  It is assumed that the solar cell efficiency of PV device is closely related
to the solar irradiance, considered the solar parameter Global Solar Irradiance
(G) and the meteorological parameters like daily data of Earth Skin Temperature
(E), Average Temperature (T), Relative Humidity (H) and Dew Frost Point (D),
for the coastal city Karachi and a non-coastal city Jacobabad, K and J is used
as a subscripts for parameters of Karachi and Jacobabad respectively. All
variables used here are dependent on the location (latitude and longitude) of
our stations except G. To employ ARIMA modeling, the first eighteen years data
is used for modeling and forecast is done for the last five years data. In most
cases results show good correlation among monthly actual and monthly forecasted
values of all the predictors. Next, multiple linear regression is employed to
the data obtained by ARIMA modeling and models for mean monthly observed G
values are constructed. For each station, two equations are constructed the R2
values are above 93% for each model, showing adequacy of the fit. Our
computations show that Solar cell efficiency can be increased if better
modeling for meteorological predictors governs the process.
