当前位置: X-MOL 学术J. Earth Syst. Sci. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Impact of SAPHIR radiances on the simulation of tropical cyclones over the Bay of Bengal using NCMRWF hybrid-4DVAR assimilation and forecast system
Journal of Earth System Science ( IF 1.9 ) Pub Date : 2020-10-12 , DOI: 10.1007/s12040-020-01473-2
Devanil Choudhury , Ankur Gupta , S Indira Rani , John P George

Abstract

Observing System Experiments (OSEs) were conducted to analyze the impact of assimilation of Megha-Tropique’s (MT) Sounder for Probing Vertical Profiles of Humidity (SAPHIR) radiances on the simulation of tracks and intensity of three tropical cyclones (Kyant, Vardah, and Maarutha) formed over the Bay of Bengal during 2016–2017 North Indian Ocean cyclone period. National Centre for Medium Range Weather Forecast (NCMRWF) Unified Model (NCUM) Hybrid-4DVAR assimilation and forecast system was used for the OSEs. Assimilation of SAPHIR radiances produced an improvement of 9% and 12%, respectively, in the cyclones’ central sea level pressure (CSLP) and the maximum sustained wind (MSW), while an improvement of 38% was seen in the cyclone tracks within the forecast lead time of 120 hrs. Initial assessment shows that the improvement in the cyclone intensity is due to the assimilation of the unique surface peaking channel of SAPHIR (channel-6), whereas the improvement in the cyclone track is due to the assimilation remaining five channels of SAPHIR. Thus, the assimilation of SAPHIR radiances in the NCUM system showed improvement in both intensity and track of the cyclones over the Bay of Bengal; however, more cyclone cases over different ocean basins have to be analyzed to make a robust conclusion. This study specifies the importance of similar microwave humidity instruments in the same frequency range for the detailed exploration of cyclone track and structure.

Highlights

  • Impact of SAPHIR humidity channel information in the NCMRWF Hybrid-4DVar assimilation and forecast system is analysed through Observing system experiments (OSEs)

  • Assimilation of SAPHIR humidity information improved both track and intensity of the cyclones compared to the control experiment, and the improvement is visible upto a lead time of 5 days

  • It is noted that the improvement in the cyclone intensity simulation is due to the assimilation of the lowest peaking channel of the SAPHIR, while the track improvement is contributed by other channels as well.

  • This study underlines the importance of SAPHIR like instruments in the low earth orbiting satellites with frequent revisit time to explore the features of cyclones.



中文翻译:

使用NCMRWF hybrid-4DVAR同化和预报系统对SAPHIR辐射度对孟加拉湾热带气旋模拟的影响

摘要

进行了观测系统实验(OSEs),以分析梅加-特罗皮克(MT)探测仪的同化对探测湿度(SAPHIR)辐射的垂直剖面的影响,对三个热带气旋(Kyant,Vardah和Maarutha)的轨迹和强度进行模拟)在2016-2017年北印度洋气旋期间形成于孟加拉湾。OSE使用了国家中型天气预报中心(NCMRWF)统一模型(NCUM)Hybrid-4DVAR同化和预报系统。SAPHIR辐射的同化使旋风分离器的中央海平面压力(CSLP)和最大持续风速(MSW)分别提高了9%和12%,而在旋风分离器内的旋风径中观察到了38%的提高。预计交货时间为120小时。初步评估表明,旋风强度的改善是由于SAPHIR的唯一表面峰化通道(通道6)被同化,而旋风径迹的改善是由于对SAPHIR其余五个通道的同化。因此,在NCUM系统中对SAPHIR辐射的吸收显示,孟加拉湾上空的气旋强度和航迹均有所改善。但是,必须对不同海洋盆地更多的气旋病例进行分析才能得出可靠的结论。这项研究指出了在相同频率范围内使用类似的微波湿度仪器对于旋风轨道和结构的详细勘探的重要性。而旋风径的改善是由于同化了SAPHIR的其余五个通道。因此,在NCUM系统中对SAPHIR辐射的吸收显示,孟加拉湾上空的气旋强度和航迹均有所改善。但是,必须对不同海洋盆地更多的气旋病例进行分析才能得出可靠的结论。这项研究指出了在相同频率范围内使用类似的微波湿度仪器对于旋风轨道和结构的详细勘探的重要性。而旋风路径的改善是由于同化了SAPHIR的其余五个通道。因此,在NCUM系统中对SAPHIR辐射的同化显示,孟加拉湾上空的气旋强度和航迹均有所改善。但是,必须分析不同海洋盆地更多的气旋情况才能得出可靠的结论。这项研究指出了在相同频率范围内使用类似的微波湿度仪器对于旋风轨道和结构的详细勘探的重要性。

强调

  • 通过观测系统实验(OSE)分析了SAPHIR湿度通道信息对NCMRWF Hybrid-4DVar同化和预报系统的影响

  • 与对照实验相比,对SAPHIR湿度信息的同化改善了旋风的航迹和强度,并且直到5天的交货时间都可以看到改善

  • 注意,旋风强度模拟的改进是由于吸收了SAPHIR的最低峰通道,而磁道的改进也是由其他通道引起的。

  • 这项研究强调了像SAPHIR这样的仪器在低地球轨道卫星中的重要性,该卫星需要经常重访以探索旋风分离器的特征。

更新日期:2020-10-12
down
wechat
bug