Tropical Cyclone Intensification Rate Research Articles

Ocean internal tides suppress tropical cyclones in the South China Sea

Tropical Cyclones (TCs) are devastating natural disasters. Analyzing four decades of global TC data, here we find that among all global TC-active basins, the South China Sea (SCS) stands out as particularly difficult ocean for TCs to intensify, despite favorable atmosphere and ocean conditions. Over the SCS, TC intensification rate and its probability for a rapid intensification (intensification by ≥ 15.4 m s−1 day−1) are only 1/2 and 1/3, respectively, of those for the rest of the world ocean. Originating from complex interplays between astronomic tides and the SCS topography, gigantic ocean internal tides interact with TC-generated oceanic near-inertial waves and induce a strong ocean cooling effect, suppressing the TC intensification. Inclusion of this interaction between internal tides and TC in operational weather prediction systems is expected to improve forecast of TC intensity in the SCS and in other regions where strong internal tides are present.

Satellite-Based Estimation of the Role of Cloud-Radiative Interaction in Accelerating Tropical Cyclone Development

Abstract Recent modeling studies have suggested a potentially important role of cloud-radiative interactions in accelerating tropical cyclone (TC) development, but there has been only limited investigation of this in observations. Here, we investigate this by performing radiative transfer calculations based on cloud property retrievals from the CloudSat Tropical Cyclone (CSTC) dataset. We examine the radius-height structure of radiative heating anomalies, compute the resulting radiatively-driven circulations, and use the moist static energy variance budget to compute radiative feedbacks. We find that inner-core mid-level ice water content and anomalous specific humidity increase with TC intensification rate, resulting in enhanced inner-core deep-layer longwave warming anomalies and shortwave cooling anomalies in rapidly-intensifying TCs. This leads to a stronger radiatively-driven deep in-up-and-out overturning circulation and inner-core radiative feedback in rapidly-intensifying TCs. The longwave-driven circulation provides radially inward momentum fluxes and upward moisture fluxes which benefit TC development, while the shortwave-driven circulation suppresses TC development. The longwave anomalies, which dominate the inner-core positive radiative feedback, are mainly generated from cloud-radiative interactions, with ice particles dominating the deep-layer circulation and liquid droplets and water vapor contributing to the shallow circulation. Moreover, the variability in ice water content, as opposed to variability in liquid water content and the effective radii of ice particles and liquid droplets, dominates the uncertainty in TC-radiative interaction. These results provide observational evidence for the importance of cloud-radiative interactions in TC development and suggest that the amount and spatial structure of ice water content is critical for determining the strength of this interaction.

The Role of the Peak Radius of Maximum Wind Contraction Rate Preceding the Peak Intensification Rate on Tropical Cyclone Lifetime Maximum Intensity

AbstractThe prevalence of the maximum radius of maximum wind (RMW) contraction rate for the tropical cyclone (TC) before the maximum TC intensification rate has been observed in several previous studies. However, it remains unclear whether and how the maximum RMW contraction rate preceding the maximum TC intensification rate affects the TC lifetime maximum intensity (LMI). In this study, tropical cyclones are grouped into three types depending on whether the peak RMW contraction rate precedes, occurs simultaneously with, or lags the time of the peak intensification rate in the North Atlantic and western North Pacific. Results indicate that when the maximum RMW contraction rate occurs before the maximum intensification rate, TCs are more likely to gain a greater LMI. TCs with the time of maximum RMW contraction rate preceding the time of the maximum intensification rate are more likely to achieve a small RMW and intermediate intensity after the maximum RMW contraction rate period, which is conducive to higher intensification rates. An intermediate initial intensity and higher maximum intensification rate both lead to a greater LMI. Environmental factors are also examined but are found to have little impact on the LMI for the three types of TCs. This work suggests that TCs with a higher LMI are often characterized by a notable maximum rate of RMW contraction before the peak intensification rate and helps to a better understanding of TC structure and intensity changes.

Increase in western North Pacific tropical cyclone intensification rates and their northwestward shifts

The tropical cyclone intensification rates (TCIRs) over the western North Pacific (WNP) are investigated on the basis of 6-hourly atmospheric and oceanic reanalyses and TC best track data from 1982 to 2020. Results indicate that 24-h-TCIRs over the WNP have increased remarkably by ∼17.2% in the past four decades. A remarkable difference before and after the changepoint 2004 is detected in 24-h TCIRs over the WNP basin. The correlation between the TCIR and sea surface temperature (SST) during 2005–2020 shows a significant positive correlation over the western Pacific. Composite analyses of atmospheric and oceanic environments between P1 (1982–2004) and P2 (2005–2020) suggest greater contributions of the underlying SST and relative vorticity (VORT) than those of vertical wind shear (VWS) and mid-tropospheric relative humidity (RH) to TCIR increase. The maximum potential intensity (MPI) has increased since the 1980s, with a significant change from P1 to P2, which further demonstrates that the environmental fields since 2004 are more favorable for TC intensification. At the same time, TCIR geolocation shows a northwestward shift over the TC-active region bounded by 10° ∼ 25°N, 125° ∼ 150°E since 2004, which is possibly modulated by the interdecadal difference of steering flow and ocean state. This study may provide inspirations to clarify the mechanisms of WNP-TCIR interdecadal increase for general TC intensity forecast.

Relating Tropical Cyclone Intensification Rate to Precipitation and Convective Features in the Inner Core

Abstract Using Tropical Rainfall Measuring Mission Microwave Imager observations of global tropical cyclones (TCs) from 1998 to 2013, relationships between TC intensification rate and inner-core convective and precipitation parameters are examined by decoupling the dependency of these parameters on TC intensity and that on TC intensification rate. A total of 16 TC intensity change–intensity categories are categorized based on the initial intensity and 24-h future intensity change. The results show that the TC inner-core mean rain rate, convective intensity, and stratiform rain occurrence, and axisymmetric index of convective intensity increase significantly with TC intensification rate for each TC intensity category. The symmetry of rain rate and stratiform rainfall occurrence also increase significantly with TC intensification rate for each intensity category, except from slowly intensifying (SI) to rapidly intensifying (RI) group when the initial intensity is major hurricane. The RI major hurricanes have significantly more asymmetric rainfall distribution and distribution of stratiform rainfall occurrence than those of SI major hurricanes. For TCs with initial intensity in tropical depression, tropical storm, and major hurricane categories, the RI group has a significantly more asymmetric pattern of shallow precipitation/convection occurrence in the inner core than the SI group, while it has a significantly more symmetric pattern of deep convection occurrence than the SI group. The inner-core size, as quantified by the radius of maximum azimuthal mean rainfall decreases with both TC intensification rate and TC intensity.

Quantifying the Environmental Effects on Tropical Cyclone Intensity Change Using a Simple Dynamically Based Dynamical System Model

Abstract Accurate prediction of tropical cyclone (TC) intensity is quite challenging due to multiple competing processes among the TC internal dynamics and the environment. Most previous studies have evaluated the environmental effects on TC intensity change from both internal dynamics and external influence. This study quantifies the environmental effects on TC intensity change using a simple dynamically based dynamical system (DBDS) model recently developed. In this simple model, the environmental effects are uniquely represented by a ventilation parameter B, which can be expressed as multiplicative of individual ventilation parameters of the corresponding environmental effects. Their individual ventilation parameters imply their relative importance to the bulk environmental ventilation effect and thus to the TC intensity change. Six environmental factors known to affect TC intensity change are evaluated in the DBDS model using machine learning approaches with the best track data for TCs over the North Atlantic, central, eastern, and western North Pacific and the Statistical Hurricane Intensity Prediction Scheme (SHIPS) dataset during 1982–2021. Results show that the deep-layer vertical wind shear (VWS) is the dominant ventilation factor to reduce the intrinsic TC intensification rate or to drive the TC weakening, with its ventilation parameter ranging between 0.5 and 0.8 when environmental VWS between 200 and 850 hPa is larger than 8 m s−1. Other environmental factors are generally secondary, with their respective ventilation parameters over 0.8. An interesting result is the strong dependence of the environmental effects on the stage of TC development.

Recent increase in the potential threat of western North Pacific tropical cyclones

Conventionally, the threat of tropical cyclones (TCs) is often described by TC intensity. However, the damage caused by TCs is also strongly related to our forecasting ability, which is usually low for TCs with high intensification rates. Here, we challenge this intensity-only criterion and propose a concept of TC potential threat (PT) for the western North Pacific TCs by jointly clustering the TC lifetime maximum intensity and intensification rate. We show that TCs can be separated via an objective algorithm, and approximately 10% of all TCs pose a great PT and feature high forecast errors. Furthermore, the annual number of TCs with high PT has increased by 22% per decade over the past 41 years, and this trend is attributed to the rise in subsurface ocean temperatures. Our study provides a perspective on the TC threat and reveals its increase due to global warming and internal climate variability.

How Does Horizontal Diffusion Influence the Intensification and Maximum Intensity of Numerically Simulated Tropical Cyclones?

Abstract Recent studies have demonstrated the sensitivity of simulated tropical cyclone (TC) intensity to horizontal diffusion in numerical models. It is unclear whether such sensitivity comes from the horizontal diffusion in or above the boundary layer. To address this issue, both an Ooyama-type model and a full-physics model are used to conduct sensitivity experiments with reduced or enlarged horizontal mixing length (lh) in the boundary layer and/or in the free atmosphere. Results from both models show that enlarging (reducing) lh throughout the model domain considerably reduces (increases) the TC intensification rate and quasi-steady intensity. A new finding is that changing lh above the boundary layer imposes a much greater influence than that in the boundary layer. Large lh above the boundary layer is found to effectively reduce the radial gradient of tangential wind inside the radius of maximum tangential wind and thus the inward flux of absolute vorticity, reducing the positive tangential wind tendency and the TC intensification rate and the steady-state intensity. In contrast, although larger lh in the boundary layer reduces the boundary layer tangential wind tendency, it also leads to the more inward-penetrated inflow and thus enhances the inward flux of absolute vorticity, which offsets part of the direct negative contribution by horizontal diffusion, making the net change in tangential wind tendency not obvious. Results from three-dimensional simulations also show that the resolved eddies contribute negatively to TC spinup when lh is small, while its effect weakens when lh is enhanced either in or above the boundary layer.

Some Refinements to the Most Recent Simple Time-Dependent Theory of Tropical Cyclone Intensification and Sensitivity

Abstract Several key issues in the simple time-dependent theories of tropical cyclone (TC) intensification developed in recent years remain, including the lack of a closure for the pressure dependence of saturation enthalpy at sea surface temperature (SST) under the eyewall and the definition of environmental conditions, such as the boundary layer enthalpy in TC environment and the TC outflow-layer temperature. In this study, some refinements to the most recent time-dependent theory of TC intensification have been accomplished to resolve those issues. The first is the construction of a functional relationship between the surface pressure under the eyewall and the TC intensity, which is derived using the cyclostrophic wind balance and calibrated using full-physics axisymmetric model simulations. The second is the definition of TC environment that explicitly includes the air–sea temperature difference. The third is the TC outflow-layer temperature parameterized as a linear function of SST based on global reanalysis data. With these refinements, the updated time-dependent theory becomes self-contained and can give both the intensity-dependent TC intensification rate (IR) and the maximum potential intensity (MPI) under given environmental thermodynamic conditions. It is shown that the pressure dependence of saturation enthalpy at SST can lead to an increase in the TC MPI and IR by about half of that induced by dissipative heating due to surface friction. Results also show that both MPI and IR increase with increasing SST, surface enthalpy exchange coefficient, environmental air–sea temperature difference, and decreasing environmental boundary layer relative humidity, but the maximum IR is insensitive to surface drag coefficient. Significance Statement A new advancement in the recent decade is the development of simple time-dependent theories of tropical cyclone (TC) intensification, which can provide quantitative understanding of TC intensity change. However, several key issues in these simple time-dependent theories remain, including the lack of a closure for the pressure dependence of saturation enthalpy at sea surface temperature under the eyewall and the definition of environmental conditions. These are resolved in this study with several refinements, which make the most recent time-dependent theory of TC intensification self-contained and practical.

Contribution of Dissipative Heating to the Intensity Dependence of Tropical Cyclone Intensification

Abstract Previous studies have demonstrated the contribution of dissipative heating (DH) to the maximum potential intensity (MPI) of tropical cyclones (TCs). Since DH is a function of near-surface wind speed and thus TC intensity, a natural question arises as to whether DH contributes to the intensity dependence of TC potential intensification rate (PIR). To address this issue, an attempt has been made to include DH in a recently developed time-dependent theory of TC intensification. With this addition, the theory predicts a shift of the maximum PIR toward the higher intensity side, which is consistent with the intensity dependence of TC intensification rate in observed strong TCs. Since the theory without DH predicts a dependence of TC PIR on the square of the MPI, the inclusion of DH results in an even higher PIR for strong TCs. Considering the projected increase in TC MPI under global warming, the theoretical work implies that as the climate continues to warm, TCs may intensify more rapidly. This may not only make the TC intensity forecasting more difficult, but also may increase the threats of TCs to the coastal populations if TCs intensify more rapidly just before they make landfall. Significance Statement Previous studies have demonstrated that dissipative heating (DH) can significantly contribute to the maximum potential intensity (MPI) that a tropical cyclone (TC) can achieve given favorable environmental thermodynamic conditions of the atmosphere and the underlying ocean. Here we show that because DH is a function of near-surface wind speed and thus TC intensity, DH can also significantly contribute to the intensity dependence of TC potential intensification rate (PIR). This has been demonstrated by introducing DH into a recently developed time-dependent theory of TC intensification. With DH the theory predicts a shift of the maximum PIR toward the higher intensity side as observed in strong TCs. Therefore, as the climate continues to warm, TCs may intensify more rapidly and become stronger.

A New Time-Dependent Theory of Tropical Cyclone Intensification

AbstractIn this study, the boundary layer tangential wind budget equation following the radius of maximum wind, together with an assumed thermodynamical quasi-equilibrium boundary layer, is used to derive a new equation for tropical cyclone (TC) intensification rate (IR). A TC is assumed to be axisymmetric in thermal-wind balance, with eyewall convection coming into moist slantwise neutrality in the free atmosphere above the boundary layer as the storm intensifies, as found recently based on idealized numerical simulations. An ad hoc parameter is introduced to measure the degree of congruence of the absolute angular momentum and the entropy surfaces. The new IR equation is evaluated using results from idealized ensemble full-physics axisymmetric numerical simulations. Results show that the new IR equation can reproduce the time evolution of the simulated TC intensity. The new IR equation indicates a strong dependence of IR on both TC intensity and the corresponding maximum potential intensity (MPI). A new finding is the dependence of TC IR on the square of the MPI in terms of the near-surface wind speed for any given relative intensity. Results from some numerical integrations of the new IR equation also suggest the finite-amplitude nature of TC genesis. In addition, the new IR theory is also supported by some preliminary results based on best-track TC data over the North Atlantic Ocean and eastern and western North Pacific Ocean. As compared with the available time-dependent theories of TC intensification, the new IR equation can provide a realistic intensity-dependent IR during weak intensity stage as seen in observations.

Strong Diurnal Pulsing of Cold Clouds in Rapidly Intensifying Tropical Cyclones

AbstractThe radially outward propagating diurnal signal in the upper‐level clouds (diurnal pulse) is a prominent cyclical feature of tropical cyclones (TCs). This study examines relationships between diurnal pulses and TC intensity changes using satellite Infrared data from 2001 to 2018. The occurrence and duration of diurnal pulses 24 hr prior to or during TC intensity change are strongly correlated with TC intensification rate. Rapidly intensifying (RI) TCs have a markedly higher frequency (60%–80%) of very long‐duration pulse (15 hr) and significantly longer mean pulse duration than steady‐state (40%–50%) and gradually intensifying TCs (50%–60%). Long‐duration pulses are infrequent in weakening TCs (20%–30%). Diurnal pulse frequency and duration are highly correlated with the initial cloud‐top cooling rate and very cold‐cloud fraction in the inner core, but less related to the initial TC intensity. In short, strong diurnal pulsing of cold clouds is an evident signature prior to or during the RI of TCs.

The Intensity-dependence of Tropical Cyclone Intensification Rate in a Simplified Energetically Based Dynamical System Model

AbstractIn this study, a simple energetically based dynamical system model of tropical cyclone (TC) intensification is modified to account for the observed dependence of the intensification rate (IR) on the storm intensity. According to the modified dynamical system model, the TC IR is controlled by the intensification potential (IP) and the weakening rate due to surface friction beneath the eyewall. The IP is determined primarily by the rate of change in the potential energy available for a TC to develop, which is a function of the thermodynamic conditions of the atmosphere and the underlying ocean, and the dynamical efficiency of the TC system. The latter depends strongly on the degree of convective organization within the eyewall and the inner-core inertial stability of the storm. At a relatively low TC intensity, the IP of the intensifying storm is larger than the frictional weakening rate, leading to an increase in the TC IR with TC intensity in this stage. As the storm reaches an intermediate intensity of 30-40 m s-1, the difference between IP and frictional weakening rate reaches its maximum, concurrent with the maximum IR. Later on, the IR decreases as the TC intensifies further because the frictional dissipation increases with TC intensity at a faster rate than the IP. Finally, the storm approaches its maximum potential intensity (MPI) and the IR becomes zero. The modified dynamical system model is validated with results from idealized simulations with an axisymmetric nonhydrostatic, cloud-resolving model.

Future Changes in the Frequency and Destructiveness of Landfalling Tropical Cyclones Over East Asia Projected by High‐Resolution AGCMs

AbstractFuture changes in the frequency and destructiveness of landfalling tropical cyclones (TCs) over East Asia were investigated by analyzing the simulations of two high‐resolution (20–25‐km) atmospheric general circulation models forced by sea surface temperature (SST) in the present period (1979–2003) and under future warming conditions (2075–2099) of the RCP8.5 scenario. The present‐day simulations capture well the genesis count, tracks, and intensity associated with TCs striking the coastal areas of Taiwan‐East China (TWCN), the South China Sea‐Indochina (SCS) and the vicinity of Japan (JP). The frequency of landfalling TCs over TWCN, SCS, and JP is projected to nearly half by the end of the 21st century. However, these landfalling TCs induce enhanced destructive threats of stronger winds and heavier precipitation under the future warmer climate. Through attribution analysis we found the reduced frequency of landfalling TCs to be mainly caused by a decline in TC genesis count (rather than TC track changes), while the increased intensity of landfalling TCs is linked with changes in the TC intensification rate (as opposed to duration changes). Diagnoses of the genesis potential index and eddy energetics further suggest that the mid‐tropospheric drying and weakened synoptic‐scale eddy activity resulting from anticyclonic and downward circulations over the main TC genesis region create an unfavorable environment for TC genesis. In contrast, warmer SST, reduced vertical wind shear and enhanced efficiency of eddy kinetic energy generations appear over the regions before TC landfall, resulting in a more rapid intensification of TCs that later approach the coastal areas.

The Role of Boundary Layer Dynamics in Tropical Cyclone Intensification. Part II: Sensitivity to Initial Vortex Structure

In Part I of this series of studies, we demonstrated that the intensification rate of a numerically simulated tropical cyclone (TC) during the primary intensification stage is insensitive to the surface drag coefficient. This leads to the question of what is the role of the boundary layer in determining the TC intensification rate given sea surface temperature and favorable environmental conditions. This part attempts to answer this question based on a boundary layer model and a full-physics model as used in Part I. Results from a boundary layer model suggest that TCs with a smaller radius of maximum wind (RMW) or of lower strength (i.e., more rapid radial decay of tangential wind outside the RMW) can induce stronger boundary layer inflow and stronger upward motion at the top of the boundary layer. This leads to stronger condensational heating inside the RMW with higher inertial stability and is thus favorable for a higher intensification rate. Results from full-physics model simulations indicate that the TC vortex initially with a smaller RMW or of lower strength has a shorter initial spinup stage due to faster moistening of the inner core and intensifies more rapidly during the primary intensification stage. This is because the positive indirect effect of boundary layer dynamics depends strongly on vortex structure, but the dissipation effect of surface friction depends little on the vortex structure. As a result, the intensification rate of the simulated TC is very sensitive to the initial TC structure.

Response of Tropical Cyclone Formation and Intensification Rates to Climate Warming in Idealized Simulations

AbstractThere is currently no theory for the rate of tropical cyclone (TC) formation given a particular climate, so our understanding of the relationship between TC frequency and large‐scale environmental factors is largely empirical. Here, we explore the sensitivity of TC formation and intensification rates to climate warming in a series of highly idealized cloud‐permitting simulations, in which TCs form spontaneously from a base state of rest on an f‐plane. The simulations reveal a nonmonotonic relationship between the time taken for a TC precursor disturbance (a “seed”) to form and the prescribed sea surface temperature (SST), with moderately long seed emergence times at both ends of the SST range tested (292 and 304 K) and a shorter seed emergence time at the middle value of SST (298 K). Genesis potential indices (GPIs) exhibit a different response to warming: either a monotonic increase if the potential intensity and midtropospheric relative humidity are used or relatively little sensitivity if the saturation deficit is used as the humidity variable. The sensitivity of elapsed time between a TC seed disturbance and TC genesis to surface warming is, however, generally well captured by GPIs, especially those that depend on the saturation deficit. The maximum intensification rate of TCs increases strongly with warming, particularly during the second half of the intensification process. Notably, storms intensify much more rapidly with increasing temperature than is predicted by extant theory based on potential intensity, suggesting that TCs in a warmer climate may intensify even more rapidly than recent studies suggest.

Ensemble Sensitivity Analysis of Tropical Cyclone Intensification Rate during the Development Stage

AbstractEnsemble sensitivity analysis based on convective-permitting ensemble simulations is used to understand the processes associated with tropical cyclone (TC) intensification under idealized conditions. Partial correlations between different variables and the future TC intensification rate, with the effect of intensity removed, are used to identify the sensitive factors. It is found that the equivalent potential temperature (θe) in the region from the radius of maximum wind (RMW) to 3 times the RMW below 2 km (hereafter, the sensitive region) has the largest correlation (over 0.7) with 2.5-h intensity change. It is found that higherθein the sensitive region is associated with not only a stronger updraft but also an inward shift of vertical motion in the mid- to upper eyewall. This suggests that higherθejust outside the RMW is favorable to TC intensification not only because of the larger amount of the heating, but also due to the heating location that is closer to the center. Trajectory analysis shows that the parcels in the sensitive region are mainly from the boundary layer inflow and the midlevel inflow. It is found that when the outer rainband is active, the midlevel inflow becomes stronger and is able to bring more low-θeair into the boundary layer, and theθeradially inward to the rainband decreases. Verification experiments justify that higherθearound the RMW to 3 times the RMW is favorable to TC intensification, while higherθeaway from 5 times the RMW is shown to be unfavorable for TC intensification.

The Role of WISHE in the Rapid Intensification of Tropical Cyclones

Abstract This study examines the role of surface heat fluxes, particularly in relation to the wind-induced surface heat exchange (WISHE) mechanism, in the rapid intensification (RI) of tropical cyclones (TCs). Sensitivity experiments with capped surface fluxes and thus reduced WISHE exhibit delayed RI and weaker peak intensity, while WISHE could affect the evolutions of TCs both before and after the onset of RI. Before RI, more WISHE leads to faster increase of equivalent potential temperature in the lower levels, resulting in more active and stronger convection. In addition, TCs in experiments with more WISHE reach a certain strength earlier, before the onset of RI. During the RI period, more surface heat fluxes could provide convective instability in the lower levels, and cause a consequent development in the convective activity. More efficient intensification in a TC is found with higher surface heat fluxes and larger inertial stability, leading to a stronger peak intensity, more significant and deeper warm core in TC center, and the axisymmetrization of convection in the higher levels. In both stages, different levels of WISHE alter the thermodynamic environment and convective-scale processes. In all, this study supports the crucial role of WISHE in affecting TC intensification rate for TCs with RI.

Control of salinity stratification on recent increase in tropical cyclone intensification rates over the postmonsoon Bay of Bengal

This study explores the variability of tropical cyclone (TC) intensification rates (IRs) in the postmonsoon Bay of Bengal (BoB) for the satellite period of 1980–2015. It is found that both number of rapid intensification (RI) events and magnitude of IRs show a robust increase, with a northeastward shift of intensification events. Analyses show that the temporal variability of sea surface temperature dominated the IR variability during 1980–1997. However, the thick barrier layer in the northern BoB was considerably responsible for IR variability during 1998–2015, which significantly contributed to the IR increase. Due to more intensification events occurring over the northeastern region in two recent decades, the thick barrier layer with strong salinity stratification in the northern BoB limits TC-induced sea surface cooling and in turn favors TC intensification. This study has an important implication that air–sea coupled climate model need to realistically simulate upper ocean salinity variability on projecting TC intensity change over the BoB.

Quantifying the Benefits of Nonlinear Methods for Global Statistical Hindcasts of Tropical Cyclones Intensity

Abstract While tropical cyclone (TC) track forecasts have become increasingly accurate over recent decades, intensity forecasts from both numerical models and statistical schemes have been trailing behind. Most operational statistical–dynamical forecasts of TC intensity use linear regression to relate the initial TC characteristics and most relevant large-scale environmental parameters along the TC track to the TC intensification rate. Yet, many physical processes involved in TC intensification are nonlinear, hence potentially hindering the skill of those linear schemes. Here, we develop two nonlinear TC intensity hindcast schemes, for the first time globally. These schemes are based on either support vector machine (SVM) or artificial neural network (ANN) algorithms. Contrary to linear schemes, which perform slightly better when trained individually over each TC basin, nonlinear methods perform best when trained globally. Globally trained nonlinear schemes improve TC intensity hindcasts relative to regionally trained linear schemes in all TC-prone basins, especially the SVM scheme for which this improvement reaches ~10% globally. The SVM scheme, in particular, partially corrects the tendency of the linear scheme to underperform for moderate intensity (category 2 and less on the Saffir–Simpson scale) and decaying TCs. Although the TC intensity hindcast skill improvements described above are an upper limit of what could be achieved operationally (when using forecasted TC tracks and environmental parameters), it is comparable to that achieved by operational forecasts over the last 20 years. This improvement is sufficiently large to motivate more testing of nonlinear methods for statistical TC intensity prediction at operational centers.