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مباحث عمومی هواشناسی تابستان 1393
- شروع کننده موضوع heaven1
- تاریخ شروع
- وضعیت
Amir Mohsen
متخصص بخش هواشناسی
آنومالی دمای کره زمین و چرخه های فعالیت های خورشیدی!!!!!!!!!!!!!!!!!
آخرین ویرایش:
Amir Mohsen
متخصص بخش هواشناسی
سلام بر دوستان
Stacked storm shot from Albuquerque, New Mexico yesterday.
Amir Mohsen
متخصص بخش هواشناسی
جدیدترین تحقیقات حکایت از این دارد که وقوع طوفان گرد و خاک در شمال افریقا و غرب خاورمیانه با فاصله زمانی یک هفته منجر به تقویت مونسون در شبه قاره هند میشود .
Amir Mohsen
متخصص بخش هواشناسی
طوفان نگوری:
Amir Mohsen
متخصص بخش هواشناسی
محققان اعلام کردند که ذرات گرد و خاک میتواند روند ذوب شدن یخ های گریلند را تسریع بخشد( تاریخ انتشار مقاله 9 جولای 2014)
الان مولفه اتمسفرى اقيانوس آرام SOI ال نينو را نشون ميده و مولفه اقيانوسى nino 3.4 لانينا را !!!
البته من فكر مى كنم بعد از اين سقوط يه صعود در پيش خواهيم داشت. .
استاد ميشه بيشتر توضيح بدهيد ؟ اينكه به چه دليل طوفان گرد و خاك در غرب خاورميانه باعث تقويت مونسون مى شود ؟ الان مونسون قوى شده ؟ ممنون
البته من فكر مى كنم بعد از اين سقوط يه صعود در پيش خواهيم داشت. .
استاد ميشه بيشتر توضيح بدهيد ؟ اينكه به چه دليل طوفان گرد و خاك در غرب خاورميانه باعث تقويت مونسون مى شود ؟ الان مونسون قوى شده ؟ ممنون
Amir Mohsen
متخصص بخش هواشناسی
درود امیر کوروش عزیز
تجزیه و تحلیل داده های ماهواره ای نشون میده که بین وقوع مونسون قوی در شبه قاره هند و شکل گیری طوفان و گرد و خاک موسوم به DUST در شمال افریقا و غرب خاورمیانه رابطه بسیار جدی وجود داره و دقیقا بعد از وقوع گرد و خاک در خاورمیانه 7 روز بعدش بارشهای حاصل از مونسون هند تقویت میشه و شدت میگیره.
مطالعات نشون میدن که ذرات معلق گرد و خاک در هوا منجر به جذب بیشتر اشعه های خورشید در غرب شبه قاره هند میشه که به این ترتیب هوا گرمتر شده و با گسترش بادهای شرق سو رطوبت و نم بیشتری رو با خودش به سمت شبه قاره هند گسیل میکنه.
بررسی ها همچنین نشون میده که انتقال ذرات طبیعی موجود در جو بوسیله باد قادر هست که بر مقادیر بارش به طرق مختلف و ناگهانی تاثیر بذاره و تغییرات در یک نقطه از این حیث میتونه به تغییرات جدیدی در اقلیم هزاران مایل اونطرفتر بشه.
Amir Mohsen
متخصص بخش هواشناسی
این موضوع میتونه ثابت کنه که فقط انسو بر مونسون هند تاثیر گذار نیست و چه بسا گاهی ممکنه النینو باشه ولی مونسون به خاطر وقوع طوفان گردو خاک در خاورمیانه و افریقا بصورت جدی تقویت بشه.
Amir Mohsen
متخصص بخش هواشناسی
تقدیم به دوستان عزیز
فوریه 2015
فوریه 2015
Amir Mohsen
متخصص بخش هواشناسی
میانگین آنومالی دمای هوا در 14 روز گذشته و میانگین آنومالی دما در 7 روز گذشته:
NEWS
Good Riddance La Niña! Hello El Niño!
With La Niña—often blamed for the worst drought in decades—now over, it’s time to look ahead at El Niño.
According to Klaus Wolter, research associate with the Cooperative Institute for Research in Environmental Sciences at the University of Colorado Boulder, El Niño has already begun. El Niño, which is La Niña’s opposite, occurs when the Pacific equatorial surface waters warm up.
Wolter expects the current El Niño to be a mild one, but that does not mean all of its impacts will necessarily be mild. "In 1997 when we had a very big El Niño, everyone was betting their future commodity money on Australia having a failed wheat crop," says Wolter. "That didn’t happen." The 1997-98 El Niño, one of the worst ever, was about three times the expected strength of the current El Niño.
During El Niño events, most of eastern Australia, where the bulk of the nation’s wheat is produced, is typically much drier than normal. Sections of eastern and northern Brazil, where some commercial crop enterprises are located, and India also tend to experience widespread drought conditions, whereas Argentina, Chile, and southern Brazil are more prone to flooding.
In the United States, the southern tier of the country as well as California tend to receive much heavier winter storms than usual in El Niño years, while the Upper Great Plains and Upper Midwest tend to be warmer than usual. A warmer-than-usual winter across the Corn Belt could help rebuild soil moistures if unfrozen soils can absorb precipitation.
"It’s not like we have an El Niño so everything will be fine," says Mike Timlin, regional climatologist with the Midwestern Regional Climate Center, Champaign, Illinois. "It isn’t a cure all for the drought." He says that the second year of a multi-year La Niña is associated with drought in the middle of the United States, but saying La Niña was the cause of the drought is pretty shaky. "I would be more concerned if we were going to into another year of La Niña. At least we are not saying, ‘Oh boy! We are having a bounce-back La Niña.’ For the drought to ease, though, the high pressure ridge that has set up over the United States needs to break down."
According to the National Weather Service, the drought far from over. Drought is expected to persist or worsen across much of the United States into November. Kansas, Nebraska, Missouri, Oklahoma, West Texas, Wyoming, Colorado, Nevada, Utah, southern Iowa, western Illinois, and eastern New Mexico will all see worsening conditions, while Indiana and much of eastern Illinois will see improvement.
Elsewhere in the world, the Middle East from Iran to Afghanistan tends to be wetter than usual in an El Niño year, while impacts in China are mixed, Wolter says.
Over the centuries, some experts have blamed El Niño events like the sinking of the Titanic in 1912 and the heavy snowfall that explorers Lewis and Clark encountered while crossing of Montana and Idaho’s Bitterroot Mountains in the winter of 1804-05.
The 1997-98 El Niño was blamed for the death of 24,000 and economic damage that reached $34 billion. That El Niño caused drought in Southeast Asia, severe winter storms along the West Coast of the United States, floods in East Africa, and a mix of floods and drought in China.
Good Riddance La Niña! Hello El Niño!
With La Niña—often blamed for the worst drought in decades—now over, it’s time to look ahead at El Niño.
According to Klaus Wolter, research associate with the Cooperative Institute for Research in Environmental Sciences at the University of Colorado Boulder, El Niño has already begun. El Niño, which is La Niña’s opposite, occurs when the Pacific equatorial surface waters warm up.
Wolter expects the current El Niño to be a mild one, but that does not mean all of its impacts will necessarily be mild. "In 1997 when we had a very big El Niño, everyone was betting their future commodity money on Australia having a failed wheat crop," says Wolter. "That didn’t happen." The 1997-98 El Niño, one of the worst ever, was about three times the expected strength of the current El Niño.
During El Niño events, most of eastern Australia, where the bulk of the nation’s wheat is produced, is typically much drier than normal. Sections of eastern and northern Brazil, where some commercial crop enterprises are located, and India also tend to experience widespread drought conditions, whereas Argentina, Chile, and southern Brazil are more prone to flooding.
In the United States, the southern tier of the country as well as California tend to receive much heavier winter storms than usual in El Niño years, while the Upper Great Plains and Upper Midwest tend to be warmer than usual. A warmer-than-usual winter across the Corn Belt could help rebuild soil moistures if unfrozen soils can absorb precipitation.
"It’s not like we have an El Niño so everything will be fine," says Mike Timlin, regional climatologist with the Midwestern Regional Climate Center, Champaign, Illinois. "It isn’t a cure all for the drought." He says that the second year of a multi-year La Niña is associated with drought in the middle of the United States, but saying La Niña was the cause of the drought is pretty shaky. "I would be more concerned if we were going to into another year of La Niña. At least we are not saying, ‘Oh boy! We are having a bounce-back La Niña.’ For the drought to ease, though, the high pressure ridge that has set up over the United States needs to break down."
According to the National Weather Service, the drought far from over. Drought is expected to persist or worsen across much of the United States into November. Kansas, Nebraska, Missouri, Oklahoma, West Texas, Wyoming, Colorado, Nevada, Utah, southern Iowa, western Illinois, and eastern New Mexico will all see worsening conditions, while Indiana and much of eastern Illinois will see improvement.
Elsewhere in the world, the Middle East from Iran to Afghanistan tends to be wetter than usual in an El Niño year, while impacts in China are mixed, Wolter says.
Over the centuries, some experts have blamed El Niño events like the sinking of the Titanic in 1912 and the heavy snowfall that explorers Lewis and Clark encountered while crossing of Montana and Idaho’s Bitterroot Mountains in the winter of 1804-05.
The 1997-98 El Niño was blamed for the death of 24,000 and economic damage that reached $34 billion. That El Niño caused drought in Southeast Asia, severe winter storms along the West Coast of the United States, floods in East Africa, and a mix of floods and drought in China.
تابستان امسال براى برخى نقاط دما كمتر براى برخى مناطق هم دما بيشتر از نرمال بوده
نميشه گفت همانند تابستان ١٣٨٦ تابستان خنكى داشتيم امسال
ميشه گفت نسبت به تابستان بسيار داغ پارسال تا الان تابستان قابل تحملى داشتيم .
PNA وارد فاز مثبت شده از اين رو فعلا افزايش بيشتر دما براى روزهاى آينده ديده ميشه :گل:
نميشه گفت همانند تابستان ١٣٨٦ تابستان خنكى داشتيم امسال
ميشه گفت نسبت به تابستان بسيار داغ پارسال تا الان تابستان قابل تحملى داشتيم .
PNA وارد فاز مثبت شده از اين رو فعلا افزايش بيشتر دما براى روزهاى آينده ديده ميشه :گل:
Amir Mohsen
متخصص بخش هواشناسی
Thursday, July 10, 2014
Upcoming Winter Shaping Up Similar to Last Winter; 2014-2015 Could Be More Severe
Upcoming Winter Shaping Up Similar to Last Winter; 2014-2015 Could Be More Severe
Note: The idea of this winter being more severe than last is a preliminary finding based on the work presented in this post. It is by no means set in stone, and is subject to revision.
After a look back at July 2013, I'm finding that July 2014 sea surface temperature anomalies are not only similar to last July, but could be foreshadowing a more severe winter than last.
Shown above is a reanalysis image of sea surface temperature anomalies from July 1, 2013 to July 8, 2013. During that timeframe, we saw a large body of warmer than normal waters controlling the northeast Pacific into the Gulf of Alaska, even stretching down towards the coastal waters near southern California. We also saw a pocket of well above normal water temperatures west of Japan, with opposing cooler than normal waters to the east. We also saw the La Nina-like water pattern along the Equatorial Pacific, which helped keep us in a Neutral-ENSO winter for this past cold season. Transitioning to the Atlantic, we saw a snaking line of below normal SST anomalies, occasionally interrupted by small bodies of positive water temperature anomalies, which were mainly confined to the northwestern Atlantic.
Now, let's compare all of that to what we've seen so far this year.
The image above now shows sea surface temperature anomalies, still on the same intervals, but now valid from July 1, 2014 to July 8, 2014. Looking to the northeast Pacific, we see that the large body of above normal-temperature waters has not only persisted, but has now intensified and expanded its influence. This was a major factor in last winter's atmospheric flow, and I don't expect things to be any different this winter. We now see the Bering Sea flooded in warmer than normal waters, though just what impact this particular feature may have is unclear right now. We see a similar opposing water temperature pattern to the west and east of Japan, though a substantial change in the Equatorial Pacific is the presence of warmer than normal water temperatures as opposed to the below normal temperatures last year at this time. This would typically indicate the presence of an El Nino, but with uncertainties as to if it will sustain itself, and if the atmosphere will actually "recognize" the presence of an El Nino, some things still need to be sorted out.
Now that we've gone over the similarities, why am I thinking that this winter could be more severe than last?
1. Above Normal Water Temperatures in the Northeast Pacific
Last winter, we experienced extreme bouts of cold, many of which were due to the proximity of the United States to the polar vortex, a massive, semi-permanent low pressure system stationed over the Arctic Circle. The polar vortex was persuaded to dip south into North America, thanks in large part to a massive ridge that constantly formed and re-formed along the west coast of the continent. Because the jet stream went up with the ridge pushing northward, it had to also dip down somewhere, and that somewhere became the United States. The big ridge originated from the body of warm waters in the northeast Pacific last winter, which is why I'm so concerned seeing that mechanism still in place today. If those warm waters stay in place in the northeast Pacific into the winter, they could make that big ridge re-appear, possibly stronger than last winter, leading to an even colder winter this year.
2. Above Normal Water Temperatures near Greenland
Something we didn't have last winter was a swath of above normal water temperatures near Greenland. This prevented high pressure from forming over that area, something that would have raised the chances of an even colder winter than what we ended up seeing. This year, as the July 2014 SST image shows, we do now have a large body of above normal SST anomalies near Greenland. This significantly raises the potential of high pressure forming in that area, buckling the jet stream to the west and resulting in an even colder winter possible. This is just another mechanism I'm watching this winter that could cool down the temperature forecasts even further.
Whether all of this ends up happening, or doesn't happen at all, is yet to be seen. The point is, based on sea surface temperature anomalies, this year is looking a lot like last year at this time. And according to preliminary looks at some key SST anomaly features, things could be more rough than last winter.
After a look back at July 2013, I'm finding that July 2014 sea surface temperature anomalies are not only similar to last July, but could be foreshadowing a more severe winter than last.
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Now, let's compare all of that to what we've seen so far this year.
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Now that we've gone over the similarities, why am I thinking that this winter could be more severe than last?
1. Above Normal Water Temperatures in the Northeast Pacific
Last winter, we experienced extreme bouts of cold, many of which were due to the proximity of the United States to the polar vortex, a massive, semi-permanent low pressure system stationed over the Arctic Circle. The polar vortex was persuaded to dip south into North America, thanks in large part to a massive ridge that constantly formed and re-formed along the west coast of the continent. Because the jet stream went up with the ridge pushing northward, it had to also dip down somewhere, and that somewhere became the United States. The big ridge originated from the body of warm waters in the northeast Pacific last winter, which is why I'm so concerned seeing that mechanism still in place today. If those warm waters stay in place in the northeast Pacific into the winter, they could make that big ridge re-appear, possibly stronger than last winter, leading to an even colder winter this year.
2. Above Normal Water Temperatures near Greenland
Something we didn't have last winter was a swath of above normal water temperatures near Greenland. This prevented high pressure from forming over that area, something that would have raised the chances of an even colder winter than what we ended up seeing. This year, as the July 2014 SST image shows, we do now have a large body of above normal SST anomalies near Greenland. This significantly raises the potential of high pressure forming in that area, buckling the jet stream to the west and resulting in an even colder winter possible. This is just another mechanism I'm watching this winter that could cool down the temperature forecasts even further.
Whether all of this ends up happening, or doesn't happen at all, is yet to be seen. The point is, based on sea surface temperature anomalies, this year is looking a lot like last year at this time. And according to preliminary looks at some key SST anomaly features, things could be more rough than last winter.
آخرین ویرایش:
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