Analysis of an Ensemble of High-Resolution WRF Simulations for the Rapid Intensification of Super Typhoon Rammasun(2014)     

Xun LI  Noel E. DAVIDSON  Yihong DUAN  Kevin J. TORY  Zhian SUN  Qinbo CAI 《大气科学进展》2020,37(2):187-210

Diagnostics are presented from an ensemble of high-resolution forecasts that differed markedly in their predictions of the rapid intensification(RI)of Typhoon Rammasun.We show that the basic difference stems from subtle differences in initializations of(a)500-850-h Pa environmental winds,and(b)midlevel moisture and ventilation.We then describe how these differences impact on the evolving convective organization,storm structure,and the timing of RI.As expected,ascent,diabatic heating and the secondary circulation near the inner-core are much stronger in the member that best forecasts the RI.The evolution of vortex cloudiness from this member is similar to the actual imagery,with the development of an inner cloud band wrapping inwards to form the eyewall.We present evidence that this structure,and hence the enhanced diabatic heating,is related to the tilt and associated dynamics of the developing inner-core in shear.For the most accurate ensemble member:(a)inhibition of ascent and a reduction in convection over the up-shear sector allow moistening of the boundary-layer air,which is transported to the down-shear sector to feed a developing convective asymmetry;(b)with minimal ventilation,undiluted clouds and moisture from the down-shear left quadrant are then wrapped inwards to the up-shear left quadrant to form the eyewall cloud;and(c)this process seems related to a critical down-shear tilt of the vortex from midlevels,and the vertical phase-locking of the circulation over up-shear quadrants.For the member that forecasts a much-delayed RI,these processes are inhibited by stronger vertical wind shear,initially resulting in poor vertical coherence of the circulation,lesser moisture and larger ventilation.Our analysis suggests that ensemble prediction is needed to account for the sensitivity of forecasts to a relatively narrow range of environmental wind shear,moisture and vortex inner-structure.  相似文献   

The writing class     

Noel Castree 《Geoforum》2002,33(1):iii

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Archaeomagnetic evidence for the age and duration of firing of mediaeval hearths from Coffee Yard, York     

Meng Zhaoqin  Mark Noel 《Geophysical Journal International》1989,97(2):357-359

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A method for correcting geographically separated remanence directions for the purpose of archaeomagnetic dating     

M. Noel  C. M. Batt 《Geophysical Journal International》1990,102(3):753-756

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The potential for photosynthesis in hydrothermal vents: a new avenue for life in the Universe?     

Noel Perez  Rolando Cardenas  Osmel Martin  Leiva-Mora Michel 《Astrophysics and Space Science》2013,346(2):327-331

We perform a quantitative assessment for the potential for photosynthesis in hydrothermal vents in the deep ocean. The photosynthetically active radiation in this case is from geothermal origin: the infrared thermal radiation emitted by hot water, at temperatures ranging from 473 up to 673 K. We find that at these temperatures the photosynthetic potential is rather low in these ecosystems for most known species. However, species which a very high efficiency in the use of light and which could use infrared photons till 1300 nm, could achieve good rates of photosynthesis in hydrothermal vents. These organisms might also thrive in deep hydrothermal vents in other planetary bodies, such as one of the more astrobiologically promising Jupiter satellites: Europa.  相似文献   

Weakening AMOC connects Equatorial Atlantic and Pacific interannual variability     

Lea Svendsen  Nils Gunnar Kvamstø  Noel Keenlyside 《Climate Dynamics》2014,43(11):2931-2941

Observations indicate that since the 1970s Equatorial Atlantic sea surface temperature (SST) variations in boreal summer tend to modulate El Niño in the following seasons, indicating that the Atlantic Ocean can have importance for predicting the El Niño–Southern Oscillation (ENSO). The cause of the change in the recent decades remains unknown. Here we show that in the Bergen Climate Model (BCM), a freshwater forced weakening of the Atlantic meridional overturning circulation (AMOC) results in a strengthening of the relation between the Atlantic and the Pacific similar to that observed since the 1970s. During the weakening AMOC phase, SST and precipitation increase in the central Equatorial Atlantic, while the mean state of the Pacific does not change significantly. In the Equatorial Atlantic the SST variability has also increased, with a peak in variability in boreal summer. In addition, the characteristic timescales of ENSO variability is shifted towards higher frequencies. The BCM version used here is flux-adjusted, and hence Atlantic variability is realistic in contrast to in many other models. These results indicate that in the BCM a weakening AMOC can change the mean background state of the Tropical Atlantic surface conditions, enhancing Equatorial Atlantic variability, and resulting in a stronger relationship between the Tropical Atlantic and Pacific Oceans. This in turn alters the variability in the Pacific.  相似文献   

Surface pressure profiles, vortex structure and initialization for hurricane prediction. Part I: analysis of observed and synthetic structures     

Yimin Ma  Menas Kafatos  Noel E. Davidson 《Meteorology and Atmospheric Physics》2012,117(1-2):5-23

Without detailed reconnaissance, consistent representation of hurricane-like vortices in initial conditions for operational prediction and research simulations still remains elusive. It is thus often necessary, particularly for high-resolution intensity forecasting, to use synthetic tropical cyclone circulations to initialize forecast models. Variants on three commonly used surface pressure profiles are evaluated for possible use. Enhancements to the original profiles are proposed that allows definition of both the inner-core and outer circulation. The latter improvement creates a vortex more consistent with the estimated outer structure which sometimes appears to be crucial to the evolving intensity of the storm. It also allows smoother merging of the synthetic vortex with the environment. Comparisons of the profiles against (a) structure estimates, (b) each other, (c) structures obtained via conservation of angular momentum, and (d) observed vorticity structures, suggest that a new enhanced Fujita profile best represents real TC structures. Student-t tests indicate that improved fitting to the observations is statistically significant.  相似文献   

Impact of the Equatorial Atlantic on the El Ni?o Southern Oscillation     

Hui Ding  Noel S. Keenlyside  Mojib Latif 《Climate Dynamics》2012,38(9-10):1965-1972

Observations indicate that the Atlantic zonal mode influences El Ni?o Southern Oscillation (ENSO) in the Pacific, as already suggested in previous studies. Here we demonstrate for the first time using partial coupled experiments that the Atlantic zonal mode indeed influences ENSO. The partial coupling experiments are performed by forcing the coupled general circulation model (ECHAM5/MPI-OM) with observed sea surface temperature (SST) in the Tropical Atlantic, but with full air-sea coupling allowed in the Pacific and Indian Ocean. The ensemble mean of a five member simulation reproduces the observational results well. Analysis of observations, reanalysis, and coupled model simulations all indicate the following mechanism: SST anomalies associated with the Atlantic zonal mode affect the Walker Circulation, driving westward wind anomalies over the equatorial Pacific during boreal summer. The wind stress anomalies increase the east-west thermocline slope and enhance the SST gradient across the Pacific; the Bjerknes positive feedback acts to amplify these anomalies favouring the development of a La Ni?a-like anomalies. The same mechanisms act for the cold phase of Atlantic zonal mode, but with opposite sign. In contrast to previous studies, the model shows that the influence on ENSO exists before 1970. Furthermore, no significant influence of the Tropical Atlantic on the Indian Monsoon precipitation is found in observation or model.  相似文献   

Stall markets in metropolitan Sydney     

Noel G. Lonergan  Peter L. Simons 《The Australian geographer》1986,17(2):170-177

Stall markets on open air, suburban sites are an important new form of retailing in Sydney. The existing literature on petty commodity forms of production argues that stall markets are conserved in underdeveloped economies for a variety of reasons but the relevance of these ideas to the markets in many cities in advanced economies has not been considered. This paper identifies the basic types of stall markets in Sydney, establishes that these markets are not ephemeral and shows that they have characteristics and parameters which are similar to those of conventional shopping centres. Thus the way is open to compare stall markets with conventional retailing, to assess the role of stall markets in post‐industrial societies and to investigate the reasons for their recent appearance in Sydney.  相似文献   

STATISTICS FOR SPATIAL DATA   总被引：3，自引：0，他引：3  

Noel Cressie 《地学学报》1992,4(5):613-617

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