[Topography and local environment][Synoptic process features][Atmospheric pressure and wind]
[Air temperature and humidity][Clouds and precipitation][Visibility, snowstorms and fogs]
[Mesoscale perturbations][Sea Ice][Photo Gallery][Climatological data]
Station synoptic index 89512 Meteorological site height above sea level 119 m Geographical coordinates 70°46' S; l = 11°50' E Beginning and end of polar day 15 November - 28 January Beginning and end of polar night 21 May - 23 June
Topography and local environment
The Novolazarevskaya station is located at the extreme southeastern tip of the Schirmacher Oasis approximately in 80 km from the Lazarev Sea coast. An ice shelf with a slightly undulating surface resting against an ice cap extends north of the station in the vicinity of Leningradsky Bay. From the south, there is a continental ice sheet slope.
The Oasis presents a bedrock area elongated in a narrow strip around 17 km long and 3 km wide in the direction from west-northwest to east-southeast. Its relief is typically hillocky with the absolute marks up to 228 m.
There are up to 180 lakes in the Oasis. The ice cover on the lakes typically persists in summer melting however on some lakes.
Climate in the Oasis has predominantly continental characteristics. It is mainly formed depending on the intensity of solar radiation. Much of the Oasis area is characterized by the absence of continuous ice cover not only in summer but also in winter.
Moraines outcrop to the surface of glaciers surrounding the Oasis. In winter, moraines and hillocky relief are partly snow-covered.
The station was opened on January 18, 1961. Its coordinates are 70°46’04” S and 11°49’54” E. The elevation above sea level is 102 m.
First constructions included service space, a living house, a mess-room and a power station, as well as glaciological, magnetic and actinometric pavilions and auxiliary space.
In 1962, in 100 km southwest of the main buildings one more panel house was constructed for accommodation of geophysical equipment and the fourth magnetic pavilion near it. Already by the time of the 20th expedition, around 15 service and living constructions were located in the station territory.
There is a runway in the station area for ski- and wheeled aircraft located in 15 km south of the station on the ice sheet surface at the 500 m elevation above sea level.
The runway has the 1200 m x 60 m dimensions and the landing course of 114°.
Synoptic process features
The atmospheric circulation pattern above the Queen Maud Land is in general as follows. In the west and east of the Queen Maud Land, two high pressure ridges of low mobility extend in the meridional direction with the axes along 8-9° W and 50° E. These ridges probably combine above the inland plateau. A quasistationary air pressure depression in the coastal zone between the ridges (4 to 37° E) is maintained by oceanic depressions intruding from the north around 20-25° E. Two branches of the meridional cyclone trajectories almost converge here, the eastern branch of the Falkland and the western branch of the South-African trajectories. The cyclones of the eastern branch of the Falkland trajectory move along the coast influencing the weather in the Oasis to a smaller extent, whereas along the western branch of the South-African trajectory, the cyclones move almost along meridian southward. They are deeper and produce a significant influence on the weather character in the coastal areas of the Queen Maud Land.
The prevailing pathways of cyclones depend not only on the time of the year, but also on the current circulation features of atmospheric processes for whose characterization the atmospheric circulation Z, MA and MB forms were determined.
A comparison of summer and winter maps of cyclone trajectories for zonal (Z) circulation reveals that during the colder period of the year, a circumpolar ring of cyclone trajectories narrows although their frequency of occurrence in winter and summer is roughly equal (around 9 events a month). At the development of macroprocesses of the MA and MB forms in summer, the trajectories of cyclones have a smaller meridional component compared with winter. Their frequency of occurrence comprises around 5 cases a month. The location of some branches of cyclonic trajectories changes. For example, at the MB circulation form, the cyclones exit to the coast of Queen Maud Land in winter along the trajectories originating in the central areas of the South Atlantic. The frequency of such cyclones in winter comprises around 10 cases a month. In summer, the pathways of such cyclones begin from the coast of Argentina. Their frequency of occurrence comprises around 5 cases a month. The cyclonic circulation is most active in winter and in the intermediate seasons when moist and relatively warm sea air masses flow from the ocean resulting in the air temperature increase and strong winds in the Oasis. Although the cyclonic activity in summer is attenuated, it is still intense.
The Schirmacher Oasis is also subjected to the influence of the peripheral area of the Antarctic High that forms clear frosty weather with dominating catabatic winds. Winter (April-September) is mild in general but with strong winds, frequent storms and snowstorms with snowfall. More than 70% of annual precipitation falls out. During the anticyclonic situation, frosty weather sets in, winds attenuate and the air temperature drops and air dryness increases. The atmospheric pressure is high and the absolute humidity is the least during the year. The frequency of occurrence of middle clouds and clear weather is high.
In spring (October-November), the atmospheric pressure sharply decreases, winds attenuate and the air temperature and humidity considerably increase although the amount of lower clouds decreases. The frequency of occurrence of upper clouds increases. Precipitation is still abundant. Active evaporation and melting of winter snow begins. In mid-October, the above zero temperatures on the snow-free soil surface are recorded.
In summer (December-January), the atmospheric pressure is the highest. There is very high temperatures and air humidity. Cloudiness (especially low clouds) increases and the frequency of clear weather decreases, the winds are comparatively weak. Snowfalls are rare and precipitation is insignificant. There is rapid snow and ice melting and intense drainage of melt water from the Oasis to the Ice Shelf.
Autumn (February-March) is characterized by decreasing air temperature and humidity and increasing total cloudiness with dominating middle clouds. Winds become stronger although snowfalls are still rare and precipitation is small. The atmospheric pressure slightly decreases, but remains high. Melt water in the Oasis freezes and ice cover forms on the lakes.
Atmospheric pressure and wind
Average annual air pressure not reduced to sea level is very low comprising 975.5 mb. This is the lowest atmospheric pressure for all coastal Antarctic stations. Annual variations of atmospheric pressure, similar to the other Antarctic stations have two maximums (in June and February) and two minimums (in April and October).
The annual amplitude of atmospheric pressure in the station area varied between 11 to 28 mb with the absolute amplitude changing from 62 to 73 mb. At the coastal Antarctic stations exposed to the action of catabatic winds, the atmospheric pressure is poorly related to other meteorological elements. The wind speed typically increases with decreasing pressure, but at its maximum values, the wind also increases.
Winds in the Schirmacher Oasis are naturally weaker than at the coast. The average annual wind speed at the Novolazarevskaya station comprised 10.2 m/s. The maximum wind speed is observed in winter with the minimum in summer. June is distinguished by the largest average wind speed (12.8 m/s). There are 196 days with strong winds on average, for a year. December and January are characterized by the lowest average wind speeds with the wind speed in January comprising 2-5 m/s in more than 45% of all cases. One maximum (in the morning and at night during the intermediate seasons) and one minimum (in the evening) are observed in daily wind speed variations.
An analysis of the frequency of occurrence of wind directions revealed that cyclonic easterly-southeasterly winds had the largest intensity (with the frequency of occurrence of 34% and the speed of 12.8 m/s), then the southeasterly winds followed (with the frequency of occurrence of 20% and the speed of 12.8 m/s) and the catabatic south-southeasterly to south-southwesterly winds (with the frequency of occurrence of 26% and the speed of 10.3 m/s) were at the third place. The frequency of occurrence of winds of other 11 directions was 13% and the average speed 3.3 m/s. The main wind types corresponding to the main weather types are identified. The cyclonic weather is accompanied with cyclonic easterly-southeasterly winds while the anticyclonic weather is characterized by the catabatic south-southeasterly to south-southwesterly winds. In winter, the atmospheric pressure decreases with changing wind type and the difference in weather conditions is more pronounced at cyclonic and catabatic winds.
Air temperature and humidity
The warming influence of the Oasis is expressed in a sufficiently higher air temperature. The average annual temperature is equal to -11.0°, i.e. higher than at the nearest coastal stations. The average temperature oscillations from year-to-year are insignificant, within 1°.
The winter air temperatures are observed already in April and persist around -14 to -15o during the next months. By the temperature regime, the winter season continues for 6 months. July is the coldest month. Summer in the Oasis is quite warm and continues for two months – December and January. The maximum temperatures and the highest minimum temperatures during the year are typically observed in the summer months. The highest temperatures are recorded between the second 10-day period of December and the second 10-day period of January, i.e. during the summer solstice. Usually at this time in the Oasis, rapid snow and ice melting occurs, numerous relief depressions are filled with melt water and there is intense discharge from the lakes to the Ice Shelf.
The duration of intermediate seasons by the temperature regime is two months: October-November (spring) and February-March (autumn). Average temperatures in spring comprise -10.2° and in autumn –6.4°.
Daily air temperature variations at the station are typical with the maximum at midday and the minimum at night. The non-periodic air temperature oscillations are related to changes in the synoptic conditions. Dramatic cooling events in winter occur with the onset of anticyclonic weather at a very weak wind.
The absolute air humidity on average for a year comprises 1.6 mb, its values from year-to-year varying only by 0.1 mb. The largest air humidity is in summer (3.2 mb) and the smallest in winter (1.0 mb). The extreme humidity values at the observation times reach almost 5 mb in summer and 0.2 mb in winter. Relative humidity on average for the station was 52%. The changes of its average annual values ranged between 48 to 56%. The largest relative humidity similar to absolute was observed in summer (58%) while in the other seasons it is lower comprising 50-51%. Complete air saturation with moisture (100%) was recorded comparatively frequently with passing cyclones bringing moist warm air typically with snowfalls from the ocean. The driest air is transported by catabatic winds.
Clouds and precipitation
Total cloudiness is equal on average for a year to 5.8 tenths. The largest cloudiness in the annual variations occurs in summer (6.2 tenths). The least total cloudiness was recorded in winter (5.6 tenths) with the minimum monthly mean observed in September 1965 (2.7 tenths).
The lower-level clouds are insignificant comprising 1.0 tenth on average for a year. The least values are observed in summer (1.4 tenths). The minimum values of lower clouds occur in spring (0.6 tenths).
The middle-level clouds prevail above the station. These are high cumulus and high stratus (with the frequency of occurrence of 42%), their largest frequency observed in autumn and the least in winter. The high-level clouds are mainly Cirrus, being observed in 26% of all observation cases. In the annual variations, the frequency of occurrence of these clouds is minimum in autumn and winter and maximum in spring and summer.
The lower-level clouds are predominantly stratus-rain clouds and stratocumulus were rare above the stations, their frequency of occurrence for the observation years comprising 9%. Clear weather prevails in winter and in general over the year, their frequency of occurrence comprises 21%.
Precipitation at the Novolazarevskaya station is mostly in the form of snow. Rime and hoarfrost, tapioca snow or wet snow were rarely recorded. The annual amount of precipitation is 309 mm.
Precipitation is almost exclusively brought by cyclones and accompanies a typically cyclonic weather with low atmospheric pressure, elevated air temperature and humidity, strong wind and almost continuous and significant low clouds. Snow falls out mainly from the stratus rain clouds whose frequency of occurrence at snowfalls comprised 45%, or from high stratus clouds (with the frequency of occurrence of 39%).
In the overwhelming majority of the cases, the cyclonic easterly-southeasterly winds or transient southeasterly winds (with the frequency of occurrence of 75 and 20%, respectively) were observed at this. Precipitation was most often recorded during snowstorms with strong winds. For example, in 67 cases of snowfalls in July-September the average wind speed was 18-23 m/s (at the average monthly wind speed of 11-14 m/s) while the air temperature was 3-5o higher than monthly means. On average for a year, there are 72 days with snowfalls in the station area. The largest amount of precipitation falls out in winter and spring with the lowest precipitation in summer and autumn.
Visibility, snowstorms and fogs
Snowstorms are the most remarkable atmospheric phenomena, i.e. frequent and strongly influencing the weather state. On average for a year, 88 days with snowstorms were recorded whereas during winter there were 10 days with snowstorms on average for a month. The snowstorms are rare in summer (2 days a month) and comparatively frequent in spring (8 days a month). During snowstorms with snowfall and storm wind, visibility often diminishes to zero. Drifting snow is more often observed, on average on 106 days a year, its frequency being especially large in spring (14 days a month). Drifting snow in summer is very rare. Fogs and haze at the station as well as the optical phenomena were very rarely recorded.
In view of remoteness of the Novolazarevskaya station from the coast, the probability of occurrence of meso-vortices is very small, especially in winter when the mesoscale cyclogenesis area moves northward to the drifting ice edge.
The recurring polynya in Leningradsky Bay between 10-14° E is the most remarkable and important feature of ice conditions in the coastal area of the Novolazarevskaya station. This is one of the most stable Antarctic polynyas persisting in most years almost throughout the year.
The development of polynyas typically begins in September being due to the breakup of the marginal landfast ice zone whose maximum width in this area comprises 40 km. At first, the polynya is mainly localized under the northwestern tip of the protruding Lazarev Ice Shelf. Then with landfast ice decay, following the breakup "wave", it extends in the general west-southwest direction and by March typically covers the entire Bay with an area of up to 5 000 sq.km.
However, the interannual variability of the final decay of local landfast ice and the corresponding maximum polynya dimensions of approximately 150 x 35 km comprises around 4 months from January to April.
North of polynya there is a belt of close drifting ice that decreases by the end of summer in February up to 30-60 miles, on average, disappearing completely in some years.
Autumn ice formation begins in the polynya area in late February-early March, but its intensity is weak up to mid-March. In addition, new ice produced in the polynya in March-April is completely exported from the Bay northward by the dominating offshore winds towards the southern edge of the belt of residual drifting ice.
The formation of new landfast ice begins on average only in late April-early May being interrupted by frequent breaks of its margins. As a result, the final freeze-up of Leningradsky Bay signifying establishment of landfast ice up to 40 km wide and disappearance of the polynya is mainly observed only during August. The average landfast ice width at the time of the spring-summer breakup comprises about 1.5 m with prevailing snow cover depth of 30 cm. The landfast ice thickness increases from 1 m near the edge to more than 2 m near the glacier barrier in connection with the intense frazil ice formation here.