Compilation of ozonesonde observation over Schirmacher oasis east Antarctic from 1999-2007

Hkkjr ekSle foKku foHkkx }kjk Hkkjrh; bysDVªks&dsfedy vkstksulkSans dh enn ls ,aVkdZfVdk ij Hkkjr ds nwljs LVs'ku eS=h ¼70-7 fMxzh n-] 11-7 fMxzh iw-½ ls vkstksu fLFkfr ¼izksQkby½ dk fu;fer eki fd;k tk jgk gSA ok;qeaMy ds mnxz LraHk esa vkstksu ds ?kuRo dh x.kuk iwjs o"kZ esa fy, x, lkIrkfgd vkstksu lkmfUMax ls dh tkrh gSA ok;qeaMyh; vkstksu dh mnxz fLFkfr ¼izksQkby vkSj vkstksu fNnz ¼gksy½ dh fo'ks"krkvksa dk v/;;u djus ds fy, flracj&vDVwcj ekg ds nkSjku cgqr ckj ifjKfIr;k¡ ¼lkmfUMax½ yh xbZ gSaA bl 'kks/k i= esa lrg ls 10 gsDVk ik- ds chp vkstksu vkSj rkieku ds ekfld ,oa okf"kZd vkSlr esa fofo/krk dh x.kuk ,oa fo'ys"k.k o"kZ 1999 ls 2007 dh vof/k esa fy, vkstksulkSans vkjksg.kksa ls fd;k x;k gSA bl v/;;u ls irk pyk gS fd vkstksu fNnz ds laca/k esa xgu vo{k; vDrwcj esa vkSj vYi ijUrq egRoiw.kZ vo{k; flracj ekg esa gqvk gSA vDrwcj esa yxHkx 250 ,oa 20 gs-ik- ds chp lcls lqLi"V vo{k; gqvk gS ftlesa vf/kdre LFkkuh; vkstksu ds Lrj esa 70 gs-ik- vkSj 10 gs- ik- ds Lrjksa ij vkSj flrEcj esa 70 gs- ik- ij fxjkoV ns[kh xbZA fHkUu&fHkUu nkc Lrjksa ds fy, vkstksu dk rkieku ds lkFk lglaca/k ls ubZ tkudkfj;ksa vkSj vkstksu ifjorZu esa foLrkj dk irk pyk gSA iwjs o"kZ esa 300 ls 50 gs- ik- ds chp U;wure okf"kZd vkSlr rkieku -55 fMxzh ls -63 fMxzh lsaVhxzsM rd cnyrk gSA vxLr vkSj flrEcj ds eghuksa esa 70 gs- ik- rFkk 100 gs- ik- Lrjksa ij rkieku dk -80 fMxzh lsaVhxzsM ls de gksuk ,oa vDrwcj ekg esa 70 gs- ik- rFkk 100 gs- ik- Lrjksa ij yxHkx -70 fMxzh lsaVhxzsM ls de gksus dh fLFkfr dks vDrwcj ekg esa vkst+ksu vo{k; ds ladsrd ds :i esa ekuk tk ldrk gSA Regular ozone profile measurement over Antarctica has been made by India Meteorological Department over Indian second station Maitri (70.7° S, 11.7° E) with the help of Indian electro-chemical ozonesonde. Ozone density in the vertical column of the atmosphere is computed with weekly ozone soundings taken throughout the year. During the month of September- October more frequent soundings were taken to study vertical profile of atmospheric ozone and features of ozone hole. The mean monthly and yearly variation of ozone and temperature from surface to 10 hPa has been computed and analyzed from the ozonesonde ascents for the period 1999 to 2007. The study has shown profound depletion in October and lesser but substantial depletion in September, in association with the ozone hole. Depletion is most pronounced between about 250 and 20 hPa in October, with maximum local ozone losses near 70 hPa & 100 hPa levels and in September at 70 hPa. Ozone correlations with temperature for several pressure levels have revealed new insights into the causes and extent of ozone change. Lowest annual mean temperature varies from -55 to -63 °C between 300 to 50 hPa in all the year. The temperature less than -80 °C in months of August & September at 70 hPa & 100 hPa levels and about -70 °C in month of October at 70 hPa & 100 hPa levels can be attributed as an indicator of ozone depletion in months of October

Weather & weather systems at Schirmacher Oasis (Maitri) during recent two decades - A review

Indian Antarctic station Maitri experiences varying external influences from interior of east Antarctica as well as moving depressions and cyclones along the coast. The relative position of circumpolar trough and strengthening of high pressure centre near pole influences variation of atmospheric pressure at Maitri. The diurnal, daily and seasonal variation of temperature mainly depend upon moving pressure systems, katabatic winds, change of solar insulation with change of seasons, reflectivity from clouds and snow surface. The katabatic winds prevail over Maitri which is highly directional from South- East sector due to increase of slope towards south. The blizzards are main weather at Maitri, fog and white out are occasional phenomena. The precipitation is mostly in form of snowfall but rain is very rare at Maitri. Heavy or moderate snowfall indicative of active front leading edge of warm air masses being transported southwards. Strong temperature variant near Schirmacher oasis give precipitation in form of snow. Fog occurred due to slow movement of relatively warm air from lower latitude over the colder surface. Winter season witnessed more snowfall accumulation at Maitri than other season. During summer rise of temperature accompanied with absorption of latent heat by ice pellets in low level of atmosphere results precipitation in form of water droplets. Highest number of blizzards occurs during winter season whereas lowest number of blizzards occurs during summer season. Normally due to cyclonic activities, warm air masses transported towards the Schirmacher oasis which causes rise of temperature at Maitri. Longer duration of the blizzards over the station depends upon strength of slow moving blocking anticyclone situated east of Maitri at lower latitude. Tremendous fluctuation of atmospheric electric field observed before onset is a pre-indication of commencement of blizzards.

Climatology of blizzards over Schirmacher Oasis, east Antarctica

Weather in Antarctica is subject to frequent and sudden changes. Strong winds and blizzards dominate Antarctic weather. A combination of blowing snow, gale force wind and very low visibility is normally defined as blizzard. Meteorological data recorded at Indian Antarctic Station Maitri, in respect of blizzards recorded during the period 1990-2005 has been studied to find out climatological features of blizzards affecting Schirmacher Oasis. At Maitri the blizzard is mostly associated with extra-tropical storms and is normally preceded by precipitation. On average during the year about 21 blizzards affects the station for 45 days during the year. During the month of April to August 3 to 4 blizzards affects the station. Maximum number of blizzards occurs in the month of August with about 7 blizzard days. Average wind speed recorded during the blizzard is about 52 kt but it exceeded 100 kt on several occasions. The duration may vary from hours to days with average of 25 hours. Longest duration of 168 hours was recorded in June 1997. There are about 12 such occasions when blizzard lasted more than 72 hours. No correlation has been found between maximum wind speed and temperature rise during blizzard and the speed is also not correlated with pressure departure during the period.

Rare and new for Antarctica species of algae from the continental waterbodies of Schirmacher Oasis

One rare (Dinobryon cylindricum) and two new (Gonium pectorale, Staurastrum orbiculare) for the Antarctic algal flora species were found in the waterbodies of Schirmacher Oasis (East Antarctica). Their locations are described. Data on morphology, ecology and distribution of the recorded species are summarized.

Evaporation over glacial lakes in Antarctica

The water cycle in glacier hydrological networks is not well known in Antarctica. We present the first evaluations of evaporation over a glacial lake located in the Schirmacher oasis, Dronning Maud Land, East Antarctica. Lake Zub/Priyadarshini is a shallow lake of the epiglacial type, and it is ice free for almost two months in summer (December–February). We evaluated evaporation over the ice free surface of Lake Zub/Priyadarshini using various methods including the eddy covariance (EC) method, the bulk aerodynamic method, and Dalton type empirical equations. The evaporation was estimated on the basis of data collected during a field experiment in December–February, 2017–2018, and regular observations at the nearest meteorological site. The EC was considered as the most accurate method providing the reference estimates for the evaporation over the lake surface. The EC method suggests that the mean daily evaporation was 3.0 mm day−1 in January, 2018. The bulk-aerodynamic method, based on observations at the lake shore as an input, yielded a mean daily evaporation of 2.3 mm day−1 for January. One of the Dalton type equations was better in estimating the summer mean evaporation, but the bulk aerodynamic method was much better in producing the day-to-day variations in evaporation. The summer evaporation over the ice-free Lake Zub/Priyadarshini exceeded the summer precipitation by a factor of 10. Hence, evaporation is a major term of the water balance of glacial lakes. Evaluation of the evaporation products of ERA5 reanalysis clearly demonstrated the need to add glacial lakes in the surface scheme of ERA5. Presently the area-averaged evaporation of ERA5 is strongly underestimated in the lake-rich region studied here.