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Plant’net Work Area | Michael Spratt

# Plant’net Work Area In the Excel version the Work area is the hub which stores all the control, species, models and daily weather data.  All annual results are also stored in this area.  All the models obtain their data and return the results to the Work Area.

### Calculated based upon the Daily Weather

DEC  Declination Solar  =-23.45*pi/180*cos(2*pi*(day+10)/365)

a = -TAN (lat*pi/180) * TAN (DEC)

Day Length  if(day<1)then day:=day+365;

DEC:=-23.45*pi/180*cos(2*pi*(day+10)/365);

a:=-TAN (lat*pi/180) * TAN (DEC)  if a>1 then result:=0 else if a<-1 then result:=24 else result:= 24/pi*ArcCos(a)

Hr = MAX(1 +Day Length)

T = (Tmin+Tmax)/2+273.16

Td = 1/(1/T – (Rv*ln(Hr/100))/L) ASSERT( ((Td-273.16)>-99) and ((Td-273.16) < 99) )

Result =Td-273.16;

tmean  = (TMIN+ TMAX)/2

NL = 24-ABS(Day Length)

ETP = Daily percipitation

ETA = Annuel parcipitation

RELH    = Relative Humidity

TDEW    = Time of Dew Point

WNDS    =convert wind speed in Km/h to meters / second = day_win * 1000 / 3600

Many other date points can be calculated from the Daily_Weather data :

PETD (ETP)

AETD (ETA)

AI D

WSI:

I_REW:

D_REW:

water:

PRCP

Pp

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### Monthly Calculations and Averages

A year’s values are also calculated monthly.  For example

Year

Date

Month

Days per month

Mean Temperature

Maximum Temperature

Minimum Temperature

Precipitation for the Month

Accumulated Precipitation for the Year

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### Check List of Elements

 Daily Monthly Averages Day Length Don’t Know?? Day in Year Day in Month Month Number latitude longitude year_no day_no day_tmn day_tmp day_tmx day_rat day_shm day_prs day_pre day_rh day_gloday_wnd Year Date Month Days per month TMEAN Mean Temperature TMAX ETA_month Max TMIN Minimum Temperature TMEAN = (TMIN+TMAX) / 2 day_pre ETP_ month day_pre PP       (ETP_month) DEC a Day Lenght Hr T Td Result TDEW RELH WNDS SRAD PETD AETD AI D WSI: I_REW: D_REW: water: PRCP Pp __________________________________________________ 