through a worksheet and calculates dewpoint from relative humidity and air temperature<br />
'' as per the Dingman book appendix.<br />
<br />
Dim inputrow As Long<br />
Dim outputrow As Long<br />
Dim inputtempcol As Integer<br />
Dim inputrhcol As Integer<br />
Dim outputdpcol As Integer<br />
Dim inputWS As Integer<br />
Dim outputWS As Integer<br />
Dim eastar As Double<br />
Dim temperature As Double<br />
Dim Wa As Double<br />
Dim ea As Double<br />
Dim dewpoint As Double<br />
<br />
inputWS = 1<br />
inputrow = 4<br />
inputtempcol = 5<br />
inputrhcol = 8<br />
outputWS = inputWS<br />
outputrow = inputrow<br />
outputdpcol = 15<br />
<br />
Do While Worksheets(inputWS).Cells(inputrow, inputtempcol).Value <> ""<br />
'' #1 Read in the values<br />
If Abs(Worksheets(inputWS).Cells(inputrow, inputtempcol).Value) <> 6999 And _<br />
Abs(Worksheets(inputWS).Cells(inputrow, inputtempcol).Value) <> 7777 And _<br />
Abs(Worksheets(inputWS).Cells(inputrow, inputtempcol).Value) <> 9999 And _<br />
Abs(Worksheets(inputWS).Cells(inputrow, inputtempcol).Value) <> 9999.9 Then<br />
temperature = Worksheets(inputWS).Cells(inputrow, inputtempcol).Value<br />
Else:<br />
temperature = 6999<br />
End If<br />
If Abs(Worksheets(inputWS).Cells(inputrow, inputrhcol).Value) <> 6999 And _<br />
Abs(Worksheets(inputWS).Cells(inputrow, inputrhcol).Value) <> 7777 And _<br />
Abs(Worksheets(inputWS).Cells(inputrow, inputrhcol).Value) <> 9999 And _<br />
Abs(Worksheets(inputWS).Cells(inputrow, inputrhcol).Value) <> 9999.9 Then<br />
Wa = Worksheets(inputWS).Cells(inputrow, inputrhcol).Value<br />
Else:<br />
Wa = 6999<br />
End If<br />
If temperature <> 6999 And Wa <> 6999 Then<br />
eastar = 0.611 * (Exp((17.3 * temperature) / (temperature + 237.3)))<br />
ea = eastar * Wa / 100<br />
dewpoint = (Log(ea) + 0.4926) / (0.0708 - 0.00421 * Log(ea))<br />
Else:<br />
dewpoint = 6999<br />
End If<br />
Worksheets(outputWS).Cells(outputrow, outputdpcol).Value = dewpoint<br />
outputrow = outputrow + 1<br />
inputrow = inputrow + 1<br />
Loop<br />
Range("A12").Select<br />
End Sub<br />
</pre></div>137.229.92.251