Quick Look

Relative humidity
Relative humidity is a measure of how much water a parcel of air contains as compared to saturation at a given temperature. It is calculated as

Relative humidity is plotted below in figures 1a-d for Salalah and figure 2a-d for Masirah. There is no monoton trend recognizable.

Lifting Condensation Level
The lifting condensation level is the level at which a raising air-parcel becomes saturated (because pressure drops as it rises). Under favorable conditions, for example when air is forced upwards by mountains as it is the case in Dhofar, the lifting condensation level coincides with the anticipated cloud base level.
Knowing the relative humidity it is possible to estimate the lifting condensation level using 2 different methods:

1. Georgakakos and Bras (1984) propose the following formula to estimate the cloud base level in terms of pressure level:

Plcl .. Pressure the lifting condensation level T0 .. Temperature measured Td .. Dew point temperature – temperature to which a parcel would have to be cooled in order to become saturated (without adding moisture) Ps .. surface pressure

Figure 3a and 4a are plots of the climatology of the lifting condensation level n mbar.

2. If using the temperature lapse rate per gain in height, one can calculate the Lifting Condensation level in m as follows:

This is a very simplistic method and shall just give us an idea how high (in m) the clouds over Salalah potentially are. Figure 3b and 4b show the climatology of cloud base in Salalah and Masirah as estimated with this method.

Relative Humidity

figure 1a: climatology of relative humidity in Salalah, calculated for 1987-1999

figure 1b: time series of relative humidity in Salalah in spring

figure 1c: time series of relative humidity in Salalah in summer

figure 1d: time series of relative humidity in Salalah in summer

figure 2a: climatology of relative humidity in Masirah, calculated for 1987-1999

figure 2b: time series of relative humidity in Masirah in spring

figure 2c: time series of relative humidity in Masirah in summer

figure 2d: time series of relative humidity in Masirah in summer

Lifting Condensation Level

figure 3a: climatology of Lifting Condensation Level in Salalah (in mbar) calculated after Georgakakos and Bras (1984) for 1987-1999

figure 3b: climatology of Lifting Condensation Level in Salalah (in km) calculated using the temperature lapse rate for 1987-1999

figure 3c: time series of Lifiting Condensation Level in Salalah (in mbar) calculated after Georgakakos and Bras (1984)

figure 3d: time series of Lifting Condensation Level in Salalah (in km) calculated using the temperature lapse rate

figure 4a: climatology of Lifting Condensation Level in Masirah (in mbar) calculated after Georgakakos and Bras (1984) for 1987-1999

figure 4b: climatology of Lifting Condensation Level in Masirah (in km) calculated using the temperature lapse rate for 1987-1999

figure 4c: time series of Lifiting Condensation Level in Masirah (in mbar) calculated after Georgakakos and Bras (1984)

figure 4d: time series of Lifting Condensation Level in Masirah (in km) calculated using the temperature lapse rate