محمد بجنورد
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سینا جان جواب شما رو باید اساتید محترم بدن ولی اگه نظر منو بخوای فکر کنم بارش بیشتر و دمای کمتر از نرمال رو خواهیم داشت،انشاالله.:گل:
درمورد nao چیزهایی میدونم ولی نمیتونم بیان کنم!!طریقه ی بیان کردنش رو نمیدونم!!!!
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مباحث عمومی هواشناسی
- شروع کننده موضوع Amir Mohsen
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سینا جان جواب شما رو باید اساتید محترم بدن ولی اگه نظر منو بخوای فکر کنم بارش بیشتر و دمای کمتر از نرمال رو خواهیم داشت،انشاالله.:گل:
درمورد nao چیزهایی میدونم ولی نمیتونم بیان کنم!!طریقه ی بیان کردنش رو نمیدونم!!!!
mehrdad_teh
متخصص بخش هواشناسی
با تشكر از امير (سعادت آباد) به خاطر اينكه عكس هاي بسيار زيباشون رو به وبلاگ من فرستادن. و من با كمال ميل عكس هاشون رو توي وبلاگم گذاشتم. :گل:
شب بر ياران ديرينه خوش :گل:
شب بر ياران ديرينه خوش :گل:
محمد بجنورد
کاربر ويژه
راستی همشهریت سامان عزیز اطلاعات بسیار خوب و جامعی در مورد nao دارن که متاسفانه هم اکنون در غیبت هستن و در فروم حضور ندارند!!
شما گفته بودید که در بهار امسال این شاخص منفی خواهد شد آیا این وضعیت را خواهیم داشت یا نه:گل:
Amir Mohsen
متخصص بخش هواشناسی
درود بر مهرداد عزیز
این دقیقا همون مهردادی هست که من می شناختمش .:گل:
و مثل همیشه عالی - جامع و بدون نقص:گل: :توافق:
محمد بجنورد
کاربر ويژه
حالا نوبت شماست!!!!!!:خنده1:،منتظر پاسختون هستیم.:گل:
Amir Mohsen
متخصص بخش هواشناسی
محمد جان سلام مهرداد عزیز حق مطلب رو به خوبی ارائه کردند و دیگه احتیاجی به توضیح من نیست و حالا باید دیگه صبر کنیم تا ببینم که گذر زمان چه سرنوشتی رو برای روزهای اینده رقم خواهد زد.
mehrdad_teh
متخصص بخش هواشناسی
من يادم نمي ياد راجع به منفي شدن شاخص حرف زده باشم. چون اصلا پيش بيني دراز مدت و فصلي براي اين شاخص امكان پذير نيست. اگه توي همون لينك توجه كني مدل ها و نمودار هاي پيش بين شاخص براي 2 هفته وجود دارن.
محمد بجنورد
کاربر ويژه
سلام بر امیرمحسن عزیز:گل:،سپاسگزارم:گل:،انشاالله که خبرهای خوبی طی روزهای آینده اعلام میکنید از این موج موردنظر:گل:،خب دوستان،امروز خواب موندمو نیم ساعت دیررسیدم مدرسه؛نامرد ناظم واسم 2ساعت اول رو غیبت زد،فقط میخواستم خفش کنم:تنبیه::تنبیه::اخطار::اخطار::خنده1::خنده1:،شب خوش،درپناه حق،یا علی:گل:
Amir Mohsen
متخصص بخش هواشناسی
Amir Mohsen
متخصص بخش هواشناسی
Amir Mohsen
متخصص بخش هواشناسی
Amir Mohsen
متخصص بخش هواشناسی
Warming Means Wetter Weather – and Drier Weather
By Tim Radford, Climate News Network
Welcome to the see-saw world of climate change. Rainy seasons will get rainier. Dry seasons will tend to become more parched. Even if the total annual rainfall does not change very much, the seasonal cycles will – with obvious consequences. Floods and droughts will become more frequent, according to Chia Chou of the University of Taipei, and colleagues from Taiwan and California.
Researchers have found evidence that in the last 30 years wet seasons have been becoming wetter and dry ones drier.
Credit: 3268Zauber
Like all pronouncements about the future, this one comes with caveats: the research is based on climate simulations of future warming, and the forecasts are only as good as the data fed into such simulations.
But the authors start with a trend they can already measure: they report in Nature Geoscience that they looked at rainfall data between 1979 and 2010 and found that the wet seasons were already clearly getting wetter, at the rate of almost a millimeter a day per century, while the dry seasons became drier with just over half a millimeter less in rainfall per day per century.
[h=3] Affecting drought and flood frequency And the gap between wet and dry seasons was widening at a rate of 1.47 millimeters per day per century. All three trends, they report, “are significant at the 99 percent confidence level.”
In the real world most of us experience, it’s hard to be sure that rainy spells are rainier, and dry seasons are drier: that is because, as the authors concede, global rainfall patterns are “spatially complex.”
But there is general agreement that such changes are taking place, with good physical reasons for doing so: a warmer world means more evaporation, and more precipitation. Furthermore, the authors say, simulations predict such a pattern and observations confirm it.
“The effect is often termed the thermodynamic contribution, or the rich-get-richer mechanism,” they write. “Even if the total amount of annual rainfall does not change significantly, the enhancement in the seasonal precipitation cycle could have marked consequences for the frequency of droughts and floods.”
Tim Radford is a reporter for Climate News Network. Climate News Network is a news service led by four veteran British environmental reporters and broadcasters. It delivers news and commentary about climate change for free to media outlets worldwide.
- Published: March 10th, 2013
By Tim Radford, Climate News Network
Welcome to the see-saw world of climate change. Rainy seasons will get rainier. Dry seasons will tend to become more parched. Even if the total annual rainfall does not change very much, the seasonal cycles will – with obvious consequences. Floods and droughts will become more frequent, according to Chia Chou of the University of Taipei, and colleagues from Taiwan and California.
Credit: 3268Zauber
Like all pronouncements about the future, this one comes with caveats: the research is based on climate simulations of future warming, and the forecasts are only as good as the data fed into such simulations.
But the authors start with a trend they can already measure: they report in Nature Geoscience that they looked at rainfall data between 1979 and 2010 and found that the wet seasons were already clearly getting wetter, at the rate of almost a millimeter a day per century, while the dry seasons became drier with just over half a millimeter less in rainfall per day per century.
[h=3] Affecting drought and flood frequency And the gap between wet and dry seasons was widening at a rate of 1.47 millimeters per day per century. All three trends, they report, “are significant at the 99 percent confidence level.”
In the real world most of us experience, it’s hard to be sure that rainy spells are rainier, and dry seasons are drier: that is because, as the authors concede, global rainfall patterns are “spatially complex.”
But there is general agreement that such changes are taking place, with good physical reasons for doing so: a warmer world means more evaporation, and more precipitation. Furthermore, the authors say, simulations predict such a pattern and observations confirm it.
“The effect is often termed the thermodynamic contribution, or the rich-get-richer mechanism,” they write. “Even if the total amount of annual rainfall does not change significantly, the enhancement in the seasonal precipitation cycle could have marked consequences for the frequency of droughts and floods.”
Tim Radford is a reporter for Climate News Network. Climate News Network is a news service led by four veteran British environmental reporters and broadcasters. It delivers news and commentary about climate change for free to media outlets worldwide.
- Posted in Trends, Projections, Climate, Extremes, Flooding, Heat, Water, Weather, Extreme Weather, International
Amir Mohsen
متخصص بخش هواشناسی
Amir Mohsen
متخصص بخش هواشناسی
Greening tundra shows Arctic heat
March 10, 2013 in Warming
EMBARGOED until 1800 GMT on Sunday 10 March
Vegetables can’t be fooled: The tundra shows the effects of spreading warmth
Image: ADialla
By Tim Radford
The Arctic is warming faster than many other parts of the planet, and plants are providing some of the clearest signs of the impacts, with vegetation now growing nearly 500 miles further north than it did a few decades ago.
LONDON, 10 March – The Arctic is on the move. The North Pole is in the same place, but Arctic conditions have begun to shift. A study of 30 years of satellite data confirms that the difference in temperatures between the seasons has diminished.
Conditions now have shifted the equivalent of four or five degrees of latitude southward. At the same time, vegetation has moved north, colonizing the thawing permafrost.
A team of 21 scientists from 17 institutions in seven nations reports in Nature Climate Change that as the cover of snow and ice has diminished and retreated in the Arctic Circle, the temperatures have begun to increase – at differing rates – during the four seasons. Although conditions differ from region to region, overall the growing season is beginning earlier, and the autumn freeze is starting later.
Conditions in northern latitudes now increasingly resemble those found several hundred miles further south 30 years ago. One of the authors, Bruce Forbes of the University of Lapland in Finland, told the Climate News Network that in his own research region of north-west Siberia “we are seeing more frequent and longer-lasting high pressure systems. In winter, the snow cover comes later, is deeper on average than in the 1960s, but is melting out earlier in spring.”
Climate is a complicated business, and there is always legitimate room for argument about the validity of one selected set of measurements, a potential bias in the observations, or the reliability of comparison data collected two generations earlier.
But vegetables can’t be fooled. Plants grow where they can. If deciduous shrubs are growing taller, and colonizing sites ever further north, then conditions must be getting warmer, and staying warmer.
Winners – and losers
Professor Forbes says that indigenous reindeer herders report that alder and willow, normally stunted by the polar winter, are growing taller: his own research team has confirmed this with dendrochronology, the science of tree ring measurement.
“In a few decades, if the current trends continue, much more of the existing low shrub tundra will start to resemble woodlands as the shrubs become tree-sized”, he says.
This enhanced warming over a longer ground-thaw season has changed the landscape: it has, says Compton Tucker of the Goddard Space Flight Center in the US, “created during the past 30 years large patches of vigorously productive vegetation, totaling more than a third of the northern landscape – over nine million km2, which is roughly about the area of the USA - resembling the vegetation that occurs further to the south.”
This warming of the high latitudes is not necessarily good news for all plants. As the tundra turns green at an accelerating rate, the growth of the boreal forests – those mighty stands of conifer species that cover northern Canada and northern Eurasia and enclose the Arctic Circle – may even be decelerating.
Boreal forest species are adapted to cold. “Some areas of boreal forest will be negatively impacted by warming temperatures, from increased drought stress as well as insect and fire disturbance”, says Scott Goetz of Woods Hole Research Center in the US, another of the co-authors.
“But this work shows that in most high latitude regions we see increased productivity resulting from a reduced range of seasonal temperature variability.”
Driving more warming
Since relative temperatures are dictated by latitude, the researchers used latitude as a measure. They selected reference sites and studied both change, and the rate of change, using three decades of Nasa satellite data, and reports from researchers and nomad observers.
One of these sites was at 64° N. Now, 30 years on, it has plant cover characteristic of 57° N. It is as if growing conditions had shifted seven degrees north, or very nearly 750 km, according to Terry Chapin, of the University of Fairbanks, Alaska.
By the end of the century, at the present rate of change, temperature seasonality will have diminished substantially, and – once again using latitude as a yardstick – will be the equivalent of a 20 degrees shift, relative to measurements made between 1951 and 1980.
Such warming is all too likely to feed back into even more global warming, as the frozen soils of the north come to life, peat and vegetation begin to decompose, and yet more reservoirs of buried methane and carbon dioxide are released into the atmosphere.
What it will mean to the peoples and the creatures of the north is hard to guess, because ecosystems will change with seasonal temperature and plant growth.
“Think of the migration of birds to the Arctic in the summer and the hibernation of bears in the winter”, says Dr Goetz. “Any significant aberrations in seasonality are likely to impact life not only in the north, but elsewhere, in ways that we do not know.” – Climate News Network
March 10, 2013 in Warming
EMBARGOED until 1800 GMT on Sunday 10 March
Image: ADialla
By Tim Radford
The Arctic is warming faster than many other parts of the planet, and plants are providing some of the clearest signs of the impacts, with vegetation now growing nearly 500 miles further north than it did a few decades ago.
LONDON, 10 March – The Arctic is on the move. The North Pole is in the same place, but Arctic conditions have begun to shift. A study of 30 years of satellite data confirms that the difference in temperatures between the seasons has diminished.
Conditions now have shifted the equivalent of four or five degrees of latitude southward. At the same time, vegetation has moved north, colonizing the thawing permafrost.
A team of 21 scientists from 17 institutions in seven nations reports in Nature Climate Change that as the cover of snow and ice has diminished and retreated in the Arctic Circle, the temperatures have begun to increase – at differing rates – during the four seasons. Although conditions differ from region to region, overall the growing season is beginning earlier, and the autumn freeze is starting later.
Conditions in northern latitudes now increasingly resemble those found several hundred miles further south 30 years ago. One of the authors, Bruce Forbes of the University of Lapland in Finland, told the Climate News Network that in his own research region of north-west Siberia “we are seeing more frequent and longer-lasting high pressure systems. In winter, the snow cover comes later, is deeper on average than in the 1960s, but is melting out earlier in spring.”
Climate is a complicated business, and there is always legitimate room for argument about the validity of one selected set of measurements, a potential bias in the observations, or the reliability of comparison data collected two generations earlier.
But vegetables can’t be fooled. Plants grow where they can. If deciduous shrubs are growing taller, and colonizing sites ever further north, then conditions must be getting warmer, and staying warmer.
Winners – and losers
Professor Forbes says that indigenous reindeer herders report that alder and willow, normally stunted by the polar winter, are growing taller: his own research team has confirmed this with dendrochronology, the science of tree ring measurement.
“In a few decades, if the current trends continue, much more of the existing low shrub tundra will start to resemble woodlands as the shrubs become tree-sized”, he says.
This enhanced warming over a longer ground-thaw season has changed the landscape: it has, says Compton Tucker of the Goddard Space Flight Center in the US, “created during the past 30 years large patches of vigorously productive vegetation, totaling more than a third of the northern landscape – over nine million km2, which is roughly about the area of the USA - resembling the vegetation that occurs further to the south.”
This warming of the high latitudes is not necessarily good news for all plants. As the tundra turns green at an accelerating rate, the growth of the boreal forests – those mighty stands of conifer species that cover northern Canada and northern Eurasia and enclose the Arctic Circle – may even be decelerating.
Boreal forest species are adapted to cold. “Some areas of boreal forest will be negatively impacted by warming temperatures, from increased drought stress as well as insect and fire disturbance”, says Scott Goetz of Woods Hole Research Center in the US, another of the co-authors.
“But this work shows that in most high latitude regions we see increased productivity resulting from a reduced range of seasonal temperature variability.”
Driving more warming
Since relative temperatures are dictated by latitude, the researchers used latitude as a measure. They selected reference sites and studied both change, and the rate of change, using three decades of Nasa satellite data, and reports from researchers and nomad observers.
One of these sites was at 64° N. Now, 30 years on, it has plant cover characteristic of 57° N. It is as if growing conditions had shifted seven degrees north, or very nearly 750 km, according to Terry Chapin, of the University of Fairbanks, Alaska.
By the end of the century, at the present rate of change, temperature seasonality will have diminished substantially, and – once again using latitude as a yardstick – will be the equivalent of a 20 degrees shift, relative to measurements made between 1951 and 1980.
Such warming is all too likely to feed back into even more global warming, as the frozen soils of the north come to life, peat and vegetation begin to decompose, and yet more reservoirs of buried methane and carbon dioxide are released into the atmosphere.
What it will mean to the peoples and the creatures of the north is hard to guess, because ecosystems will change with seasonal temperature and plant growth.
“Think of the migration of birds to the Arctic in the summer and the hibernation of bears in the winter”, says Dr Goetz. “Any significant aberrations in seasonality are likely to impact life not only in the north, but elsewhere, in ways that we do not know.” – Climate News Network
ali.doosti
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دزفول در حال انفجار...
ali.doosti
کاربر ويژه
اینم که باز همون جاست!:خنده1:
بابا برو یه کشور دیگه عکس بگیر:سوت:
طرح مشارکت همگانی
ترسیم از من تفسیر با دوستان:گل:
یکشنبه 17 مارس ساعت 00:30 بوقت ایران»»»
محسن جان می‌شه منبع این نقشه رو بگین؟ احیانن راهنمای نقشه نداشت که اون لوزی‌های زرد رو توضیح بده که چی هستند؟ یا اون فلش قرمز نازک که کم‌فشار رو در جنوب ایران نشون می‌ده؟ یا اون فلش قرمز کلفت که آیا داره محور پشته رو نشون می‌ده یا خیر؟ و اون فلش‌های سبز که آیا جهت حرکت رطوبت در تراز میانی حول پشته در جهت ساعتگرد رو داره نشون می‌ده یا خیر!
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