Data Analysis and Visualization in Python for Polar Meteorological Data

Identifying And Eliminating Errors In The Data

The statistical data of hourly temperature, wind speed, wind direction and air pressure used in this study are summarized in histograms (Figure 1). These statistical parameters are calculated separately using all yearly available datasets, polar day (from 10 November–24 January) and for polar night (from 19 May–27 July). Statistical properties of data summarized in the histogram of all year temperature (Figure 1a) is skewed to the left. The abrupt end of the right tail (Figure 1a) is associated with the melting barrier of the snow and ice in the region. In response to a favorable temperature increase, ice melting may take place. The associated modifications in the snow-ice surface energy budget lead to a limitation of temperature increase. The histogram of temperatures shows two relatively small local maxima which are related to the temperature values corresponding to cold and warm seasons in the region (Figure 1b & c). The temperature distribution for polar day (Figure 1b) is unimodal and asymmetric.

The distribution of temperature for polar night (Figure 1c) presents less asymmetry than the corresponding distribution for polar day (Figure 1b). Since cold season, the decrease in the frequency in the right tail of the histogram, towards positive temperature, is less abrupt than in the case of the polar day histogram. The histogram of polar night temperatures (Figure 1c) suggests also a possible multimodality in the distribution. The air pressure histograms all show bell-shaped distributions (Figure 1d–f) suggesting a Gaussian probability distribution function of this variable. During polar night, due to the absence of the solar radiation, the surface temperature is negative and hence the pressure shows various range from 970-980 hPa. The histograms of wind speed (Figure 1g–i) show a typical Weibull distribution. The double mode that is seen in wind speed (Figure 1g) is more likely to appear on polar night wind speed than polar day. The histograms of the wind direction (Figure 1j–l) show one prominent peak at about 250° that is related to the typical synoptic disturbances in the region, which are associated with the katabatic and supergeostrophic winds, respectively.

Figure 1a.

Histogram of hourly measurements during the period 2012–2016: temperature for all years

Figure 1b.

Histogram of hourly measurements during the period 2012–2016: temperature for all polar days

Figure 1c.

Histogram of hourly measurements during the period 2012–2016: temperature for all polar nights