سلام امیرحسین جان
من همیشه عکسهای بسیار زیبایی رو که میگیری در وبلاگت میبینم
و گاهگاهی هم با اجازت با نام خدتون و وبلاگ شهر بهشت اینجا قرار میدادم
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مباحث عمومی هواشناسی
- شروع کننده موضوع Amir Mohsen
- تاریخ شروع
- وضعیت
سلام امیرحسین جان
من همیشه عکسهای بسیار زیبایی رو که میگیری در وبلاگت میبینم
و گاهگاهی هم با اجازت با نام خدتون و وبلاگ شهر بهشت اینجا قرار میدادم
Amir-Hossein
کاربر ويژه
اختیار دارید ، کار خیلی خوبی میکنید
البته عکس های من که به خوبی عکس های شما و آقا امیرمحسن نمیرسه
اتفاقا الان میخواستم بگم که یادش بخیر پارسال همین موقع شما عکس های من و در انجمن گذاشتین :خنده2:
وااای چه عالی
خدا کنه همینطور که شما میگی باشه. هیچ چیز لذت بخش تر از یه بارش پیش بینی نشده نیست.
Amir Mohsen
متخصص بخش هواشناسی
این سامانه که امروز به شکل TEAR-off low بود در حال حاضر به مرحله Cut-off low رسیده. شدت تاوایی در هسته مرکزی سامانه بسیار بالاست
در سطح زمین از طریق عرضهای جنوبی- خلیج پارس و دریای سرخ تغذیه رطوبت فوق العاده ای داره همین وضعیت هم با شدت بسیار بالا در تراز 700 میلی بار به چشم میخوره
آپدیت جدید:
در سطح زمین از طریق عرضهای جنوبی- خلیج پارس و دریای سرخ تغذیه رطوبت فوق العاده ای داره همین وضعیت هم با شدت بسیار بالا در تراز 700 میلی بار به چشم میخوره
آپدیت جدید:
من جام گرمم ونرم بودم ولي اروم وقرار نداشتم مثل امير حسين شرايط منبود
Amir-Hossein
کاربر ويژه
دوستـــــــــــان ، شب همگی بـــــــــــــــــــــخـــــــــــــــــــــــــیــــــــــــــــــــــــــر :بای:
Amir Mohsen
متخصص بخش هواشناسی
3.1.2 The Influence of ENSO on Cutoff Cyclone Frequency The frequency of 500-hPa cutoff cyclones in the Northeast US from 2000 through 2007 by ENSO condition shows a pronounced separation in the frequency of cutoff cyclones by ENSO phase (Fig. 3.2). Maxima in the number of cutoff cyclones occurred when ENSO was neutral and cooling, neutral and warming, warm and cooling, and warm and warming, with greater than 25 cutoff cyclones each, while minima occurred for all of the ENSO cool phases in addition to ENSO neutral and steady and ENSO warm and steady, with fewer than 15 cutoff cyclones each.
As discussed in section 3.1.1, there was a large difference in the number of weeks characterized by the various ENSO phases, which likely affected the cutoff cyclone frequency for each ENSO phase. To remove any bias caused by the frequency of each ENSO phase, the cutoff cyclone frequency was divided by the number of weeks characterized by each ENSO phase.
As discussed in section 3.1.1, there was a large difference in the number of weeks characterized by the various ENSO phases, which likely affected the cutoff cyclone frequency for each ENSO phase. To remove any bias caused by the frequency of each ENSO phase, the cutoff cyclone frequency was divided by the number of weeks characterized by each ENSO phase.
Amir Mohsen
متخصص بخش هواشناسی
ای کاش ما هم برای کشورمون از این تحقیقات کرده بودیم و اینقدر به NAO و AO رو ختم نمیکردیم:
3.2.2The Influence of the MJO on Cutoff Cyclone Frequency
The frequency of 500-hPa cutoff cyclones in the Northeast US from 2000 through 2007 by MJO phase indicates that cutoff cyclones occurred most often during phase 8 of the MJO (Fig. 3.6), when enhanced convection was located in the Western Hemisphere. Conversely, cutoff cyclones occurred least often during phase 4 of the MJO, when enhanced convection was located over the Maritime Continent. When compared to the composites of 500-hPa geopotential height anomalies for each MJO phase, the maximum in cutoff cyclone frequency during phase 8 of the MJO agrees well with the presence of a large negative 500-hPa geopotential height anomaly over the eastern US during this phase (Fig. 3.5h). In addition, the minimum in cutoff cyclone frequency during phase 4 of the MJO is supported by the presence of a positive 500-hPa geopotential height anomaly over the eastern US in the composite for this phase (Fig. 3.5d), which is suggestive of unfavorable conditions for cutoff cyclone development. As with the results for the various ENSO phases, the bootstrap method was used to determine the statistical significance of the distribution of cutoff cyclone frequency by MJO phase. While the maximum in cutoff cyclone frequency for phase 8 of the MJO and the minimum in phase 4 differ by a total of 17 cutoff cyclones, the overlapping error bars in Fig. 3.6 indicate that the distribution of cutoff cyclones by MJO phase is not statistically significant at the 95% confidence level.
3.2.2The Influence of the MJO on Cutoff Cyclone Frequency
The frequency of 500-hPa cutoff cyclones in the Northeast US from 2000 through 2007 by MJO phase indicates that cutoff cyclones occurred most often during phase 8 of the MJO (Fig. 3.6), when enhanced convection was located in the Western Hemisphere. Conversely, cutoff cyclones occurred least often during phase 4 of the MJO, when enhanced convection was located over the Maritime Continent. When compared to the composites of 500-hPa geopotential height anomalies for each MJO phase, the maximum in cutoff cyclone frequency during phase 8 of the MJO agrees well with the presence of a large negative 500-hPa geopotential height anomaly over the eastern US during this phase (Fig. 3.5h). In addition, the minimum in cutoff cyclone frequency during phase 4 of the MJO is supported by the presence of a positive 500-hPa geopotential height anomaly over the eastern US in the composite for this phase (Fig. 3.5d), which is suggestive of unfavorable conditions for cutoff cyclone development. As with the results for the various ENSO phases, the bootstrap method was used to determine the statistical significance of the distribution of cutoff cyclone frequency by MJO phase. While the maximum in cutoff cyclone frequency for phase 8 of the MJO and the minimum in phase 4 differ by a total of 17 cutoff cyclones, the overlapping error bars in Fig. 3.6 indicate that the distribution of cutoff cyclones by MJO phase is not statistically significant at the 95% confidence level.
Amir Mohsen
متخصص بخش هواشناسی
3.3 The Combined Influence of ENSO and the MJO
Sections 3.1 and 3.2 have shown that examination of the separate influence of ENSO and the MJO on cutoff cyclone frequency in the Northeast US does not yield statistically significant results. As discussed in section 1.2.4, changes in sea surface temperature in the equatorial Pacific Ocean associated with ENSO may act to modify the development of deep convection, including the MJO. Therefore, it may be worthwhile to examine the combined influence of ENSO and the MJO on cutoff cyclone frequency to determine if the relationship is strengthened by considering these two tropical modes together.
The MJO phase was determined for weeks during the cool, neutral, and warm phases of ENSO for 2000–07. After removal of weak amplitude MJO weeks, there were fewer than 10 weeks characterized by each MJO phase during the cool and warm phases of ENSO. Due to the small sample sizes, the influence of the MJO by ENSO cool, neutral, and warm phases will not be discussed here; rather, the focus of this section will be on the influence of the MJO by ENSO trend on cutoff cyclone frequency in the Northeast US. The number of weeks characterized by each phase of the MJO for ENSO cooling, steady, and warming for 2000–07 is shown in Table IV. Once again, due to the relatively small sample sizes for MJO phases during the steady ENSO trend, the influence of the tropical modes during this ENSO trend will not be discussed.
Sections 3.1 and 3.2 have shown that examination of the separate influence of ENSO and the MJO on cutoff cyclone frequency in the Northeast US does not yield statistically significant results. As discussed in section 1.2.4, changes in sea surface temperature in the equatorial Pacific Ocean associated with ENSO may act to modify the development of deep convection, including the MJO. Therefore, it may be worthwhile to examine the combined influence of ENSO and the MJO on cutoff cyclone frequency to determine if the relationship is strengthened by considering these two tropical modes together.
The MJO phase was determined for weeks during the cool, neutral, and warm phases of ENSO for 2000–07. After removal of weak amplitude MJO weeks, there were fewer than 10 weeks characterized by each MJO phase during the cool and warm phases of ENSO. Due to the small sample sizes, the influence of the MJO by ENSO cool, neutral, and warm phases will not be discussed here; rather, the focus of this section will be on the influence of the MJO by ENSO trend on cutoff cyclone frequency in the Northeast US. The number of weeks characterized by each phase of the MJO for ENSO cooling, steady, and warming for 2000–07 is shown in Table IV. Once again, due to the relatively small sample sizes for MJO phases during the steady ENSO trend, the influence of the tropical modes during this ENSO trend will not be discussed.
Amir Mohsen
متخصص بخش هواشناسی
3.2.2 The Influence of ENSO and the MJO on Cutoff Cyclone Frequency
In comparing the frequency of 500-hPa cutoff cyclones in the Northeast US by phase of the MJO for ENSO warming and cooling, there is a discernable difference. During ENSO cooling, the frequency peaks at 11 cutoff cyclones during phases 3 and 4 of the MJO (Fig. 3.9), when enhanced convection is located over the eastern Indian Ocean or the Maritime Continent (Figs. 3.7c,d). In addition, there is a distinct minimum in cutoff cyclones, with only one cutoff cyclone, during ENSO cooling and phase 7 of the MJO, when enhanced convection is entering the Western Hemisphere (Fig. 3.4g). The distribution of cutoff cyclone frequency by MJO phase during ENSO warming appears to be reversed from that of ENSO cooling. During ENSO warming, there is a maximum in cutoff cyclone occurrence during phase 8 of the MJO, with 14 cutoff cyclones, and a minimum in phase 4, with only 2 cutoff cyclones.
The cutoff cyclone frequency distribution by MJO phase for ENSO warming agrees reasonably well with the 500-hPa geopotential height anomaly composites. The peak in cutoff cyclones during ENSO warming and phase 8 of the MJO coincides with strong negative 500-hPa geopotential height anomalies over the eastern US (Fig. 3.8h). In addition, the minimum in cutoff cyclones during ENSO warming and phase 4 of the MJO agrees with the presence of strong positive 500-hPa geopotential height anomalies over the Northeast US (Fig. 3.8d); however, this agreement is likely related to the very small number of cutoff cyclone days (n=2) included in the composite for these conditions. In contrast, the cutoff cyclone frequency distribution by MJO phase for ENSO cooling does not agree well with the composites of 500-hPa geopotential height anomalies. While there is a minimum in cutoff cyclones for ENSO cooling and phase 7 of the MJO, the composite for this phase indicates a large negative geopotential height anomaly over eastern Canada extending into the Northeast US, suggesting favorable conditions for cutoff cyclone development (Fig. 3.7g). Similarly, the peak in cutoff cyclones during ENSO cooling and phases 3 and 4 of the MJO disagrees with the positive 500-hPa geopotential height anomalies over the Northeast US in the composite for these phases (Fig. 3.7c,d).
Amir Mohsen
متخصص بخش هواشناسی
شب دوستان عزیز خوش و بدرود:گل:
Amir Mohsen
متخصص بخش هواشناسی
سلام دوستان و صبح همگی شما عزیزان بخیر:گل:
به به چه امضای زیبایی:تعجب2:
چه عکس پروفایل زیبایی:خنده2:
Amir Mohsen
متخصص بخش هواشناسی
سلام هادی جان
از اینکه در نقشه ها روند خوبی رو می بینم خیلی خوشحالم.
سرانجام مادر زیبا و مهربان زمستان قراره با وجود سرشارش همه ما رو در آغوش بگیره و دامن سفید و پاکش رو در گستره ایران زمین پهن کنه:گل:
آخرین ویرایش:
سلام هادی جان
از اینکه در نقشه های روند خوبی رو می بینم خیلی خوشحالم.
سرانجام مادر زیبا و مهربان زمستان قراره با وجود سرشارش همه ما رو در آغوش بگیره و دامن سفید و پاکش رو در گستره ایران زمین پهن کنه:گل:
به به!!!
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