The spatial effect on precipitation magnitude (Fig. 9), precipitation magnitude decreased at the same area but it stayed at the same magnitude when changing from one place to another, however, a small decreasing in the magnitude of precipitation when moving between different places.
Similarly, precipitation magnitude decreased at three urban areas; points 1 and 2 (Fig. 10), points 3 and 4 (Fig. 11), points 5 and 6 (Fig. 12), however, precipitation increased at points 7 and 8 (Fig. 13). On the other hand, some studies focused on the effect of topography on spatial distribution of precipitation such as mountains (Alijani 2008), while other researchers referred to the characteristics of spatial distribution of precipitation over a whole country such as Thailand (Laonamsai et al. 2021). Therefore, there is no similar studies were mentioned to the impact of spatial parameter on precipitation magnitudes close to measuring points to show the similarities and differences.
Respective to temporal effect on precipitation magnitudes, day and night hours affected precipitation magnitude (Fig. 14). Starting with the first measuring points (points 1 and 2), at dawn (4:38 am) precipitation was recorded as 4.6 mm, which was the highest magnitude during the whole storm in both day and night hours. After this, during the morning times, precipitation rates decreased to 1.8 mm, and precipitation continued at a decreasing rate, from 0.2 mm to 0.1 mm closing to sunset time. However, precipitation increased at night but it decreased to 0.5 mm during the last hour of the day.
Precipitation increased and decreased on day and night hours. During the day, precipitation decreased from the maximum of 4.6 mm to the minimum magnitude of 0.1 mm. This could be because the sun’s rays still exist behind clouds, decreasing the level of precipitation. On the other hand, precipitation increased from 0.1 mm to 0.5 mm at night. This increase could be due to the natural change between day and night sunrays. Other studies did not mention to the effect of day and night hours on precipitation but they referred to the effect of the whole season on precipitation by many methods such as, creating modelling (Guo et al. 2020), analysing weather data (Gocic and Trajkovic 2014; Tabari and Talaee 2011). Their results are similar to our study respective to winter which was the most effective season on precipitation, because the rainy day was occurred on a day in winter season.
Precipitation magnitudes fluctuated with wind speed (Fig. 15), through the course of one day, twelve continuous storms were recorded at four measuring points pairs. The maximum precipitation rate was recorded with wind speeds of 2.8 km/h, but precipitation rates decreased to 1.8 mm when the wind speed decreased to 0.5 km/h. Precipitation decreased to 0.2 mm and wind speed decreased to 1.1 km/h. Surprisingly, precipitation rate was recorded at the same rate of 0.2 mm, while there was a small decrease in the wind speed to 0.9 km/h. Similarly, (Back and Bretherton, 2005) pointed out fast winds helps to increase precipitation, however, their results were adopted daily records from satellite images during five years but our study methodology depends on hand-held device to record the measurements.
In contrast, when wind speed increased to 2.0 km/h, I recorded the minimum precipitation rate of 0.1 mm. Unexpectedly, the precipitation rate stayed constant at 1.0 mm as wind speed increased to 1.7 km/h, however, these results are contradicted other studies (Back and Bretherton 2005; Um et al. 2017). Thus, at the last four measuring points, both of precipitation and wind speed decrease. Therefore, the relation between wind speed and precipitation is back to a proportional relation.
In terms of the relationship between wind direction and precipitation (Fig. 16), maximum magnitude of precipitation was observed towards west direction at points 1 and 2, however, the direction between measuring points is upwind. This result is similar to (Johansson and Chen 2003) that they mentioned to precipitation increased at upwind side. The minimum value was recorded towards leeward side, which is similar to (Johansson and Chen 2003).