Evidence for the significant role of sea surface temperature distributions over remote tropical oceans in tropical cyclone intensity

An estimation of water origins in the vicinity of a tropical cyclone’s center and associated dynamic processes

“…The influence of the remote ocean vapor on the TC is delayed because it takes time to undergo both largescale vapor transport via the MCB and vapor import into the TC inner region due to radial inflow within the boundary layer, which is consistent with Hegde et al (2016), who found that changes in the TC intensity and track, which are regulated by the enhancement/weakening of the MCB, become evident at its mature phase. This study supports the hypothesis of the TC-MCB feedback process.…”

“…We have conducted a colored moisture analysis (CMA) using the isotopic regional spectral model (IsoRSM) for Typhoon Man-yi (2007) to evaluate the vapor import from the underlying ocean and the remote ocean into the TC system and to validate a positive feedback process between the TC intensity and the moisture conveyor belt (MCB) that has been suggested by previous studies (Kudo et al 2014;Hegde et al 2016). Although the stable oxygen isotope ratio (δ 18 O) data of precipitation observed on a daily basis was limited, we used the available δ 18 O data and confirmed that the IsoRSM has the ability to capture the basic nature of moisture transport in association with TCs.…”

“…K2014 postulated that the MCB is formed when the induced westerly flow overlaps with low-level monsoon westerlies around the South China Sea. Hegde et al (2016) (hereafter H2016) further investigated the relationship between MCB formation and the TC intensity and track by performing sensitivity experiments that modified sea surface temperature (SST) distributions over the Indian Ocean and the South China Sea in order to validate the working hypothesis that the MCB may be an active player in facilitating the development and persistence of the TC itself. They found that while the MCB is interrupted over the South China Sea in warm SST occurrences, large-scale vapor transport into the TC system is systematically reduced, leading to both the attenuated intensity and eastward track shift of the cyclone.…”

A Positive Feedback Process Between Tropical Cyclone Intensity and the Moisture Conveyor Belt Assessed With Lagrangian Diagnostics

“…We also conducted a nonexistent TC run to confirm that a TC can trigger the formation of the MCB under background monsoon westerlies and investigated another TC (Halong 2002) to validate that the TC‐MCB feedback is applicable to other western North Pacific TCs. The major findings in this study are briefly summarized as follows: Forward and backward trajectory analyses based on a real SST experiment (CNTL run) show that air parcels of remote ocean origin gain a large amount of moisture from the underlying ocean while they are transported by the MCB, resulting in the release of latent heat within the TC inner core region in a few days. SST sensitivity experiments that modified the observed SST field over the Indian Ocean and the South China Sea reveal that TC intensity tends to be strong (weak) at its mature stage when the MCB is well (ill) organized, which is quite consistent with the results of Hegde et al (). The same results were also derived from simulations for Halong (2002), implying that Man‐yi is not an extraordinary case. The establishment and reinforcement of the MCB facilitate the transport of very moist air parcels to the vicinity of the TC via the MCB, leading to the active intrusion of those parcels into the TC's inner region through the atmospheric boundary layer due to the inflow of radial wind relevant to the secondary TC circulation.…”

Remote Thermodynamic Impact of the Kuroshio Current on a Developing Tropical Cyclone Over the Western North Pacific in Boreal Fall

“…Recently, Kudo et al (2014) and Takakura et al (2018) postulated that developing TCs over the western North Pacific in boreal summer have the ability to accumulate abundant water vapor from remote tropical oceans through a large-scale vapor flux zone in the lower troposphere, called the moisture conveyor belt (MCB). The MCB tends to lie from the Indian Ocean through the Philippine Sea, concurrent with a northward-migrating TC in the vicinity of the Philippine Sea, and the connection between MCB formation and TC development is very robust (Fujiwara et al, 2017;Hegde et al, 2016). Fujiwara et al (2017) claimed that the MCB is not formed unless the westward propagation of equatorial waves induced by TC diabatic heating overlaps with the background summer monsoon westerlies, and they proposed a possible interaction between TC intensity and the MCB.…”