Snow cover plays an important role in the fields of climatology and cryospheric science. Remotely-sensed data have been proven to be effective in monitoring snow covers. Improved methods to process the 8-day snow-cove...Snow cover plays an important role in the fields of climatology and cryospheric science. Remotely-sensed data have been proven to be effective in monitoring snow covers. Improved methods to process the 8-day snow-cover products derived from MODIS Terra/Aqua data can dramatically increase the data quality and reduce noise. A five-step algorithm for removing cloud effects was designed to improve the quality of MODIS snow products, and the overall accuracy of the MODIS snow data without cloud（defined as cloud-free snow-cover dataset） was enhanced by more than 90% based on direct and indirect validation methods. The snow-cover frequency（SCF） and snow-cover rate（SCR） of Central Asia were analyzed from 2000 to 2015 using trend analysis and empirical orthogonal functions（EOFs）. Over the plain regions, the SCF displayed a significant north-south declining trend with a rate of 0.03 per degree of latitude, and the SCR showed a similar north-south gradient. In the mountainous areas, the SCF significantly increased with altitude by 0.12 per kilometer. Within the study area, the SCF in 65% of the study area experienced an increasing trend, but only 4.3% of the SCF-increasing pixels passed a significance test. The remaining 35% of the area underwent a decreasing trend of SCF, but only 5.2% of the SCF-decreasing pixels passed a significance test. For the entire Central Asia, the inter-annual variations of snow-cover presented a slight and insignificant increase trend from 2000 to 2015. However, the change trends of snow cover are different between the plain and mountainous regions. That is, the annual mean SCR in the plain areas displayed an increasing trend, but a decreasing trend was found in the mountainous areas.展开更多
The old-aged confrontation between “East” and “West”, between “civilization” and “barbarism”, between “Christianity” and “Islam” came to new heights in the early modern times and found its arena in Central...The old-aged confrontation between “East” and “West”, between “civilization” and “barbarism”, between “Christianity” and “Islam” came to new heights in the early modern times and found its arena in Central Europe. Since the late 15th century, the Ottoman Turks had been feared as menace, as the most dreadful enemies not only of the inhabitants of the Habsburg ruled countries but of the whole world of Christianity, and the Ottoman Turks did pose a permanent threat to their neighbours in Central Europe. The situation changed around 1700 when the Habsburgs succeeded in integrating the entire Hungarian Kingdom into their empire. From the early 18th century onwards the Ottoman Turks were no longer regarded as fierce fighters but increasingly as neighbours living in an unknown and totally different world and gained more and more curious attention. This change was not only the consequence of the new balance in power politics but mainly a sequel of gaining much more information. Up to the late 17th century the knowledge about the Ottoman Turks was based primarily on what had been reported by ambassadors travelling to Constantinople while in the 18th century people of several strands of life reported about their experiences. After the Peace of Passarowitz in 1718 trade agreements between the two states enabled activities of merchants and tradesmen who learned to know things about their eastern neighbours which were totally new to the Middle European contemporaries. Additionally, some elements of this ＂oriental＂ culture were taken over and were to become typical for Central Europe later on. The Turks were curiously observed as strange and fascinating neighbours. In the course of the movement of enlightenment from the middle of the 18th century onwards one aspect of this culture lost much of its dreadfulness： the fact that the Ottoman Turks were infidels. So it did not take very long until Ottomans were seen as being capable of true humanity regardless their religion. In the 19th century the multiethnic state organizations of the Ottoman Empire and the Habsburg Monarchy became outmoded in this age of nationalism. They realized their common interests and started a cooperation which eventually ended up as alliance in theWorld War I. From the point of view of power politics however, the Ottoman Empire was regarded as “sick man at the Bosporus”. In the following the changes of the image are shown as an overview by observing the criteria against the background of the most important historical events. The details of how this process worked are still pretty murky. Further investigations are already on the way and will bring more light into the reasons and the mechanism of this development.展开更多
基金funded by the National Key Research and Development Program of China (2016YFA0602302,2016YFB0502502)
文摘Snow cover plays an important role in the fields of climatology and cryospheric science. Remotely-sensed data have been proven to be effective in monitoring snow covers. Improved methods to process the 8-day snow-cover products derived from MODIS Terra/Aqua data can dramatically increase the data quality and reduce noise. A five-step algorithm for removing cloud effects was designed to improve the quality of MODIS snow products, and the overall accuracy of the MODIS snow data without cloud（defined as cloud-free snow-cover dataset） was enhanced by more than 90% based on direct and indirect validation methods. The snow-cover frequency（SCF） and snow-cover rate（SCR） of Central Asia were analyzed from 2000 to 2015 using trend analysis and empirical orthogonal functions（EOFs）. Over the plain regions, the SCF displayed a significant north-south declining trend with a rate of 0.03 per degree of latitude, and the SCR showed a similar north-south gradient. In the mountainous areas, the SCF significantly increased with altitude by 0.12 per kilometer. Within the study area, the SCF in 65% of the study area experienced an increasing trend, but only 4.3% of the SCF-increasing pixels passed a significance test. The remaining 35% of the area underwent a decreasing trend of SCF, but only 5.2% of the SCF-decreasing pixels passed a significance test. For the entire Central Asia, the inter-annual variations of snow-cover presented a slight and insignificant increase trend from 2000 to 2015. However, the change trends of snow cover are different between the plain and mountainous regions. That is, the annual mean SCR in the plain areas displayed an increasing trend, but a decreasing trend was found in the mountainous areas.
文摘The old-aged confrontation between “East” and “West”, between “civilization” and “barbarism”, between “Christianity” and “Islam” came to new heights in the early modern times and found its arena in Central Europe. Since the late 15th century, the Ottoman Turks had been feared as menace, as the most dreadful enemies not only of the inhabitants of the Habsburg ruled countries but of the whole world of Christianity, and the Ottoman Turks did pose a permanent threat to their neighbours in Central Europe. The situation changed around 1700 when the Habsburgs succeeded in integrating the entire Hungarian Kingdom into their empire. From the early 18th century onwards the Ottoman Turks were no longer regarded as fierce fighters but increasingly as neighbours living in an unknown and totally different world and gained more and more curious attention. This change was not only the consequence of the new balance in power politics but mainly a sequel of gaining much more information. Up to the late 17th century the knowledge about the Ottoman Turks was based primarily on what had been reported by ambassadors travelling to Constantinople while in the 18th century people of several strands of life reported about their experiences. After the Peace of Passarowitz in 1718 trade agreements between the two states enabled activities of merchants and tradesmen who learned to know things about their eastern neighbours which were totally new to the Middle European contemporaries. Additionally, some elements of this ＂oriental＂ culture were taken over and were to become typical for Central Europe later on. The Turks were curiously observed as strange and fascinating neighbours. In the course of the movement of enlightenment from the middle of the 18th century onwards one aspect of this culture lost much of its dreadfulness： the fact that the Ottoman Turks were infidels. So it did not take very long until Ottomans were seen as being capable of true humanity regardless their religion. In the 19th century the multiethnic state organizations of the Ottoman Empire and the Habsburg Monarchy became outmoded in this age of nationalism. They realized their common interests and started a cooperation which eventually ended up as alliance in theWorld War I. From the point of view of power politics however, the Ottoman Empire was regarded as “sick man at the Bosporus”. In the following the changes of the image are shown as an overview by observing the criteria against the background of the most important historical events. The details of how this process worked are still pretty murky. Further investigations are already on the way and will bring more light into the reasons and the mechanism of this development.
