The research was conducted at Ismailia Agricultural Research
Station, Agric. Res. Central (ARC) to study some of weather phenomena
in moist air near soil surface. To achieve this goal, the phenomena
measurements of air temperature (T, oC), vapor pressure (VP, kPa) were
recorded, which the values of relative humidity (RH %) and saturation
vapor pressure (SVP, kPa) were calculated, and dew point temperature
(TDP, oC) were recorded as well as may calculate from the weather
station of Ismailia Agric. Res. Station.
Air temperature (T, oC) had started to be hot from 7a.m. and
the peak at 3p.m. This differed from month to another through the average
day hourly (h), during the twelve months of the year. Meanwhile, along
the 24 day's hours relative humidity (RH, %) had depressing manner
opposite to air temperature depressing trend. However, relative humidity
(RH, %) showed depressing with increasing of air temperature (T, oC).
Saturated vapor pressure (SVP, kPa) was high at August and
low at December, January and February. This trend was related to air
temperature. Vapor pressure (VP,kPa) were low and the depression more
or less at 3 p.m. for all months, where at very low at January and February
and relatively high at July and August.
The relations between both air temperature (T, oC) and dew
point temperature (TDP, oC), along the months of (T- air, oC) values
were more than the corresponding values of (TDP, oC). The distance
between the rise in (T, oC) and the depression in (TDP, oC) was as far as
at ~ 3 p.m. and were more obvious during the months of June, July and
August.
The relations between all of SVP (kPa), VP ,(kPa), T-air (oC), RH
(%) and TDP (oC) can be represented by mathematical formals in five
equations, where they were (1) polynomial, (2) logarithmic, (3)
exponential, (4) power and (5) linear.
The better relation of the studied weather formula was
polynomial compared with other equations, whereas the regression
coefficient ( r ) for polynomial equation at SVP, VP, T, RH, and TDP
were 0.83, 0.80, 0.81, 0.77, 0.83, respectively, and the best regression
coefficient were for SVP and TDP.