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تجزیه و تحلیل وضعیت جوی در سال زراعی 93-94 /فصل اول( مهر- آبان-آذر)
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There’s growing evidence that global warming is driving crazy winters
By Chris Mooney November 20 Follow chriscmooney
Visualization of a very wavy northern hemisphere jet stream. Credit: NASA
It may be the timeliest -- and most troubling -- idea in climate science.
Back in 2012, two researchers with a particular interest in the Arctic, Rutgers' Jennifer Francis and the University of Wisconsin-Madison's Stephen Vavrus, published a paper called "Evidence linking Arctic amplification to extreme weather in mid-latitudes." In it, they suggested that the fact that the Arctic is warming so rapidly is leading to an unexpected but profound effect on the weather where the vast majority of us live -- a change that, if their theory is correct, may have something to do with the extreme winter weather the U.S. has seen lately.
In their paper, Francis and Vavrus suggested that a rapidly warming Arctic should interfere with the jet stream, the river of air high above us that flows eastward around the northern hemisphere and brings with it our weather. Sometimes, the jet stream flows relatively directly from west to east; but other times, it takes long, wavy loops, as in the image above. And according to Francis and Vavrus, Arctic warming should make the jet stream more wavy and loopy on average – some have called it “drunk” -- with dramatic weather consequences.
Here's the atmospheric physics behind the idea: Warm air expands, and naturally there is much more warm air at the equator than at the poles. Thus, the atmosphere is thicker at the equator, and the jet stream's motion is driven by the decline in atmospheric thickness as one moves in a poleward direction -- in effect, its atmospheric river flows "downhill," in Francis’s words. However, if the Arctic is warming faster than the mid-latitudes, then the difference in thickness as you move in a poleward direction should decrease. And this should slow the jet stream, leading to more loops and turns -- and consequently, weather of all types getting stuck in place for longer. There's a nice video explanation of this by Francis here:
Rutgers University's Jennifer Francis, who published a paper linking Arctic amplification to extreme weather in mid-latitudes, explained her theory that may have something to do with extreme winter, like what we’ve seen this week. (StormCenter Communications)
According to Francis, the extreme U.S. winter of last year and now, the extremes at the beginning of this season, fit her theory. "This winter looks a whole lot like last winter, it’s a very amplified jet stream pattern," she says. "We know that when we get these patterns, it tends to be very persistent. And it is definitely the type of pattern that we expect to see more often as the Artic continues to warm so fast."
To be sure, Francis acknowledges that our recent bout of extreme cold was kickstarted most directly by Typhoon Nuri, which swerved up into the mid-latitudes and exploded into an atmospheric bomb over the Bering Sea. "That had the downstream effect of basically taking the jet stream and giving it a whip, whipping a wave into it," says Francis. But she also suspects that the jet stream is more susceptible to these kinds of dramatic influences because it is weaker now. In general, her theory does not say global warming caused any particular weather event, only that it is shifting the overall pattern of jet stream behavior, making certain kinds of persistent weather extremes more likely to occur.
Francis isn't the only one to suggest this. The widely read weather blogger Jeff Masters mused yesterday on whether the extreme snowfall in western New York this week might be due to "jet stream weirdness." "We've seen an unusual number of extreme jet stream patterns like this in the past fifteen years, which happens to coincide with the period of time we've been observing record loss of summertime Arctic sea ice and record retreat of springtime snow cover in the Arctic," noted Masters -- although he refrained from fully embracing the theory, noting that it still has its detractors. Capital Weather Gang's Jason Samenow also just discussedthe evidence behind Francis's idea, which he calls "controversial."
Francis argues, however, that the evidence in her favor is mounting -- she cites no fewer than five (1, 2, 3, 4, 5) scientific papers published in the last year or so that she considers supportive, and hints that more are coming. "We’ve got 5 papers that all look at that particular mechanism in different ways -- different analysis, different data sets, observation and models -- and they all come to the same conclusion and they all identify this mechanism independently," she says.
You can't call Francis's idea fully established. You can't say there's a "scientific consensus" on it. And you can't say that the august U.N. Intergovernmental Panel on Climate Change embraces it. Not yet. But it's certainly a very serious idea and one of the most discussed theories in climate science. Call it a contender. And if it's right, well...then we all know, already, what global warming feels like.
Chris Mooney reports on science and the environment.
By Chris Mooney November 20 Follow chriscmooney
Visualization of a very wavy northern hemisphere jet stream. Credit: NASA
It may be the timeliest -- and most troubling -- idea in climate science.
Back in 2012, two researchers with a particular interest in the Arctic, Rutgers' Jennifer Francis and the University of Wisconsin-Madison's Stephen Vavrus, published a paper called "Evidence linking Arctic amplification to extreme weather in mid-latitudes." In it, they suggested that the fact that the Arctic is warming so rapidly is leading to an unexpected but profound effect on the weather where the vast majority of us live -- a change that, if their theory is correct, may have something to do with the extreme winter weather the U.S. has seen lately.
In their paper, Francis and Vavrus suggested that a rapidly warming Arctic should interfere with the jet stream, the river of air high above us that flows eastward around the northern hemisphere and brings with it our weather. Sometimes, the jet stream flows relatively directly from west to east; but other times, it takes long, wavy loops, as in the image above. And according to Francis and Vavrus, Arctic warming should make the jet stream more wavy and loopy on average – some have called it “drunk” -- with dramatic weather consequences.
Here's the atmospheric physics behind the idea: Warm air expands, and naturally there is much more warm air at the equator than at the poles. Thus, the atmosphere is thicker at the equator, and the jet stream's motion is driven by the decline in atmospheric thickness as one moves in a poleward direction -- in effect, its atmospheric river flows "downhill," in Francis’s words. However, if the Arctic is warming faster than the mid-latitudes, then the difference in thickness as you move in a poleward direction should decrease. And this should slow the jet stream, leading to more loops and turns -- and consequently, weather of all types getting stuck in place for longer. There's a nice video explanation of this by Francis here:
Rutgers University's Jennifer Francis, who published a paper linking Arctic amplification to extreme weather in mid-latitudes, explained her theory that may have something to do with extreme winter, like what we’ve seen this week. (StormCenter Communications)
According to Francis, the extreme U.S. winter of last year and now, the extremes at the beginning of this season, fit her theory. "This winter looks a whole lot like last winter, it’s a very amplified jet stream pattern," she says. "We know that when we get these patterns, it tends to be very persistent. And it is definitely the type of pattern that we expect to see more often as the Artic continues to warm so fast."
To be sure, Francis acknowledges that our recent bout of extreme cold was kickstarted most directly by Typhoon Nuri, which swerved up into the mid-latitudes and exploded into an atmospheric bomb over the Bering Sea. "That had the downstream effect of basically taking the jet stream and giving it a whip, whipping a wave into it," says Francis. But she also suspects that the jet stream is more susceptible to these kinds of dramatic influences because it is weaker now. In general, her theory does not say global warming caused any particular weather event, only that it is shifting the overall pattern of jet stream behavior, making certain kinds of persistent weather extremes more likely to occur.
Francis isn't the only one to suggest this. The widely read weather blogger Jeff Masters mused yesterday on whether the extreme snowfall in western New York this week might be due to "jet stream weirdness." "We've seen an unusual number of extreme jet stream patterns like this in the past fifteen years, which happens to coincide with the period of time we've been observing record loss of summertime Arctic sea ice and record retreat of springtime snow cover in the Arctic," noted Masters -- although he refrained from fully embracing the theory, noting that it still has its detractors. Capital Weather Gang's Jason Samenow also just discussedthe evidence behind Francis's idea, which he calls "controversial."
Francis argues, however, that the evidence in her favor is mounting -- she cites no fewer than five (1, 2, 3, 4, 5) scientific papers published in the last year or so that she considers supportive, and hints that more are coming. "We’ve got 5 papers that all look at that particular mechanism in different ways -- different analysis, different data sets, observation and models -- and they all come to the same conclusion and they all identify this mechanism independently," she says.
You can't call Francis's idea fully established. You can't say there's a "scientific consensus" on it. And you can't say that the august U.N. Intergovernmental Panel on Climate Change embraces it. Not yet. But it's certainly a very serious idea and one of the most discussed theories in climate science. Call it a contender. And if it's right, well...then we all know, already, what global warming feels like.
Chris Mooney reports on science and the environment.
2014 Will Be Earth's Hottest Year on Record, Despite US Cold
By Becky Oskin | LiveScience.com – 19 hours ago
Wintry storms could bury Buffalo, New York, under heaps of snow until Christmas, but 2014 will still be the hottest year on Earth since 1880, climate scientists said today (Nov. 20).
"It's becoming pretty clear that 2014 will end up the warmest year on record," said Deke Arndt, chief of the climate monitoring branch at the National Climate Data Center. "The remaining question is, by how much."
The eastern United States was one of Earth's cold zones this year, with temperatures running 2.7 degrees Fahrenheit (1.5 degrees Celsius) below average, scientists from the National Oceanic and Atmospheric Administration (NOAA) said today during the agency's monthly climate briefing. But the bitter cold couldn't offset record-breaking heat waves in California, Europe and Australia this year, nor the incredible warmth in the world's oceans. [In Images: Extreme Weather Around the World]
"Notably, every major ocean basin and every continent all had some pieces — and some had significant pieces of their area — that were the warmest on record [during 2014]," Arndt said. "It's virtually certain that California will have its warmest year on record, even if California has record cold in December."
October was the sixth straight month of chart-busting heat in the oceans, according to NOAA. Last month was also the hottest October on record for land temperatures.
Combining land and sea temperatures, the average worldwide temperature of 58.43 F (14.74 C) for October 2014 topped the previous high set in October 2003 by 0.02 F (0.01 C). November 2013 through November 2014 is now the warmest 12-month stretch on record for any 12-month period recorded since 1880, NOAA said.
With less than two months left in 2014, the planet is on track to beat the warmest years in the historical record. So far this year, worldwide temperatures are averaging 58.62 F (14.78 C). The entire planet would have to go through a cold snap for 2014 to miss finishing in the top 10. (And it may feel that way for people in eastern North America and eastern Russia, where heavy snows arrived early this year.)
Two giant pools of warmer-than-average water in the Pacific Ocean helped boost global temperatures in 2014, NOAA scientists said. One pool is sloshing around the eastern Pacific along the equator, and is related to the El Niño climate pattern that is struggling to develop. The other pool is a large mass of warm water stretching from Alaska to California. These warm, West Coast waters suggest that a decades-long natural climate pattern called the Pacific Decadal Oscillation (PDC) has flipped into its positive phase, said NOAA forecaster David Unger. The PDO influences weather in North America by shifting the jet stream and changing where rain and snow fall, similar to El Niño's worldwide effects.
Sea surface temperatures in the northern Pacific Ocean haven't been this warm in 10 years, Unger said. "Whether it will stay this way, only time will tell," he said. The PDO has generally been in a negative, or cold phase, since 1998, scientists think.
Follow Becky Oskin @beckyoskin. Follow Live Science @livescience, Facebook & Google+. Originally published on Live Science.
By Becky Oskin | LiveScience.com – 19 hours agoWintry storms could bury Buffalo, New York, under heaps of snow until Christmas, but 2014 will still be the hottest year on Earth since 1880, climate scientists said today (Nov. 20).
"It's becoming pretty clear that 2014 will end up the warmest year on record," said Deke Arndt, chief of the climate monitoring branch at the National Climate Data Center. "The remaining question is, by how much."
The eastern United States was one of Earth's cold zones this year, with temperatures running 2.7 degrees Fahrenheit (1.5 degrees Celsius) below average, scientists from the National Oceanic and Atmospheric Administration (NOAA) said today during the agency's monthly climate briefing. But the bitter cold couldn't offset record-breaking heat waves in California, Europe and Australia this year, nor the incredible warmth in the world's oceans. [In Images: Extreme Weather Around the World]
"Notably, every major ocean basin and every continent all had some pieces — and some had significant pieces of their area — that were the warmest on record [during 2014]," Arndt said. "It's virtually certain that California will have its warmest year on record, even if California has record cold in December."
October was the sixth straight month of chart-busting heat in the oceans, according to NOAA. Last month was also the hottest October on record for land temperatures.
Combining land and sea temperatures, the average worldwide temperature of 58.43 F (14.74 C) for October 2014 topped the previous high set in October 2003 by 0.02 F (0.01 C). November 2013 through November 2014 is now the warmest 12-month stretch on record for any 12-month period recorded since 1880, NOAA said.
With less than two months left in 2014, the planet is on track to beat the warmest years in the historical record. So far this year, worldwide temperatures are averaging 58.62 F (14.78 C). The entire planet would have to go through a cold snap for 2014 to miss finishing in the top 10. (And it may feel that way for people in eastern North America and eastern Russia, where heavy snows arrived early this year.)
Two giant pools of warmer-than-average water in the Pacific Ocean helped boost global temperatures in 2014, NOAA scientists said. One pool is sloshing around the eastern Pacific along the equator, and is related to the El Niño climate pattern that is struggling to develop. The other pool is a large mass of warm water stretching from Alaska to California. These warm, West Coast waters suggest that a decades-long natural climate pattern called the Pacific Decadal Oscillation (PDC) has flipped into its positive phase, said NOAA forecaster David Unger. The PDO influences weather in North America by shifting the jet stream and changing where rain and snow fall, similar to El Niño's worldwide effects.
Sea surface temperatures in the northern Pacific Ocean haven't been this warm in 10 years, Unger said. "Whether it will stay this way, only time will tell," he said. The PDO has generally been in a negative, or cold phase, since 1998, scientists think.
Follow Becky Oskin @beckyoskin. Follow Live Science @livescience, Facebook & Google+. Originally published on Live Science.
سلام بر دوستان
طلاعیه شماره 25بررسی نقشه ها و مدل هاي هواشناسي نشان دهنده تأثیرگذاری جریانات کم فشار طی 24 ساعت آینده در سطح استان می باشد .بر این اساس :
طلاعیه شماره 25بررسی نقشه ها و مدل هاي هواشناسي نشان دهنده تأثیرگذاری جریانات کم فشار طی 24 ساعت آینده در سطح استان می باشد .بر این اساس :
- سرعت وزش باد ، طی امشب و فردا (یکشنبه 93/9/2)در سطح استان شدت خواهد یافت بطوریکه در پاره ای نقاط سرعت وزش باد نسبتاً شدید تا شدید ( خصوصاً در نوار شمالی استان و پاره ای نقاط از نقاط واقع در نیمه جنوبی ، وزش باد شدید ) پیش بینی می شود .
[*]با توجه به افزايش سرعت وزش باد ، احتمال وقوع خسارت در برخي مناطق استان دور از انتظار نيست.
تاریخ انتشار: 1393/09/01
تعداد بازدید: 1103
تعداد بازدید: 1103
[FONT=BMitra !important]اخطاریه شماره 44 شنبه مورخ 93/9/1
پیرو اخطاریه شماره 43 مورخ 93/08/30 به اطلاع می رساند با تداوم بارشهای سامانه فعال بر روی کشور، آب گرفتگی معابر عمومی به سبب بارش باران و رعدوبرق و اختلال در تردد در جاده های کوهستانی به سبب بارش برف و لغزندگی طی سه روز آینده به شرح ذیل پیش بینی می شود:
شنبه 93/09/01: در استانهای لرستان، شمال خوزستان، کرمانشاه، ایلام، کردستان، آذربایجان شرقی، جنوب آذربایجان غربی، زنجان، اردبیل و از اواخر شب در استان گیلان.
یکشنبه 93/09/02: در استانهای گیلان، غرب مازندران، بوشهر، مناطق مرکزی فارس.
دوشنبه 93/09/03: در استانهای خوزستان، بوشهر، فارس، کهگیلویه وبویراحمد، چهارمحال و بختیاری، گیلان و غرب مازندران و با شدت کمتر شمال کرمان و غرب اصفهان.
از این رو توصیه می شود تمهیدات و تجهیزات لازم برای تردد در جاده ها در مناطق فوق به کار گرفته شود. لازم به ذکر است طی روزهای یکشنبه و دوشنبه دریای خزر مواج و توفانی می باشد.
همچنین طی روزهای یکشنبه تا سه شنبه به سبب نفوذ جریانات سرد شمالی کاهش دما بین 5 تا 8 درجه در استانهای واقع در نوار شمالی بویژه سواحل دریای خزر رخ خواهد داد.
Amir Mohsen
متخصص بخش هواشناسی
سلام
به شخصه برای تهران در طی روزهای دوشنبه و سه شنبه بارشهای خوبی رو متصور هستم.
به شخصه برای تهران در طی روزهای دوشنبه و سه شنبه بارشهای خوبی رو متصور هستم.
سلام و صبح بخیر
65 کیلومتری شمال مشهد در مسیر کلات جهت صرف صبحانه در همین لحظه و جای دوستان عزیز خالی
وای خدای من!خیلی رویاییه1
اینها باید بعنوان پوستر طبیعت پاییزی در خراسان چاپ بشه
Amir Mohsen
متخصص بخش هواشناسی
| 1 | Orumieh (Iran) | 18.0 mm |
| 2 | Mohabad (Iran) | 14.4 mm |
| 3 | Maragheh (Iran) | 13.0 mm |
| 4 | Ilam (Iran) | 11.6 mm |
| 5 | Khorram Abad (Iran) | 11.3 mm |
| 6 | Kermanshah (Iran) | 8.9 mm |
| 7 | Tabriz (Iran) | 8.6 mm |
| 8 | Pars Abad Moghan (Iran) | 8.0 mm |
| 9 | Sanandaj (Iran) | 7.0 mm |
| 10 | Saghez (Iran) | 6.9 mm |
| 11 | Khoy (Iran) | 5.0 mm |
| 12 | Ali-Goodarz (Iran) | 4.7 mm |
| 13 | Masjed-Soleyman (Iran) | 4.3 mm |
| 14 | Ahar (Iran) | 3.6 mm |
| 15 | Makko (Iran) | 3.4 mm |
| 16 | Hamedan (Iran) | 2.8 mm |
| 17 | Sarab (Iran) | 2.8 mm |
| 18 | Ahwaz (Iran) | 1.9 mm |
| 19 | Zanjan (Iran) | 1.7 mm |
| 20 | Safi-Abad Dezful (Iran) | 1.6 mm |
| 21 | Arak (Iran) | 1.2 mm |
| 22 | Omidieh (Iran) | 0.6 mm |
| 23 | Abadan (Iran) | 0.5 mm |
| 24 | Ardebil (Iran) | 0.4 mm |
| 25 | Ghazvin (Iran) | 0.3 mm |
| 26 | Shahre-Kord (Iran) | 0.2 mm |
| 27 | Gach Saran Du Gunbadan (Iran) | 0.1 mm |
| 28 | Rasht (Iran) | 0.0 mm |
| 29 | Tehran-Mehrabad (Iran) | 0.0 mm |
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