-
توجه: در صورتی که از کاربران قدیمی ایران انجمن هستید و امکان ورود به سایت را ندارید، میتوانید با آیدی altin_admin@ در تلگرام تماس حاصل نمایید.
تجزیه و تحلیل وضعیت جوی در سال زراعی 93-94 /فصل دوم( دي- بهمن-اسفند)
- شروع کننده موضوع heaven1
- تاریخ شروع
- وضعیت
Amir Mohsen
متخصص بخش هواشناسی
Amir Mohsen
متخصص بخش هواشناسی
محمد بجنورد
کاربر ويژه
درود بر دوستان عزیز
بنظرمیاد جی اف اس خوب آپدیت کرده:
بنظرمیاد جی اف اس خوب آپدیت کرده:
Amir Mohsen
متخصص بخش هواشناسی
محمد بجنورد
کاربر ويژه
Deforestation impacts monsoon rains, says IISc study
Updated: Mar 4, 2015 07:02 AM , By N. Gopal Raj | 0 comments
Widespread deforestation, especially in the northern high latitudes, takes a toll on the monsoon across the northern hemisphere, with rains over India particularly badly affected, according to a new study from researchers at the Indian Institute of Science in Bangalore. By the 1750s, only about seven per cent of the global land area had been cleared for agriculture and that proportion has since risen to around one-third.
Govindasamy Bala, a professor at the IISc’s Divecha Centre for Climate Change, along with post-doctoral researcher N. Devaraju and a doctoral student, Angshuman Modak, used a climate model to investigate the effects of large-scale deforestation. With the climate model, they could simulate what happened when extensive deforestation took place across the whole globe, just in the northern high latitudes, only in temperate areas as well as when it was restricted to the tropics.
Such deforestation reduced rains in the monsoon regions of the northern hemisphere. India was affected the most, with global deforestation producing an 18 per cent reduction in its summer monsoon rains, the scientists noted in a paper in the Proceedings of the National Academy of Sciences. On the other hand, the deforestation led to moderately increased rains over South Africa, South America and Australia in the southern hemisphere.
India is the most affected, with 18 p.c. drop in summer rains
Updated: Mar 4, 2015 07:02 AM , By N. Gopal Raj | 0 comments
Widespread deforestation, especially in the northern high latitudes, takes a toll on the monsoon across the northern hemisphere, with rains over India particularly badly affected, according to a new study from researchers at the Indian Institute of Science in Bangalore. By the 1750s, only about seven per cent of the global land area had been cleared for agriculture and that proportion has since risen to around one-third.
Govindasamy Bala, a professor at the IISc’s Divecha Centre for Climate Change, along with post-doctoral researcher N. Devaraju and a doctoral student, Angshuman Modak, used a climate model to investigate the effects of large-scale deforestation. With the climate model, they could simulate what happened when extensive deforestation took place across the whole globe, just in the northern high latitudes, only in temperate areas as well as when it was restricted to the tropics.
Such deforestation reduced rains in the monsoon regions of the northern hemisphere. India was affected the most, with global deforestation producing an 18 per cent reduction in its summer monsoon rains, the scientists noted in a paper in the Proceedings of the National Academy of Sciences. On the other hand, the deforestation led to moderately increased rains over South Africa, South America and Australia in the southern hemisphere.
India is the most affected, with 18 p.c. drop in summer rains
Sun's heliosphere dominated by two solar jets: NASA
IANS | Washington Mar 04, 2015 02:04 PM IST
Contrary to earlier visualisations, the sun's heliosphere is dominated by two giant jets of material shooting backwards over the north and south poles of the sun.
The heliosphere is created by the solar wind, the changed particles emitted by the sun. The heliosphere extends far beyond the planets of the solar system. These two jets are confined by the interaction of the sun's magnetic field with the interstellar magnetic field.
"Everyone's assumption has been that the shape of the heliosphere was molded by the flow of interstellar material passing around it," said Merav Opher, astronomer at Boston University and lead author of the NASA-funded study.
Scientists have for decades visualised the heliosphere in the shape of a comet, with a very long tail extending some 464 billion miles. The two jets are similar to other astrophysical jets seen in space, so studying them locally could open doors to understanding such jets throughout the universe.
"Scientists thought the solar wind flowing down the tail could easily pull the magnetic fields in the heliosphere along as it flowed by, creating this long tail. But it turns out that the magnetic fields are strong enough to resist that pull - so instead they squeeze the solar wind and create these two jets," said Opher.
The team could determine the new shape when they adjusted simulations of the heliosphere based on observations collected from NASA's Voyager 1 spacecraft.
The spacecraft recently moved outside of the heliosphere into interstellar space. "If there were no interstellar flow, then the magnetic fields around the sun would shape the solar wind into two jets pointing straight north and south," said Jim Drake at the University of Maryland in College Park.
"If we're right about all of this, it gives us a local test bed for exploring some very important physics," Drake concluded.
The study findings were detailed in the Astrophysical Journal Letters.
IANS | Washington Mar 04, 2015 02:04 PM IST
Contrary to earlier visualisations, the sun's heliosphere is dominated by two giant jets of material shooting backwards over the north and south poles of the sun.
The heliosphere is created by the solar wind, the changed particles emitted by the sun. The heliosphere extends far beyond the planets of the solar system. These two jets are confined by the interaction of the sun's magnetic field with the interstellar magnetic field.
"Everyone's assumption has been that the shape of the heliosphere was molded by the flow of interstellar material passing around it," said Merav Opher, astronomer at Boston University and lead author of the NASA-funded study.
Scientists have for decades visualised the heliosphere in the shape of a comet, with a very long tail extending some 464 billion miles. The two jets are similar to other astrophysical jets seen in space, so studying them locally could open doors to understanding such jets throughout the universe.
"Scientists thought the solar wind flowing down the tail could easily pull the magnetic fields in the heliosphere along as it flowed by, creating this long tail. But it turns out that the magnetic fields are strong enough to resist that pull - so instead they squeeze the solar wind and create these two jets," said Opher.
The team could determine the new shape when they adjusted simulations of the heliosphere based on observations collected from NASA's Voyager 1 spacecraft.
The spacecraft recently moved outside of the heliosphere into interstellar space. "If there were no interstellar flow, then the magnetic fields around the sun would shape the solar wind into two jets pointing straight north and south," said Jim Drake at the University of Maryland in College Park.
"If we're right about all of this, it gives us a local test bed for exploring some very important physics," Drake concluded.
The study findings were detailed in the Astrophysical Journal Letters.
Amir Mohsen
متخصص بخش هواشناسی
Amir Mohsen
متخصص بخش هواشناسی
CFSv2 داره خیلی خوب برای ماه آپریل آپدیت میزنه:
با سلام
در خصوص سامانه ی روز جمعه نیروی دریایی که داره بهتر اپ میکنه بقیه هم عالین فقط یک چیزی کانتر 540 واسه اومدن برف کفایت میکنه یا نه ؟ اگه اینجوری باشه که بارش روز جمعه ی ما بشکل برف خواهد بود و قطعا هم قابل خواهد بود.نکته جالب هم که تو نقشه های نیروی دریایی وجود داره واسه هفته ی دیگس که بازهم شاهد کاهش دما و برف خواهیم بود
عید سرد و برفی داریم ایا؟؟:گل:
در خصوص سامانه ی روز جمعه نیروی دریایی که داره بهتر اپ میکنه بقیه هم عالین فقط یک چیزی کانتر 540 واسه اومدن برف کفایت میکنه یا نه ؟ اگه اینجوری باشه که بارش روز جمعه ی ما بشکل برف خواهد بود و قطعا هم قابل خواهد بود.نکته جالب هم که تو نقشه های نیروی دریایی وجود داره واسه هفته ی دیگس که بازهم شاهد کاهش دما و برف خواهیم بود
عید سرد و برفی داریم ایا؟؟:گل:
با سلام
میشه توضیح بدید دقیقا چه اتفاق عجیبی افتاده؟
- وضعیت