Stosunki termiczne i wilgotnościowe w Zatoce Treurenberg i na masywie Olimp (NE Spitsbergen) w okresie od 1.VIII.1899 - 15.VIII.1900

The paper describes weather conditions (based on air temperature and humidity) in Treurenberg Bay and Massif Olimp (NE Spitsbergen) for the period from 1st August 1899 to 15th August 1900. The hourly data of the meteorological elements under analysis were collected by the Swedish-Russian scientific expedition, which was sent to Spitsbergen in 1899 to measure an arc of the Earth?s meridian. During the expedition two meteorological stations were established (Fig. 1): the main one (21.9 m a.s.l.) located by the sea in Treurenberg Bay (hereafter 'Treurenberg') and a secondary station (408 m a.s.l.) situated on Massif Olimp (hereafter 'Olimp'). The quality of data were checked and assessed as being very good, especially for the Treurenberg station. The air temperature (T) in Treurenberg in the annual march was highest in August (mean monthly T = 2.1°C) and lowest in March (-27.0°C) (Tab. 2, Fig. 2). Mean yearly T was equal to -9.8°C. The values of T in this part of Spitsbergen are significantly lower than in the western coastal part of the island where, for example, the average annual T for the period 1975-2000 was about twice as high (see Przybylak et al. 2004). On the other hand, mean monthly daily T ranges in Treurenberg are greater (Fig. 3). Day-to-day T changes in the annual cycle were greatest in the cold half-year, and lowest in summer (Fig. 4). These changes are lower here than in the western coastal part of Spitsbergen. Mean monthly daily courses of T are clearest from April to September, showing maximum T in the afternoon, and minimum in the early morning hours (Fig. 5). From October to March (but especially during the polar night) the average daily courses were smooth. Air humidity in Treurenberg was characterized using three commonly used variables: water vapor pressure, relative humidity, and saturation deficit. Due to very low T and quite a large thermic continentality of the climate in NE Spitsbergen, water vapor pressure in Treurenberg is lower than in the western coastal part of Spitsbergen. The highest values in Treurenberg occurred in summer (on average about 6 hPa) and the lowest in late winter (below 1 hPa) (Tab. 2, Fig. 6). Generally, similar relations in the annual march are also seen for two other air humidity variables (see Tab. 2, Fig. 6). The annual cycles of day-to-day changes of all humidity variables in Treurenberg are not clear, as they consist of many maximums and minimums (Fig. 7). These changes are lower here than in other parts of Spitsbergen (see Table 15 in Przybylak 1992a). Mean daily courses of relative humidity are smooth for most months. Only in April and in the period from June to September do we see normal daily cycles with lowest values in 'day' hours and highest values in 'night' hours (Fig. 9). The annual course of T in the Olimp station is similar to that occurring in Treurenberg (Figs. 2 and 10). Of course, the upper station was colder, but only by 1oC for mean annual values (Fig. 11). The drop of T in the Treurenberg region - a drop that is lower than is normally observed in the atmosphere (0.6oC/100 m) - was probably caused by measurement errors (the thermograph at the Olimp station was wrapped in thin material in order to stop the snow accumulating around the metallic sensor). Only limited air humidity data were gathered for the Olimp station due to measurement problems of this element in cold half-year. Therefore, most observations were made only in summer, and they show that the relative humidity was in most cases greater here than at the Treurenberg station. The investigation shows that weather conditions in the NE part of Spitsbergen differ significantly from those observed in the western coastal part of the island. Both T and air humidity are significantly lower in the study area, and these differences in the case of T are especially large in winter.