Topographic meandering of Antarctic Circumpolar Current and Antarctic Circumpolar Wave in the ice‐ocean‐ atmosphere system

Topographic meandering of Antarctic Circumpolar Current (ACC) is found to be an impediment in the propagation of Antarctic Circumpolar Wave (ACW) in the Indian Ocean sector of Antarctica. Reasons for this are attributed to the southward advection of the ACW anomalies associated with the topographic meandering of the ACC. The southward meandering of ACC facilitates warming up of the region east of 20°E by about 1°C during winter, thereby reducing the sea ice; these processes interfere with the eastward propagating positive sea‐ice anomalies, and reduce its strength. Warming of ocean induced by topographic meandering leads to upward vertical velocities between 40°–60°E, where the ocean surface velocities are weak and southward, and the vertical/meridional advection of temperature dominates the zonal advection in the atmosphere. This results in the decoupling of the ACW in the region east of 40°E. In regions out side the Indian Ocean sector, vertical advection is minimum and zonal velocity of ACC becomes positive, which facilitates the ACW propagation in the Central Pacific, Ross and Weddell Seas

Spatiotemporal change analysis for snowmelt over the Antarctic ice shelves using scatterometers

Using Scatterometer-based backscatter data, the spatial and temporal melt dynamics of Antarctic ice shelves were tracked from 2000 to 2018. We constructed melt onset and duration maps for the whole Antarctic ice shelves using a pixel-based, adaptive threshold approach based on backscatter during the transition period between winter and summer. We explore the climatic influences on the spatial extent and timing of snowmelt using meteorological data from automatic weather stations and investigate the climatic controls on the spatial extent and timing of snowmelt. Melt extent usually starts in the latter week of November, peaks in the end of December/January, and vanishes in the first/second week of February on most ice shelves. On the Antarctic Peninsula (AP), the average melt was 70 days, with the melt onset on 20 November for almost 50% of the region. In comparison to the AP, the Eastern Antarctic experienced less melt, with melt lasting 40–50 days. For the Larsen-C, Shackleton, Amery, and Fimbul ice shelf, there was a substantial link between melt area and air temperature. A significant correlation is found between increased temperature advection and high melt area for the Amery, Shackleton, and Larsen-C ice shelves. The time series of total melt area showed a decreasing trend of −196 km2/yr which was statistical significant at 97% interval. The teleconnections discovered between melt area and the combined anomalies of Southern Annular Mode and Southern Oscillation Index point to the high southern latitudes being coupled to the global climate system. The most persistent and intensive melt occurred on the AP, West Ice Shelf, Shackleton Ice Shelf, and Amery Ice Shelf, which should be actively monitored for future stability

Did Covid-19 lockdown positively affect the urban environment and UN- Sustainable Development Goals?

Nigam, R., Tripathi, G., Priya, T., Luis, A. J., Vaz, E., Kumar, S., Shakya, A., Damásio, B., Kotha, M., & Yu, B. (Ed.) (2022). Did Covid-19 lockdown positively affect the urban environment and UN- Sustainable Development Goals? PLoS ONE, 17(9), 1-21. [e0274621]. https://doi.org/10.1371/journal.pone.0274621This work quantifies the impact of pre-, during- and post-lockdown periods of 2020 and 2019 imposed due to COVID-19, with regards to a set of satellite-based environmental parameters (greenness using Normalized Difference Vegetation and water indices, land surface temperature, night-time light, and energy consumption) in five alpha cities (Kuala Lumpur, Mexico, greater Mumbai, Sao Paulo, Toronto). We have inferenced our results with an extensive questionnaire-based survey of expert opinions about the environment-related UN Sustainable Development Goals (SDGs). Results showed considerable variation due to the lockdown on environment-related SDGs. The growth in the urban environmental variables during lockdown phase 2020 relative to a similar period in 2019 varied from 13.92% for Toronto to 13.76% for greater Mumbai to 21.55% for Kuala Lumpur; it dropped to −10.56% for Mexico and −1.23% for Sao Paulo city. The total lockdown was more effective in revitalizing the urban environment than partial lockdown. Our results also indicated that Greater Mumbai and Toronto, which were under a total lockdown, had observed positive influence on cumulative urban environment. While in other cities (Mexico City, Sao Paulo) where partial lockdown was implemented, cumulative lockdown effects were found to be in deficit for a similar period in 2019, mainly due to partial restrictions on transportation and shopping activities. The only exception was Kuala Lumpur which observed surplus growth while having partial lockdown because the restrictions were only partial during the festival of Ramadan. Cumulatively, COVID-19 lockdown has contributed significantly towards actions to reduce degradation of natural habitat (fulfilling SDG-15, target 15.5), increment in available water content in Sao Paulo urban area(SDG-6, target 6.6), reduction in NTL resulting in reducied per capita energy consumption (SDG–13, target 13.3).publishersversionpublishe

Semiautomated detection and mapping of vegetation distribution in the Antarctic environment using spatial-spectral characteristics of WorldView-2 imagery.

Effective monitoring of changes in the geographic distribution of cryospheric vegetation requires high-resolution and accurate baseline maps. The rationale of the present study is to compare multiple feature extraction approaches to remotely mapping vegetation in Antarctica, assessing which give the greatest accuracy and reproducibility relative to those currently available. This study provides precise, high-resolution, and refined baseline information on vegetation distribution as is required to enable future spatiotemporal change analyses of the vegetation in Antarctica. We designed and implemented a semiautomated customized normalized difference vegetation index (NDVI) approach for extracting cryospheric vegetation by incorporating very high resolution (VHR) 8-band WorldView-2 (WV-2) satellite data. The viability of state-of-the-art target detection, spectral processing/matching, and pixel-wise supervised classification feature extraction techniques are compared with the customized NDVI approach devised in this study. An extensive quantitative and comparative assessment was made by evaluating four semiautomatic feature extraction approaches consisting of 16 feature extraction standalone methods (four customized NDVI plus 12 existing methods) for mapping vegetation on Fisher Island and Stornes Peninsula in the Larsemann Hills, situated on continental east Antarctica. The results indicated that the customized NDVI approach achieved superior performance (average bias error ranged from ~6.44 ± 1.34% to ~11.55 ± 1.34%) and highest statistical stability in terms of performance when compared with existing feature extraction approaches. Overall, the accuracy analysis of the vegetation mapping relative to manually digitized reference data (supplemented by validation with ground truthing) indicated that the 16 semi-automatic mapping methods representing four general feature extraction approaches extracted vegetated area from Fisher Island and Stornes Peninsula totalling between 2.38 and 3.72 km2 (2.85 ± 0.10 km2 on average) with bias values ranging from 3.49 to 31.39% (average 12.81 ± 1.88%) and average root mean square error (RMSE) of 0.41 km2 (14.73 ± 1.88%). Further, the robustness of the analyses and results were endorsed by a cross-validation experiment conducted to map vegetation from the Schirmacher Oasis, East Antarctica. Based on the robust comparative analysis of these 16 methods, vegetation maps of the Larsemann Hills and Schirmacher Oasis were derived by ensemble merging of the five top-performing methods (Mixture Tuned Matched Filtering, Matched Filtering, Matched Filtering/Spectral Angle Mapper Ratio, NDVI-2, and NDVI-4). This study is the first of its kind to detect and map sparse and isolated vegetated patches (with smallest area of 0.25 m2) in East Antarctica using VHR data and to use ensemble merging of feature extraction methods, and provides access to an important indicator for environmental change

Exploratory mapping of blue ice regions in Antarctica using very high resolution satellite remote sensing data

Mapping spatiotemporal changes in the distribution of blue ice regions (BIRs) in Antarctica requires repeated, precise, and high-resolution baseline maps of the blue ice extent. This study demonstrated the design and application of a newly-developed semi-automatic method to map BIRs in the Antarctic environment using very high-resolution (VHR) WorldView-2 (WV-2) satellite images. We discussed the potential of VHR satellite data for the mapping of BIRs in the Antarctic environment using a customized normalized-difference blue-ice index (NDBI) method devised using yellow, green, and near-infrared spectral bands of WV-2 data. We compared the viability of the newly developed customized NDBI approach against state-of-the-art target detection (TD), spectral processing (SP) and pixel-wise supervised (PSC) feature extraction (FE) approaches. Four semi-automatic FE approaches (three existing plus one newly developed) consisting of 16 standalone FE methods (12 existing + four customized) were evaluated using an extensive quantitative and comparative assessment for mapping BIRs in the vicinity of Schirmacher Oasis, on the continental Antarctic coastline. The results suggested that the customized NDBI approach gave a superior performance and the highest statistical stability when compared with existing FE techniques. The customized NDBI generally rendered the lowest level of misclassification (average RMSE = 654.48 ± 58.26 m2), followed by TD (average RMSE = 987.81 ± 55.05 m2), SP (average RMSE = 1327.09 ± 127.83 m2) and PSC (average RMSE = 2259.43 ± 115.36 m2) for mapping BIRs. Our results indicated that the use of the customized NDBI approach can greatly improve the semi-automatic mapping of BIRs in the Antarctic environment. This study presents the first refined map of distribution of BIRs around the Schirmacher Oasis. The total area of blue ice in the study area was estimated to be 106.875 km2, approximately 61% of the study area. The WV-2 derived BIR map area presented in this study locally refined the existing BIR map derived using Landsat Enhanced Thematic Mapper Plus (ETM+) and the Moderate Resolution Imaging Spectroradiometer (MODIS)-based mosaic of Antarctica (MOA) dataset by ~31% (~33.40 km2). Finally, we discussed the practical challenges and future directions in mapping BIRs across Antarctica

Oceanographic features of the Indian Ocean sector of Coastal Antarctica (Short Communication)

A review is presented on physical oceanographic features based on expendable CTD data collected in the Indian Ocean sector of the Southern Ocean. The thermohaline structure is dominated by Circumpolar Deep Water. The temperature and salinity are affected by cyclonic circulation in the Weddell Sea and Prydz Bay. High chlorophyll-a blooms (2-4 mg m-3) evolve during austral summer due to stratification which is caused by freshwater generated from the sea ice melt and the glacial outflow which traps phytoplankton in a shallow mixed layer, where they are exposed to higher irradiances of photosynthetically active radiation. Attempts have been made to relate the physical characteristics to biomass inferred from data published from previous Indian Scientific expeditions. More in-situ observations related to biophysical and chemical are recommended in the near future projects

High-resolution multispectral mapping facies on glacier surface in the Arctic using WorldView-3 data

Glaciers are important and sensitive part of our environment which can be used as indicator of global warming and climate change. Glacier facies represent distinct regions of a glacier surface characterized by near surface structure and density that develop as a function of spatial variations in surface melt and accumulation. The facies mapping aids in delineating different zones of the glacier, which are useful in computing glacier mass balance and modeling. In this study we tested traditional and advanced classification techniques on the Edithbreen glacier situated in Ny-lesund, Svalbard, using WorldView-3 and Landsat 8 OLI. The comparison of the accuracy was conducted using error matrices. Six measures of accuracy were derived from the error matrices and were compared with each other to find the method delivering the most adequate output for facies mapping. The pixel-based approach applied to Landsat-8 data yielded higher accuracies (>80%) when compared to that. The object-oriented classification revealed a much better accuracy and high kappa coefficient for both low and high-resolution datasets. The study clearly indicates that the object-oriented classification provides better results for glacier facies classification when high spatial resolution is used, but for lower spatial resolution, pixel-based methods are adequate

QuikSCAT-based momentum flux analysis over the Southern Ocean

47-54Using QuikSCAT vector winds, the seasonal and interannual variability of momentum flux were studied to explore the underlining dynamics for its modulation over the Southern Ocean (SO) during August 1999 to July 2003. The wind speed validation of ship and QuikSCAT measurements in the western Indian sector of the SO showed a bias and root mean square error of 0.3 and 1.6 m/s, respectively. On seasonal time scales, the spatial wind stress patterns reveal a basin-wide variability and the boreal summer monsoon significantly influencing it in the Indian Ocean (IO) sector. The temporal march of the momentum flux for different ocean sectors exhibit a seasonal cycle with a maximum range between 0.13 and 0.18 N/m2 during August-September and a minimum range between 0.07 and 0.11 N/m2 during December – January, with a temporal shift of ±1 month between the sectors. The atmospheric pressure gradient between tropics and high latitudes enhances the momentum flux in the IO sector during austral winter. On interannual time scales the momentum flux maps indicate a marked regional variability which is highest in IO sector and an evolution of cyclonic circulation south of 50°S during austral winter. Based on earlier studies and after a detailed examination of SST and wind stress curl fields, it is argued that orientation of the SST gradient relative to direction of wind stress drive an atmospheric response through wind stress curl and divergence modulations, which in turn dictates the intensity of momentum flux on seasonal time scales

Näkymätön käyntikortti : Psykoottisten sielunhoito sairaalapappien näkökulmasta

Tutkin kahdeksan sairaalapapin näkemystä psykoottisten sielunhoidosta haastattelemalla heitä teemahaastattelumenetelmällä. Tutkimuskysymykseni olivat 1) miten sairaalapapit kokevat psykoottisten potilaiden kohtaamisen sielunhoitotilanteessa ja 2) mitkä ovat sairaalapappien käsitykset sielunhoidon auttamismahdollisuuksista psykoottisten potilaiden kohdalla. Litteroin haastatteluaineiston ja analysoin sen sisällönanalyysimenetelmällä. Esiin nousi kolme pääteemaa, joiden alle tutkimustulokset jakautuivat. Kaksi ensimmäistä teemaa liittyivät ensimmäiseen tutkimuskysymykseen, ja ne olivat sairaalapapin sisäinen maailma eli heidän omat ajatuksensa ja tunteensa, sekä psykoottisen potilaan hengellisyyden rooli sielunhoitotyössä. Kolmas teema oli sielunhoidon tuoma konkreettinen apu, ja se liittyi toiseen tutkimuskysymykseen. Tutkimuksen perusteella tein neljä johtopäätöstä. Ensinnäkin psykoottisten sielunhoidolle on kova tarve, sillä sen tuoma apu voi olla hyvin konkreettista. Toiseksi sairaalapapeille on näin ollen kova tarve, eikä heitä voi korvata muiden alojen asiantuntijoilla. Kolmanneksi psykoottisten sielunhoidolle on kuitenkin vaikea määritellä tavoitteita, eikä sillä siten ole myöskään mittareita vaikuttavuuden arviointiin. Neljäs johtopäätös on, että psykoottisten sielunhoidon suurimmat haasteet eivät ole itse sielunhoitotilanteessa vaan sitä ympäröivissä rakenteissa, joihin liittyvät liian pienet resurssit ja joissain tapauksissa myös puutteellinen yhteistyö hoitohenkilökunnan kanssa. Mitä tiiviimmin sairaalalappi koetaan hoitotiimin osana, sitä enemmän siitä hyötyy potilas. Johtopäätöksillä on toisiinsa nähden riippuvuussuhde. Esitän, että jos sielunhoidon tutkimus lähestyisi asiaa tavoitteiden ja vaikuttavuuden näkökulmasta, psykoottisten sielunhoidon tarpeellisuus voitaisiin nähdä yhteiskunnallisessa ja kirkollisessa keskustelussa paremmin. Tällä voitaisiin vaikuttaa ympäröiviin rakenteisiin, eli saada sairaalapapit aidosti osaksi hoitotiimiä ja tukea heidän työnsä olemassaolon oikeutusta. Kun työn vaikuttavuus voitaisiin paremmin todentaa, saattaisi se tuoda sairaalasielunhoidolle lisäresursseja, jolloin suurin haaste poistuisi. Kaikki tämä vastaisi psykoottisten sielunhoidon huutavaan tarpeeseen. Lisäksi tutkielma kiinnitti huomiota siihen, että sielunhoidon teorioiden ja käytännön välillä on ristiriita: sielunhoidon teoriassa tärkeää näkökulmaa näyttelevä toivo ja sen merkitys eivät muodostaneet merkittävää osaa sielunhoidon käytännön työssä. Sielunhoidon tavoitteiden ja vaikuttavuuden tutkiminen ja toivon merkityksen analysointi suhteessa niihin saattaisi tuoda uutta näkemystä sekä sielunhoidon teoriaan että yhteiskunnalliseen ja kirkolliseen arvostukseen, ja sitä kautta myös käytäntöön